<PAGE>   1

                                                                  EXHIBIT 3.1.9

                      CERTIFICATE OF DESIGNATION OF VOTING
                        POWER, PREFERENCES AND RELATIVE,
              PARTICIPATING, OPTIONAL AND OTHER SPECIAL RIGHTS AND
                   LIMITATIONS AND RESTRICTIONS OF 7% SERIES F
                 CONVERTIBLE REDEEMABLE PREFERRED STOCK DUE 2010
                                       OF
                          NEXTLINK COMMUNICATIONS, INC.

                            -------------------------


                         Pursuant to Section 151 of the
                General Corporation Law of the State of Delaware

                            -------------------------

              NEXTLINK Communications, Inc., a corporation organized and
existing under and by virtue of the General Corporation Law of the State of
Delaware (the "Company") does hereby certify that the following resolution was
duly adopted by action of the Board of Directors of the Company (the "Board of
Directors") on June 13, 2000.

              RESOLVED that pursuant to the authority expressly granted to and
vested in the Board of Directors by the provisions of Section 3 of the Amended
and Restated Certificate of Incorporation of the Company (the "Certificate of
Incorporation"), and in accordance with Section 151 of the General Corporation
Law of the State of Delaware, the Board of Directors hereby designates, creates,
authorizes and provides for the issue of a series of preferred stock having a
par value of $0.01 per share, which shall be designated as 7% Series F
Convertible Redeemable Preferred Stock Due 2010 (the "Series F Preferred Stock")
consisting of 110,000 shares, and each share of Series F Preferred Stock shall
have the following voting powers, preferences and relative, participating,
optional and other special rights, and qualifications, limitations and
restrictions thereof as follows:

1.            CERTAIN DEFINITIONS.

              Unless the context otherwise requires, the terms defined in this
paragraph 1 shall have, for all purposes of this resolution, the meanings herein
specified (with terms defined in the singular having comparable meanings when
used in the plural).

              Affiliate: The term "Affiliate" of any specified Person shall mean
any other Person directly or indirectly controlling or controlled by or under
direct or indirect common control with such specified Person. For the purposes
of this definition, "control," when used with respect to any specified Person
means the power to direct or cause the direction of the management and policies
of such Person, directly or indirectly, whether through the ownership of voting
securities, by contract or otherwise; and the terms "controlling" and
"controlled" have meanings correlative to the foregoing.

<PAGE>   2

              Applicable Redemption Price: The term "Applicable Redemption Price
means a price per share equal to the redemption price specified below (expressed
as percentages of the Liquidation Preference thereof), in each case together
with accumulated and unpaid dividends (including an amount in cash equal to a
prorated dividend for any partial dividend period) to the date of redemption if
redeemed during the 12-month period commencing on June 1 of each of the years
set forth below:

<TABLE>
<CAPTION>
                                 YEAR                          REDEMPTION PRICE
                                 ----                          ----------------
<S>                              <C>                                <C>
                                 2003                               105.125%
                                 2004                               105.125
                                 2005                               105.125
                                 2006                               104.100
                                 2007                               103.075
                                 2008                               102.050
                                 2009                               101.025
</TABLE>
              and thereafter, 100%.

              Board of Directors: The term "Board of Directors" shall mean the
Board of Directors of the Company or a committee of such Board duly authorized
to act for it hereunder.

              Business Day: The term "Business Day" shall mean each Monday,
Tuesday, Wednesday, Thursday and Friday which is not a day on which the banking
institutions in San Jose, California are authorized or obligated by law or
executive order to close or be closed.

              Closing Price: The term "Closing Price" shall have the meaning
specified in Section 7(e)(7).

              Commission: The term "Commission" shall mean the Securities and
Exchange Commission.

              Common Stock: The term "Common Stock" shall mean any stock of any
class of the Company which has no preference in respect of dividends or of
amounts payable in the event of any voluntary or involuntary liquidation,
dissolution or winding up of the Company and which is not subject to redemption
by the Company. Subject to the provisions of Section 7(f), however, shares
issuable on conversion of Series F Preferred Stock shall include only shares of
the class designated as Class A common stock of the Company at the date of this
Certificate of Designation or shares of any class or classes resulting from any
reclassification or reclassifications thereof and which have no preference in
respect of dividends or of amounts payable in the event of any voluntary or
involuntary liquidation, dissolution or winding up of the Company and which are
not subject to redemption by the Company; provided that if at any time there
shall be more than one such resulting class, the shares of each such class then
so issuable shall be substantially in the proportion which the total number of
shares of such class resulting from all such reclassifications bears to the
total number of shares of all such classes resulting from all such
reclassifications.

                                      -2-
<PAGE>   3

              Company: The term "Company" shall mean NEXTLINK Communications,
Inc., a Delaware corporation, having its principal office at 1505 Farm Credit
Drive, McLean, VA 22102 and shall include its successors and assigns, successor
by merger to Concentric Network Corporation, a Delaware corporation
("Concnentric").

              Conversion Price: The term "Conversion Price" shall have the
meaning specified in Section 7(d).

              Convertible Security: The term "Convertible Security" shall be any
security that, by its terms, is convertible into Common Stock at the option of
the holder thereof.

              Exchange Act: The term "Exchange Act" shall mean the Securities
Exchange Act of 1934, as amended, and the rules and regulations promulgated
thereunder, as in effect from time to time.

              Merger: The term "Merger" shall mean the merger of Concentric with
and into the Company pursuant to the Amended and Restated Agreement and Plan of
Merger and Share Exchange Agreement by and among NEXTLINK Communications, Inc.,
Concentric, Eagle River Investments, L.L.C., Craig O. McCaw and the Company.

              Original Certificate of Designation: The term "Original
Certificate of Designation" shall mean the Amended Certificate of Designation of
Voting Power, Designation Preferences and Relative, Participating, Optional and
Other Special Rights and Qualifications, Limitations and Restrictions of Series
C 7% Convertible Redeemable Preferred Stock due 2010 of Concentric, pursuant to
which Concentric, as predecessor to the Company, issued Series C 7% Convertible
Redeemable Preferred Stock due 2010 which was converted in the Merger into the
right to receive Series F Preferred Stock.

              Person: The term "Person" shall mean a corporation, an
association, a partnership, a limited liability corporation, an individual, a
joint venture, a joint stock company, a trust, an unincorporated organization or
a government or an agency or a political subdivision thereof.

              Restricted Securities: The term "Restricted Securities" shall have
the meaning specified in Section 2.5.

              Securities Act: The term "Securities Act" shall mean the
Securities Act of 1933, as amended, and the rules and regulations promulgated
thereunder.

              Series A Preferred Stock: The term "Series A Preferred Stock"
shall mean the Company's 14% Series A Senior Redeemable Preferred Stock.

              Series B Preferred Stock: The term "Series B Preferred Stock"
shall mean the Company's 6 1/2% Series B Convertible Preferred Stock.

              Series C Preferred Stock: The term "Series C Preferred Stock"
shall mean the Company's Series C Cumulative Convertible Participating Preferred
Stock.

                                      -3-
<PAGE>   4

              Series D Preferred Stock: The term "Series D Preferred Stock"
shall mean the Company's Series D Cumulative Convertible Preferred Stock.

              Series E Preferred Stock: The term "Series E Preferred Stock"
shall mean the Company's 13 1/2% Series E Senior Redeemable Exchangeable
Preferred Stock due 2010.

              Series F Preferred Stock: The term "Series F Preferred Stock"
shall mean the Company's 7% Series F Convertible Redeemable Preferred Stock due
2010.

              Share register: The term "Share register" shall have the meaning
specified in Section 2(e).

              Trading Day: The term "Trading Day" shall have the meaning
specified in Section 7(e)(6).

              Trigger Event: The term "Trigger Event" shall have the meaning
specified in Section 7(e)(4).

2.            ISSUE, DESIGNATION AND FORM

              (a)    The Series F Preferred Stock shall be designated as "7%
Series F Redeemable Convertible Preferred Stock due 2010."

              (b)    The certificates evidencing shares of Series F Preferred
Stock shall be substantially in the form set forth in Exhibit A to the Original
Certificate, which is incorporated in and made a part of this Certificate of
Designation; provided that the Company may substitute such certificates with a
revised certificate reflecting the consummation of the Merger. Any of such
certificates may have such letters, numbers or other marks of identification and
such notations, legends and endorsements as the officers executing the same may
approve (execution thereof to be conclusive evidence of such approval) and as
are not inconsistent with the provisions of this Certificate of Designation, or
as may be required to comply with any law or with any rule or regulation made
pursuant thereto or with any rule or regulation of any securities exchange or
automated quotation system on which the Series F Preferred Stock may be listed,
or to conform to usage.

              (c)    The Series F Preferred Stock shall be issuable in
registered form in denominations of $1000.00 Liquidation Preference and integral
multiples thereof including Shares of Series F Preferred Stock issued by the
Company pursuant to Section 4(a). Every certificate evidencing Series F
Preferred Stock shall be dated the date of its execution.

              (d)    The certificates evidencing shares of Series F Preferred
Stock shall be signed in the name and on behalf of the Company by the facsimile
signature of its Chief Executive Officer, President, any Executive or Senior
Vice President or any Vice President (whether or not designated by a number or
numbers or word or words added before or after the title "Vice President") and
attested by the facsimile signature of its Secretary or any of its Assistant
Secretaries or Treasurer or any of its Assistant Treasurers (which may be
printed, engraved or otherwise reproduced thereon, by facsimile or otherwise).

                                      -4-
<PAGE>   5

              (e)    The Company shall maintain a register (the "Share
register") in which, subject to such reasonable regulations as it may prescribe,
the Company shall provide for the registration of shares of Series F Preferred
Stock and of transfers of shares of Series F Preferred Stock. The Share register
shall be in written form or in any form capable of being converted into written
form within a reasonably prompt period of time. Upon surrender for registration
of transfer of any shares of Series F Preferred Stock to the Share registrar or
any co- registrar, and satisfaction of the requirements for such transfer set
forth in this Section 2(e), the Company shall execute, one or more new
certificates evidencing shares of Series F Preferred Stock of any authorized
denominations and of a like aggregate Liquidation Preference and bearing such
restrictive legends as may be required by this Certificate of Designation.

              (f)    Shares of Series F Preferred Stock may be exchanged for
other shares of Series F Preferred Stock of any authorized denominations and of
a like aggregate Liquidation Preference, upon surrender of the Series F
Preferred Stock to be exchanged at any such office or agency maintained by the
Company for such purposes. Whenever any shares of Series F Preferred Stock are
so surrendered for exchange, the Company shall execute the shares of Series F
Preferred Stock which the holder making the exchange is entitled to receive
bearing registration numbers not contemporaneously outstanding. All certificates
evidencing Series F Preferred Stock presented or surrendered for registration of
transfer or for exchange, redemption or conversion shall (if so required by the
Share registrar) be duly endorsed, or be accompanied by a written instrument or
instruments of transfer in form satisfactory to the Company. No service charge
shall be made for any registration of transfer or exchange of shares of Series F
Preferred Stock, but the Company may require payment of a sum sufficient to
cover any tax, assessment or other governmental charge that may be imposed in
connection with any registration of transfer or exchange of such shares. Neither
the Company nor any Share registrar shall be required to exchange or register a
transfer of (a) any shares of Series F Preferred Stock for a period of fifteen
(15) days next preceding any selection of shares of Series F Preferred Stock to
be redeemed or (b) any shares of Series F Preferred Stock called for redemption
pursuant to Section 4 or (c) any shares of Series F Preferred Stock surrendered
for conversion pursuant to Section 7 or (d) during the period of time from a
Record Date until the next succeeding Dividend Payment Date.

              (g)    Until the expiration of the holding period applicable to
sales thereof under Rule 144(k) under the Securities Act (or any successor
provision), any certificate evidencing shares of Series F Preferred Stock (and
all securities issued in exchange therefor or substitution thereof, other than
Common Stock, if any, issued upon conversion thereof, which shall bear the
legend set forth in Section 2(h), if applicable) shall bear a legend in
substantially the following form, unless such Series F Preferred Stock has been
sold pursuant to a registration statement that has been declared effective under
the Securities Act (and which continues to be effective at the time of such
transfer), or unless otherwise agreed by the Company in writing:

              THE SERIES F PREFERRED STOCK EVIDENCED HEREBY
              HAS NOT BEEN REGISTERED UNDER THE UNITED
              STATES SECURITIES ACT OF 1933, AS AMENDED (THE
              "SECURITIES ACT"), OR ANY STATE SECURITIES
              LAWS, AND, ACCORDINGLY, MAY NOT BE OFFERED OR
              SOLD WITHIN THE UNITED STATES OR TO, OR FOR
              THE


                            -5-
<PAGE>   6

              ACCOUNT OR BENEFIT OF, UNITED STATES PERSONS
              EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE.
              BY ITS ACQUISITION HEREOF, THE HOLDER (1)
              REPRESENTS THAT (A) IT IS AN INSTITUTIONAL
              "ACCREDITED INVESTOR" (AS DEFINED IN RULE
              501(A)(1), (2), (3) OR (7) UNDER THE
              SECURITIES ACT) ("INSTITUTIONAL ACCREDITED
              INVESTOR") OR (B) IT IS NOT A UNITED STATES
              PERSON AND IS ACQUIRING THE SERIES F PREFERRED
              STOCK EVIDENCED HEREBY IN AN OFFSHORE
              TRANSACTION; (2) AGREES THAT IT WILL NOT,
              PRIOR TO EXPIRATION OF THE HOLDING PERIOD
              APPLICABLE TO SALES OF THE SERIES F PREFERRED
              STOCK EVIDENCED HEREBY UNDER RULE 144(K) UNDER
              THE SECURITIES ACT (OR ANY SUCCESSOR
              PROVISION), RESELL OR OTHERWISE TRANSFER THE
              SERIES F PREFERRED STOCK EVIDENCED HEREBY OR
              THE COMMON STOCK ISSUABLE UPON CONVERSION OF
              SUCH SERIES F PREFERRED STOCK WITHIN THE
              UNITED STATES OR TO, OR FOR THE ACCOUNT OR
              BENEFIT OF, U.S. PERSONS EXCEPT (A) TO
              CONCENTRIC NETWORK CORPORATION OR ANY
              SUBSIDIARY THEREOF, (B) TO AN INSTITUTIONAL
              ACCREDITED INVESTOR THAT, PRIOR TO SUCH
              TRANSFER, FURNISHES TO CONCENTRIC NETWORK
              CORPORATION, A SIGNED LETTER CONTAINING
              CERTAIN REPRESENTATIONS AND AGREEMENTS
              RELATING TO THE RESTRICTIONS ON TRANSFER OF
              THE SERIES F PREFERRED STOCK EVIDENCED HEREBY,
              (C) PURSUANT TO THE EXEMPTION FROM
              REGISTRATION PROVIDED BY RULE 144 UNDER THE
              SECURITIES ACT (IF AVAILABLE) OR (D) PURSUANT
              TO A REGISTRATION STATEMENT WHICH HAS BEEN
              DECLARED EFFECTIVE UNDER THE SECURITIES ACT
              (AND WHICH CONTINUES TO BE EFFECTIVE AT THE
              TIME OF SUCH TRANSFER); (3) AGREES THAT PRIOR
              TO SUCH TRANSFER (OTHER THAN A TRANSFER
              PURSUANT TO CLAUSE 2(D) ABOVE), IT WILL
              FURNISH TO CONCENTRIC NETWORK CORPORATION,
              SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER
              INFORMATION AS IT MAY REASONABLY REQUIRE TO
              CONFIRM THAT SUCH TRANSFER IS BEING MADE
              PURSUANT TO AN EXEMPTION FROM, OR IN A
              TRANSACTION NOT SUBJECT TO, THE REGISTRATION
              REQUIREMENTS OF THE SECURITIES ACT AND (4)
              AGREES THAT IT WILL DELIVER TO EACH PERSON TO
              WHOM THE SERIES F PREFERRED STOCK EVIDENCED
              HEREBY IS


                            -6-
<PAGE>   7

              TRANSFERRED A NOTICE SUBSTANTIALLY TO THE
              EFFECT OF THIS LEGEND. IF THE PROPOSED
              TRANSFEREE IS A PURCHASER WHO IS NOT A UNITED
              STATES PERSON OR AN INSTITUTIONAL ACCREDITED
              INVESTOR, THE HOLDER MUST, PRIOR TO SUCH
              TRANSFER, FURNISH TO CONCENTRIC NETWORK
              CORPORATION, SUCH CERTIFICATIONS, LEGAL
              OPINIONS OR OTHER INFORMATION AS IT MAY
              REASONABLY REQUIRE TO CONFIRM THAT SUCH
              TRANSFER IS BEING MADE PURSUANT TO AN
              EXEMPTION FROM, OR IN A TRANSACTION NOT
              SUBJECT TO, THE REGISTRATION REQUIREMENTS OF
              THE SECURITIES ACT. THIS LEGEND WILL BE
              REMOVED UPON THE EARLIER OF THE TRANSFER OF
              THE SERIES F PREFERRED STOCK EVIDENCED HEREBY
              PURSUANT TO CLAUSE 2(D) ABOVE OR UPON ANY
              TRANSFER OF THE SERIES F PREFERRED STOCK
              EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE
              SECURITIES ACT (OR ANY SUCCESSOR PROVISION).

Any Series F Preferred Stock (or security issued in exchange or substitution
therefor) as to which such restrictions on transfer shall have expired in
accordance with their terms or as to the conditions for removal of the foregoing
legend set forth therein have been satisfied may, upon surrender of such Series
F Preferred Stock for exchange to the Share registrar in accordance with the
provisions of this Section 2(g), be exchanged for a new Series F Preferred
Stock, of like tenor and Liquidation Preference.

              (h)    Until the expiration of the holding period applicable to
sales thereof under Rule 144(k) under the Securities Act (or any successor
provision), any stock certificate representing Common Stock issued upon
conversion of such Series F Preferred Stock shall bear a legend in substantially
the following form, unless such Common Stock has been sold pursuant to a
registration statement that has been declared effective under the Securities Act
(and which continues to be effective at the time of such transfer) or such
Common Stock has been issued upon conversion of Series F Preferred Stock that
have been transferred pursuant to a registration statement that has been
declared effective under the Securities Act, or unless otherwise agreed by the
Company in writing with written notice thereof to the transfer agent:

              THE COMMON STOCK EVIDENCED HEREBY HAS NOT BEEN
              REGISTERED UNDER THE U.S. SECURITIES ACT OF
              1933, AS AMENDED (THE "SECURITIES ACT"), OR
              ANY STATE SECURITIES LAWS, AND, ACCORDINGLY,
              MAY NOT BE OFFERED OR SOLD WITHIN THE UNITED
              STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT
              OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE
              FOLLOWING SENTENCE. THE HOLDER HEREOF AGREES
              THAT UNTIL THE EXPIRATION OF THE HOLDING
              PERIOD APPLICABLE TO SALES OF THE SECURITY
              EVIDENCED HEREBY


                            -7-
<PAGE>   8

              UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR
              ANY SUCCESSOR PROVISION), (1) IT WILL NOT
              RESELL OR OTHERWISE TRANSFER THE COMMON STOCK
              EVIDENCED HEREBY WITHIN THE UNITED STATES OR
              TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S.
              PERSONS EXCEPT (A) TO CONCENTRIC NETWORK
              CORPORATION OR ANY SUBSIDIARY THEREOF, (B) TO
              AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS
              DEFINED IN RULE 501(A)(1), (2), (3) OR (7)
              UNDER THE SECURITIES ACT) THAT PRIOR TO SUCH
              TRANSFER FURNISHES TO CHASEMELLON SHAREHOLDER
              SERVICES, LLC, AS TRANSFER AGENT (OR A
              SUCCESSOR TRANSFER AGENT, AS APPLICABLE), A
              SIGNED LETTER CONTAINING CERTAIN
              REPRESENTATIONS AND AGREEMENTS RELATING TO THE
              RESTRICTIONS ON TRANSFER OF THE COMMON STOCK
              EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN
              BE OBTAINED FROM SUCH TRANSFER AGENT OR A
              SUCCESSOR TRANSFER AGENT, AS APPLICABLE), (C)
              PURSUANT TO THE EXEMPTION FROM REGISTRATION
              PROVIDED BY RULE 144 UNDER THE SECURITIES ACT
              (IF AVAILABLE), OR (D) PURSUANT TO A
              REGISTRATION STATEMENT WHICH HAS BEEN DECLARED
              EFFECTIVE UNDER THE SECURITIES ACT (AND WHICH
              CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH
              TRANSFER); (2) PRIOR TO SUCH TRANSFER (OTHER
              THAN A TRANSFER PURSUANT TO CLAUSE 1(D)
              ABOVE), IT WILL FURNISH TO CHASEMELLON
              SHAREHOLDER SERVICES, LLC, AS TRANSFER AGENT
              (OR A SUCCESSOR TRANSFER AGENT, AS
              APPLICABLE), SUCH CERTIFICATIONS, LEGAL
              OPINIONS OR OTHER INFORMATION AS IT MAY
              REASONABLY REQUIRE TO CONFIRM THAT SUCH
              TRANSFER IS BEING MADE PURSUANT TO AN
              EXEMPTION FROM, OR IN A TRANSACTION NOT
              SUBJECT TO, THE REGISTRATION REQUIREMENTS OF
              THE SECURITIES ACT AND (3) IT WILL DELIVER TO
              EACH PERSON TO WHOM THE COMMON STOCK EVIDENCED
              HEREBY IS TRANSFERRED (OTHER THAN A TRANSFER
              PURSUANT TO CLAUSE 1(D) ABOVE) A NOTICE
              SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.
              THIS LEGEND WILL BE REMOVED UPON THE EARLIER
              OF THE TRANSFER OF THE COMMON STOCK EVIDENCED
              HEREBY PURSUANT TO CLAUSE 1(D) ABOVE OR UPON
              ANY TRANSFER OF THE COMMON STOCK EVIDENCED
              HEREBY AFTER THE EXPIRATION OF THE HOLDING
              PERIOD APPLICABLE TO SALES OF THE SECURITY


                            -8-
<PAGE>   9

              EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE
              SECURITIES ACT (OR ANY SUCCESSOR PROVISION).

Any such Common Stock as to which such restrictions on transfer shall have
expired in accordance with their terms or as to which the conditions for removal
of the foregoing legend set forth therein have been satisfied may, upon
surrender of the certificates representing such shares of Common Stock for
exchange in accordance with the procedures of the transfer agent for the Common
Stock, be exchanged for a new certificate or certificates for a like number of
shares of Common Stock, which shall not bear the restrictive legend required by
this Section 2(h).

Any Series F Preferred Stock or Common Stock issued upon the conversion or
exchange of any Series F Preferred Stock that, prior to the expiration of the
holding period applicable to sales thereof under Rule 144(k) under the
Securities Act (or any successor provision), is purchased or owned by the
Company or any Affiliate thereof may not be resold by the Company or such
Affiliate unless registered under the Securities Act or resold pursuant to an
exemption from the registration requirements of the Securities Act in a
transaction which results in such Series F Preferred Stock or Common Stock, as
the case may be, no longer being "restricted securities" (as defined under Rule
144).

              (i)    In case any certificate representing shares of Series F
Preferred Stock shall become mutilated or be destroyed, lost or stolen, the
Company in its discretion may execute a new certificate representing shares of
Series F Preferred Stock, bearing a number not contemporaneously outstanding, in
exchange and substitution for the mutilated certificate, or in lieu of and in
substitution for the certificate so destroyed, lost or stolen. In every case the
applicant for a substituted certificate shall furnish to the Company, such
security or indemnity as may be required by them to save each of them harmless
for any loss, liability, cost or expense caused by or connected with such
substitution, and, in every case of destruction, loss or theft, the applicant
shall also furnish to the Company, evidence to their satisfaction of the
destruction, loss or theft of such certificate and of the ownership thereof.

              (j)    Following receipt by the Company of satisfactory security
or indemnity and evidence, as described in the preceding paragraph, any such
substituted certificate and make available for delivery such certificate. Upon
the issuance of any substituted certificate, the Company may require the payment
of a sum sufficient to cover any tax or other governmental charge that may be
imposed in relation thereto and any other expenses connected therewith. In case
any certificate which has been called for redemption or has been tendered for
redemption (and not withdrawn) or is about to be converted into Common Stock
shall become mutilated or be destroyed, lost or stolen, the Company may, instead
of issuing a substitute certificate, pay or authorize the payment of or convert
or authorize the conversion of the same (without surrender thereof except in the
case of a mutilated certificate), as the case may be, if the applicant for such
payment or conversion shall furnish to the Company such security or indemnity as
may be required by them to save each of them harmless for any loss, liability,
cost or expense caused by or connected with such substitution, and, in case of
destruction, loss or theft, evidence satisfactory to the Company of the
destruction, loss or theft of such certificate and of the ownership thereof.

                                      -9-
<PAGE>   10

              (k)    All certificates representing shares of Series F Preferred
Stock surrendered for the purpose of payment, redemption, conversion, exchange
or registration of transfer, shall, if surrendered to the Company or any paying
agent or any Stock registrar or any conversion agent, be surrendered to the
Company and promptly canceled by it, or, if surrendered to the Company, shall be
promptly canceled by it, and no Series F Preferred Stock shall be issued in lieu
thereof except as expressly permitted by any of the provisions of this
Certificate of Designation.

              (l)    The Company in issuing the Series F Preferred Stock may use
"CUSIP" numbers, and may use "CUSIP" numbers in notices of redemption as a
convenience to holders.

3.            RANKING.

              The Series F Preferred Stock shall rank, with respect to dividend
distributions and distributions upon the liquidation, winding-up and dissolution
of the Company, (i) senior to all classes of common stock of the Company and to
each other class of capital stock of the Company the terms of which expressly
provide by their terms that such class or series rank, or will rank junior to
the Series F Preferred Stock as to dividend distributions and distributions upon
the liquidation, winding-up and dissolution of the Company (collectively
referred to with the common stock of the Company as "Junior Securities"); (ii)
on a parity with (A) Series B Preferred Stock, (B) any additional shares of
Series F Preferred Stock issued by the Company in the future and (C) any other
class of capital stock or series of preferred stock issued by the Company in the
future, the terms of which expressly provide that such class or series will rank
on a parity with the Series F Preferred Stock as to dividend distributions and
distributions upon the liquidation, winding-up and dissolution of the Company
(collectively referred to as "Parity Securities"); and (iii) junior to the
Series A Preferred Stock, Series C Preferred Stock, Series D Preferred Stock and
Series E Preferred Stock (collectively, the "Senior Securities") or other
preferred stock of the Company by its terms senior to the Series F Preferred
Stock.

4.            DIVIDENDS.

              (a)    The holders of shares of the Series F Preferred Stock
(other than shares as to which conversion is deemed effective pursuant to
Section 7 and as to which all accrued dividends have been paid) shall be
entitled to receive, when, as and if dividends are declared by the Board of
Directors out of funds of the Company legally available therefor, cumulative
preferential dividends from the issue date under the Original Certificate
accumulating at the rate of seven percent (7%) of the Liquidation Preference per
share per annum, payable quarterly in arrears on each June 1, September 1,
December 1 or March 1 of each year or, if any such date is not a Business Day,
on the next succeeding Business Day (each, a "Dividend Payment Date"), to the
holders of record of such shares of Series F Preferred Stock as of the next
preceding May 15, August 15, November 15 or February 15 (each, a "Record Date").
Dividends may be paid, at the Company's option, to any holder of Series F
Preferred Stock by the issuance of additional shares of Series F Preferred Stock
having an aggregate Liquidation Preference (rounded to the nearest $1000.00)
equal to the amount of such dividends payable on all shares of Series F
Preferred Stock held by such holder. The issuance of such additional shares of
Series F Preferred Stock shall constitute "payment" of the related dividend for
all purposes of this Certificate of Designation. The first dividend payment on
the Series F Preferred Stock shall be payable on September 1, 1999 (except with
respect to shares of Series F Preferred Stock converted prior to


                                      -10-
<PAGE>   11

such date, if any). Dividends payable on the Series F Preferred Stock will be
computed on the basis of a 360-day year consisting of twelve 30-day months and
will be deemed to accumulate on a daily basis on the Liquidation Preference of
the Series F Preferred Stock. In the event a holder elects to convert shares of
Series F Preferred Stock into Common Stock pursuant to Section 7, on a date
other than a Dividend Payment Date, the Company shall have the right to pay all
accrued and unpaid dividends on such Series F Preferred Stock in cash through
the date of conversion.

              (b)    Dividends on the Series F Preferred Stock shall accrue
whether or not the Company has earnings or profits, whether or not there are
funds legally available for the payment of such dividends and whether or not
dividends are declared. Dividends will accumulate to the extent they are not
paid on the Dividend Payment Date for the period to which they relate.

              (c)    No dividend whatsoever shall be declared or paid upon, or
any sum set apart for the payment of dividends upon, any outstanding share of
the Series F Preferred Stock with respect to any dividend period unless all
dividends for all preceding dividend periods have been declared and paid, or
declared and a sufficient sum set apart for the payment of such dividend, upon
all outstanding shares of Series F Preferred Stock. Unless full cumulative
dividends on all outstanding shares of Series F Preferred Stock for all past
dividend periods shall have been declared and paid, or declared and a sufficient
sum for the payment thereof set apart, then: (i) no cash dividend (other than a
dividend payable solely in shares of any Junior Securities) shall be declared or
paid upon, or any sum set apart for the payment of dividends upon, any shares of
Junior Securities; (ii) no other distribution shall be declared or made upon, or
any sum set apart for the payment of any distribution upon, any shares of Junior
Securities, other than a distribution consisting solely of Junior Securities;
and (iii) no monies shall be paid into or set apart or made available for a
sinking or other like fund for the purchase, redemption or other acquisition or
retirement for value of any shares of Junior Securities by the Company or any of
its Subsidiaries, except in the ordinary course of the Company's business.
Holders of the Series F Preferred Stock will not be entitled to any dividends,
whether payable in cash, property or stock, in excess of the full cumulative
dividends as herein described.

5.            LIQUIDATION RIGHTS.

              Upon any voluntary or involuntary liquidation, dissolution or
winding-up of the Company or reduction or decrease in its capital stock
resulting in a distribution of assets to the holders of any class or series of
the Company's capital stock (other than shares of Senior Securities), each
holder of shares of the Series F Preferred Stock will be entitled to payment out
of the assets of the Company available for distribution of an amount equal to
the Liquidation Preference per share of Series F Preferred Stock held by such
holder, if any, to the date fixed for liquidation, dissolution, winding-up or
reduction or decrease in capital stock, before any distribution is made on any
Junior Securities, including, without limitation, Common Stock of the Company.
After payment in full of the Liquidation Preference and all accumulated
dividends, if any, to which holders of Series F Preferred Stock are entitled,
such holders will not be entitled to any further participation in any
distribution of assets of the Company. If, upon any voluntary or involuntary
liquidation, dissolution or winding-up of the Company, the amounts payable with
respect to the Series F Preferred Stock and all other Parity Securities are not
paid in full, the holders of the Series F Preferred Stock and the Parity
Securities will share equally and ratably in any distribution of assets of the
Company in proportion to the full Liquidation Preference and


                                      -11-
<PAGE>   12

accumulated and unpaid dividends, if any, to which each is entitled. However,
neither the voluntary sale, conveyance, exchange or transfer (for cash, shares
of stock, securities or other consideration) of all or substantially all of the
property or assets of the Company nor the consolidation or merger of the Company
with or into one or more Persons will be deemed to be a voluntary or involuntary
liquidation, dissolution or winding-up of the Company or reduction or decrease
in capital stock, unless such sale, conveyance, exchange or transfer shall be in
connection with a liquidation, dissolution or winding-up of the business of the
Company or reduction or decrease in capital stock.

6.            REDEMPTION BY THE COMPANY.

              (a)    On September 1, 2010 (the "Mandatory Redemption Date"), the
Company shall be required to redeem (subject to the legal availability of funds
therefor) all outstanding shares of Series F Preferred Stock at a price in cash
equal to the Liquidation Preference thereof, plus accumulated and unpaid
dividends (including an amount in cash equal to a prorated dividend for any
partial dividend period) to the date of redemption. The Company shall not be
required to make sinking fund payments with respect to the Series F Preferred
Stock.

              (b)    Except as set forth below, the Series F Preferred Stock may
not be redeemed at the option of the Company prior to June 1, 2003. Each share
of Series F Preferred Stock will be subject to redemption at any time on or
after June 1, 2003, at the option of the Company at the Application Redemption
Price; provided, however, that the Series F Preferred Stock will not be
redeemable at the option of the Company on or after June 1, 2003, and before
June 1, 2005 unless the arithmetic average of the Closing Price (determined as
set forth in Section 7(e)(6)) during the twenty-five Trading Days immediately
prior to the date notice of redemption is sent in accordance with Section 6(c)
represents a multiple of 2.5, or greater, times the Conversion Price.

              (c)    In case of redemption of less than all of the shares of
Series F Preferred Stock at the time outstanding, the shares to be redeemed
shall be selected pro rata or by lot as determined by the Company in its sole
discretion.

              (d)    Notice of any redemption shall be sent by or on behalf of
the Company not less than 30 nor more than 60 days prior to the date specified
for redemption in such notice (including the Mandatory Redemption Date, the
"Redemption Date"), by first class mail, postage prepaid, to all holders of
record of the Series F Preferred Stock at their last addresses as they shall
appear on the books of the Company; provided, however, that no failure to give
such notice or any defect therein or in the mailing thereof shall affect the
validity of the proceedings for the redemption of any shares of Series F
Preferred Stock except as to the holder to whom the Company has failed to give
notice or except as to the holder to whom notice was defective. In addition to
any information required by law or by the applicable rules of any exchange upon
which Series F Preferred Stock may be listed or admitted to trading, such notice
shall state: (i) the Redemption Date; (ii) the Applicable Redemption Price;
(iii) the number of shares of Series F Preferred Stock to be redeemed and, if
less than all shares held by such holder are to be redeemed, the number of such
shares to be redeemed; (iv) the place or places where certificates for such
shares are to be surrendered for payment of the Applicable Redemption Price; and
(v) that dividends on the shares to be redeemed will cease to accumulate on the
Redemption Date.


                                      -12-
<PAGE>   13

Upon the mailing of any such notice of redemption, the Company shall become
obligated to redeem at the time of redemption specified thereon all shares
called for redemption.

              (e)    If notice has been mailed in accordance with Section 7(d)
above and provided that on or before the Redemption Date specified in such
notice, all funds necessary for such redemption shall have been set aside by the
Company, separate and apart from its other funds in trust for the pro rata
benefit of the holders of the shares so called for redemption, so as to be, and
to continue to be available therefor, then, from and after the Redemption Date,
dividends on the shares of the Series F Preferred Stock so called for redemption
shall cease to accumulate, and said shares shall no longer be deemed to be
outstanding and shall not have the status of shares of Series F Preferred Stock,
and all rights of the Holders thereof as stockholders of the Company (except the
right to receive from the Company the Applicable Redemption Price) shall cease.
Upon surrender, in accordance with said notice, of the certificates for any
shares so redeemed (properly endorsed or assigned for transfer, if the Company
shall so require and the notice shall so state), such shares shall be redeemed
by the Company at the Applicable Redemption Price. In case fewer than all the
shares represented by any such certificate are redeemed, a new certificate or
certificates shall be issued representing the unredeemed shares without cost to
the holder thereof.

              (f)    No Series F Preferred Stock may be redeemed except with
funds legally available for the purpose.

              (g)    All shares of Series F Preferred Stock redeemed pursuant to
this Section 7 shall be restored to the status of authorized and unissued shares
of Series F Preferred Stock, without designation as to series and may thereafter
be reissued as shares of any series of preferred stock other than shares of
Series F Preferred Stock.

7.            CONVERSION

              (a)    Subject to and upon compliance with the provisions of this
Certificate of Designation, the holder of any Series F Preferred Stock shall
have the right, at its option, at any time after the date of this Certificate of
Designation to convert any shares of Series F Preferred Stock, into that number
of fully paid and non-assessable shares of Common Stock (as such shares shall
then be constituted) obtained by dividing the aggregate Liquidation Preference
on the shares of Series F Preferred Stock to be converted (plus, in the event
such shares are converted on a date other than a Dividend Payment Date, accrued
and unpaid dividends on such Series F Preferred Stock through the date such
Series F Preferred Stock is deemed to be converted in accordance with this
Section 7, unless the Company shall elect to pay such accrued and unpaid
dividend in cash as set forth in Section 4(a) above) by the Conversion Price in
effect at such time, by surrender of the certificate evidencing such shares of
Series F Preferred Stock so to be converted in the manner provided. A holder of
Series F Preferred Stock is not entitled to any rights of a holder of Common
Stock until such holder has converted shares of Series F Preferred Stock to
Common Stock, and only to the extent such Series F Preferred Stock are deemed to
have been converted to Common Stock under this Section 7.

              (b)    In order to exercise the conversion privilege with respect
to any shares of Series F Preferred Stock, the holder of shares to be converted
shall surrender such shares, duly


                                      -13-
<PAGE>   14

endorsed, at an office or agency maintained by the Company for such purposes,
and shall give written notice of conversion in the form provided on the
certificate evidencing Series F Preferred Stock (or such other notice which is
acceptable to the Company) to the office or agency that the holder elects to
convert shares of Series F Preferred Stock. Such notice shall also state the
name or names (with address or addresses) in which the certificate or
certificates for shares of Common Stock which shall be issuable on such
conversion shall be issued, and shall be accompanied by transfer taxes, if
required pursuant to Section 7(g) which shall be Microsoft Corporation or an
Affiliate thereof if such conversion occurs on or before 18 months after the
date hereof. Each share of Series F Preferred Stock surrendered for conversion
shall, unless the shares issuable on conversion are to be issued in the same
name as the registration of such Series F Preferred Stock, be duly endorsed by,
or be accompanied by instruments of transfer in form satisfactory to the Company
duly executed by, the holder or his duly authorized attorney. As promptly as
practicable after satisfaction of the requirements for conversion set forth
above, subject to compliance with any restrictions on transfer if shares
issuable on conversion are to be issued in a name other than that of the holder
(as if such transfer were a transfer of the Series F Preferred Stock), the
Company shall issue and shall deliver to such holder at the office or agency
maintained by the Company for such purpose, a certificate or certificates for
the number of full shares of Common Stock to be issued by the Company upon the
conversion of shares of Series F Preferred Stock accordance with the provisions
of this Section 7 and a check or cash in respect of any fractional interest in
respect of a share of Common Stock arising upon such conversion, as provided in
Section 7(c), and, if the Company elects to pay accrued and unpaid dividends on
such shares pursuant to Section 4(a), a check or cash in respect of such
amounts. In case any Series F Preferred Stock of a denomination greater than
$1000.00 shall be surrendered for partial conversion, the Company shall execute
and deliver to the holder of the Series F Preferred Stock so surrendered,
without charge to him, a new certificate evidencing the unconverted shares of
Series F Preferred Stock evidenced by the surrendered certificate.

              Each conversion shall be deemed to have been effected as to any
such Series F Preferred Stock on the date on which the requirements set forth
above in this Section 7(b) have been satisfied as to such Series F Preferred
Stock, and the Person in whose name any certificate or certificates for shares
of Common Stock shall be issuable upon such conversion shall be deemed to have
become on said date the holder of record of the shares represented thereby;
provided, however, that any such surrender on any date when the stock transfer
books of the Company shall be closed shall constitute the Person in whose name
the certificates are to be issued as the record holder thereof for all purposes
on the next succeeding day on which such stock transfer books are open, but such
conversion shall be at the Conversion Price in effect on the date upon which
such Series F Preferred Stock shall be surrendered.

              (c)    No fractional shares of Common Stock or scrip representing
fractional shares shall be issued upon conversion of Series F Preferred Stock.
If any fractional share of stock would be issuable upon the conversion of any
share or shares of Series F Preferred Stock, the Company shall make an
adjustment and payment therefor in cash at the current market price thereof to
the holder of such shares. The current market price of a share of Common Stock
shall be the Closing Price on the last Business Day immediately preceding the
day on which the Series F Preferred Stock is deemed to have been converted.

                                      -14-
<PAGE>   15

              (d)    The conversion price applicable to the Series F Preferred
Stock shall be $31.0258 (herein called the "Conversion Price"), subject to
adjustment as provided in this Section 7.

              (e)    The Conversion Price shall be adjusted from time to time by
the Company as follows:

                     (1)    In case the Company shall hereafter pay a dividend
or make a distribution to all holders of the outstanding Common Stock in shares
of Common Stock, the Conversion Price in effect at the opening of business on
the date following the date fixed for the determination of stockholders entitled
to receive such dividend or other distribution shall be reduced by multiplying
such Conversion Price by a fraction of which the numerator shall be the number
of shares of Common Stock outstanding at the close of business on the date fixed
for such determination and the denominator shall be the sum of such number of
shares and the total number of shares constituting such dividend or other
distribution, such reduction to become effective immediately after the opening
of business on the day following the date fixed for such determination. The
Company will not pay any dividend or make any distribution on shares of Common
Stock held in the treasury of the Company. If any dividend or distribution of
the type described in this Section 7(e)(1) is declared but not so paid or made,
the Conversion Price shall again be adjusted to the Conversion Price which would
then be in effect if such dividend or distribution had not been declared.

                     (2)    In case the Company shall issue rights or warrants
to all holders of its outstanding shares of Common Stock entitling them (for a
period expiring within forty-five (45) days after the date fixed for
determination of stockholders entitled to receive such rights or warrants) to
subscribe for or purchase shares of Common Stock at a price per share less than
the Current Market Price (as defined below) on the date fixed for determination
of stockholders entitled to receive such rights or warrants, the Conversion
Price shall be adjusted so that the same shall equal the price determined by
multiplying the Conversion Price in effect immediately prior to the date fixed
for determination of stockholders entitled to receive such rights or warrants by
a fraction of which the numerator shall be the number of shares of Common Stock
outstanding at the close of business on the date fixed for determination of
stockholders entitled to receive such rights and warrants plus the number of
shares which the aggregate offering price of the total number of shares so
offered would purchase at such Current Market Price, and of which the
denominator shall be the number of shares of Common Stock outstanding on the
date fixed for determination of stockholders entitled to receive such rights and
warrants plus the total number of additional shares of Common Stock offered for
subscription or purchase. Such adjustment shall be successively made whenever
any such rights and warrants are issued, and shall become effective immediately
after the opening of business on the day following the date fixed for
determination of stockholders entitled to receive such rights or warrants. To
the extent that shares of Common Stock are not delivered after the expiration of
such rights or warrants, the Conversion Price shall be readjusted to the
Conversion Price which would then be in effect had the adjustments made upon the
issuance of such rights or warrants been made on the basis of delivery of only
the number of shares of Common Stock actually delivered. In the event that such
rights or warrants are not so issued, the Conversion Price shall again be
adjusted to be the Conversion Price which would then be in effect if such date
fixed for the determination of stockholders entitled to receive such rights or
warrants had not been fixed. In determining


                                      -15-
<PAGE>   16

whether any rights or warrants entitle the holders to subscribe for or purchase
shares of Common Stock at less than such Current Market Price, and in
determining the aggregate offering price of such shares of Common Stock, there
shall be taken into account any consideration received by the Company for such
rights or warrants, the value of such consideration, if other than cash, to be
determined by the Board of Directors.

                     (3)    In case outstanding shares of Common Stock shall be
subdivided into a greater number of shares of Common Stock, the Conversion Price
in effect at the opening of business on the day following the day upon which
such subdivision becomes effective shall be proportionately reduced, and
conversely, in case outstanding shares of Common Stock shall be combined into a
smaller number of shares of Common Stock, the Conversion Price in effect at the
opening of business on the day following the day upon which such combination
becomes effective shall be proportionately increased, such reduction or
increase, as the case may be, to become effective immediately after the opening
of business on the day following the day upon which such subdivision or
combination becomes effective.

                     (4)    In case the Company shall, by dividend or otherwise,
distribute to all holders of its Common Stock shares of any class of capital
stock of the Company (other than any dividends or distributions to which Section
7(e)(1) applies) or evidences of its indebtedness or assets (including
securities, but excluding any rights or warrants referred to in Section 7(e)(2),
and excluding any dividend or distribution (x) paid exclusively in cash or (y)
referred to in Section 7(e)(1) (any of the foregoing hereinafter in this Section
7(e)(4) called the "Securities")), then, in each such case (unless the Company
elects to reserve such Securities for distribution to the holders upon the
conversion of the shares of Series F Preferred Stock so that any such holder
converting shares will receive upon such conversion, in addition to the shares
of Common Stock to which such holder is entitled, the amount and kind of such
Securities which such holder would have received if such holder had converted
its shares of Series F Preferred Stock into Common Stock immediately prior to
the record date (as defined in Section 7(e)(7) for such distribution of the
Securities)), the Conversion Price shall be reduced so that the same shall be
equal to the price determined by multiplying the Conversion Price in effect on
the record date with respect to such distribution by a fraction of which the
numerator shall be the Current Market Price per share of the Common Stock on
such record date less the fair market value (as determined by the Board of
Directors, whose determination shall be conclusive, and described in a
resolution of the Board if Directors) on the record date of the portion of the
Securities so distributed applicable to one share of Common Stock and the
denominator shall be the Current Market Price per share of the Common Stock,
such reduction to become effective immediately prior to the opening of business
on the day following such record date; provided, however, that in the event the
then fair market value (as so determined) of the portion of the Securities so
distributed applicable to one share of Common Stock is equal to or greater than
the Current Market Price of the Common Stock on the record date, in lieu of the
foregoing adjustment, adequate provision shall be made so that each holder shall
have the right to receive upon conversion the amount of Securities such holder
would have received had such holder converted each share of Series F Preferred
Stock on the record date. In the event that such dividend or distribution is not
so paid or made, the Conversion Price shall again be adjusted to be the
Conversion Price which would then be in effect if such dividend or distribution
had not been declared. If the Board of Directors determines the fair market
value of any distribution for purposes of this Section 7(e)(4) by reference to
the actual or


                                      -16-
<PAGE>   17

when issued trading market for any securities, it must in doing so consider the
prices in such market over the same period used in computing the Current Market
Price of the Common Stock.

              In the event that the Company implements a stockholders' rights
plan ("Rights Plan"), such Rights Plan must provide that, subject to customary
exceptions, upon conversion of the shares of Series F Preferred Stock the
Holders will receive, in addition to the Common Stock issuable upon conversion,
such rights whether or not such rights have separated from the Common Stock at
the time of such conversion.

              Rights or warrants distributed by the Company to all holders of
Common Stock entitling the holders thereof to subscribe for or purchase shares
of the Company's capital stock (either initially or under certain
circumstances), which rights or warrants, until the occurrence of a specified
event or events ("Trigger Event"): (i) are deemed to be transferred with such
shares of Common Stock; (ii) are not exercisable; and (iii) are also issued in
respect of future issuances of Common Stock, shall be deemed not to have been
distributed for purposes of this Section 7(e) (and no adjustment to the
Conversion Price under this Section 7(e) will be required) until the occurrence
of the earliest Trigger Event, whereupon such rights and warrants shall be
deemed to have been distributed and an appropriate adjustment (if any is
required) to the Conversion Price shall be made under this Section 7(e)(4). If
any such right or warrant, including any such existing rights or warrants
distributed prior to the date of this Certificate of Designation, are subject to
events, upon the occurrence of which such rights or warrants become exercisable
to purchase different securities, evidences of indebtedness or other assets,
then the date of the occurrence of any and each such event shall be deemed to be
the date of distribution and record date with respect to new rights or warrants
with such rights (and a termination or expiration of the existing rights or
warrants without exercise by any of the holders thereof). In addition, in the
event of any distribution (or deemed distribution) of rights or warrants, or any
Trigger Event or other event (of the type described in the preceding sentence)
with respect thereto that was counted for purposes of calculating a distribution
amount for which an adjustment to the Conversion Price under this Section 7(e)
was made, (1) in the case of any such rights or warrants which shall all have
been redeemed or repurchased without exercise by any holders thereof, the
Conversion Price shall be readjusted upon such final redemption or repurchase to
give effect to such distribution or Trigger Event, as the case may be, as though
it were a cash distribution, equal to the per share redemption or repurchase
price received by a holder or holders of Common Stock with respect to such
rights or warrants (assuming such holder had retained such rights or warrants),
made to all holders of Common Stock as of the date of such redemption or
repurchase, and (2) in the case of such rights or warrants which shall have
expired or been terminated without exercise by any holders thereof, the
Conversion Price shall be readjusted as if such rights and warrants had not been
issued.

              For purposes of this Section 7(e)(4) and Sections 7(e)(1) and
7(e)(2), any dividend or distribution to which this Section 7(e)(4) is
applicable that also includes shares of Common Stock, or rights or warrants to
subscribe for or purchase shares of Common Stock (or both), shall be deemed
instead to be (1) a dividend or distribution of the evidences of indebtedness,
assets or shares of capital stock other than such shares of Common Stock or
rights or warrants (and any Conversion Price reduction required by this Section
7(e)(4) with respect to such dividend or distribution shall then be made)
immediately followed by (2) a dividend or distribution of such shares of Common
Stock or such rights or warrants (and any further


                                      -17-
<PAGE>   18

Conversion Price reduction required by Sections 7(e)(1) and (2) with respect to
such dividend or distribution shall then be made), except (A) the record date of
such dividend or distribution shall be substituted as "the date fixed for the
determination of stockholders entitled to receive such dividend or other
distribution" and "the date fixed for such determination" within the meaning of
Sections 7(e)(1) and (2) and (B) any shares of Common Stock included in such
dividend or distribution shall not be deemed "outstanding at the close of
business on the date fixed for such determination" within the meaning of Section
7(1).

                     (5)    In case the Company shall, by dividend or otherwise,
distribute to all holders of its Common Stock, or to all holders of any series
of preferred stock or other equity security with respect to which dividends are
payable, cash (excluding (x) any quarterly cash dividend on the Common Stock to
the extent the aggregate cash dividend per share of Common Stock in any fiscal
quarter does not exceed the greater of (A) the amount per share of Common Stock
of the next preceding quarterly cash dividend on the Common Stock to the extent
that such preceding quarterly dividend did not require any adjustment of the
Conversion Price pursuant to this Section 7(e)(5) (as adjusted to reflect
subdivisions or combinations of the Common Stock), and (B) 1.75% in the case of
Common Stock or any Convertible Security, or 3.75% in the case of any series of
preferred stock or other equity security to which this Section 7(e)(5) applies
which is not a Convertible Security, of the arithmetic average of the Closing
Price (determined as set forth in Section 7(e)(6)) during the twenty-five
Trading Days immediately prior to the date of declaration of such dividend, and
(y) any dividend or distribution in connection with the liquidation, dissolution
or winding up of the Company, whether voluntary or involuntary), then, in such
case, the Conversion Price shall be reduced so that the same shall equal the
price determined by multiplying the Conversion Price in effect immediately prior
to the close of business on such record date by a fraction of which the
numerator shall be the Current Market Price of the Common Stock on the record
date less the amount of cash so distributed (and not excluded as provided above)
applicable to one share of Common Stock and the denominator shall be such
Current Market Price of the Common Stock, such reduction to be effective
immediately prior to the opening of business on the day following the record
date; provided, however, that in the event the portion of the cash so
distributed applicable to one share of Common Stock is equal to or greater than
the Current Market Price of the Common Stock on the record date, in lieu of the
foregoing adjustment, adequate provision shall be made so that each holder shall
have the right to receive upon conversion the amount of cash such holder would
have received had such holder converted each share of Series F Preferred Stock
on the record date. In the event that such dividend or distribution is not so
paid or made, the Conversion Price shall again be adjusted to be the Conversion
Price which would then be in effect if such dividend or distribution had not
been declared. If any adjustment is required to be made as set forth in this
Section 7(e)(5) as a result of a distribution that is a quarterly dividend, such
adjustment shall be based upon the amount by which such distribution exceeds the
amount of the quarterly cash dividend permitted to be excluded pursuant hereto.
If an adjustment is required to be made as set forth in this Section 7(e)(5)
above as a result of a distribution that is not a quarterly dividend, such
adjustment shall be based upon the full amount of the distribution.

                     (6)    In case the Company shall issue additional shares of
Common Stock or Convertible Securities, issued for no consideration or for a
consideration per share less than the Conversion Price (determined on an "as
converted" basis in the case of a Convertible Security) (other than shares of
Common Stock issued or issuable (i) upon conversion or exercise


                                      -18-
<PAGE>   19

of warrants or other convertible securities outstanding as of June 21, 1999 and
(ii) pursuant to stock incentive or option plans approved by the Company's Board
of Directors) then and in such event, the Conversion Price for the Series F
Preferred Stock shall be reduced, concurrently with such issue, by multiplying
such Conversion Price by a fraction, the numerator of which shall be the number
of shares of Common Stock outstanding immediately prior to such issue plus the
number of shares of Common Stock which the aggregate consideration received by
the Company for the total number of additional shares of Common Stock so issued
would purchase at such Conversion Price in effect immediately prior to such
issuance, and the denominator of which shall be the number of shares of Common
Stock outstanding immediately prior to such issue plus the number of such
additional shares of Common Stock so issued; provided, however, that if the
additional shares of Common Stock are issued pursuant to a firmly underwritten
public offering than the foregoing adjustment shall be made only if the
consideration per share is less than the Current Market Price of the Common
Stock. For the purpose of the above calculation, the number of shares of Common
Stock outstanding immediately prior to such issue shall be calculated on a fully
diluted basis, as if all shares of Series B or C Preferred Stock and all
convertible securities had been fully converted into shares of Common Stock
immediately prior to such issuance and any outstanding warrants, options or
other rights for the purchase of shares of stock or convertible securities had
been fully exercised immediately prior to such issuance (and the resulting
securities fully converted into shares of Common Stock, if so convertible) as of
such date.

                     (7)    For purposes of this Section 7(e), the following
terms shall have the meaning indicated:

                            a.     "Closing Price" with respect to any
                     securities on any day shall mean the closing sale price
                     regular way on such day or, in case no such sale takes
                     place on such day, the average of the reported closing bid
                     and asked prices, regular way, in each case on the NASDAQ
                     National Market ("NNM"), or, if such security is not listed
                     or admitted to trading on NNM, on the principal national
                     security exchange or quotation system on which such
                     security is quoted or listed or admitted to trading, or, if
                     not quoted or listed or admitted to trading on any national
                     securities exchange or quotation system, the average of the
                     closing bid and asked prices of such security on the
                     over-the-counter market on the day in question as reported
                     by the National Quotation Bureau Incorporated, or a similar
                     generally accepted reporting service, or if not so
                     available, in such manner as furnished by any National
                     Association of Securities Dealers firm selected from time
                     to time by the Board of Directors for that purpose, or a
                     price determined in good faith by the Board of Directors
                     or, to the extent permitted by applicable law, a duly
                     authorized committee thereof, whose determination shall be
                     conclusive.

                            b.     "Current Market Price" shall mean the average
                     of the daily Closing Prices per share of Common Stock for
                     the twenty-five consecutive Trading Days immediately prior
                     to the date in question; provided, however, that (1) if the
                     "ex" date (as hereinafter defined) for any event that
                     requires an adjustment to the Conversion Price pursuant to
                     Section 7(e)(1),


                                      -19-
<PAGE>   20

                     (2), (3), (4), (5) or (6) occurs during such twenty-five
                     consecutive Trading Days, the Closing Price for each
                     Trading Day prior to the "ex" date for such other event
                     shall be adjusted by multiplying such Closing Price by the
                     same fraction by which the Conversion Price is so required
                     to be adjusted as a result of such other event, or (2) if
                     the "ex" date for any event that requires an adjustment to
                     the Conversion Price pursuant to Section 7(e)(1), (2), (3),
                     (4), (5) or (6) occurs on or after the "ex" date for the
                     issuance or distribution requiring such computation and
                     prior to the day in question, the Closing Price for each
                     Trading Day on and after the "ex" date for such other event
                     shall be adjusted by multiplying such Closing Price by the
                     reciprocal of the fraction by which the Conversion Price is
                     so required to be adjusted as a result of such other event.
                     For purposes of any computation under Section 7(e)(5), the
                     Current Market Price of the Common Stock on any date shall
                     be deemed to be the average of the daily Closing Prices per
                     share of Common Stock for such day and the next two
                     succeeding Trading Days. For purposes of this paragraph,
                     the term "ex" date, (1) when used with respect to any
                     issuance or distribution, means the first date on which the
                     Common Stock trades regular way on the relevant exchange or
                     in the relevant market from which the Closing Price was
                     obtained without the right to receive such issuance or
                     distribution, and (2) when used with respect to any
                     subdivision or combination of shares of Common Stock, means
                     the first date on which the Common Stock trades regular way
                     on such exchange or in such market after the time at which
                     such subdivision or combination becomes effective.

                            c.     "fair market value" shall mean the amount
                     which a willing buyer would pay a willing seller in an
                     arm's length transaction.

                            d.     "record date" shall mean, with respect to any
                     dividend, distribution or other transaction or event in
                     which the holders of Common Stock have the right to receive
                     any cash, securities or other property or in which the
                     Common Stock (or other applicable security) is exchanged
                     for or converted into any combination of cash, securities
                     or other property, the date fixed for determination of
                     stockholders entitled to receive such cash, securities or
                     other property (whether such date is fixed by the Board of
                     Directors or by statute, contract or otherwise).

                            e.     "Trading Day" shall mean (x) if the
                     applicable security is listed or admitted for trading on
                     the New York Stock Exchange or another national security
                     exchange, a day on which the New York Stock Exchange or
                     another national security exchange is open for business or
                     (y) if the applicable security is quoted on the NNM, a day
                     on which trades may be made on thereon or (z) if the
                     applicable security is not so listed, admitted for trading
                     or quoted, any day other than a Saturday or Sunday or a day
                     on which banking institutions in the State of California
                     are authorized or obligated by law or executive order to
                     close.

                                      -20-
<PAGE>   21

                     (8)    The Company may make such reductions in the
Conversion Price, in addition to those required by Sections 7(e)(1), (2), (3),
(4), (5) or (6) as the Board of Directors considers to be advisable to avoid or
diminish any income tax to holders of Common Stock or rights to purchase Common
Stock resulting from any dividend or distribution of stock (or rights to acquire
stock) or from any event treated as such for income tax purposes.

              To the extent permitted by applicable law, the Company from time
to time may reduce the Conversion Price by any amount for any period of time if
the period is at least twenty (20) days, the reduction is irrevocable during the
period and the Board of Directors shall have made a determination that such
reduction would be in the best interests of the Company, which determination
shall be conclusive. Whenever the Conversion Price is reduced pursuant to the
preceding sentence, the Company shall mail to holders of record of the Series F
Preferred Stock a notice of the reduction at least fifteen (15) days prior to
the date the reduced Conversion Price takes effect, and such notice shall state
the reduced Conversion Price and the period during which it will be in effect.

                     (9)    No adjustment in the Conversion Price shall be
required unless such adjustment would require an increase or decrease of at
least one percent (1%) in such price; provided, however, that any adjustments
which by reason of this Section 7(e)(9) are not required to be made shall be
carried forward and taken into account in any subsequent adjustment. All
calculations under this Section 7 shall be made by the Company and shall be made
to the nearest cent or to the nearest one-hundredth (1/100) of a share, as the
case may be. No adjustment need be made for rights to purchase Common Stock
pursuant to a Company plan for reinvestment of dividends or interest. To the
extent the Series F Preferred Stock become convertible into cash, assets,
property or securities (other than capital stock of the Company), no adjustment
need be made thereafter as to the cash, assets, property or such securities.
Interest will not accrue on the cash.

                     (10)   Whenever the Conversion Price is adjusted as herein
provided, the Company shall prepare a notice of such adjustment of the
Conversion Price setting forth the adjusted Conversion Price and the date on
which each adjustment becomes effective and shall mail such notice of such
adjustment of the Conversion Price to each holder of Series F Preferred Stock at
his last address appearing on the Share register, within twenty (20) days after
the effectiveness thereof. Failure to deliver such notice shall not affect the
legality or validity of any such adjustment.

                     (11)   In any case in which this Section 7(e) provides that
an adjustment shall become effective immediately after a record date for an
event, the Company may defer until the occurrence of such event (i) issuing to
the holder of any Series F Preferred Stock converted after such record date and
before the occurrence of such event the additional shares of Common Stock
issuable upon such conversion by reason of the adjustment required by such event
over and above the Common Stock issuable upon such conversion before giving
effect to such adjustment and (ii) paying to such holder any amount in cash in
lieu of any fraction pursuant to Section 7(c).

                     (12)   For purposes of this Section 7(e), the number of
shares of Common Stock at any time outstanding shall not include shares held in
the treasury of the Company but


                                      -21-
<PAGE>   22

shall include shares issuable in respect of scrip certificates issued in lieu of
fractions of shares of Common Stock. The Company will not pay any dividend or
make any distribution on shares of Common Stock held in the treasury of the
Company.

              (f)    If any of the following events occur, namely (i) any
reclassification or change of the outstanding shares of Common Stock (other than
a subdivision or combination to which Section 7(e)(3) applies), (ii) any
consolidation, merger or combination of the Company with another corporation as
a result of which holders of Common Stock shall be entitled to receive stock,
securities or other property or assets (including cash) with respect to or in
exchange for such Common Stock, or (iii) any sale or conveyance of the
properties and assets of the Company as, or substantially as, an entirety to any
other corporation as a result of which holders of Common Stock shall be entitled
to receive stock, securities or other property or assets (including cash) with
respect to or in exchange for such Common Stock, then the Company or the
successor or purchasing corporation, as the case may be, shall amend this
Certificate of Designation to provide that such shares of Series F Preferred
Stock shall be convertible into the kind and amount of shares of stock and other
securities or property or assets (including cash) receivable upon such
reclassification, change, consolidation, merger, combination, sale or conveyance
by a holder of a number of shares of Common Stock issuable upon conversion of
such shares of Series F Preferred Stock (assuming, for such purposes, a
sufficient number of authorized shares of Common Stock available to convert all
such shares of Series F Preferred Stock) immediately prior to such
reclassification, change, consolidation, merger, combination, sale or conveyance
assuming such holder of Common Stock did not exercise his rights of election, if
any, as to the kind or amount of securities, cash or other property receivable
upon such consolidation, merger, statutory exchange, sale or conveyance
(provided that, if the kind or amount of securities, cash or other property
receivable upon such consolidation, merger, statutory exchange, sale or
conveyance is not the same for each share of Common Stock in respect of which
such rights of election shall not have been exercised ("nonelecting share")),
then for the purposes of this Section 7(f), the kind and amount of securities,
cash or other property receivable upon such consolidation, merger, statutory
exchange, sale or conveyance for each non-electing share shall be deemed to be
the kind and amount so receivable per share by a plurality of the non-electing
shares. Such amendment shall provide for adjustments which shall be as nearly
equivalent as may be practicable to the adjustments provided for in this
Section. The Company shall cause notice of the amendment of this Certificate of
Designation to be mailed to each holder of Series F Preferred Stock, at its
address appearing on the Share register, within twenty (20) days after execution
thereof. Failure to deliver such notice shall not affect the legality or
validity of such amendment. The above provisions of this Section shall similarly
apply to successive reclassifications, changes, consolidations, mergers,
combinations, sales and conveyances. If this Section 7(f) applies to any event
or occurrence, Section 7(e) shall not apply.

              (g)    The issue of stock certificates on conversions of shares of
Series F Preferred Stock shall be made without charge to the converting holder
for any tax in respect of the issue thereof. The Company shall not, however, be
required to pay any tax which may be payable in respect of any transfer involved
in the issue and delivery of stock in any name other than that of the holder of
any share of Series F Preferred Stock converted, and the Company shall not be
required to issue or deliver any such stock certificate unless and until the
Person or Persons requesting the issue thereof shall have paid to the Company
the amount of such tax or shall have established to the satisfaction of the
Company that such tax has been paid.

                                      -22-
<PAGE>   23

              (h)    The Company shall provide, free from preemptive rights, out
of its authorized but unissued shares or shares held in treasury, sufficient
shares of Common Stock to provide for the conversion of the shares of Series F
Preferred Stock from time to time as such are presented for conversion. Before
taking any action which would cause an adjustment reducing the Conversion Price
below the then par value, if any, of the shares of Common Stock issuable upon
conversion of the Series F Preferred Stock, the Company will take all corporate
action which may, in the opinion of its counsel, be necessary in order that the
Company may validly and legally issue shares of such Common Stock at such
adjusted Conversion Price. The Company covenants that all shares of Common Stock
which may be issued upon conversion of Series F Preferred Stock will upon issue
be fully paid and non-assessable by the Company and free from all taxes, liens
and charges with respect to the issue thereof.

              (i)    In case:

                     (1)    the Company shall declare a dividend (or any other
distribution) on its Common Stock that would require an adjustment in the
Conversion Price pursuant to Section 7(e); or

                     (2)    the Company shall authorize the granting to the
holders of all or substantially all of its Common Stock of rights or warrants to
subscribe for or purchase any share of any class or any other rights or
warrants; or

                     (3)    of any reclassification or reorganization of the
Common Stock of the Company (other than a subdivision or combination of its
outstanding Common Stock, or a change in par value, or from par value to no par
value, or from no par value to par value), or of any consolidation or merger to
which the Company is a party and for which approval of any stockholders of the
Company is required, or of the sale or transfer of all or substantially all of
the assets of the Company;

the Company shall cause to be mailed to each holder of Series F Preferred Stock
at his address appearing on the Share register provided for in Section 2(e) of
this Certificate of Designation, as promptly as possible but in any event at
least fifteen (15) days prior to the applicable date hereinafter specified, a
notice stating (x) the date on which a record is to be taken for the purpose of
such dividend, distribution or rights or warrants, or, if a record is not to be
taken, the date as of which the holders of Common Stock of record to be entitled
to such dividend, distribution or rights are to be determined, or (y) the date
on which such reclassification, consolidation, merger, sale, transfer,
dissolution, liquidation or winding up is expected to become effective or occur,
and the date as of which it is expected that holders of Common Stock of record
shall be entitled to exchange their Common Stock for securities or other
property deliverable upon such reclassification, consolidation, merger, sale,
transfer, dissolution, liquidation or winding up. Failure to give such notice,
or any defect therein, shall not affect the legality or validity of such
dividend, distribution, reclassification, consolidation, merger, sale, transfer,
dissolution, liquidation or winding up.

                                      -23-
<PAGE>   24

8.            CONSOLIDATION; MERGER; SALE OF ASSETS.

              Nothing contained in this Certificate of Designation shall prevent
any consolidation or merger of the Company with or into any other corporation or
corporations (whether or not affiliated with the Company), or successive
consolidations or mergers in which the Company or its successor or successors
shall be a party or parties, or shall prevent any sale, conveyance or lease (or
successive sales, conveyances or leases) of all or substantially all of the
property of the Company, to any other corporation (whether or not affiliated
with the Company), authorized to acquire and operate the same and which shall be
organized under the laws of the United States of America, any state thereof or
the District of Columbia; provided that upon any such consolidation, merger,
sale, conveyance or lease, the due and punctual payment of the Liquidation
Preference and any dividends on all of the Series F Preferred Stock, according
to their terms shall be expressly assumed by the corporation (if other than the
Company) formed by such consolidation, or into which the Company shall have been
merged, or by the corporation which shall have acquired or leased such property,
and such amendment shall provide for the applicable conversion rights set forth
in Section 7(f).

9.            VOTING RIGHTS.

              Except as otherwise provided in this Designation or as required by
law, the holders of record of shares of the Series F Preferred Stock shall have
no voting rights.

10.           AMENDMENT.

              (a)    The Company shall not, without the affirmative vote or
consent of the holders of at least seventy-five percent (75%) of the outstanding
Liquidation Preference of Series F Preferred Stock then outstanding (with shares
held by the Company or any of its Affiliates not being considered to be
outstanding for this purpose) voting or consenting as the case may be, as one
class, amend or otherwise alter this Certificate of Designation (including the
provisions of this Section 10) in any manner that adversely affects the
specified rights, preferences, privileges or voting rights of holders of Series
F Preferred Stock.

              (b)    Without the consent of each holder affected, an amendment
or waiver of the Company's Certificate of Incorporation or of this Certificate
of Designation may not (with respect to any shares of Series F Preferred Stock
held by a non-consenting holder):

                     (i)    reduce the number of shares of Series F Preferred
              Stock whose holders must consent to an amendment, supplement or
              waiver;

                     (ii)   reduce the Liquidation Preference of or change the
              Mandatory Redemption Date of any share of Series F Preferred Stock
              or alter the provisions with respect to the redemption of the
              Series F Preferred Stock;

                     (iii)  reduce the rate of or change the time for payment of
              dividends on any share of Series F Preferred Stock;

                     (iv)   make any share of Series F Preferred Stock payable
              in any form other than that stated in this Certificate of
              Designation;

                                      -24-
<PAGE>   25

                     (v)    make any change in the provisions of this
              Certificate of Designation relating to waivers of the rights of
              holders of Series F Preferred Stock to receive the Liquidation
              Preference and dividends on the Series F Preferred Stock;

                     (vi)   waive a redemption payment with respect to any share
              of Series F Preferred Stock (except as provided with respect to
              Section 10 hereof); or

                     (vii)  make any change in the foregoing amendment and
              waiver provisions.

              (c)    The Company in its sole discretion may without the vote or
consent of any holders of the Series F Preferred Stock amend or supplement this
Certificate of Designation:

                     (i)    to cure any ambiguity, defect or inconsistency;

                     (ii)   to provide for uncertificated Series F Preferred
              Stock in addition to or in place of certificated Series F
              Preferred Stock;

                     (iii)  to make any change that would provide any additional
              rights or benefits to the holders of the Series F Preferred Stock
              or that does not adversely affect the legal rights under this
              Certificate of Designation of any such holder; or

                     (iv)   to make any amendment required by Section 7(f) or 8.

              Except as set forth above, the creation, authorization or issuance
of, or the increase or decrease in the authorized amount of, capital stock of
any class, including any Series F Preferred Stock, shall not require the consent
of the holders of the Series F Preferred Stock and shall not be deemed to affect
adversely the rights, preferences, privileges, special rights or voting rights
of holders of shares of Series F Preferred Stock.

11.           EXCLUSION OF OTHER RIGHTS.

              Except as may otherwise be required by law, the shares of Series F
Preferred Stock shall not have any voting powers, preferences and relative,
participating, optional or other special rights, other than those specifically
set forth in this Certificate of Designation (as amended from time to time) and
in the Certificate of Incorporation. The shares of Series F Preferred Stock
shall have no preemptive or subscription rights.

12.           PROVISION FOR FINANCIAL INFORMATION.

              The Company will, within 15 days of each file with the Commission
the annual reports, quarterly reports which the Company would have been required
to file with the Commission pursuant to Section 13(a) or 15(d), transmit by mail
to all holders, as their names and addresses appear in the Share register,
without cost to such holders copies of the annual reports, quarterly reports
documents which the Company is required to file with the Commission pursuant to
Section 13(a) or 15(d) of the Exchange Act.



                                      -25-
<PAGE>   26


13.           HEADINGS OF SUBDIVISIONS.

              The headings of the various subdivisions hereof are for
convenience of reference only and shall not affect the interpretation of any of
the provisions hereof.

14.           SEVERABILITY OF PROVISIONS.

              If any voting powers, preferences and relative, participating,
optional and other special rights of the Series F Preferred Stock and
qualifications, limitations and restrictions thereof set forth in this
resolution (as such resolution may be amended from time to time) is invalid,
unlawful or incapable of being enforced by reason of any rule of law or public
policy, all other voting powers, preferences and relative, participating,
optional and other special rights of Series F Preferred Stock and
qualifications, limitations and restrictions thereof set forth in this
resolution (as so amended) which can be given effect without the invalid,
unlawful or unenforceable voting powers, preferences and relative,
participating, optional and other special rights of Series F Preferred Stock and
qualifications, limitations and restrictions thereof shall, nevertheless, remain
in full force and effect, and no voting powers, preferences and relative,
participating, optional or other special rights of Series F Preferred Stock and
qualifications, limitations and restrictions thereof herein set forth shall be
deemed dependent upon any other such voting powers, preferences and relative,
participating, optional or other special rights of Series F Preferred Stock and
qualifications, limitations and restrictions thereof unless so expressed herein.

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                                      -26-