<PAGE>

                                                                     Exhibit 3.1

                          CERTIFICATE OF DESIGNATION
                                      OF

                 SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                        (Pursuant to Section 151 of the
                       Delaware General Corporation Law)

     Adaptive Broadband Corporation, a corporation organized and existing under
the General Corporation Law of the State of Delaware (hereinafter called the
"Company"), hereby certifies that the following resolution was adopted by the
Board of Directors of the Corporation as required by Section 151 of the General
Corporation Law by Unanimous Written Consent on February 10, 2000:

          Resolved, that pursuant to the authority granted to and vested in the
     Board of Directors of the Company in accordance with the provisions of its
     Amended and Restated Certificate of Incorporation, the Board of Directors
     hereby creates a series of Preferred Stock, par value $.10 per share, of
     the Company and hereby states the designation and number of shares, and
     fixes the relative designations and the powers, preferences and rights, and
     the qualifications, limitations and restrictions thereof (in addition to
     the provisions set forth in the Certificate of Incorporation of the
     Company, which are applicable to the Preferred Stock of all classes and
     series), as follows:

          Series A Junior Participating Preferred Stock:

     Section 1.  Designation and Amount.  Five Million (5,000,000) shares of
Preferred Stock, $.10 par value, are designated "Series A Junior Participating
Preferred Stock" with the designations and the powers, preferences and rights,
and the qualifications, limitations and restrictions specified herein (the
"Junior Preferred Stock").  Such number of shares may be increased or decreased
by resolution of the Board of Directors; provided, that no decrease shall reduce
the number of shares of Junior Preferred Stock to a number less than the number
of shares then outstanding plus the number of shares reserved for issuance upon
the exercise of outstanding options, rights or warrants or upon the conversion
of any outstanding securities issued by the Company convertible into Junior
Preferred Stock.

                                       1
<PAGE>

     Section 2.  Dividends and Distributions.

          (A)  Subject to the rights of the holders of any shares of any series
of Preferred Stock (or any similar stock) ranking prior and superior to the
Junior Preferred Stock with respect to dividends, the holders of shares of
Junior Preferred Stock, in preference to the holders of Common Stock, par value
$.10 per share (the "Common Stock"), of the Company, and of any other junior
stock, shall be entitled to receive, when, as and if declared by the Board of
Directors out of funds legally available for the purpose, quarterly dividends
payable in cash on the first day of April, July, October and January in each
year (each such date being referred to herein as a "Quarterly Dividend Payment
Date"), commencing on the first Quarterly Dividend Payment Date after the first
issuance of a share or fraction of a share of Junior Preferred Stock, in an
amount per share (rounded to the nearest cent) equal to the greater of (a) $l.00
or (b) subject to the provision for adjustment hereinafter set forth, 100 times
the aggregate per share amount of all cash dividends, and 100 times the
aggregate per share amount (payable in kind) of all non-cash dividends or other
distributions, other than a dividend payable in shares of Common Stock or a
subdivision of the outstanding shares of Common Stock (by reclassification or
otherwise), declared on the Common Stock since the immediately preceding
Quarterly Dividend Payment Date or, with respect to the first Quarterly Dividend
Payment Date, since the first issuance of any share or fraction of a share of
Junior Preferred Stock. In the event the Company shall at any time declare or
pay any dividend on the Common Stock payable in shares of Common Stock, or
effect a subdivision or combination or consolidation of the outstanding shares
of Common Stock (by reclassification or otherwise than by payment of a dividend
in shares of Common Stock) into a greater or lesser number of shares of Common
Stock, then in each such case the amount to which holders of shares of Junior
Preferred Stock were entitled immediately prior to such event under clause (b)
of the preceding sentence shall be adjusted by multiplying such amount by a
fraction, the numerator of which is the number of shares of Common Stock
outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that were outstanding immediately prior to such
event.

          (B)  The Company shall declare a dividend or distribution on the
Junior Preferred Stock as provided in paragraph (A) of this Section immediately
after it declares a dividend or distribution on the Common Stock (other than a
dividend payable in shares of Common Stock); provided, that in the event no
dividend or distribution shall have been declared on the Common Stock during the
period between any Quarterly Dividend Payment Date and the next subsequent
Quarterly Dividend Payment Date, a dividend of $1.00 per share on the Junior
Preferred Stock shall nevertheless be payable on such subsequent Quarterly
Dividend Payment Date.

          (C)  Dividends shall begin to accrue and be cumulative on outstanding
shares of Junior Preferred Stock from the Quarterly Dividend Payment Date next
preceding the date of issue of such shares, unless the date of issue of such
shares is prior to the record date for the first Quarterly Dividend Payment
Date, in which case dividends on such shares shall begin to accrue from the date
of issue of such shares, or unless the date of issue is a Quarterly Dividend
Payment Date or is a date after the record date for the determination of holders
of shares of Junior Preferred Stock entitled to receive a quarterly dividend and
before such Quarterly Dividend Payment Date, in either of which events such
dividends shall begin to accrue and be cumulative from such Quarterly Dividend
Payment Date. Accrued but unpaid dividends shall not bear interest. Dividends
paid on the shares of Junior Preferred Stock in an amount less than the total

                                       2
<PAGE>

amount of such dividends at the time accrued and payable on such shares shall be
allocated pro rata on a share-by-share basis among all such shares at the time
outstanding. The Board of Directors may fix a record date for the determination
of holders of shares of Junior Preferred Stock entitled to receive payment of a
dividend or distribution declared thereon, which record date shall be not more
than 60 days prior to the date fixed for the payment thereof.

     Section 3.  Voting Rights.  The holders of shares of Junior Preferred Stock
shall have the following voting rights:

          (A)  Subject to the provision for adjustment hereinafter set forth,
each share of Junior Preferred Stock shall entitle the holder thereof to 100
votes on all matters submitted to a vote of the stockholders of the Company. In
the event the Company shall at any time declare or pay any dividend on the
Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the number of votes per share to which holders of shares of Junior
Preferred Stock were entitled immediately prior to such event shall be adjusted
by multiplying such number by a fraction, the numerator of which is the number
of shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

          (B)  Except as otherwise provided herein, in any other Certificate of
Designation creating a series of Preferred Stock or any similar stock, or by
law, the holders of shares of Junior Preferred Stock and the holders of shares
of Common Stock and any other capital stock of the Company having general voting
rights shall vote together as one class on all matters submitted to a vote of
stockholders of the Company.

          (C)  Except as set forth herein, or as otherwise provided by law,
holders of Junior Preferred Stock shall have no special voting rights and their
consent shall not be required (except to the extent they are entitled to vote
with holders of Common Stock as set forth herein) for taking any corporate
action.

     Section 4.  Certain Restrictions.

          (A)  Whenever quarterly dividends or other dividends or distributions
payable on the Junior Preferred Stock as provided in Section 2 are in arrears,
thereafter and until all accrued and unpaid dividends and distributions, whether
or not declared, on shares of Junior Preferred Stock outstanding shall have been
paid in full, the Company shall not:

               (i)    declare or pay dividends, or make any other distributions,
on any shares of stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Junior Preferred Stock;

               (ii)   declare or pay dividends, or make any other distributions,
on any shares of stock ranking on a parity (either as to dividends or upon
liquidation, dissolution or winding up) with the Junior Preferred Stock, except
dividends paid ratably on the Junior

                                       3
<PAGE>

Preferred Stock and all such parity stock on which dividends are payable or in
arrears in proportion to the total amounts to which the holders of all such
shares are then entitled;

               (iii)  redeem or purchase or otherwise acquire for consideration
shares of any stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Junior Preferred Stock, provided that the
Company may at any time redeem, purchase or otherwise acquire shares of any such
junior stock in exchange for shares of any stock of the Company ranking junior
(either as to dividends or upon dissolution, liquidation or winding up) to the
Junior Preferred Stock; or

               (iv)   redeem or purchase or otherwise acquire for consideration
any shares of Junior Preferred Stock, or any shares of stock ranking on a parity
(either as to dividends or upon liquidation, dissolution or winding up) with the
Junior Preferred Stock, except in accordance with a purchase offer made in
writing or by publication (as determined by the Board of Directors) to all
holders of such shares upon such terms as the Board of Directors, after
consideration of the respective annual dividend rates and other relative rights
and preferences of the respective series and classes, shall determine in good
faith will result in fair and equitable treatment among the respective series or
classes.

          (B)  The Company shall not permit any subsidiary of the Company to
purchase or otherwise acquire for consideration any shares of stock of the
Company unless the Company could, under paragraph (A) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

     Section 5.  Reacquired Shares.  Any shares of Junior Preferred Stock
purchased or otherwise acquired by the Company in any manner whatsoever shall be
retired and cancelled promptly after the acquisition thereof. All such shares
shall upon their cancellation become authorized but unissued shares of Preferred
Stock and may be reissued as part of a new series of Preferred Stock subject to
the conditions and restrictions on issuance set forth herein, in the Amended and
Restated Certificate of Incorporation, or in any other Certificate of
Designation creating a series of Preferred Stock or any similar stock or as
otherwise required by law.

     Section 6.  Liquidation, Dissolution or Winding Up.  Upon any liquidation,
dissolution or winding up of the Company, no distribution shall be made (1) to
the holders of shares of stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Junior Preferred Stock unless,
prior thereto, the holders of shares of Junior Preferred Stock shall have
received $100 per share, plus an amount equal to accrued and unpaid dividends
and distributions thereon, whether or not declared, to the date of such payment,
provided that the holders of shares of Junior Preferred Stock shall be entitled
to receive an aggregate amount per share, subject to the provision for
adjustment hereinafter set forth, equal to 100 times the aggregate amount to be
distributed per share to holders of shares of Common Stock, or (2) to the
holders of shares of stock ranking on a parity (either as to dividends or upon
liquidation, dissolution or winding up) with the Junior Preferred Stock, except
distributions made ratably on the Junior Preferred Stock and all such parity
stock in proportion to the total amounts to which the holders of all such shares
are entitled upon such liquidation, dissolution or winding up.  In the event the
Company shall at any time declare or pay any dividend on the Common Stock
payable in shares of Common Stock, or effect a subdivision or combination or
consolidation of

                                       4
<PAGE>

the outstanding shares of Common Stock (by reclassification or otherwise than by
payment of a dividend in shares of Common Stock) into a greater or lesser number
of shares of Common Stock, then in each such case the aggregate amount to which
holders of shares of Junior Preferred Stock were entitled immediately prior to
such event under the proviso in clause (1) of the preceding sentence shall be
adjusted by multiplying such amount by a fraction the numerator of which is the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

     Section 7.  Consolidation, Merger, etc.  In case the Company shall enter
into any consolidation, merger, combination or other transaction in which the
shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case each share of
Junior Preferred Stock shall at the same time be similarly exchanged or changed
into an amount per share, subject to the provision for adjustment hereinafter
set forth, equal to 100 times the aggregate amount of stock, securities, cash
and/or any other property (payable in kind), as the case may be, into which or
for which each share of Common Stock is changed or exchanged. In the event the
Company shall at any time declare or pay any dividend on the Common Stock
payable in shares of Common Stock, or effect a subdivision or combination or
consolidation of the outstanding shares of Common Stock (by reclassification or
otherwise than by payment of a dividend in shares of Common Stock) into a
greater or lesser number of shares of Common Stock, then in each such case the
amount set forth in the preceding sentence with respect to the exchange or
change of shares of Junior Preferred Stock shall be adjusted by multiplying such
amount by a fraction, the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event.

     Section 8.  No Redemption.  The shares of Junior Preferred Stock shall not
be redeemable.

     Section 9.  Rank.  The Junior Preferred Stock shall rank, with respect to
the payment of dividends and the distribution of assets, junior to all series of
any other class of the Company's Preferred Stock.

     Section 10.  Amendment.  The Amended and Restated Certificate of
Incorporation of the Company shall not be amended in any manner which would
materially alter or change the powers, preferences or special rights of the
Junior Preferred Stock so as to affect them adversely without the affirmative
vote of the holders of at least two-thirds of the outstanding shares of Junior
Preferred Stock, voting together as a single class.

                                       5
<PAGE>

     IN WITNESS WHEREOF, the undersigned have executed this certificate as of
February 25, 2000.


                              /s/ Kenneth J. Wees
                              -----------------------------------
                              Kenneth J. Wees
                              Secretary

                                       6
<PAGE>

                             AMENDED AND RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                         ADAPTIVE BROADBAND CORPORATION

     Adaptive Broadband Corporation, a corporation organized and existing under
the laws of the State of Delaware (the or this "Corporation") hereby certifies
that:

     1.  The name of the Corporation is Adaptive Broadband Corporation.  The
Corporation was originally incorporated under the name California Microwave,
Inc.

     2.  The date of filing of the Corporation's original Certificate of
Incorporation was September 21, 1987.

     3.  The Amended and Restated Certificate of Incorporation of the
Corporation as provided in Exhibit A hereto was duly adopted in accordance with
the provisions of Section 242 and Section 245 of the General Corporation Law of
the State of Delaware by the Board of Directors of the Corporation.

     4.  Pursuant to Section 245 of the Delaware General Corporation Laws,
approval of the stockholders of the Corporation has been obtained.

     5.  The Amended and Restated Certificate of Incorporation so adopted reads
in full as set forth in Exhibit A attached hereto and is hereby incorporated by
reference.

     In Witness Whereof, the undersigned has signed this certificate this 5th
day of November, 1999, and hereby affirms and acknowledges under penalty of
perjury that the filing of this Amended and Restated Certificate of
Incorporation is the act and deed of Adaptive Broadband Corporation.


                                     Adaptive Broadband Corporation


                                     By: /s/ Kenneth J. Wees
                                         -------------------
                                           Kenneth J. Wees
                                           Secretary
<PAGE>

                                   Exhibit A
                                   ---------

                              AMENDED AND RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                         ADAPTIVE BROADBAND CORPORATION


                                      I.

     The name of this Corporation is Adaptive Broadband Corporation.

                                      II.

     The address of the registered office of the Corporation in the State of
Delaware is 1209 Orange Street, City of Wilmington, 19805, County of New Castle
and the name of the registered agent of the corporation in the State of Delaware
at such address is The Corporation Trust Company.

                                     III.

     The name and mailing address of the incorporator of the Corporation is:

     George L. Spillane
     990 Almanor Avenue
     Sunnyvale, California 94086

                                      IV.

     The purpose of this Corporation is to engage in any lawful act or activity
for which a corporation may be organized under the General Corporation Law of
the State of Delaware.

                                      V.

     This Corporation is authorized to issue two classes of stock to be
designated, respectively, "Common Stock" and "Preferred Stock." The total number
of shares which the corporation is authorized to issue is Thirty-Five Million
(35,000,000) shares. Thirty Million (30,000,000) shares shall be Common Stock,
each having a par value of $.10. Five Million (5,000,000) shares shall be
Preferred Stock, each having a par value of $.10.

     The Common Stock shall be issued in series. The first series of Common
Stock shall consist of Twenty-Nine Million Two Hundred Thousand (29,200,000)
shares. All other shares of Common Stock shall be designated, as a group,
"Series A Junior Common Stock" and shall consist in the aggregate of Eight
Hundred Thousand (800,000) shares.

     The Preferred Stock may be issued from time to time in one or more series.
The Board of Directors is hereby authorized, by filing a certificate (a
"Preferred Stock Designation") pursuant to the Delaware General Corporation Law,
to fix or alter from time to time the designation,
<PAGE>

powers, preferences and rights of the shares of each such series and the
qualifications, limitations or restrictions of any wholly unissued series of
Preferred Stock, and to establish from time to time the number of shares
constituting any such series or any of them; and to increase or decrease the
number of shares of any series subsequent to the issuance of shares of that
series, but not below the number of shares of such series then outstanding. In
case the number of shares of any series shall be decreased in accordance with
the foregoing sentence, the shares constituting such decrease shall resume the
status that they had prior to the adoption of the resolution originally fixing
the number of shares of such series.

     A.  The Common Stock and Series A Junior Common Stock shall have the
rights, preferences, privileges and restrictions set forth below:

         1.  Voting Rights.  The holders of Common Stock and Series A Junior
             -------------
Common Stock shall vote together as a single class. The holders of Common Stock
shall have one (1) vote for each share of Common Stock and the holders of Series
A Junior Common Stock shall have one-twentieth (1/20) of one vote for each share
of Series A Junior Common Stock on all matters submitted to a vote of the
holders of the common shares. The determination of a quorum shall be based upon
the presence of shares representing a majority of the voting power of the entire
class of common shares.

         2.  Liquidation.  In the event of any liquidation, dissolution, or
             -----------
winding up of the Corporation, the holders of the Series A Junior Common Stock
shall receive one-twentieth (1/20) of the amount per share to be received per
share by the holders of Common Stock. Notwithstanding anything in this
subsection (2) to the contrary, the Corporation may repurchase shares of Series
A Junior Common Stock without further notifying or obtaining the consent of the
holders of Common Stock.

         3.  Dividends.   In the event that any dividend is declared on Common
             ---------
Stock, the holders of Series A Junior Common Stock shall concurrently receive,
out of any funds legally available therefor, a dividend in an amount per share
of Series A Junior Common Stock equal to one-twentieth (1/20) of the amount paid
with respect to a share of Common Stock.

     B.  1.  Definitions.  For purposes of this section (B), the following terms
shall have the meanings set forth below:

             a. "Applicable accounting principles" shall mean generally
accepted accounting principles as consistently applied by the Corporation in the
preparation of its consolidated financial statements from time to time and shall
reflect changes in generally accepted accounting principles or in the procedures
or methodologies applied by the Corporation, except as otherwise provided in
this section (B) and except that in determining Earnings Per Share, the shares
of Common Stock into which the Series A Junior Common Stock are then convertible
shall be deemed issued and outstanding during the applicable period.

             b. "Earnings Per Share" shall mean the consolidated net income
(including any extraordinary gains or losses) per share of Common Stock of the
Corporation, on a fully diluted basis, computed in accordance with applicable
accounting principles.
<PAGE>

             c. "Cumulative Earnings Per Share" shall mean for any period of
quarters the sum of the earnings per share amounts for all quarters included in
such period.

             d. "Sales" shall mean for any period the consolidated net sales of
the Corporation for such period computed in accordance with applicable
accounting principles.

         2.  Conversion Events.  Series A Junior Common Stock shall
             -----------------
automatically convert into Common Stock upon the earliest to occur of the
following conversion events ("Conversion Events"):

             a.  The attaining for any consecutive four (4) fiscal quarters of
Sales in the aggregate amount of Two Hundred Two Million Dollars ($202,000,000)
and Earnings Per Share on a fully diluted basis in the aggregate amount of One
and 30/100 Dollars ($1.30), provided that the Cumulative Earnings Per Share for
such four fiscal quarter periods and the immediately preceding eight (8) fiscal
quarters is not less than Two and 90/100 Dollars ($2.90).

             b.  The (i) merger of the Corporation with or into another
corporation or the sale of all or substantially all of the assets of the
Corporation to another person or entity, in which, in either case, stockholders
of the Corporation are to receive cash or other securities or property in
exchange for their shares of the Corporation; or (ii) the acquisition by any
person (directly or indirectly) in any transaction or series of transactions of
more than fifty percent (50%) of the voting power of the voting securities of
the Corporation then outstanding ("person" shall mean any person, firm,
association or company or affiliates or subsidiaries thereof or other person or
entity which controls, is controlled by or is under common control with the
designated party; "control" shall mean ownership of voting securities entitled
to elect a majority of the authorized number of directors or majority in
interest in profits, as the case may be; "voting securities" shall mean common
shares and any other securities of the Corporation entitled to vote generally
for the election of directors).

         3.  Conversion Ratio. Each share of Series A Junior Common Stock shall
             ----------------
convert into Common Stock in accordance with the applicable ratio ("Conversion
Ratio") set forth in this section:

             a.  If the Conversion Event is the event described in subsection
(2)(a), the Conversion Ratio shall be on a share-for-share basis if the
Conversion Event occurs by June 30, 1987 and shall be reduced by ten (10)
percentage points for each quarter that expires after June 30, 1987, e.g., if
the Conversion Event does not occur until December 31, 1987, then the Conversion
Ratio shall be .8 shares of Common Stock for each share of Series A Junior
Common Stock converted.

             b.  If the Conversion Event is as described under subsection (2)(b)
above, each share of Series A Junior Common Stock shall convert into one (1)
share of Common Stock.
<PAGE>

         4.  Conversion Date. The date of conversion ("Conversion Date") shall
be determined as follows:

             (x)  With respect to the Conversion Event provided for in
subsection (2)(a), the Conversion Date shall be the date on which the chief
financial officer of the Corporation presents to the Board of Directors a
certificate, detailing computations with respect to the Conversion Event and
specifying the Conversion Ratio, accompanied by a letter from the Corporation's
independent auditors, stating that based upon their review of the computations
and upon a reading of this Article V, nothing came to their attention that
caused them to believe that the computations were not made in accordance with
the provisions of subsections (1) through (3) hereof.

             (y)  With respect to the Conversion Event provided for in
subsection (2)(b)(i), the Conversion Date shall be the date on which such merger
or sale of assets is consummated and the conversion shall be deemed to have
occurred immediately prior thereto.

             (z)  With respect to the Conversion Event provided for in
subsection (2)(b)(ii), the Conversion Date shall be the date immediately
following the date on which the acquisition of more than fifty percent (50%) of
the voting power of the voting securities occurs.

         5.  Adjustments.  In the case of a significant change in generally
accepted accounting principles that would in the opinion of the Board of
Directors render the use of "Applicable Accounting Principles" burdensome,
impractical or not meaningful, or in the case of a change in the Corporation's
fiscal year or other unusual significant non-recurring event, the Board of
Directors may in its discretion, acting upon the advice of such professional
advisors as the Board deems appropriate, make equitable adjustments to one or
more of the definitions in subsection (1), the Conversion Events in subsection
(2) or the Conversion Ratios set forth in subsection (3).

         6.  Share Certificates; Fractional Shares. A holder of Series A Junior
             -------------------------------------
Common Stock shall not be entitled to the rights of a holder of Common Stock
until the Conversion Date and until he or she surrenders the certificate or
certificates therefor, duly endorsed, at the office of the Corporation or of any
transfer agent for Common Stock, in exchange for new certificates representing
shares of Common Stock. No fractional shares of Common Stock shall be issued
upon conversion of Series A Junior Stock. In lieu of any fractional shares to
which the holder would otherwise be entitled, the Corporation shall pay cash
equal to such fraction multiplied by the fair market value per share of Common
Stock on the Conversion Date as determined in good faith by the Board of
Directors.

     C.  In the event of any stock split, reverse stock split or other
subdivision or combination of the Common Stock, any stock dividend or other
distribution on the Common Stock payable in Common Stock, or any
recapitalization, a pro rata adjustment, if appropriate, shall be made in the
voting, liquidation and dividend rights set forth in section (A), and in the
Conversion Events and Conversion Ratios set forth in section (B), all as
determined by the Board of Directors in the exercise of its discretion, acting
upon the advice of such professional advisors as the Board deems appropriate.

                                      VI.
<PAGE>

     In furtherance and not in limitation of the powers conferred by statute,
the Board of Directors is expressly authorized to adopt, amend or repeal from
time to time any or all of the Bylaws of this Corporation.
<PAGE>

                                     VII.

     The number of directors which shall constitute the whole Board of Directors
of this Corporation shall be as specified in the Bylaws of this Corporation,
subject to the provisions of Article VI and this Article VII.

                                     VIII.

     Any action required or permitted to be taken by the stockholders of the
Corporation must be effected at a duly called annual or special meeting of
stockholders of the Corporation and may not be effected by any consent in
writing by the stockholders. Special meetings of the stockholders of this
Corporation for any purpose or purposes may be called at any time by the Board
of Directors, the President, the Chairman of the Board of Directors, by a
committee of the Board of Directors which has been duly designated by the Board
of Directors and whose powers and authority, as provided in resolution of the
Board of Directors or in the Bylaws of this Corporation, include the power to
call such meetings, and by stockholders of the Corporation owning, directly or
indirectly, shares possessing not less than ten percent (10%) of the votes
eligible to be cast for the election of directors at the time in question, but
such special meetings may not be called by any other person or persons.

                                      IX.

     A.  In addition to any affirmative vote required by law or this Certificate
of Incorporation or a certificate filed under Section 151(g) of the General
Corporation Law of the State of Delaware or the Bylaws and except as otherwise
expressly permitted in paragraph (B) of this Article IX, a Business Combination
(as hereafter defined) with, for, or on behalf of, any Interested Stockholder
(as hereafter defined) or any Affiliate or Associate (as hereafter defined) of
such Interested Stockholder shall require the affirmative vote of at least
sixty-six and two-thirds percent (66-2/3%) of the votes entitled to be cast by
the holders of all the then outstanding Voting Stock (as hereafter defined),
voting together as a single class. Such affirmative vote shall be required
notwithstanding the fact that no vote may be required, or that a lesser
percentage of a separate class vote may otherwise be specified, by law or by any
agreement between the Corporation and any national securities exchange or
otherwise.

     B.  The provisions of paragraph (A) of this Article IX shall not be
applicable to any particular Business Combination, and such Business Combination
shall require only such vote, if any, as is required by law or by any other
provisions of this Certificate of Incorporation or a certificate filed under
Section 151(g) of the General Corporation Law of the State of Delaware or the
Bylaws, or by any agreement between the Corporation and any national securities
exchange, if (i) such Business Combination shall have been specifically approved
by a majority of the Disinterested Directors (as hereafter defined) at the time
or (ii) all the conditions specified in each of the following Subparagraphs (1),
(2), (3), (4), (5) and (6) are satisfied:

         1.  The aggregate amount of cash and the Fair Market Value (as
hereafter defined) as of the Consummation Date (as hereafter defined) of any
consideration other than cash to be received per share by holders of Voting
Stock in such Business Combination, shall be at least equal to the highest
amount determined under clauses (i) and (ii) below:
<PAGE>

             (i)  (if applicable) the highest per share price (including any
brokerage commissions, transfer taxes and soliciting dealers' fees) paid by or
on behalf of such Interested Stockholder for any share of Voting Stock in
connection with the acquisition by the Interested Stockholder of Beneficial
Ownership (as hereafter defined) of shares of Voting Stock (A) within the five-
year period immediately prior to the Announcement Date (as hereafter defined) or
(B) in the transaction or series of transactions in which it became an
Interested Stockholder, whichever is higher, in either case adjusted for any
subsequent stock split, stock dividend, subdivision or reclassification with
respect to Voting Stock; or

             (ii) the Fair Market Value per share of Voting Stock on the
Announcement Date or the Determination Date (as hereafter defined), whichever is
higher, as adjusted for any subsequent stock split, stock dividend, subdivision
or reclassification with respect to Voting Stock.

         2.  The consideration to be received by holders of a particular class
or series of outstanding Voting Stock shall be in cash or in the same form as
previously has been paid by or on behalf of the Interested Stockholder in
connection with its direct or indirect acquisition of Beneficial Ownership of
shares of such class or series of Voting Stock. If the consideration so paid for
shares of any class or series of Voting Stock varied as to form, the form of
consideration for such class or series of Voting Stock shall either be cash or
the form used to acquire Beneficial Ownership of the largest number of shares of
such class or series of Voting Stock acquired by the Interested Stockholder
during the five (5) year period prior to the Announcement Date. If non-cash
consideration is to be paid, the Fair Market Value of such non-cash
consideration shall be determined on and as of the Consummation Date.

         3.  After the Determination Date and prior to the Consummation Date
there shall have been (A) no failure to declare and pay at the regular date
therefor any full quarterly dividends (whether or not cumulative) payable in
accordance with the terms of any outstanding Voting Stock; (B) no reduction in
the annual rate of dividends paid on the Voting Stock (except as necessary to
reflect any split or subdivision of the Voting Stock), except as approved by a
majority of the Disinterested Directors; (C) an increase in such annual rate of
dividends (as necessary to prevent any such reduction) in the event of any
reclassification (including any reverse stock split or combination of shares),
recapitalization, reorganization or any similar transaction that has the effect
of reducing the number of outstanding shares of the Voting Stock, unless the
failure so to increase such annual rate is approved by a majority of the
Disinterested Directors; and (D) no transaction by which such Interested
Stockholder has become the Beneficial Owner of any additional shares of Voting
Stock except as part of the transaction that results in the Interested
Stockholder becoming an Interested Stockholder and except in a transaction that,
after giving effect thereto, would not result in any increase in the Interested
Stockholder's percentage Beneficial Ownership of any class or series of Voting
Stock.

         4.  After the Determination Date, such Interested Stockholder shall not
have received the benefit, directly or indirectly (except as a stockholder of
the Corporation, in proportion to its stockholding), of any loans, advances,
guarantees or similar financial assistance or any tax credits or tax advantages
provided by the Corporation (collectively, "Financial Assistance"), whether in
anticipation of or in connection with such Business Combination or otherwise.
<PAGE>

         5.  A proxy or information statement describing the proposed Business
Combination and complying with the requirements of the Securities Exchange Act
of 1934, as amended, and the rules and regulations thereunder (or any subsequent
provisions replacing such Act, rules or regulations) shall be mailed to
stockholders of the Corporation at least thirty (30) days prior to the
consummation of such Business Combination (whether or not such proxy or
information statement is required to be mailed pursuant to such Act, rules or
regulations, or subsequent provisions). The proxy or information statement shall
contain on the first page thereof, in a prominent location, any statement as to
the advisability or inadvisability of the Business Combination that the
Disinterested Directors, or any of them, may desire to make and, if deemed
advisable by a majority of the Disinterested Directors, the proxy or information
statement shall contain the opinion of an independent investment banking firm
selected by a majority of the Disinterested Directors as to the fairness or lack
of fairness of the terms of the Business Combination from a financial point of
view to the holders of the outstanding shares of Voting Stock other than the
Interested Stockholder and its Affiliates or Associates, such investment banking
firm to be paid a reasonable fee for its services by this Corporation.

         6.  Such Interested Stockholder shall not have made any major change in
this Corporation's business or equity capital structure without the approval of
a majority of the Disinterested Directors.

     C.  The following definitions shall apply with respect to this Article IX:

         1.  The terms "Affiliate" and "Associate" shall have the respective
meanings ascribed to those terms in Rule 12b-2 under the Securities Exchange Act
of 1934, as amended, and as in effect on the date that this Certificate of
Incorporation is filed with the Secretary of State of the State of Delaware (the
term "registrant" in said Rule 12b-2 meaning in this case the Corporation).

         2.  The term "Announcement Date" with respect to any Business
Combination means the date of the first public announcement of the proposal of
such Business Combination.

         3.  A person shall be a "Beneficial Owner" of, or have "Beneficial
Ownership" of, or "Beneficially Own," any Voting Stock over which such person or
any of its Affiliates or Associates, directly or indirectly, through any
contract, arrangement, understanding or relationship, has or shares or, upon the
exercise of any conversion right, exchange right, warrant, option or similar
interest (whether or not then exercisable) would have or share, either (i)
voting power (including the power to vote or to direct the voting) of such
security or (ii) investment power (including the power to dispose or direct the
disposition) of such security. For the purposes of determining whether a person
is an Interested Stockholder, the number of shares of Voting Stock deemed to be
outstanding shall include any shares Beneficially Owned by such person even
though not actually outstanding, but shall not include any other shares of
Voting Stock which are not outstanding but which may be issuable to other
persons pursuant to any agreement, arrangement or understanding, or upon
exercise of any conversion right, exchange right, warrant, option or similar
interest.
<PAGE>

         4.  The term "Business Combination" shall mean:

             (i)   any merger or consolidation of this Corporation or any
Subsidiary (as hereafter defined) with (A) any Interested Stockholder (as
hereafter defined) or (B) any other corporation (whether or not itself an
Interested Stockholder) which after such merger or consolidation would be an
Affiliate or Associate of an Interested Stockholder; or

             (ii)  any sale, lease, exchange, mortgage, pledge, transfer or
other disposition or security agreement, investment, loan, advance, guarantee,
agreement to purchase, agreement to pay, extension of credit, joint venture
participation or other arrangement (in one transaction or a series of related
transactions) with or for the benefit of any Interested Stockholder or any
Affiliate or Associate of any Interested Stockholder, involving any assets,
securities, or commitments of this Corporation, any Subsidiary or any Interested
Stockholder or any Affiliate or Associate of any Interested Stockholder which,
together with all other such arrangements (including all contemplated future
events) have an aggregate Fair Market Value (as hereafter defined) and/or
involve aggregate commitments of Five Million Dollars ($5,000,000) or more; or

             (iii) the issuance or transfer by the Corporation or any Subsidiary
(in one transaction or a series of related transactions) to an Interested
Stockholder or Associate or Affiliate of an Interested Stockholder of any
securities of the Corporation or any Subsidiary in exchange for cash, securities
or other property (or a combination thereof) having an aggregate Fair Market
Value as of the Announcement Date of Five Million Dollars ($5,000,000) or more,
other than the issuance of securities upon the conversion or exchange of
securities of the Corporation or in exchange for securities of any Subsidiary
which were acquired by an Interested Stockholder from the Corporation or a
Subsidiary in a Business Combination which was approved by a vote of the
stockholders pursuant to this Article IX: or

             (iv)  the adoption of any plan or proposal for the liquidation or
dissolution of the Corporation proposed by or on behalf of any Interested
Stockholder; or

             (v)   any reclassification of any securities of the Corporation
(including any reverse stock split), any recapitalization of the Voting Stock of
the Corporation, any merger or consolidation of the Corporation with or into any
of its Subsidiaries, or any other transaction (whether or not with or otherwise
involving any Interested Stockholder) that has the effect, directly or
indirectly, of increasing the proportionate share of the outstanding shares of
any class of Voting Stock or series thereof of the Corporation or of any
Subsidiary Beneficially Owned by any Interested Stockholder or Associate or
Affiliate of an Interested Stockholder or as a result of which the stockholders
of the Corporation would cease to be stockholders of a corporation having, as
part of its certificate or articles of incorporation, provisions to the same
effect as this Article IX and the provisions of Article XIII of this Certificate
of Incorporation relating to the provisions of this Article IX; or

             (vi)  any agreement, contract or other arrangement providing for
one (1) or more of the actions specified in the foregoing paragraphs (i) through
(v), or any series of transactions which, if taken together, would constitute
one (1) or more of the actions specified in the foregoing paragraphs (i) through
(v).
<PAGE>

         5.  The term "Consummation Date" means the date of the consummation of
a Business Combination.

         6.  The term "Determination Date" in respect to an Interested
Stockholder means the date on which such Interested Stockholder first became an
Interested Stockholder.

         7.  The term "Disinterested Director" with respect to a Business
Combination means any member of the Board of Directors of the Corporation who is
not an Interested Stockholder or an Affiliate or Associate of, and was not
directly or indirectly a nominee of, any Interested Stockholder involved in such
Business combination or any Affiliate or Associate of such Interested
Stockholder and who either (i) was a member of the Board of Directors prior to
the time that such Interested Stockholder became an Interested Stockholder, or
(ii) is a successor of a Disinterested Director and was nominated to succeed a
Disinterested Director by a majority of the Disinterested Directors at the time
of his nomination. Any reference to "Disinterested Directors" shall refer to a
single Disinterested Director if there be but one. Any matter referred to as
requiring or having the approval of, or having been approved by, a majority of
the Disinterested Directors shall mean the matter requires the approval of, or
has been approved by, the Board without giving effect to the vote of any
Director who is not a Disinterested Director and with the affirmative vote of a
majority of the Disinterested Directors.

         8.  The term "Fair Market Value" as of any particular date means: (i)
in the case of cash, the amount of such cash; (ii) in the case of stock
(including Voting Stock), the highest closing price per share of such stock
during the thirty (30) day period immediately preceding the date in question on
the largest United States securities exchange registered under the Securities
Exchange Act of 1934, as amended, on which such stock is listed or, if such
stock is not listed on any such exchange, the highest last sales price as
reported by the National Association of Securities Dealers, Inc. Automated
Quotation System ("NASDAQ") during the thirty (30) day period immediately
preceding the date in question if the stock is a National Market System
security, or, if such stock is not a National Market System security, the
highest reported closing bid quotation for a share of such stock during the
thirty (30) day period preceding the date in question on NASDAQ or any successor
quotation reporting system or, if quotations are not available in such system,
as furnished by the National Quotation Bureau Incorporated or any similar
organization furnishing quotations, or if no such quotations are available, the
fair market value on the date in question of a share of such stock as determined
by a majority of the Disinterested Directors in good faith; and (iii) in the
case of stock of any class or series which is not traded on any securities
exchange or in the over-the-counter market, or in the case of property other
than cash or stock, or in the case of Financial Assistance, the fair market
value of such stock, property or Financial Assistance, as the case may be, on
the date in question as determined by a majority of the Disinterested Directors
in good faith.

         9.  The term "Interested Stockholder" shall mean any person, other than
this Corporation, any Subsidiary or any employee benefit plan of this
Corporation or any Subsidiary, who or which:

             (i)  is or has announced or publicly disclosed a plan or intention
to become the Beneficial Owner, directly or indirectly, of shares of Voting
Stock
<PAGE>

representing fifteen percent (15%) or more of the total votes which all of the
then outstanding shares of Voting Stock are entitled to cast in the election of
directors; or

              (ii)  is an Affiliate or Associate of any person described in
clause (i) of this subparagraph 9 at any time during the five (5) year period
immediately preceding the date in question; or

              (iii) acts with any other person as a partnership, limited
partnership, syndicate, or other group for the purpose of acquiring, holding or
disposing of securities of the Corporation, and such group is the Beneficial
Owner, directly or indirectly, of shares of Voting Stock representing fifteen
percent (15%) or more of the total votes which all of the then outstanding
shares of Voting Stock are entitled to cast in the election of directors.

          Any reference to a particular Interested Stockholder involved in a
Business Combination shall also refer to any Affiliate or Associate thereof, any
predecessor thereto and any other person acting as a member of a partnership,
limited partnership, syndicate or group with such particular Interested
Stockholder within the meaning of the foregoing clause (iii) of this
subparagraph (9).

          10. A "person" shall mean any individual, firm, company, corporation
(which shall include a business trust), partnership, joint venture, trust or
estate, association or other entity.

          11. The term "Subsidiary" in respect of the Corporation means any
corporation or partnership of which a majority of any class of its equity
securities is owned, directly or indirectly, by the Corporation.

          12. The term "Voting Stock" shall mean all shares of capital stock
that entitle the holder to vote for the election of directors, including,
without limitation, the Corporation's Common Stock and Series A Junior Common
Stock.

      D.  A majority of the Disinterested Directors shall have the power and
duty to determine, on the basis of information known to them after reasonable
inquiry, all facts necessary to determine compliance with this Article IX,
including, without limitation (1) whether a person is an Interested Stockholder,
(2) the number of shares of Voting Stock Beneficially Owned by any person, (3)
whether a person is an Affiliate or Associate of another person, (4) whether the
requirements of paragraph (B) of this Article IX, have been met with respect to
any Business Combination, (5) whether the proposed transaction is with, or
proposed by, or on behalf of an Interested Stockholder or an Affiliate or
Associate of an Interested Stockholder, and (6) whether the assets which are the
subject of any Business Combination have, or the consideration to be received
for the issuance or transfer of securities by the Corporation or any Subsidiary
in any Business Combination has, an aggregate Fair Market Value of Five Million
Dollars ($5,000,000) or more. The good faith determination of a majority of the
Disinterested Directors on such matters shall be conclusive and binding for all
purposes of this Article IX.

      E.  Nothing contained in this Article IX shall be construed to relieve any
Interested Stockholder from any fiduciary obligation imposed by law.
<PAGE>

      F.  The fact that any Business Combination complies with paragraph (B) of
this Article IX shall not be construed to impose any fiduciary duty, obligation
or responsibility on the Board of Directors, or any member thereof, to approve
such Business Combination or recommend its adoption or approval to the
Stockholders of this Corporation, nor shall such compliance limit, prohibit or
otherwise restrict in any manner the Board, or any member thereof, with respect
to evaluations of or actions and responses taken with respect to such Business
Combination.

      G.  For purposes of this Article IX a Business Combination or any proposal
to amend, repeal or adopt any provision of the Certificate of Incorporation
inconsistent with this Article IX (collectively, "Proposed Action") is presumed
to have been proposed by, or on behalf of, an Interested Stockholder or an
Affiliate or Associate of an Interested Stockholder or a person who thereafter
would become such if (1) after the Interested Stockholder became such, the
Proposed Action is proposed following the election of any director of this
Corporation who, with respect to such Interested Stockholder, would not qualify
to serve as a Disinterested Director or (2) such Interested Stockholder,
Affiliate, Associate or person votes for or consents to the adoption of any such
Proposed Action, unless as to such Interested Stockholder, Affiliate, Associate
or person, a majority of the Disinterested Directors makes a good faith
determination that such Proposed Action is not proposed by or on behalf of such
Interested Stockholder, Affiliate, Associate or person, based on information
known to them after reasonable inquiry.

                                      X.

      A.  If a Qualifying Offer (as defined below) is made to purchase all of
the outstanding Common Stock then, after the end of the ninetieth (90th) day
after such Qualifying Offer is first published or sent to securityholders, if
holders of ten percent (10%) or more of the then-outstanding shares of Common
Stock (other than shares held by any person or group making such Qualifying
Offer or such person's or group's affiliates or associates (each as defined in
Rule 12b-2 of General Rules and Regulations under the Securities Exchange Act of
1934, as amended)) request by notice to the Corporation in accordance with its
By-laws (the "Notice") that the Corporation call a special meeting of its
stockholders (the "Special Meeting") in order to consider and vote whether to
require the Corporation to Redeem the Rights Plan (as defined below), a Special
Meeting shall be held on a date selected by the Board of Directors, which date
shall be not more than sixty (60) days following the receipt of the Notice.

      B.  If at the Special Meeting, holders of sixty-six and two-thirds percent
(66-2/3%) of the then-outstanding Common Stock (other than shares held by any
person or group making such Qualifying Offer or such person's or group's
affiliates or associates (each as defined in Rule 12b-2 of General Rules and
Regulations under the Securities Exchange Act of 1934, as amended)) shall vote
to Redeem the Rights Plan, then the Corporation shall Redeem the Rights Plan as
promptly as practicable. In the event that the Special Meeting is not held on or
prior to the sixtieth (60th) day following receipt of the Notice, the
Corporation shall Redeem the Rights Plan. The record date for the Special
Meeting shall be selected by the Board of Directors. Notwithstanding the
foregoing, the Corporation shall not be required to hold the Special Meeting
unless at such time such Qualifying Offer has an expiration date which is at
least ten (10) Business Days thereafter.
<PAGE>

      C.  The Corporation shall not adopt or amend the Rights Agreement or
similar rights agreement unless the Rights Agreement or such other rights
agreement shall specifically state that its terms and conditions are subject to
this Article X.

The following definitions shall apply with respect to this Article X:

          1.  "Redeem the Rights Plan" shall mean redeem the outstanding Rights
or take other action so that the existence of the Rights does not interfere with
the consummation of a Qualifying Offer.

          2.  A "Qualifying Offer" shall mean:

              (a)  an all-cash tender offer for all outstanding Common Stock
made by a person or group who beneficially owns one percent (1%) or less of the
outstanding Common Stock as of the date the offer is delivered, provided that
the person or group making the tender offer must, prior to or upon commencing
such offer, have provided the Corporation firm written commitments from
responsible financial institutions, which have been accepted by such person or
group, to provide, subject only to customary terms and conditions (which shall
in no event include conditions requiring access by such financial institutions
to non-public information to be provided by the Corporation, conditions based on
the accuracy of any information concerning the Corporation other than such as
would be the subject of representations and warranties in a public financing by
the Corporation or conditions requiring the Corporation to make any
representations, warranties or covenants in connection with such financing),
funds for such offer which, when added to the amount of cash and cash
equivalents which such person or group then has available and has irrevocably
committed in writing to the Corporation to utilize for purposes of the offer if
consummated, and to set apart and maintain available for such purposes until the
offer is consummated or withdrawn, will be sufficient to pay for all shares
outstanding on a fully diluted basis and all related expenses; or

              (b)  an exchange offer for all outstanding Common Stock made by a
person or group who beneficially owns one percent (1%) or less of the
outstanding Common Stock outstanding as of the date the offer is delivered,
provided that the consideration offered in such exchange offer is (x) freely
tradeable common stock (of the class carrying the principal voting rights of the
issuer) of the person or group making such offer that is approved for listing or
quotation upon notice of issuance on the New York Stock Exchange or the Nasdaq
National Market and the issuer of such common stock is eligible to register its
securities for primary sales on Form S-3 under the Securities Act of 1933, as
amended (or any successor form) or (y) a combination of common stock meeting the
requirements of clause (x) of this sentence and cash meeting the requirements of
the proviso of clause (a) of this sentence.

In addition, such offer must meet all of the following additional conditions:

                   (i)    such person or group must own, after consummating such
offer, at least two-thirds of the then outstanding Common Stock;

                   (ii)   such offer must remain open for at least sixty (60)
Business Days and at least ten (10) Business Days after the Special Meeting, and
must be extended for at
<PAGE>

least twenty (20) Business Days after the last increase in the price offered and
after any bona fide higher alternative offer is made, and shall be subject only
to customary terms and conditions, which shall in no event include satisfaction
of any conditions relating to the business, financial condition, results of
operations or prospects of the Corporation other than such as are based on
information publicly disclosed by the Corporation or any conditions relating to
approval of the offeror's stockholders; and

                   (iii)  prior to or upon commencing such offer, such person or
group must irrevocably commit in writing to the Corporation and in the offer to
purchase relating to the offer:

                          a.  to consummate promptly upon completion of the
offer a transaction whereby all shares of Common Stock not tendered into the
offer will be acquired at the same price per share and for the same
consideration paid pursuant to the offer, and otherwise not to purchase any
Common Shares following completion of the offer,

                          b.  that such person or group will not materially
amend such offer, except to increase the price offered, and

                          c.  that such person or group will not make any offer
for any equity securities of the Corporation for six months after commencement
of the original offer if the original offer does not result in the tender of the
number of shares required to be purchased pursuant to subsection (i) above,
unless another offer with a per share offer price at least ten percent (10%)
higher than the last price offered by the person or group making the original
offer and which also meets the conditions for a Qualifying Offer is commenced by
another person or persons not affiliated or associated with, acting in concert
with, or instigated or financed by, the person or group making the original
offer or with whom the person or group making the original offer has any
agreement, arrangement or understanding relating to the Corporation or any
assets or securities of it or any of its subsidiaries.

         3.  "Rights" shall mean the Rights issued pursuant to the Rights
Agreement.

         4.  "Rights Agreement" shall mean the Rights Agreement, dated as of
July 21, 1999, between the Corporation and BankBoston, N.A., as Rights Agent, as
amended from time to time.

         5.  "Business Day" shall mean any day other than a Saturday, a Sunday,
or a day on which banking institutions in the State of Massachusetts are
authorized or obligated by law or executive order to be closed.

     This Article X shall apply to Qualifying Offers that are outstanding on the
date this Article X becomes effective, but the ninety (90)-day period provided
for in this Article X shall not begin to run until October 29, 1999.  This
Article X shall expire at, and be of no further force or effect after, 5:00 p.m.
Pacific Time on June 30, 2002.
<PAGE>

                                      XI.

     At all elections of directors of the Corporation, a holder of any class or
series of stock then entitled to vote in such election shall be entitled to as
many votes as shall equal the number of votes which (except for this Article as
to cumulative voting) he would be entitled to cast for the election of directors
with respect to his shares of stock multiplied by the number of directors to be
elected in the election in which his class or series of stock is entitled to
vote, and each stockholder may cast all of such votes for a single nominee for
director or may distribute them among the number to be voted for, or for any two
(2) or more of them as he may see fit. Elections of directors at an annual or
special meeting of stockholders need not be by written ballot unless the Bylaws
of the Corporation shall so provide.

                                     XII.

     A director of the Corporation shall not be personally liable to the
Corporation or its stockholders for monetary damages for any breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the Corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the Delaware General Corporation
Law or (iv) for any transaction from which the director derived an improper
personal benefit.  Neither the amendment nor repeal of this certificate of
incorporation or bylaws or of any statute inconsistent with this Article XII,
shall eliminate or reduce the effect of this Article XII in respect of any acts
or omissions occurring prior to such amendment, repeal or adoption of an
inconsistent provision.

                                     XIII.

     A.  This Corporation reserves the right at any time and from time to time
to amend, alter, change or repeal any provision contained herein, and other
provisions authorized by the laws of the State of Delaware at the time in force
may be added or inserted, in the manner now or hereafter prescribed by law, and
all rights, preferences, and privileges of whatsoever nature conferred upon
stockholders, directors, or any other person whosoever by or pursuant to the
Certificate of Incorporation in its present form or as hereafter are granted,
subject to the rights reserved in this Article XIII.

     B.  In addition to any requirements of law and any other provisions hereof
(and notwithstanding the fact that approval by a lesser vote may be permitted by
law or any other provision hereof), the affirmative vote of the holders of
sixty-six and two-thirds percent (66-2/3%) or more of the combined voting power
of the then-outstanding shares of the Voting Stock, voting together as a single
class, shall be required to amend alter or repeal, or adopt any provision
inconsistent with this Article XIII or Articles VIII and IX hereof.
<PAGE>

                          CERTIFICATE OF AMENDMENT OF
             AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF
                        ADAPTIVE BROADBAND CORPORATION

     Adaptive Broadband Corporation, a corporation organized and existing under
and by virtue of the Delaware General Corporation Law (the "Company"), does
hereby certify:

     First:   The name of the Company is Adaptive Broadband Corporation.

     Second:  The original certificate of incorporation of this Company was
filed with the Secretary of State of the State of Delaware on September 21, 1987
under the name of California Microwave, Inc.

     Third:   The Board of Directors of the Company, acting in accordance
with the provisions of Sections 141 and 242 of the Delaware General Corporation
Law, adopted resolutions amending the Company's Amended and Restated Certificate
of Incorporation as follows:

          The first and second paragraphs of Article V shall be amended and
     restated to read in their entirety as follows:

          "This Corporation is authorized to issue two classes of stock to be
     designated, respectively, "Common Stock" and "Preferred Stock."  The total
     number of shares which the corporation is authorized to issue is Two
     Hundred Fifty-Five Million (255,000,000) shares.  Two Hundred Fifty Million
     (250,000,000) shares shall be Common Stock, each having a par value of
     $.10.  Five Million (5,000,000) shares shall be Preferred Stock, each
     having a par value of $.10.

          The Common Stock shall be issued in series.  The first series of
     Common Stock shall consist of Two Hundred Forty-Nine Million Two Hundred
     Thousand (249,200,000) shares.  All other shares of Common Stock shall be
     designated, as a group, "Series A Junior Common Stock" and shall consist in
     the aggregate of Eight Hundred Thousand  (800,000) shares."

     Fourth:  Thereafter, pursuant to a resolution of the Board of Directors,
this Certificate of Amendment was submitted to the stockholders of the Company
for their approval, and was duly adopted in accordance with the provisions of
Section 242 of the Delaware Corporation Law.

     IN WITNESS WHEREOF, the undersigned has signed this Certificate of
Amendment this 14th day of March 2000, and hereby affirms and acknowledges under
penalty of perjury that the filing of this Certificate of Amendment is the act
and deed of Adaptive Broadband Corporation.

                                              Adaptive Broadband Corporation

                                              By:   /s/ Kenneth J. Wees
                                                 ------------------------------
                                                 Kenneth J. Wees
                                                 Vice President, General Counsel
                                                   and Secretary