<PAGE>   1
                                                                    Exhibit 4.2

THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED, OR
OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT
OR PURSUANT TO RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
CORPORATION AND ITS COUNSEL, THAT SUCH REGISTRATION IS NOT REQUIRED.

                            WARRANT TO PURCHASE STOCK

Corporation:  WAVO Corporation
Number of Shares:  (subject to provisions set forth below)
Class of Stock:  Common
Initial Exercise Price: $5.42
Issue Date: September 24, 1999
Expiration Date: September 24, 2002

                  THIS WARRANT CERTIFIES THAT, for the agreed upon value of
$1.00 and for other good and valuable consideration, SILICON VALLEY BANK
("Holder") is entitled to purchase the number of fully paid and nonassessable
shares of the class of securities (the "Shares") of the corporation (the
"Company") at the initial exercise price per Share (the "Warrant Price") all as
set forth above and as adjusted pursuant to Article 2 of this Warrant, subject
to the provisions and upon the terms and conditions set forth in this Warrant.
Holder shall be entitled to 7,500 Shares upon execution of this Warrant. In the
event the Equity Event as described in that certain Loan and Security Agreement
between Holder and Company dated October 14, 1997, as amended from time to time
(the "Loan Agreement") has not occurred by October 24, 1999, Holder shall be
entitled to an additional 5,000 Shares. Additionally for each two weeks
thereafter in which the Equity Event has not occurred Holder shall be entitled
to an additional 5,000 Shares (the "Additional Shares"). Notwithstanding the
foregoing, such grant of the Additional Shares shall not be construed in any way
as Bank's agreement to (i) waive an Event of Default under the Loan Agreement;
(ii) forbear from exercising its rights and remedies if an Event of Default
occurs, exists or continues under the Loan Agreement; or (iii) extend Revolving
Loan Maturity Date.

ARTICLE 1. EXERCISE.

            1.1 Method of Exercise. Holder may exercise this Warrant by
delivering a duly executed Notice of Exercise in substantially the form attached
as Appendix 1 to the principal office of the Company. Unless Holder is
exercising the conversion right set forth in Section 1.2, Holder shall also
deliver to the Company a check for the aggregate Warrant Price for the Shares
being purchased.

            1.2 Conversion Right. In lieu of exercising this Warrant as
specified in Section 1.1, Holder may from time to time convert this Warrant, in
whole or in part, into a number of Shares determined by dividing (a) the
aggregate fair market value of the Shares or other securities otherwise issuable
upon exercise of this Warrant minus the aggregate Warrant Price of such Shares
by (b) the fair market value of one Share. The fair market value of the Shares
shall be determined pursuant to Section 1.4.

            1.3 Intentionally Omitted

            1.4 Fair Market Value. If the Shares are traded in a public market,
the fair market value of the Shares shall be the closing price of the Shares (or
the closing price of the Company's stock into which the Shares are convertible)
reported for the business day immediately before Holder delivers its Notice of
Exercise to the Company. If the Shares are not traded in a public market, the
Board of Directors of the Company shall determine fair market value in its
reasonable good faith judgment. The foregoing notwithstanding, if Holder advises
the Board of Directors in writing that Holder disagrees with such determination,
then the Company and Holder shall promptly agree upon a reputable investment
banking firm to undertake such valuation. If the valuation of such investment
banking firm is greater than that determined by the Board of Directors, then all
fees and expenses of such investment banking firm shall be paid by the Company.
In all other circumstances, such fees and expenses shall be paid by Holder.
<PAGE>   2
            1.5 Delivery of Certificate and New Warrant. Promptly after Holder
exercises or converts this Warrant, the Company shall deliver to Holder
certificates for the Shares acquired and, if this Warrant has not been fully
exercised or converted and has not expired, a new Warrant representing the
Shares not so acquired.

            1.6 Replacement of Warrants. On receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, on delivery of an
indemnity agreement reasonably satisfactory in form and amount to the Company
or, in the case of mutilation, on surrender and cancellation of this Warrant,
the Company at its expense shall execute and deliver, in lieu of this Warrant, a
new warrant of like tenor.

            1.7 Repurchase on Sale, Merger, or Consolidation of the Company.

                1.7.1. "Acquisition". For the purpose of this Warrant,
"Acquisition" means any sale, license, or other disposition of all or
substantially all of the assets of the Company, or any reorganization,
consolidation, or merger of the Company where the holders of the Company's
securities before the transaction beneficially own less than 50% of the
outstanding voting securities of the surviving entity after the transaction.

                1.7.2. Assumption of Warrant. Upon the closing of any
Acquisition the successor entity shall assume the obligations of this Warrant,
and this Warrant shall be exercisable for the same securities, cash, and
property as would be payable for the Shares issuable upon exercise of the
unexercised portion of this Warrant as if such Shares were outstanding on the
record date for the Acquisition and subsequent closing. The Warrant Price shall
be adjusted accordingly.

ARTICLE 2. ADJUSTMENTS TO THE SHARES.

            2.1 Stock Dividends, Splits, Etc. If the Company declares or pays a
dividend on its common stock (or the Shares if the Shares are securities other
than common stock) payable in common stock, or other securities, subdivides the
outstanding common stock into a greater amount of common stock, or, if the
Shares are securities other than common stock, subdivides the Shares in a
transaction that increases the amount of common stock into which the Shares are
convertible, then upon exercise of this Warrant, for each Share acquired, Holder
shall receive, without cost to Holder, the total number and kind of securities
to which Holder would have been entitled had Holder owned the Shares of record
as of the date the dividend or subdivision occurred.

            2.2 Reclassification, Exchange or Substitution. Upon any
reclassification, exchange, substitution, or other event that results in a
change of the number and/or class of the securities issuable upon exercise or
conversion of this Warrant, Holder shall be entitled to receive, upon exercise
or conversion of this Warrant, the number and kind of securities and property
that Holder would have received for the Shares if this Warrant had been
exercised immediately before such reclassification, exchange, substitution, or
other event. Such an event shall include any automatic conversion of the
outstanding or issuable securities of the Company of the same class or series as
the Shares to common stock pursuant to the terms of the Company's Articles of
Incorporation upon the closing of a registered public offering of the Company's
common stock. The Company or its successor shall promptly issue to Holder a new
Warrant for such new securities or other property. The new Warrant shall provide
for adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Article 2 including, without limitation,
adjustments to the Warrant Price and to the number of securities or property
issuable upon exercise of the new Warrant. The provisions of this Section 2.2
shall similarly apply to successive reclassifications, exchanges, substitutions,
or other events.

            2.3 Adjustments for Combinations, Etc. If the outstanding shares are
combined or consolidated, by reclassification or otherwise, into a lesser number
of shares, the Warrant Price shall be proportionately increased.

            2.4 Adjustments for Diluting Issuances. The Warrant Price and the
number of Shares issuable upon exercise of this Warrant or, if the Shares are
Preferred Stock, the number of shares



                                       2
<PAGE>   3
of common stock issuable upon conversion of the Shares, shall be subject to
adjustment, from time to time in the manner set forth on Exhibit A in the event
of Diluting Issuances (as defined on Exhibit A).

            2.5 No Impairment. The Company shall not, by amendment of its
Articles of Incorporation or through a reorganization, transfer of assets,
consolidation, merger, dissolution, issue, or sale of securities or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms to be observed or performed under this Warrant by the Company, but
shall at all times in good faith assist in carrying out of all the provisions of
this Article 2 and in taking all such action as may be necessary or appropriate
to protect Holder's rights under this Article against impairment. If the Company
takes any action affecting the Shares or its common stock other than as
described above that adversely affects Holder's rights under this Warrant, the
Warrant Price shall be adjusted downward and the number of Shares issuable upon
exercise of this Warrant shall be adjusted upward in such a manner that the
aggregate Warrant Price of this Warrant is unchanged.

            2.6 Fractional Shares. No fractional Shares shall be issuable upon
exercise or conversion of the Warrant and the number of Shares to be issued
shall be rounded down to the nearest whole Share. If a fractional share interest
arises upon any exercise or conversion of the Warrant, the Company shall
eliminate such fractional share interest by paying Holder an amount computed by
multiplying the fractional interest by the fair market value of a full Share.

            2.7 Certificate as to Adjustments. Upon each adjustment of the
Warrant Price, the Company at its expense shall promptly compute such
adjustment, and furnish Holder with a certificate of its Chief Financial Officer
setting forth such adjustment and the facts upon which such adjustment is based.
The Company shall, upon written request, furnish Holder a certificate setting
forth the Warrant Price in effect upon the date thereof and the series of
adjustments leading to such Warrant Price.

ARTICLE 3. REPRESENTATIONS AND COVENANTS OF THE COMPANY.

            3.1 Representations and Warranties. The Company hereby represents
and warrants to the Holder as follows:

                (a) The initial Warrant Price referenced on the first page of
this Warrant is not greater than (i) the price per share at which the Shares
were last issued in an arms-length transaction in which at least $500,000 of the
Shares were sold and (ii) the fair market value of the Shares as of the date of
this Warrant.

                (b) All Shares which may be issued upon the exercise of the
purchase right represented by this Warrant, and all securities, if any, issuable
upon conversion of the Shares, shall, upon issuance, be duly authorized, validly
issued, fully paid and nonassessable, and free of any liens and encumbrances
except for restrictions on transfer provided for herein or under applicable
federal and state securities laws.

                (c) The Capitalization Table attached to this Warrant is true
and complete as of the Issue Date.

            3.2 Notice of Certain Events. If the Company proposes at any time
(a) to declare any dividend or distribution upon its common stock, whether in
cash, property, stock, or other securities and whether or not a regular cash
dividend; (b) to offer for subscription pro rata to the holders of any class or
series of its stock any additional shares of stock of any class or series or
other rights; (c) to effect any reclassification or recapitalization of common
stock; (d) to merge or consolidate with or into any other corporation, or sell,
lease, license, or convey all or substantially all of its assets, or to
liquidate, dissolve or wind up; or (e) offer holders of registration rights the
opportunity to participate in an underwritten public offering of the company's
securities for cash, then, in connection with each such event, the Company shall
give Holder (1) at least 20 days prior written notice of the date on which a
record will be taken for such dividend, distribution, or subscription rights
(and specifying the date on which the holders of common stock will be entitled
thereto) or for determining rights to vote, if any, in respect of the matters
referred to in (c) and (d) above; (2) in the case of the matters referred to in
(c) and (d) above at least 20 days prior

                                       3
<PAGE>   4
written notice of the date when the same will take place (and specifying the
date on which the holders of common stock will be entitled to exchange their
common stock for securities or other property deliverable upon the occurrence of
such event); and (3) in the case of the matter referred to in (e) above, the
same notice as is given to the holders of such registration rights.

            3.3 Information Rights. So long as the Holder holds this Warrant
and/or any of the Shares, the Company shall deliver to the Holder (a) promptly
after mailing, copies of all notices or other written communications to the
shareholders of the Company, (b) within ninety (90) days after the end of each
fiscal year of the Company, the annual audited financial statements of the
Company certified by independent public accountants of recognized standing and
(c) such other financial statements required under and in accordance with any
loan documents between Holder and the Company (or if there are no such
requirements [or if the subject loan(s) no longer are outstanding]), then within
forty-five (45) days after the end of each of the first three quarters of each
fiscal year, the Company's quarterly, unaudited financial statements.

            3.4 Registration Under Securities Act of 1933, as amended. The
Company agrees that the Shares or, if the Shares are convertible into common
stock of the Company, such common stock, shall be subject to the registration
rights set forth on Exhibit B, if attached.

ARTICLE 4. MISCELLANEOUS.

            4.1 Term. This Warrant is exercisable, in whole or in part, at any
time and from time to time on or before the Expiration Date set forth above.

            4.2 Legends. This Warrant and the Shares (and the securities
issuable, directly or indirectly, upon conversion of the Shares, if any) shall
be imprinted with a legend in substantially the following form:

         THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,
         AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED
         WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT OR PURSUANT TO
         RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
         CORPORATION AND ITS COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

            4.3 Compliance with Securities Laws on Transfer. This Warrant and
the Shares issuable upon exercise this Warrant (and the securities issuable,
directly or indirectly, upon conversion of the Shares, if any) may not be
transferred or assigned in whole or in part without compliance with applicable
federal and state securities laws by the transferor and the transferee
(including, without limitation, the delivery of investment representation
letters and legal opinions reasonably satisfactory to the Company, as reasonably
requested by the Company). The Company shall not require Holder to provide an
opinion of counsel if the transfer is to an affiliate of Holder or if there is
no material question as to the availability of current information as referenced
in Rule 144(c), Holder represents that it has complied with Rule 144(d) and (e)
in reasonable detail, the selling broker represents that it has complied with
Rule 144(f), and the Company is provided with a copy of Holder s notice of
proposed sale.

            4.4 Transfer Procedure. Subject to the provisions of Section 4.3
Holder may transfer all or part of this Warrant or the Shares issuable upon
exercise of this Warrant (or the securities issuable, directly or indirectly,
upon conversion of the Shares, if any) at any time to Silicon Valley Bancshares
or The Silicon Valley Bank Foundation, or to any affiliate of Holder, or, to any
other transferree by giving the Company notice of the portion of the Warrant
being transferred setting forth the name, address and taxpayer identification
number of the transferee and surrendering this Warrant to the Company for
reissuance to the transferee(s) (and Holder if applicable). Unless the Company
is filing financial information with the SEC pursuant to the Securities Exchange
Act of 1934, the Company shall have the right to refuse to transfer any portion
of this Warrant to any person who directly competes with the Company.


                                       4
<PAGE>   5
            4.5 Notices. All notices and other communications from the Company
to the Holder, or vice versa, shall be deemed delivered and effective when given
personally or mailed by first-class registered or certified mail at such address
as may have been furnished to the Company or the Holder, as the case may be, in
writing by the Company or such holder from time to time. All notices to be
provided under this Warrant shall be sent to the following address:

                           Silicon Valley Bank
                           Attn: Treasury Department
                           3003 Tasman Drive
                           Santa Clara, CA  95054

            4.6 Waiver. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

            4.7 Attorneys Fees. In the event of any dispute between the parties
concerning the terms and provisions of this Warrant, the party prevailing in
such dispute shall be entitled to collect from the other party all costs
incurred in such dispute, including reasonable attorneys' fees.

            4.8 Governing Law. This Warrant shall be governed by and construed
in accordance with the laws of the State of California, without giving effect to
its principles regarding conflicts of law.

                                   "COMPANY"

                                   WAVO CORPORATION

                                   By:      ______________________________

                                   Name:    ______________________________
                                            (Print)

                                   Title:   Chairman of the Board, President or
                                            Vice President

                                   By:      ______________________________

                                   Name:    ______________________________
                                            (Print)

                                   Title:   Chief Financial Officer, Secretary,
                                            Assistant Treasurer or Assistant
                                            Secretary



                                       5
<PAGE>   6
                                   APPENDIX 1

                               NOTICE OF EXERCISE

         1. The undersigned hereby elects to purchase shares of the
Common/Preferred Series ___ [Strike one] Stock of ______________. pursuant to
the terms of the attached Warrant, and tenders herewith payment of the purchase
price of such shares in full.

         1. The undersigned hereby elects to convert the attached Warrant into
Shares/cash [strike one] in the manner specified in the Warrant. This conversion
is exercised with respect to _____________________ of the Shares covered by the
Warrant.

         [Strike paragraph that does not apply.]

         2. Please issue a certificate or certificates representing said shares
in the name of the undersigned or in such other name as is specified below:

                           -------------------------------------------
                                    (Name)

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

                           -------------------------------------------
                                    (Address)

         3. The undersigned represents it is acquiring the shares solely for its
own account and not as a nominee for any other party and not with a view toward
the resale or distribution thereof except in compliance with applicable
securities laws.

                                            ------------------------------------
                                                     (Signature)

--------------------
     (Date)
<PAGE>   7
                                   EXHIBIT "A"
                               SILICON VALLEY BANK
                             ANTIDILUTION AGREEMENT

         THIS ANTIDILUTION AGREEMENT is entered into as of September 24, 1999,
by and between Silicon Valley Bank, a California-chartered bank ("Purchaser")
and the Company whose name appears on the last page of this Antidilution
Agreement.

                                    RECITALS

         A. Concurrently with the execution of this Antidilution Agreement, the
Purchaser is purchasing from the Company a Warrant to Purchase Stock (the
"Warrant') pursuant to which Purchaser has the right to acquire from the Company
the Shares (as defined in the Warrant).

         B. By this Antidilution Agreement, the Purchaser and the Company desire
to set forth the adjustment in the number of Shares issuable upon exercise of
the Warrant as a result of a Diluting Issuance (as defined in Exhibit A to the
Warrant).

         C. Capitalized terms used herein shall have the same meaning as set
forth in the Warrant.

                  NOW, THEREFORE, in consideration of the mutual promises,
covenants and conditions hereinafter set forth, the parties hereto mutually
agree as follows:

                  1. Definitions. As used in this Antidilution Agreement, the
following terms have the following respective meanings:

                     (a) "Option" means any right, option, or warrant to
subscribe for, purchase, or otherwise acquire common stock or Convertible
Securities.

                     (b) "Convertible Securities" means any evidences of
indebtedness, shares of stock, or other securities directly or indirectly
convertible into or exchangeable for common stock.

                     (c) "Issue" means to grant, issue, sell, assume, or fix a
record date for determining persons entitled to receive, any security (including
Options), whichever of the foregoing is the first to occur.

                     (d) "Additional Common Shares" means all common stock
(including reissued shares) issued (or deemed to be issued pursuant to Section
2) after the date of the Warrant. Additional Common Shares does not include,
however, any common stock issued in a transaction described in Sections 2.1 and
2.2 of the Warrant; any common stock Issued upon conversion of preferred stock
outstanding on the date of the Warrant; the Shares; or common stock Issued as
incentive or in a nonfinancing transaction to employees, officers, directors, or
consultants to the Company.

                     (e) The shares of common stock ultimately Issuable upon
exercise of an Option (including the shares of common stock ultimately Issuable
upon conversion or exercise of a Convertible Security Issuable pursuant to an
Option) are deemed to be Issued when the Option is Issued. The shares of common
stock ultimately Issuable upon conversion or exercise of a Convertible Security
(other than a Convertible Security Issued pursuant to an Option) shall be deemed
Issued upon Issuance of the Convertible Security.

         2. Deemed Issuance of Additional Common Shares. The shares of common
stock ultimately Issuable upon exercise of an Option (including the shares of
common stock ultimately Issuable upon conversion or exercise of a Convertible
Security Issuable pursuant to an Option) are deemed to be Issued when the Option
is Issued. The shares of common stock ultimately Issuable upon conversion or
exercise of a Convertible Security (other than a Convertible Security Issued
pursuant to an Option) shall be deemed Issued upon Issuance of the Convertible
Security. The maximum amount of common stock
<PAGE>   8
Issuable is determined without regard to any future adjustments permitted under
the instrument creating the Options or Convertible Securities.

         3. Adjustment of Warrant Price for Diluting Issuances.

            3.1 Ratchet Adjustment. If the Company issues Additional Common
Shares after the date of the Warrant and the consideration per Additional Common
Share (determined pursuant to Section 9) is less than the Warrant Price in
effect immediately before such Issue, the Warrant Price shall be reduced to the
lesser of:

                (a) the amount of such consideration per Additional Common
Share; or

                (b) if the Company's common stock is traded on a national
securities exchange or the National Association of Securities Dealers Automated
Quotation System, the last reported bid or sale price of the Company's common
stock on the first trading day following a public announcement of the Issuance.

            3.2 Adjustment of Number of Shares. Upon each adjustment of the
Warrant Price, the number of Shares issuable upon exercise of the Warrant shall
be increased to equal the quotient obtained by dividing (a) the product
resulting from multiplying (i) the number of Shares issuable upon exercise of
the Warrant and (ii) the Warrant Price, in each case as in effect immediately
before such adjustment, by (b) the adjusted Warrant Price.

            3.3 Securities Deemed Outstanding. For the purpose of this Section
3, all securities issuable upon exercise of any outstanding Convertible
Securities or Options, warrants, or other rights to acquire securities of the
Company shall be deemed to be outstanding.

         4. No Adjustment for Issuances Following Deemed Issuances. No
adjustment to the Warrant Price shall be made upon the exercise of Options or
conversion of Convertible Securities.

         5. Adjustment Following Changes in Terms of Options or Convertible
Securities. If the consideration payable to, or the amount of common stock
Issuable by, the Company increases or decreases, respectively, pursuant to the
terms of any outstanding Options or Convertible Securities, the Warrant Price
shall be recomputed to reflect such increase or decrease. The recomputation
shall be made as of the time of the Issuance of the Options or Convertible
Securities. Any changes in the Warrant Price that occurred after such Issuance
because other Additional Common Shares were Issued or deemed Issued shall also
be recomputed.

         6. Recomputation Upon Expiration of Options or Convertible Securities.
The Warrant Price computed upon the original Issue of any Options or Convertible
Securities, and any subsequent adjustments based thereon, shall be recomputed
when any Options or rights of conversion under Convertible Securities expire
without having been exercised. In the case of Convertible Securities or Options
for common stock, the Warrant Price shall be recomputed as if the only
Additional Common Shares Issued were the shares of common stock actually Issued
upon the exercise of such securities, if any, and as if the only consideration
received therefor was the consideration actually received upon the Issue,
exercise or conversion of the Options or Convertible Securities. In the case of
Options for Convertible Securities, the Warrant Price shall be recomputed as if
the only Convertible Securities Issued were the Convertible Securities actually
Issued upon the exercise thereof, if any, and as if the only consideration
received therefor was the consideration actually received by the Company
(determined pursuant to Section 9), if any, upon the Issue of the Options for
the Convertible Securities.

         7. Limit on Readjustments. No readjustment of the Warrant Price
pursuant to Sections 5 or 6 shall increase the Warrant Price more than the
amount of any decrease made in respect of the Issue of any Options or
Convertible Securities.


                                       2
<PAGE>   9
         8. 30 Day Options. In the case of any Options that expire by their
terms not more than 30 days after the date of Issue thereof, no adjustment of
the Warrant Price shall be made until the expiration or exercise of all such
Options.

         9. Computation of Consideration. The consideration received by the
Company for the Issue of any Additional Common Shares shall be computed as
follows:

               (a) Cash shall be valued at the amount of cash received by the
Corporation, excluding amounts paid or payable for accrued interest or accrued
dividends.

               (b) Property. Property other than cash shall be computed at the
fair market value thereof at the time of the Issue as determined in good faith
by the Board of Directors of the Company.

               (c) Mixed Consideration. The consideration for Additional common
Shares Issued together with other property of the Company for consideration that
covers both shall be determined in good faith by the Board of Directors.

               (d) Options and Convertible Securities. The consideration per
Additional Common Share for Options and Convertible Securities shall be
determined by dividing:

                   (i) the total amount, if any, received or receivable by the
Company for the Issue of the Options or Convertible Securities, plus the minimum
amount of additional consideration (as set forth in the instruments relating
thereto, without regard to any provision contained therein for a subsequent
adjustment of such consideration) payable to the Company upon exercise of the
Options or conversion of the Convertible Securities, by

                   (ii) the maximum amount of common stock (as set forth in the
instruments relating thereto, without regard to any provision contained therein
for a subsequent adjustment of such number) ultimately Issuable upon the
exercise of such Options or the conversion of such Convertible Securities.

         10.      General.

                10.1 Governing Law. This Antidilution Agreement shall be
governed in all respects by the laws of the State of California as such laws are
applied to agreements between California residents entered into and to be
performed entirely within California.

                10.2 Successors and Assigns. Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of
the parties hereto.

                10.3 Entire Agreement. Except as set forth below, this
Antidilution Agreement and the other documents delivered pursuant hereto
constitute the full and entire understanding and agreement between the parties
with regard to the subjects hereof and thereof.

                10.4 Notices, etc. All notices and other communications required
or permitted hereunder shall be in writing and shall be mailed by first class
mail, postage prepaid, certified or registered mail, return receipt requested,
addressed (a) if to Purchaser at Purchaser's address as set forth below, or at
such other address as Purchaser shall have furnished to the Company in writing,
or (b) if to the Company, at the Company's address set forth below, or at such
other address as the Company shall have furnished to the Purchaser in writing.

                10.5 Severability. In case any provision of this Antidilution
Agreement shall be invalid, illegal, or unenforceable, the validity, legality
and enforceability of the remaining provisions of this Antidilution Agreement
shall not in any way be affected or impaired thereby.


                                       3
<PAGE>   10
                10.6 Titles and Subtitles. The titles of the sections and
subsections of this Agreement are for convenience of reference only and are not
to be considered in construing this Antidilution Agreement.

                10.7 Counterparts. This Antidilution Agreement may be executed
in any number of counterparts, each of which shall be an original, but all of
which together shall constitute one instrument.

PURCHASER                                  COMPANY

SILICON VALLEY BANK<<

By:_______________________________         By:__________________________________
Name:_____________________________         Name:________________________________
(Print):__________________________         (Print):_____________________________
Title:____________________________         Title:Chairman of the Board,
                                                 President or Vice President

Address:                                   Address:



                                       4
<PAGE>   11
                                   EXHIBIT "B"

                               SILICON VALLEY BANK

                          REGISTRATION RIGHTS AGREEMENT

         THIS REGISTRATION RIGHTS AGREEMENT is entered into as of September 24,
1999, by and between Silicon Valley Bank, a California-chartered bank
("Purchaser") and the Company whose name appears on the last page of this
Agreement.

                                    RECITALS

         A. Concurrently with the execution of this Agreement, the Purchaser is
purchasing from the Company a Warrant to Purchase Stock (the "Warrant") pursuant
to which Purchaser has the right to acquire from the Company the Shares (as
defined in the Warrant).

         B. By this Agreement, the Purchaser and the Company desire to set forth
the registration rights of the Shares all as provided herein.

                  NOW, THEREFORE, in consideration of the mutual promises,
covenants and conditions hereinafter set forth, the parties hereto mutually
agree as follows:

         1. Registration Rights. The Company covenants and agrees as follows:

            1.1 Definitions. For purposes of this Section 1:

                (a) The term "register," "registered," and "registration" refer
to a registration effected by preparing and filing a registration statement or
similar document in compliance with the Securities Act of 1933, as amended (the
"Securities Act"), and the declaration or ordering of effectiveness of such
registration statement or document;

                (b) The term "Registrable Securities" means (i) the Shares (if
Common Stock) or all shares of Common Stock of the Company issuable or issued
upon conversion of the Shares and (ii) any Common Stock of the Company issued as
(or issuable upon the conversion or exercise of any warrant, right or other
security which is issued as) a dividend or other distribution with respect to,
or in exchange for or in replacement of, any stock referred to in (i).

                (c) The terms "Holder" or "Holders" means the Purchaser or
qualifying transferees under subsection 1.8 hereof who hold Registrable
Securities.

                (d) The term "SEC" means the Securities and Exchange Commission.

            1.2 Company Registration.

                    (a) Registration. If at any time or from time to time, the
Company shall determine to register any of its securities, for its own account
or the account of any of its shareholders, other than a registration on Form S-1
or S-8 relating solely to employee stock option or purchase plans, or a
registration on Form S-4 relating solely to an SEC Rule 145 transaction, or a
registration on any other form (other than Form S-1, S-2, S-3 or S-18, or their
successor forms) or any successor to such forms, which does not include
substantially the same information as would be required to be included in a
registration statement covering the sale of Registrable Securities, the Company
will:


                                       5
<PAGE>   12
                                    (i) promptly give to each Holder written
notice thereof (which shall include a list of the jurisdictions in which the
Company intends to attempt to qualify such securities under the applicable blue
sky or other state securities laws); and

                                    (ii) include in such registration (and
compliance), and in any underwriting involved therein, all the Registrable
Securities specified in a written request or requests, made within 30 days after
receipt of such written notice from the Company, by any Holder or Holders,
except as set forth in subsection 1.2(b) below.

                    (b) Underwriting. If the registration of which the Company
gives notice is for a registered public offering involving an underwriting, the
Company shall so advise the Holders as a part of the written notice given
pursuant to subsection 1.2(a)(i). In such event the right of any Holder to
registration pursuant to this subsection 1.2 shall be conditioned upon such
Holder's participation in such underwriting and the inclusion of such Holder's
Registrable Securities in the underwriting to the extent provided herein. All
Holders proposing to distribute their securities through such underwriting shall
(together with the Company and the other shareholders distributing their
securities through such underwriting) enter into an underwriting agreement in
customary form with the underwriter or underwriters selected for such
underwriting by the Company.

                 1.3 Expenses of Registration. All expenses incurred in
connection with any registration, qualification or compliance pursuant to this
Section 1 including without limitation, all registration, filing and
qualification fees, printing expenses, fees and disbursements of counsel for the
Company and expenses of any special audits incidental to or required by such
registration, shall be borne by the Company except the Company shall not be
required to pay underwriters' fees, discounts or commissions relating to
Registrable Securities. All expenses of any registered offering not otherwise
borne by the Company shall be borne pro rata among the Holders participating in
the offering and the Company.

                 1.4 Registration Procedures. In the case of each registration,
qualification or compliance effected by the Company pursuant to this
Registration Rights Agreement, the Company will keep each Holder participating
therein advised in writing as to the initiation of each registration,
qualification and compliance and as to the completion thereof. Except as
otherwise provided in subsection 1.3, at its expense the Company will:

                           (a) Prepare and file with the SEC a registration
statement with respect to such Registrable Securities and use its best efforts
to cause such registration statement to become effective, and, upon the request
of the Holders of a majority of the Registrable Securities registered
thereunder, keep such registration statement effective for up to 120 days.

                           (b) Prepare and file with the SEC such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement as may be necessary to comply with the
provisions of the Securities Act with respect to the disposition of all
securities covered by such registration statement.

                           (c) Furnish to the Holders such numbers of copies of
a prospectus, including a preliminary prospectus, in conformity with the
requirements of the Securities Act, and such other documents as they may
reasonably request in order to facilitate the disposition of Registrable
Securities owned by them.

                           (d) Use its best efforts to register and qualify the
securities covered by such registration statement under such other securities or
Blue Sky laws of such jurisdictions as shall be reasonably requested by the
Holders, provided that the Company shall not be required in connection therewith
or as a condition thereto to qualify to do business or to file a general consent
to service of process in any such states or jurisdictions.


                                       6
<PAGE>   13
                           (e) In the event of any underwritten public offering,
enter into and perform its obligations under an underwriting agreement, in usual
and customary form, with the managing underwriter of such offering. Each Holder
participating in such underwriting shall also enter into and perform its
obligations under such an agreement.

                           (f) Notify each Holder of Registrable Securities
covered by such registration statement at any time when a prospectus relating
thereto is required to be delivered under the Securities Act or the happening of
any event as a result of which the prospectus included in such registration
statement, as then in effect, includes an untrue statement of a material fact or
omits to state a material fact required to be stated therein or necessary to
make the statements therein not misleading in the light of the circumstances
then existing.

                 1.5       Indemnification.

                           (a) The Company will indemnify each Holder of
Registrable Securities and each of its officers, directors and partners, and
each person controlling such Holder, with respect to which such registration,
qualification or compliance has been effected pursuant to this Rights Agreement,
and each underwriter, if any, and each person who controls any underwriter of
the Registrable Securities held by or issuable to such Holder, against all
claims, losses, expenses, damages and liabilities (or actions in respect
thereto) arising out of or based on any untrue statement (or alleged untrue
statement) of a material fact contained in any prospectus, offering circular or
other document (including any related registration statement, notification or
the like) incident to any such registration, qualification or compliance, or
based on any omission (or alleged omission) to state therein a material fact
required to be stated therein or necessary to make the statement therein not
misleading, or any violation or alleged violation by the Company of the
Securities Act, the Securities Exchange Act of 1934, as amended, ("Exchange
Act") or any state securities law applicable to the Company or any rule or
regulation promulgated under the Securities Act, the Exchange Act or any such
state law and relating to action or inaction required of the Company in
connection with any such registration, qualification of compliance, and will
reimburse each such Holder, each of its officers, directors and partners, and
each person controlling such Holder, each such underwriter and each person who
controls any such underwriter, within a reasonable amount of time after incurred
for any reasonable legal and any other expenses incurred in connection with
investigating, defending or settling any such claim, loss, damage, liability or
action; provided, however, that the indemnity agreement contained in this
subsection 1.5(a) shall not apply to amounts paid in settlement of any such
claim, loss, damage, liability, or action if such settlement is effected without
the consent of the Company (which consent shall not be unreasonably withheld);
and provided further, that the Company will not be liable in any such case to
the extent that any such claim, loss, damage or liability arises out of or is
based on any untrue statement or omission based upon written information
furnished to the Company by an instrument duly executed by such Holder or
underwriter specifically for use therein.

                           (b) Each Holder will, if Registrable Securities held
by or issuable to such Holder are included in the securities as to which such
registration, qualification or compliance is being effected, indemnify the
Company, each of its directors and officers, each underwriter, if any, of the
Company's securities covered by such a registration statement, each person who
controls the Company within the meaning of the Securities Act, and each other
such Holder, each of its officers, directors and partners and each person
controlling such Holder, against all claims, losses, expenses, damages and
liabilities (or actions in respect thereof) arising out of or based on any
untrue statement (or alleged untrue statement) of a material fact contained in
any such registration statement, prospectus, offering circular or other
document, or any omission (or alleged omission) to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and will reimburse the Company, such Holders, such directors,
officers, partners, persons or underwriters for any reasonable legal or any
other expenses incurred in connection with investigating, defending or settling
any such claim, loss, damage, liability or action, in each case to the extent,
but only to the extent, that such untrue statement (or alleged untrue statement)
or omission (or alleged omission) is made in such registration statement,
prospectus, offering circular or other document in reliance upon and in
conformity with written information furnished to the Company by an instrument
duly executed by such Holder specifically for use therein;


                                       7
<PAGE>   14
provided, however, that the indemnity agreement contained in this subsection
1.5(b) shall not apply to amounts paid in settlement of any such claim, loss,
damage, liability or action if such settlement is effected without the consent
of the Holder, (which consent shall not be unreasonably withheld); and provided
further, that the total amount for which any Holder shall be liable under this
subsection 1.5(b) shall not in any event exceed the aggregate proceeds received
by such Holder from the sale of Registrable Securities held by such Holder in
such registration.

                           (c) Each party entitled to indemnification under this
subsection 1.5 (the "Indemnified Party") shall give notice to the party required
to provide indemnification (the "Indemnifying Party") promptly after such
Indemnified Party has actual knowledge of any claim as to which indemnity may be
sought, and shall permit the Indemnifying Party to assume the defense of any
such claim or any litigation resulting therefrom; provided that counsel for the
Indemnifying Party, who shall conduct the defense of such claim or litigation,
shall be approved by the Indemnified Party (whose approval shall not be
unreasonably withheld), and the Indemnified Party may participate in such
defense at such party's expense; and provided further, that the failure of any
Indemnified Party to give notice as provided herein shall not relieve the
Indemnifying Party of its obligations hereunder, unless such failure resulted in
prejudice to the Indemnifying Party; and provided further, that an Indemnified
Party (together with all other Indemnified Parties which may be represented
without conflict by one counsel) shall have the right to retain one separate
counsel, with the fees and expenses to be paid by the Indemnifying Party, if
representation of such Indemnified Party by the counsel retained by the
Indemnifying Party would be inappropriate due to actual or potential differing
interests between such Indemnified Party and any other party represented by such
counsel in such proceeding. No Indemnifying Party, in the defense of any such
claim or litigation, shall, except with the consent of each Indemnified Party,
consent to entry of any judgment or enter into any settlement which does not
include as an unconditional term thereof the giving by the claimant or plaintiff
to such Indemnified Party of a release from all liability in respect to such
claim or litigation.

                 1.6 Information by Holder. Any Holder or Holders of Registrable
Securities included in any registration shall promptly furnish to the Company
such information regarding such Holder or Holders and the distribution proposed
by such Holder or Holders as the Company may request in writing and as shall be
required in connection with any registration, qualification or compliance
referred to herein.

                 1.7 Rule 144 Reporting. With a view to making available to
Holders the benefits of certain rules and regulations of the SEC which may
permit the sale of the Registrable Securities to the public without
registration, the Company agrees at all times to:

                           (a) make and keep public information available, as
those terms are understood and defined in SEC Rule 144, after 90 days after the
effective date of the first registration filed by the Company for an offering of
its securities to the general public;

                           (b) file with the SEC in a timely manner all reports
and other documents required of the Company under the Securities Act and the
Exchange Act (at any time after it has become subject to such reporting
requirements); and

                           (c) so long as a Holder owns any Registrable
Securities, to furnish to such Holder forthwith upon request a written statement
by the Company as to its compliance with the reporting requirements of said Rule
144 (at any time after 90 days after the effective date of the first
registration statement filed by the Company for an offering of its securities to
the general public), and of the Securities Act and the Exchange Act (at any time
after it has become subject to such reporting requirements), a copy of the most
recent annual or quarterly report of the Company, and such other reports and
documents so filed by the Company as the Holder may reasonably request in
complying with any rule or regulation of the SEC allowing the Holder to sell any
such securities without registration.

                 1.8 Transfer of Registration Rights. Holders' rights to cause
the Company to register their securities and keep information available, granted
to them by the Company under subsections 1.2

                                       8
<PAGE>   15
and 1.7 may be assigned to a transferee or assignee of a Holder's Registrable
Securities not sold to the public, provided, that the Company is given written
notice by such Holder at the time of or within a reasonable time after said
transfer, stating the name and address of said transferee or assignee and
identifying the securities with respect to which such registration rights are
being assigned. The Company may prohibit the transfer of any Holders' rights
under this subsection 1.8 to any proposed transferee or assignee who the Company
reasonably believes is a competitor of the Company.

         2.       General.

                 2.1 Waivers and Amendments. With the written consent of the
record or beneficial holders of at least a majority of the Registrable
Securities, the obligations of the Company and the rights of the Holders of the
Registrable Securities under this agreement may be waived (either generally or
in a particular instance, either retroactively or prospectively, and either for
a specified period of time or indefinitely), and with the same consent the
Company, when authorized by resolution of its Board of Directors, may enter into
a supplementary agreement for the purpose of adding any provisions to or
changing in any manner or eliminating any of the provisions of this Agreement;
provided, however, that no such modification, amendment or waiver shall reduce
the aforesaid percentage of Registrable Securities without the consent of all of
the Holders of the Registrable Securities. Upon the effectuation of each such
waiver, consent, agreement of amendment or modification, the Company shall
promptly give written notice thereof to the record holders of the Registrable
Securities who have not previously consented thereto in writing. This Agreement
or any provision hereof may be changed, waived, discharged or terminated only by
a statement in writing signed by the party against which enforcement of the
change, waiver, discharge or termination is sought, except to the extent
provided in this subsection 2.1.

                 2.2 Governing Law. This Agreement shall be governed in all
respects by the laws of the State of California as such laws are applied to
agreements between California residents entered into and to be performed
entirely within California.

                 2.3 Successors and Assigns. Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of
the parties hereto.

                 2.4 Entire Agreement. Except as set forth below, this Agreement
and the other documents delivered pursuant hereto constitute the full and entire
understanding and agreement between the parties with regard to the subjects
hereof and thereof.

                 2.5 Notices, etc. All notices and other communications required
or permitted hereunder shall be in writing and shall be mailed by first class
mail, postage prepaid, certified or registered mail, return receipt requested,
addressed (a) if to Holder, at such Holder's address as set forth below, or at
such other address as such Holder shall have furnished to the Company in
writing, or (b) if to the Company, at the Company's address set forth below, or
at such other address as the Company shall have furnished to the Holder in
writing.

                 2.6 Severability. In case any provision of this Agreement shall
be invalid, illegal, or unenforceable, the validity, legality and enforceability
of the remaining provisions of this Agreement or any provision of the other
Agreement s shall not in any way be affected or impaired thereby.

                 2.7 Titles and Subtitles. The titles of the sections and
subsections of this Agreement are for convenience of reference only and are not
to be considered in construing this Agreement.

                 2.8 Counterparts. This Agreement may be executed in any number
of counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.


                                       9
<PAGE>   16
PURCHASER                                                 COMPANY

SILICON VALLEY BANK

By:__________________                                     By:___________________
Name:________________                                     Name:_________________
Title:_______________                                     Title:________________

                                                          By:___________________
                                                          Name:_________________
                                                          Title:________________

Address:                                                  Address:


                                       10