Document:

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                                                                   EXHIBIT 10.22

                        AMENDMENT TO EMPLOYMENT AGREEMENT

      Amendment to Employment Agreement, dated as of May 30, 2000 (this
"Amendment"), by and between Datascope Corp., a Delaware corporation (the
"Corporation"), and Lawrence Saper, as individual residing at 812 Park Avenue,
New York, New York (the "Executive").

                              W I T N E S S E T H:

      WHEREAS, the Corporation and the Executive entered into an Employment
Agreement dated as of July 1, 1996 (the "Employment Agreement"); and

      WHEREAS, the Corporation and the Executive desire to amend the Employment
Agreement as set forth below.

      NOW THEREFORE, in consideration of the premises and mutual agreements
herein set forth, the parties do hereby agree as follows:

      1.    Amendment. Section 8(d) of the Employment Agreement is hereby
            amended and restated to read as follows:

            "(d) Termination by the Executive. The Executive may terminate his
            employment hereunder (i) for Good Reason, or (ii) if his health
            should become impaired such that his continued performance of his
            duties hereunder is hazardous to his physical or mental health or
            his life. For purposes of this Agreement, "Good Reason" shall mean
            (A) a change in control of the Corporation (as defined below), (B)
            any assignment to the Executive of any duties inconsistent with his
            present duties as Chief Executive Officer and President of the
            Corporation or a change in his present responsibilities without his
            express written consent, (C) any removal of the Executive
            without his consent from, or any failure to re-elect the Executive
            to, the office of President of the Corporation, except in connection
            with termination of the Executive's employment for Cause or as a
            result of his death or disability or by him other than for Good
            Reason, (D) a reduction in the Executive's Base Salary as in effect
            on the date of this Agreement or as the same may be increased from
            time to time, or a reduction in the Executive's other benefits or
            any other failure by the Corporation to comply with Section 5
            hereof, (E) failure by the Corporation to comply with Section 4
            hereof, or (F) failure of the Corporation to obtain from any
            successor the assumption of or the agreement to perform this
            Agreement (as contemplated in Section 10), or (G) any purported
            termination of the Executive's employment which is not effected
            pursuant to a Notice of Termination satisfying the requirements of
            paragraph 8(e). For purposes of this Agreement, a "change in control
            of the Corporation" shall mean a change in control of a nature that
            would be required to be reported in a current report on Form 8-K, as
            in effect on the date of this Agreement, or pursuant to Section 13
            or 14(d) of the Securities Exchange Act of 1934, as amended (the
            "Exchange Act"); including, without limitation, (i) the acquisition
            of beneficial ownership (as defined in Rule 13d-3 under the Exchange
            Act), directly or indirectly, by any "person" (as such term is used
            in Sections 13(d) and 14(d) of the Exchange Act), other than the
            Corporation or the Executive or an entity directly or indirectly
            controlled by the Executive, of securities of the Corporation
            representing 20% or more of the combined voting power of the
            Corporation's then outstanding securities unless the Executive and
            the Corporation's Board of Directors, within fifteen (15) business
            days after having been advised of such acquisition of beneficial
            ownership, adopts a resolution approving such acquisition, (ii) the
            Corporation shall have consummated the sale of all or substantially
            all of the assets of the Corporation, (iii) the stockholders of the
            Corporation approve a merger or consolidation of the Corporation
            with any other corporation (or other entity), other than a merger or
            consolidation which would result in the voting securities of the
            Corporation outstanding immediately prior thereto continuing to
            represent (either by remaining outstanding or by being converted
            into voting securities of the surviving entity) more than 50% of the
            voting power of the voting securities of the Corporation or such
            surviving entity outstanding immediately after such merger or
            consolidation, (iv) the stockholders of the Corporation approve a
            plan of complete liquidation of the Corporation, or (v) the
            following individuals cease for any reason to constitute a majority
            of the number of directors then serving: individuals who, on the
            date hereof, constitute the Board of Directors and any new director
            (other than a director whose initial assumption of office is in
            connection with an actual or threatened election contest, including
            but not limited to a consent solicitation, relating to the election
            of directors of the Corporation) whose appointment or election by
            the Board of Directors or nomination for election by the
            Corporation's stockholders was approved or recommended by a vote of
            at least two-thirds (2/3) of the directors then still in office who
            either were directors on the date hereof or whose appointment,
            election or nomination for election was previously so approved or
            recommended."

      2. Employment Agreement. Except as set forth in this Amendment, all other
terms and conditions of the Employment Agreement shall remain unchanged and in
full force and effect.

      3. Counterparts. This Amendment may be executed in one or more
counterparts, each of which shall for all purposes be deemed to be an original
and all of which shall constitute the same instrument.

      4. Headings. The headings of the paragraphs herein are included solely for
convenience of reference and shall not control the meaning or interpretation of
any provision of this Amendment.

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      IN WITNESS WHEREOF, each of the parties hereto has caused this Amendment
to be executed on its behalf as of the date first above written.

                                        DATASCOPE CORP.

                                        By:_____________________________________
                                           Name:
                                           Title: ______________________________

                                        ________________________________________
                                        LAWRENCE SAPER

                                       3<PAGE>   1

                                                                     EXHIBIT 4.1

   Number                        [OmniSKY LOGO]                     Shares
SKY-
-------------                                                  ---------------

                                    OmniSKY
                              OMNISKY CORPORATION
              INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE

                                            SEE REVERSE FOR CERTAIN DEFINITIONS
                                            CUSIP 68213L 10 3

              --------------------------------------------------
              THIS CERTIFIES THAT

                            is the record holder of

              ---------------------------------------------------
    FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK, $.001 PAR VALUE, OF

                              OMNISKY CORPORATION

   transferable on the books of the Corporation by the holder hereof in person
or by duly authorized attorney upon surrender of this certificate properly
endorsed. This certificate is not valid until countersigned by the Transfer
Agent and registered by the Registrar.
   WITNESS the facsimile seal of the Corporation and the facsimile signatures
of its duly authorized officers.
   Dated:

                                [CORPORATE SEAL]

/s/ SCOTT WORNOW                                    /s/ PATRICK MCVEIGH
-------------------------                           ---------------------------
SECRETARY                                           CHIEF EXECUTIVE OFFICER

COUNTERSIGNED AND REGISTERED:
  CHASEMELLON SHAREHOLDER SERVICES, L.L.C.
                TRANSFER AGENT AND REGISTRAR

BY:
   -----------------------------------------
                AUTHORIZED SIGNATURE

<PAGE>   2

     The Corporation shall furnish without charge to each stockholder who so
requests a statement of the powers, designations, preferences and relative,
participating, optional, or other special rights of each class of stock of the
Corporation or series thereof and the qualifications, limitations or
restrictions of such preferences and/or rights. Such requests shall be made to
the Corporation's Secretary at the principal office of the Corporation.

     The following abbreviations, when used in the inscription on the face of
the certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<TABLE>
<CAPTION>
<S>          <C>                                  <C>
TEN COM  --  as tenants in common                 UNIF GIFT MIN ACT -- ________ Custodian _____________
TEN ENT  --  as tenants by the entireties                               (Cust)               (Minor)
JT TEN   --  as joint tenants with right of                            under Uniform Gifts to Minors
             survivorship and not as tenants                           Act ____________________________
             in common                                                              (State)

                                                  UNIF TRF MIN ACT  -- _____ Custodian (until age_____)
                                                                       (Cust)
                                                                       ________ under Uniform Transfers
                                                                        (Minor)
                                                                       to Minors Act __________________
                                                                                          (State)
</TABLE>

   Additional abbreviations may also be used though not in the above list.

     For value Received, ____________________________________ hereby sell(s),
assign(s) and transfer(s) unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
    IDENTIFYING NUMBER OF ASSIGNEE
---------------------------------------

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

-------------------------------------------------------------------------------
  (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

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

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

------------------------------------------------------------------------ Shares
of the common stock represented by the within certificate, and do hereby

irrevocably constitute and appoint                                     Attorney
                                   -----------------------------------
to transfer the said stock on the books of the within named Corporation
with full power of substitution in the premises.

Dated:
       ----------------------------

                                            X
                                              --------------------------------

                                            X
                                              --------------------------------
                                      NOTICE: THE SIGNATURE TO THIS ASSIGNMENT
                                              MUST CORRESPOND WITH THE NAME AS
                                              WRITTEN UPON THE FACE OF THE
                                              CERTIFICATE IN EVERY PARTICULAR,
                                              WITHOUT ALTERATION OR ENLARGEMENT
                                              OR ANY CHANGE WHATEVER.

Signature(s) Guaranteed

By
   ------------------------------------------
   THE SIGNATURE(S) MUST BE GUARANTEED BY
   AN ELIGIBLE GUARANTOR INSTITUTION (BANKS,
   STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS
   AND CREDIT UNIONS WITH MEMBERSHIP IN AN
   APPROVED SIGNATURE GUARANTEE MEDALLION
   PROGRAM), PURSUANT TO S.E.C. RULE 17Ad-15.

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