<ARTICLE> 5

<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          APR-30-1998
<PERIOD-START>                             MAY-01-1997
<PERIOD-END>                               JAN-31-1998
<CASH>                                          11,531
<SECURITIES>                                    17,467
<RECEIVABLES>                                   15,450
<ALLOWANCES>                                       392
<INVENTORY>                                     11,614
<CURRENT-ASSETS>                                60,597
<PP&E>                                          39,821
<DEPRECIATION>                                  20,826
<TOTAL-ASSETS>                                  90,719
<CURRENT-LIABILITIES>                            9,113
<BONDS>                                              0
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<COMMON>                                            12
<OTHER-SE>                                      90,717
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<SALES>                                         60,568
<TOTAL-REVENUES>                                60,568
<CGS>                                           34,666
<TOTAL-COSTS>                                   34,666
<OTHER-EXPENSES>                                 9,823<F1>
<LOSS-PROVISION>                                    45<F2>
<INTEREST-EXPENSE>                                   8
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<INCOME-TAX>                                     1,211
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<EPS-PRIMARY>                                      .33
<EPS-DILUTED>                                      .29
<FN>
<F1>RESEARCH AND DEVELOPMENT EXPENSES
<F2>PROVISION FOR BAD DEBT
</FN>