This Gaithersburg-based maker of data communications and

measurement instruments said that its first-quarter results declined significantly as a previously announced plan to increase spending related to new products went into effect.

The company, which saw its earnings fall by nearly one-third, said its costs increased as it stepped up spending for engineering and marketing to help support production and sales in the second half of its fiscal year.

Revenue fell slightly during the same period. The company blamed a "continued sluggish economy and the general softening" in certain segments of its market.

Penril, which was recently named in Forbes magazine's list of "The 200 Best Small Companies," also said it would redeem at par $3.8 million in 12.5 percent senior subordinated notes to help lower interest costs.

Three months ended 10/31/91

.. .. .. Revenue.. .. .. .. .. Net.. .. .. .. Share

'91.. ..12,028,000.. .. .. ..820,000.. .. .. .0.12

..12,446,000.. .. ...1,182,000.. .. .. ..0.18

% change.. ..-3.4.. .. .. .. .-30.6.. .. .. .. -33.3