Precision Supercomponents For Critical Applications PSC-4490 22.6 MHZ NYQUIST BANDPASS FILTER FOR DIGITAL TO ANALOG CONVERTER FEATURES DESCRIPTION • INVERSE SINC, SQUARE ROOT NYQUIST ( ARBITRARY SHAPING AVAILABLE) • FLAT GROUP DELAY • SHARP ATTENUATION • COMPACT SIZE The Comstron Model PSC-4490 is a Nyquist bandpass filter used in a DAC( digital to analog converter). The purpose of the filter is to normalize the amplitude response of an input (Sin x)/x signal spectrum, and to reject unwanted frequencies while maintaining low group delay variation in the passband. The equalizing • FREQUENCY RANGE; 1 MHZ - 3000 MHZ πf) shape over the passband is |x/sin x|2 where x = (--------- fs and fs=50.0 MSPS (sampling rate). PSC-4490 PSC-4490 SPECIFICATIONS CHARACTERISTICS RESPONSE CURVES TYPICAL LIMITS PASSBAND 200 HZ TO 22.6 MHZ - EQUALIZING SHAPE 20LOG(X/SINX) DB WITHIN ± .075 DB <± .1 DB VSWR <1.15:1 <1.2:1 INSERTION LOSS GROUP DELAY VARIATION OVER .6 TO 22.6 MHZ 6.0 ± .5 DB AT 200 HZ 15 NS < 20 NS STOPBAND REJECTION AT 3 HZ AND BELOW >60 DB AT 27.4 MHZ AND ABOVE > 30 DB AT 38.75 MHZ AND ABOVE > 50 DB OUTLINE DRAWING 3.50 Figure 1: Overall Response 2.00 1.00 MAX .25 .25 1.00 .25 .25 Figure 2: Passband Response Precision Supercomponents For Critical Applications 35 South Service Road Plainview, NY 11803 TEL: 516-694-6700 FAX: 516-694-2562