a EROFLEX Precision Supercomponenits For Critical Applications COMSTRON PSC-4490 22.6 MHZ NYQUIST BANDPASS FILTER FOR DIGITAL TO ANALOG CONVERTER FEATURES DESCRIPTION INVERSE SINC, SQUARE ROOT NYQUIST The Comstron Model PSC-4490 is a Nyquist bandpass ( ARBITRARY SHAPING AVAILABLE) filter used in a DAC( digital to analog converter). The FLAT GROUP DELAY 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 SHARP ATTENUATION COMPACT SIZE FREQUENCY RANGE; 1 MHZ - 3000 MHZ shape over the passband is |x/sin x|?_ where x = ep and fs=50.0 MSPS (sampling rate). PSC-4490SPECIFICATIONS PSC-4490 CHARACTERISTICS TYPICAL LIMITS PASSBAND 200 HZ TO 22.6 MHZ EQUALIZING SHAPE 20LOG(X/SINX) DB WITHIN + .075 DB <+.1DB VSWR <1.15:1 <1.2:1 INSERTION LOSS 6.0 + .5 DB AT 200 HZ GROUP DELAY VARIATION OVER 15 NS <20NS 6TO 22.6 MHZ STOPBAND REJECTION, AT 3 HZAND BELOW >60 DB AT 27.4 MHZ AND ABOVE >30DB AT 38.75 MHZ AND ABOVE >50DB OUTLINE DRAWING lq iS,- LF? (\EROFLEX 2.00 COMSTRON (.\EROFLEX T ke RESPONSE CURVES REF LEVEL /DIV MARKER 27 444 875, ODOHz 5S. 638d8 10. o00dB MAG CUDF> 46. 284dB O. 00Sd8 5. 0O00dB MARKER 22 613 625. OOOHz MAG CUDF> -21, 566d8 START 100 000. OOOHz AMPTD 15. OdBm STOP 36 750 O00. oOOHz Figure 1: Overall Response REF LEVEL -5. GO7dB 102. 44nSEC /DIV OFFSET 22 600 O00. OOOHz Oo. 299d08 MAG CUDF> 3. 041d8 10. OO0nSEC MARKER 943 750. OOOH= DELAY CUOF> 104. O9nSEC sTop 22 600 000. COOHz START 100 00. OOOHz AMPTO 15. OdBm Figure 2: Passband Response Precision Supercomponents For Critical Applications 35 South Service Road - Plainview, NY 11803 TEL: 516-694-6700 FAX: 516-694-2562 COMSTRON