TOUCH_TONE_BAND_REJECT_FILTER

Published:2009/7/14 8:34:00 Author:May | From:SeekIC

Cascaded notch filters with active limiter at output provide 20-dB attenuation of either low (697-941 Hz) or high (1209-1633 Hz) groups of tones, as aid to decoding for repeater control functions. All coils are 88-mH toroid. RA is between 5600 and 22,000 ohms, and RB is 1000 to 3000 ohms. Article gives tuning procedure for selecting resistor values and adjusting toroids so each stage rejects different tone in its band.-B. Bretz, Multi-Function FM Repeater Decoder, Ham Radio, Jan. 1973, p 24-32.



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