TWO_TONE_ENCODER

Published:2009/7/14 21:23:00 Author:May | From:SeekIC

741 opamps and 2N2924 transistors are connected as single-tone encoders producing different audio frequencies、with outputs connected together For2000-Hz tone, use 0.01 μF for c1 and c2 and use 8K for R3 and R4. Formula for frequency of each encoder is f = 0.159/RC where f is in hertz, R in megohms, and C in microfarads; R = R3 = R4 and C = C1 = C2. Frequencies can be chosen for Touch-Tone signaling.-C. D. Rakes, integrated Circuit Projects, Howard W. Sams, Indianapolis, IN, 1975, p 95-97,



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