FM Stereo Encoder CD4066

Circuit schematics IC1-4069 in the Y1, Y2 formation of a 76 KHZ frequency of the oscillator, the Y3-Y6 isolation plastic, into IC2 dual JK flip-flop CD4027 composed of two components- frequency circuit, a symmetrical + / 38KHZ-19 KHZ and the square wave, + / -38 KHZ IC3 the square used to control analog switches CD4066, a stereo audio input signal after switching modulation used for the 19 KHZ frequency mixed signal to the transistor into FM 9014 after isolation Modulator.

Click to access the debug FM modulator and 5 V power supply, with a multimeter measured IC1CD4069 the legs and IC2 CP, Q, Q, the legs should be half the supply voltage, the oscillator has been start-up. If a digital frequency meter measured IC1 output frequency, frequency regulation RW1 to 75 KHZ + /-10HZ can. If not, can be transferred to the prospective radios, RW2 half-good, and then transferred RW1, the bright lights stereo radio, and no speakers in the temple frequency whistle sounds. From the input into the stereo audio signal (1.5 Vpp, output amplifier available), this will be able to receive stereo radio broadcasting.

Input signal can be obtained from the line, but at R7 should be changed. Finally, can be transferred R7 to the smallest high-frequency noise, in fact R6, R7 equivalent BA1404 in 13, 14 feet of external components, the Pilot mixed signal and composite signal circuits, and input to the amplifier, the circuit of is 9014, and BA1404 from 12 feet on the entry.