FM-AM tuning circuit

Shown is an FM/AM tuning circuit , the main body of the circuit is AN 7273/S. The intermediate frequency amplification and frequency discrimination
circuit of FM radio circuit, and the high frequency amplification, local oscillator, mixing, intermediate frequency amplification and detection circuit of AM radio are all integrated in AN 7273/S. The AM radio
frequency signal is input through pin ③, the FM intermediate frequency signal is input through pin ①, and the audio signal is output from pin @ after internal processing. Pin @ outputs AM intermediate frequency signal
, which is sent to the intermediate frequency amplification circuit in pin ⑦ via intermediate frequency transformer T3 and intermediate frequency filter CF1. The @ pin is connected to the frequency identification coil , and the @ pin is connected to the AM
local oscillator coil .