FM radio high frequency amplification and mixing circuit

Shown is the high amplifier and mixing circuit of an FM radio . VT2 (2SC930) is the local oscillator of FM . The radio frequency (RF) radio signal received by the antenna is sent to the base of the VT1 high-frequency amplifier , and then amplified by VT1 and output from the collector to the base of the mixer VT3. At the same time, the oscillation signal of the local oscillator VT2 It is also sent to the base of mixer VT3. The two signals are mixed in VT3. After the output selected by the intermediate frequency transformer Ti, the intermediate frequency signal (10.7 MHz) is sent to the base of the intermediate frequency amplifier circuit VT4. After VT4 is amplified, the collector output is output through the intermediate frequency filter CF1. Then sent to the frequency identification circuit.