Second frequency conversion circuit block diagram

The block diagram of the second frequency conversion circuit of Toshiba TSR-CA satellite receiver is shown in the figure. This circuit is at the front end of the receiver and directly
receives the signal from the tuner . The tuner converts the microwave signal of the satellite into a first intermediate frequency signal of 950-1 750 MHz and then sends it to the second frequency
converter through RF amplifier 1, AGC circuit and RF amplifier 2 respectively to amplify the first intermediate frequency signal, and then through The channel preselector is sent to
the second mixer to mix with the local oscillator signal sent from the local oscillator. The mixer outputs the second intermediate frequency signal. The second intermediate frequency signal is amplified by the intermediate frequency
amplifier 1 and is amplified by two A band-pass filter composed of a surface acoustic wave filter (SAW) filters out interference signals outside the frequency band, and is finally
amplified by the second IF amplifier and sent to the FM demodulator (TA8754AF) for frequency identification. The video image signal and
audio carrier frequency signal are picked up from the intermediate frequency carrier wave and output from the ⑩ pin of the second frequency converter.