Mixing circuit composed of integrated analog multiplier (MC1496)

 At present, high-quality communication receivers mostly use diode ring mixers and mixers composed of dual differential pairs of balanced modulators. The mixing circuit
composed of an integrated analog multiplier ( MC1496 ) is shown in the figure.   The local oscillator voltage HL and the input signal voltage are input from the input channel respectively, and the 50kfl potentiometer is adjusted to make the DC potential difference between pins ① and ④ zero.   In addition to the input signal voltage P and the local oscillator voltage R, there are also interference and noise signals acting on the mixer. Any two of them may produce a combined frequency. If the frequency of these combined signals is equal to or close to the intermediate frequency, it will pass through the intermediate frequency amplifier and demodulator with the input signal, causing interference to the output stage and affecting signal reception, which is inevitable. The ground will cause interference, the most influential of which are intermediate frequency interference and image interference.     The intermediate frequency signal (9MHz) is taken out from the special band-pass filter after the single-ended output of pin ⑥.