AbstractThe output of a doubly-balanced mixer of atelevision tuner is terminated by a network which exhibitsthe characteristic impedance of the mixer for both the sumand difference frequency components. The differencefrequency component termination simply consists of aninductor and a capacitor connected as a series-tunedcircuit and a resistive element connected in seriesbetween the output of the mixer and signal ground. Theinductor and capacitor are selected resonate at afrequency in the passband of the IF section and theresistive element is selected to exhibit thecharacteristic impedance of the mixer. The sum frequencycomponent termination simply consists of a capacitor and aresistive element connected in series between the outputof the mixer and signal ground. The capacitor is selectedto exhibit negligible impedance just below the lowestfrequency of the sum frequency component and the resistiveelement is selected to exhibit the characteristicimpedance of the mixer.
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