Theoretical Notes on Certain Features of Television Receiving Circuits

Four main items are treated in these notes. The first is the determination of the product of capacity and resistance required in a television amplifier in order that the distortion of low-frequency flat-topped waves shall not exceed a specified percentage, the wave being passed through a single stage of resistance coupled amplification. The influence of multiple-spiral scanning systems is mentioned. The second item deals with the addition of small amounts of inductance to the circuit of a resistance coupled amplifier. A set of generalized graphs are presented for the purpose of greatly expediting computation of the best amount of inductance to use for given conditions. One pair of curves shows results for a simple case, without inductance, corresponding to the resistance couplied amplifier. One curve of the pair is used for the amount of amplification, the other for the phase shift which corresponds to this. A second pair of curves deals with the condition of added inductance best suited to minimum phase shift, while a third pair deals with the condition obtained with the amount of inductance best suited to constant amplification. The third item shows the use of these curves by applying them to specific cases. The fourth item refers to the use of a type of push-pull detector circuit useful for minimizing the by-passing of desired high-frequency currents in the output of a detector.