New amplifier techniques

Three new techniques in television amplifier design are discussed. These are:¿ (a) The Cathode Repeater. (b) Shunt-regulated Amplifiers. (c) Feedback Amplifiers with desired amplitude frequency characteristics. (a) The Cathode Repeater represents the first of three attempts to improve upon the performance of simple valve amplifiers at video frequencies and it is shown that by its use, the designer has choice of input and output impedance. (b) Shunt-regulated Amplifiers are shown to have improved athplitude linearity, higher gain, improved frequency response and greater conversion efficiency than conventional amplifiers and are particularly attractive for television modulator applications. Some types have the properties of positive, zero or negative output impedance, positive, infinite or negative input impedance, and are stabilized inherently against supply fluctuations. (c) Feedback Amplifiers with desired amplitude frequency characteristics. It is shown that by the use of complex feedback, amplifiers may have amplitude frequency response characteristics of: Aperiodic flatness; Maximal flatness; Optimal flatness. It is shown that by the application of optimal feedback, stage gains comparable with those possible with 4-terminal coupling networks are easily achieved. Practical circuits and experimental results are given for all the technupies described.