Band I television-transmitter design, with particular reference to the transmitters at Crystal Palace

The paper describes television transmitting equipment designed to operate in two parallel chains to ensure reliability. The vision transmitters are designed to work with considerable distortion and noise in the input signal, and the noise-rejection and clamp circuits developed for this purpose are discussed. The use of tetrodes in the output stage of the vision transmitter enables receiver-type valves to be used throughout the modulator, and permits the advantage of high-level modulation to be exploited. The methods of phasing of both radio and vision frequencies are described. The implications of colour television on design are discussed and the means adopted in these transmitters to assure faithful colour transmission are described.