U.H.F. television transmitter

The paper describes a low-level driver transmitter for both vision and sound, which has full colour-correction circuits, and which gives an output power on vision carrier of 10W, or 75W if an extra amplifier is included. This driver transmitter may be used to drive any one of a series of medium- or high-power vision and sound amplifiers. In this paper one such amplifier, rated for vision at 25kW, is described. The equipment is designed for any of the following CCIR standards: G, H, I and K, and for the FCC standard. The relative merits of klystrons and tetrodes for the main amplifier are discussed, and the reasons for finally using klystrons are given. A new form of video modulation is described, and its advantages of simplicity of operation and high quality of performance are explained. Correction circuits for colour performance are explained, and the performance obtained is described.