Transistorized 2¿24 channel carrier telegraph equipment

The transistorized 2×24-channel carrier telegraph equipment consists of two FM (frequency modulation) type 24-channel systems in a bay, as recommended by the CCITT (International Telegraph and Telephone Consultative Committee). Taking account of the major weakness of the transistor circuit and of the center frequency variation of the FM system caused by temperature rise, the various parts and circuits have been specially designed, including, for example, the use of afc (automatic frequency control), electronic relay, and special circuits for the oscillator and discriminator. This paper describes these features and characteristics.