Pulse-time modulated multiplex radio relay system-terminal equipment
14 June 1946
The terminal equipment for a 24-telephone channel duplex p.t.m. relay system is described for use on a transmission bandwidth of 2.8 Mc/s. The pulses representing the channels plus a "marker" are switched in sequence by the Cyclophon, a c.r.t. with rotating electron beam which acts as a cyclic switch and modulator, or demodulator. Advantages claimed are: (1) improved signal/noise ratio; (2) min. interchannel crosstalk, independent of the number of repeater stations; (3) an output unaffected by transmission vagaries.