Slips of the Pen.

A communication system with same frequency repeater station capability operates on a single channel and generally includes at least one repeater station which receives and transmits simultaneously on a single frequency, and a plurality of remote receiver transmitting stations, all of which operate on the same frequency as the repeater station. The repeater station includes a continuously operating transmitter, the keying of which is controlled by a local oscillator. Each of the remote stations includes a similar transmitter which is normally quiescent, but which is energized for local modulation and transmission by a push-to-talk button. Each cycle of the repeater station oscillator is modified by pulses received from a remote transmitting station, to reduce or increase the period as needed to produce identical periods and synchronization in each oscillator. The pulses received at the repeater station are not perceptible during its own transmission and hence, no control is then exerted. Hence, an equilibrium condition is immediately established at the repeater station in which the departure from coincidence of transmitted and received pulses at the repeater station is proportioned to its need for control. The transmissions from the repeater station are received by the remote stations not then transmitting. Intelligent modulation of the pulse period at these receiving remote stations is then evident and may be recovered.