Synchronisation of distant digital equipment - employs returned clock pulses to block clock counter unless pulses are coincident

摘要

Synchronisation of digital equipment located some distance from the principal equipment is obtained by compensating for transmission time delay. Clock signals are returned by the remote equipment to block the clock counter except when there is coincidence. Clock pulses are applied through a gate (7) to a binary counter (8) for application to a bipolar pulse generator (10). These signals are gated (26) with signals from a logic gating circuit (25) for transmission to the remote equipment via a two way cable. Returned signals enter an integrity detector (17) whose output is applied to a coincidence gate (23) with sync. frame signals (2). A bistable (24) ensures that the counter is blocked when non-coincidence occurs.