Transmitting electrical signals with a transmission time independent of distance between transmitter and receiver

摘要

Two time varying signals are transmitted in opposite directions over transmission means between signal generator means and a signal receiver. The signal receiver includes means for sensing when the combination of signals arriving at the receiver reaches a predetermined trigger state, and the generator means includes means for causing the signals to vary with time in a manner selected to cause the signal combination to reach the trigger state at a time dependent upon the length of the transmission means but independent of the distance between the generator and receiver.