JPS5735774A - Synchronizing system for supersonic switch - Google Patents

Abstract

PURPOSE:To prevent mutual interference between similar aparatus in an apparatus that detects existence of bodies by sending and receiving supersonic pulses by emitting a synchronizing signal of different frequency while reflected waves are present and suppressing a trigger signal while receiving a synchronizing signal. CONSTITUTION:By instruction of a trigger circuit 1, an oscillator 2 outputs f1 and an oscillator 12 outputs a synchronizing signal f2 and emits through an adder 11, an amplifier 3 and a transmitter 4. The output of a wave receiver 5 separates f1 in a filter 13 and controls the oscillator 12, and at the same time, rectifies and shapes in a signal processing circuit 15 to make it an output signal. The f2 separated in the filter 14 controls the trigger signal generating circuit 1 by a trigger suppressing signal generating circuit 10 through a rectifying circuit 16. However, while reflected waves f1 are present, the oscillator 12 continues to work by the output of the filter 13. The signal processing circuit 15 is controlled by a gate circuit 9 that determines timing to prevent detoured entrance of direct waves and incidence from remote places beyond the object of detection. By this way, mutual interference between nearby similar apparatus can be prevented surely through radio frequency f2.