Remote control system capable of transmitting the information with the aid of an infra red beam using PPM or an ultrasonic beam using PDM

摘要

A remote control system for TV receiver control. The system uses infra-red transmission to trasmit an infra-red data pulse on each edge of a pulse duration signal comprising a coded pattern of binary 0 and 1 bits which are formed by pulses of respective different lengths. The original pulse duration signal can be reconstituted at a receiver by a bistable element which is responsive to the infra-red data pulses. Since the regenerated modulating waveform could be in anti-phase with the original modulating waveform, the sequence of data pulses is transmitted twice and an additional data pulse is transmitted between successive transmissions, so that one or the other of the two regenerated modulating waveforms must be in phase with the original modulating waveform.