Transmission circuitry for rectangular signals over long transmission path - has pair of twisted conductors respectively coupled at input end to collector and emitter of output transistor of optical coupler receiving signal, and conductors coupled at output by respective ohmic resistors

摘要

The transmission circuitry includes a pair of twisted electrical conductors (1,2) with a conversion screening, respectively coupled at the input end to the collector and emitter of an output transistor (8) of an optical coupler (3) receiving the rectangular signal. The conductors are coupled at the output end via respective ohmic resistors (R1, R2) to the positive and negative inputs of a difference amplifier (7) providing the rectangular signal at its output. The positive input of the difference amplifier is coupled to earth via a third resistor (R3), with a fourth resistor (R4) between the output of the difference amplifier and its negative input. ADVANTAGE - Simple transmission of signals over relatively long path without electromagnetic interference.