Electronic and IR optical system for PCM transmission - has modulation stage with pulse shapers controlled by Schmitt trigger circuit and monostable stage

摘要

The pulse modulated transmission system uses time multiplex transmission and infra-red radiation in a quasi optical arrangement. The arrangement has pulse modulated signals passed to a monostable timing stage for transformation into needle pulses and connected by a coaxial cable through a protective resistance to a Schmitt trigger stage for regenerating the pulse edges. This is followed by a delay stage and a pulse shaper operated by increasing edges of the pulses. The radiation system has e.g. three inputs, each with an input capacitor connected across it passing control pulses through a monitoring resistance to an infra-red diode. This is followed by two parallel branches each with a parallel capacitor and resistance, to a pair of switching transistors with a load switch on each base, forming pulse, driver stages. Connected to each input is a monitoring transistor stage with an AND-gate at the output.