Periodic signal appts. for signal transmission paths - tests quality by injecting digital square wave signal for evaluation by shift register and comparator together with reference

摘要

Test signals (2) in the form of square wave inputs are fed to an A-D converter (4) coupled to a line (5) that supplies a shift register (A). In addition short duration signal 'spikes' (3) are also supplied. Within the clock period of the A-D converter the pulses are moved between register stages (a1-a14). The register has ten outputs fed to multiplier stages together with the outputs of a memory (B) providing a reference pulse (6). The values are added together (7) to supply an output shift register (C) that provides a well defined signal output. ADVANTAGE - Efficient noise suppression for fast testing requiring no synchronisation of test signal.