Periodic noise suppression circuit for telecommunication system - uses interrupt switch to break link when motor thyristors noise appears

摘要

The periodic noise suppression circuit prevents the periodic noise generated by thyristors or triac etc. used to control motors from interfering with the quality of reception in a voice or data telecommunications system. This is achieved by using the noise to open a switch connected into the voice or data path. A first timer (containing a noise-spike integrator) is started by the noise spike and has a period less than that of the noise itself. At the end of this timer's period a second timer is started having a period equal to or larger than the duration of the noise. This second timer operates the interrupt switch.