Squelch in ISM-RF Receivers

By: Martin Stoehr

Abstract: Many industrial/scientific/medical (ISM) band radio frequency (RF) receivers use a simple external data slicer to generate the baseband digital output. These simple baseband systems can generate unwanted digital output when there are no active radio transmissions. This tutorial provides a basic description of squelch and gives examples for how to implement it in an amplitude-shift keying (ASK)/on-off keying (OOK) or frequency-shift keying (FSK) system.