Detecting the leading edge of a pulse

摘要

The level of incoming signal 32 is sensed by upper and lower hysteresis comparators 24,26 and a controller 22 in response operates positive and negative qualification timers 28,30 to determine whether the signal 32 has a valid leading edge. Signal 32 may be a heavily modulated RF signal (fig 2) such as a digitally modulated signal and valid leading and trailing pulse edges can be qualified without losing signal content, despite the presence of noise.