For a long pulse, the capacitor charge voltage will be > v, hence comparator outputs a high. Thus, we get pulses at the comparator output whenever input pulse widths exceed the required pulse width, ...

There are many ways to detect a heartbeat electronically. One of the simpler ways is to take [Orlando’s] approach. He’s built a finger-mounted pulse detector using a few simple componen… ...

Current-Reused Single-Ended Current-Output Multiplier as a Core Circuit in a UWB Pulse Detector FCC allocated 3.1 to 10.6GHz band as the spectrum of the Ultra-Wide Band Impulse Radio (UWB-IR) system.