A Tuneable CMOS Pulse Generator for Detecting the Cracks in Concrete Walls

Abstract

A CMOS impulse generator was designed as a part of Ultra Wide Band (UWB) wireless communication system. An input square wave signal is delayed by using differential pairs and then XORed with the input signal to produce short duration pulses. An RLC circuit works as a Band Pass Filter (BPF) used to generate Gaussian monopulse from the obtained short duration pulses. It operates with center frequency at 4.782 GHz and -3dB band width of 20.36 GHz. The output peak to peak amplitude of the signal is 44.11 mV with pulse duration of 300 picoseconds. The UWB pulse generator has been simulated in 0.18μm CMOS technology.