A delta-sigma baseband phase detector realizing AGC-free PSK and FSK receivers

By directly detecting the phase of a baseband signal from the ratio of the in-phase and the quadrature phase components, a delta-sigma phase detector can realize an AGC-free mobile communication receiver. The paper studies the performance of the phase detector applied to digital communication systems. We explain theoretically the phase quantization noise of the detector and show the performance of a PSK/FSK receiver using it. Simulation results tell that the required clock frequency of the phase detector is less than a tenth of that of a conventional scheme which detects the phase of a limiting-amplified IF signal by digital processing.