DIGITAL PHASE DETECTOR

摘要

A digital phase detector which periodically detects the phase angle .theta.k of a carrier signal in which data are encoded as phase changes. A coherent or differential phasemodulated carrier signal is split into its in-phase and quadrature phase components RoSin .theta.(t) and RoCos .theta.(t). Each signal component is sampled at a predetermined modulation interval and converted into a digital word having the form RoCos .theta.k and RoSin .theta.k. In one configuration, the two signal components are applied to a digital divider network which forms the quotient ? of the two digital words such that ¦?¦ ? 1. The quotient ? is applied to a data look-up ROM, programmed for Tan-1 operation, which forms a digital reference phase angle .PHI. limited to an angle ? 45.degree.. Phase angle .PHI. is corrected by selection logic to form the desired phase angle .theta.k. Once .theta.k is known for each modulation interval, the encoded data may be readily extracted, since .theta.k represents the encoded data.