A single-channel and multi-channel coherent demodulation devices with no pil ot signal

摘要

The estimation of phase derived from a predetermined summing function is used in a PPL circuit to determine phase and allow demodulation of signals. An estimation of phase shift is obtained by producing a signed value with respect to the argument of the summed signal, with the aid of a predetermined function. The summed signal is itself obtained from the received signal by demodulation in quadrature, complex de-spreading and summing of N samples. The phase shift estimation is used in a phase locked loop circuit, so that the system converges on a null error. Further circuits are provided in order to lift the residual static phase ambiguity introduced by the application of the predetermined function.