Differential and pseudo-coherent digital data demodulator - proceeds two quadrature components by mixing with time delayed components using delay circuits and low-pass filter

摘要

The demodulator is used for differential and pseudo coherent digital signals and has an input for receiving an intermediate frequency, modulated carrier, a carrier reference frequency signal generator and a coupler connected to receive the generator outputs of two quadrature components of the reference signal. Two linear mixers receive the respective components and are also coupled to receive the demodulator input signal. The mixer outputs are coupled through respective low pass filters to delay circuits which apply a delay period T to the signals, a processor has inputs connected both to the delay circuits inputs and outputs to receive signals at a given time. The processor effects at least a combination of the four components to provide a resulting signal characteristic of the modulation. (17).