Signal demodulator including data normalization

A digital demodulator for recovering a baseband signal from a selectable bit rate PSK modulated signal. Carrier recovery and bit timing recovery are accomplished by using the digital equivalent of an analog in phase-quadrature (I/Q) phase locked loop. The recovered I and Q components are directed through matched filters to remove unwanted out-of-band signal components. A normalization loop responds to the output of the filters to provide normalized signals whose amplitudes do not significantly vary with changes in data rate or signal to noise ratio. Circuitry is provided for tailoring the parameters of a loop filter used in the carrier recovery loop in accordance with the data rate of the incoming signal. A lock detector is provided for determining the signal-lock status of the demodulator, and for controlling the operation of a carrier sweep control. Several numerically controlled oscillators are disclosed for use in the carrier recovery and bit timing recovery loops.