Abstract: A symbol synchronizer, as for use with apparatus for detecting MPSK signals to provide complex sampled data descriptive of keying signal phase, in which the timing of the resampling can be controlled with resolution that is a fraction of the time between successive complex data samples.The symbol synchronizer uses a first digital controlled oscillator to recover the MPSK baseband signal sampled at a frequency f.sub.i rate. The MPSK signal is operated on to recover a sampled data description of the envelope of the MPSK signal sampled at a frequency f.sub.s, which may equal f.sub.i or be down-sampled therefrom. This is digitally filtered to provide a sampled data locking signal to a second digital controlled oscillator, which uses modular arithmetic to generate a digital sampled data description at f.sub.s rate of a sawtooth waveform repetitive at f.sub.k keying rate. In this second digital-controlled oscillator an adder sums its output as delayed by a full f.sub.