Synchronization system for pulse orthogonal multiplexing systems

Claim 1

A synchronization system for synchronizing the demultiplexer of a pulse orthogonal multiplexing system in both frequency and phase with respect to the received signals from the multiplexer, comprising: a. a system input to which signals from the multiplexer are fed; b. a voltage controlled oscillator which is controlled in frequency and phase to provide a reference frequency to be phase locked with the multiplexer; c. a demultiplexer waveform generator connected to the output of said voltage controlled oscillator for generating synchronization waveform signals used for phase locking with input signal waveforms from the multiplexer; d. an active loop filter which includes loop filter portions for frequency acquisition, coarse phase-lock and fine phase-lock, respectively; e. first, sEcond, third and fourth multipliers, each of which derive a d.c. voltage as a function of the phase angle between the input signals from the multiplexer and respective synchronization waveform signals from the demultiplexer waveform generator; f. frequency acquisition phase-lock circuitry which includes a first switch means operable to be connected between said system input and the input of said voltage controlled oscillator via the frequency acquisition portion of said active loop filter for controlling said oscillator upon actuation of said first switch means, said first multiplier output operating to actuate said first switch means; g. coarse phase-lock circuitry which includes said second multiplier and a second switch means connected between said system input and the input of said voltage controlled oscillator via the coarse phase-lock portion of said active loop filter, also for controlling said oscillator and operable to be disconnected upon actuation of said second switch means; said fourth multiplier output operating to actuate said second switch means; h. fine phase-lock circuitry which includes said third multiplier connected between said system input and the input of said voltage controlled oscillator via the fine phase-lock portion of said active loop filter also for controlling said oscillator; i. select synchronization subcarrier waveforms from said demultiplexer waveform generator being used to actuate said first, second, third and fourth multipliers, respectively; j. said frequency acquisition phase-lock circuitry initially acquiring the frequency of an unknown incoming signal received from the multiplexer at said system input; k. said coarse phase-lock circuitry providing a phase-error signal to reduce phase error; l. said fine phase-lock circuitry providing final synchronization adjustment; m. said frequency acquisition and coarse phase-lock circuits being sequentially switched out of operation by said first and said second switch means, respectively, as each step in synchronization is achieved wherein continuous monitoring of the synchronization status and exclusion or inclusion of error signals is automatically achieved to optimize synchronization performance.