Demodulation apparatus for a time-divisional multiplex phase-shift keyed signal of burst mode

Claim 1

A demodulation apparatus for performing coherent detection and code regeneration of a time divisional multiplex phase-shift keyed (PSK) signal of burst mode including signals transmitted from a plurality of communicating stations, comprising: input terminal means for receiving said PSK signal, a plurality of reference carrier regenerators each for regenerating a reference-phase carrier wave for said coherent detection, means for generating a first control pulse at the start or end of each burst, a first switching means connected to said first control pulse means for actuation by said first control pulses, said first switching means having contacts coupled to said input means and inputs of said reference carrier regenerators for successively distributing the PSK signal to The reference carrier regenerators in response to said first control pulses generated in synchronism with the start or end of each burst, means for generating a second control pulse after a first delay time, as measured from each first control pulse, wherein said first delay time is equal to the time necessary to produce the reference-phase carrier wave of a desired signal-to-noise ratio in each of the reference carrier regenerators, a second switching means connected to said second control pulse means for actuation by said second control pulses, said second switching means having an output contact which is successively coupled to outputs of said reference carrier regenerators for successively switching the outputs of the reference carrier regenerators in response to the second control pulses, a delay means coupled to said input terminal means for delaying the PSK signal for a time equal to said first delay time, a coherent detector having a first input coupled to an output of the delay means and a second input coupled to said output contact of the second switching means for performing said coherent detection of the PSK signal passed through the delay means by the use of the output of the second switching means, a plurality of clock regenerators each for regenerating a clock wave for said code regeneration, a third switching means connected to said second control pulse means for actuation by said second control pulses, said third switching means having contacts coupled to said input terminal means and to the inputs of said clock regenerators for successively distributing the PSK signal to the clock regenerators in synchronism with the first control pulses a fourth switching means connected to said third control pulse means for actuation by said third control pulses, said fourth switching means having contacts coupled to the output of said clock regenerators for successively switching the outputs of the clock regenerators in synchronism with the second control pulses, and a code regenerator coupled to outputs of said coherent detector and said fourth switching means for receiving the output of the coherent detector and for performing said code regeneration by the use of the output of the fourth switching means.