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Apparatus and method for synchronizing an SCDMA upstream or any other type upstream to an MCNS downstream or any other type downstream with a different clock rate than the upstream

  • US 6,243,369 B1
  • Filed: 05/06/1998
  • Issued: 06/05/2001
  • Est. Priority Date: 05/06/1998
  • Status: Expired due to Term
First Claim
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1. A data transceiver node, comprising:

  • a master clock having an output at which a master clock signal is generated;

    a timebase having an input coupled to receive said master clock signal and having an output at which a downstream and upstream clock signal generated from said master clock signal appears, each of said upstream and downstream clock signals being phase coherent with said master clock signal;

    a downstream data input;

    an SCDMA downstream modulator coupled to said downstream data input and coupled to receive said downstream clock signal and having a chips output;

    a downstream carrier synthesizer coupled to receive said master clock signal and having a downstream carrier output at which a downstream carrier appears which is phase coherent with said master clock signal;

    a first mixer having a first input coupled to said chips output and having a second input coupled to said downstream carrier output and having an output at which modulated downstream signals appear for coupling to a transmission media or media transmitter;

    a second mixer having an input for coupling to a transmission medium or media receiver, and having a carrier input for receiving an upstream carrier, and having an output at which baseband demodulated upstream signals appear;

    an upstream carrier synthesizer coupled to receive said master clock signal and having an output at which a synthesized upstream carrier signal appears which is phase coherent with said master clock signal, said output coupled to said carrier input of said second mixer; and

    an SCDMA upstream demodulator having an input coupled to said output of said second mixer and having an input coupled to receive said upstream clock signal, and having an output at which recovered upstream data appears, and including means for correcting phase and amplitude errors in incoming constellation points transmitted from other data transmission nodes located at varying distances from said data transceiver, and further comprising means for achieving frame synchronization or minislot boundary synchronization.

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