Abstract A clock synchronizing circuit comprises a voltage controlled oscillator (VCO) (5) for producing an output signal whose oscillation frequency changes in response to control signals (S3). A phase comparator (1) compares a phase of an input signal and a phase of the output signal to thereby generate a phase difference signal (S1). A filter (2) filters the phase difference signal to thereby output a filtered phase difference signal (S2). A frequency synchronizing circuit responsive to the filtered phase difference signal generates a first compensation signal for controlling a frequency of the output signal. A phase synchronizing circuit responsive to the filtered phase difference signal generates a second compensation signal for controlling a phase of the output signal. A signal supplying circuit feeds the first and second compensation signals as said control signals.
A clock synchronizing circuit comprising: a voltage controlled oscillator (VCO) for producing an output signal whose oscillation frequency changes in response to control signals; comparing means for comparing a phase of an input signal and a phase of said output signal to thereby generate a phase difference signal; filter means for filtering said phase difference signal to thereby output a filtered phase difference signal; frequency synchronizing means responsive to said filtered phase difference signal for generating a first compensation signal for controlling a frequency of said output signal; phase synchronizing means responsive to said filtered phase difference signal for generating a second compensation signal for controlling a phase of said output signal; and means for feeding said first and second compensation signals as said control signals.
Claim 2
Dependent Claim
39 words
A circuit as claimed in claim 1, further comprising: means for generating an interruption signal on detecting interruption of said input signal; and means responsive to said interruption signal for controlling generation of said first and second compensation signals.
Claim 3
Dependent Claim
34 words
A circuit as claimed in claim 1 or 2, further comprising: means for generating a temperature compensation signal matching an ambient temperature; and means for adding said temperature compensation signal to said control signals.
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