Abstract A phase synchronizing circuit includes a voltage-controlled oscillator wherein the oscillatory frequency changes around a center fo by control against a digital input signal being modulated in n-phases of which the carrier frequency is f0; nphase detectors; n-comparators; a logic circuit having n-input terminals which performs an ''''exclusive or'''' or ''''negation of exclusive or'''' operation; and, a low-pass filter. The input signal, an output of the oscillator and the n-phase detectors are connected so as to detect PHASE COMPONENTS IN THE INPUT SIGNAL WHEREIN AN OUTPUT OF THE OSCILLATOR IS THE REFERENCE PHASE. The outputs of each detector are applied to the n-comparators respectively, the outputs of the n-comparators to n-input terminals of the logic circuit, and the output of the logic circuit is connected so as to control the oscillatory frequency of the voltage-controlled oscillator through the low-pass filter.
A phase synchronizing circuit comprising: a voltage-controlled oscillator whose frequency may be varied around the center frequency fo with respect to a digital input signal modulated in n-phases and a carrier frequency fo; n-phase detectors coupled to said oscillator to detect phase components of the iNput signal; n-comparators coupled respectively to said detectors; a logic circuit having n-input terminals respectively coupled to said comparators for determining ''''exclusive or'''' or ''''negation of exclusive or'''' function; and a low-pass filter coupled between said logic circuit and said voltage-controlled oscillator for controlling the oscillatory frequency of said oscillator.
Claim 2
Dependent Claim
95 words
A phase synchronizing circuit comprising: a voltage-controlled oscillator whose frequency may be varied around the center frequency fo with respect to a digital input signal modulated in n-phases and a carrier frequency fo; n-phase detectors coupled to said oscillator to detect phase components of the iNput signal; n-comparators coupled respectively to said detectors; a logic circuit having n-input terminals respectively coupled to said comparators for determining ''''exclusive or'''' or ''''negation of exclusive or'''' function; and a low-pass filter coupled between said logic circuit and said voltage-controlled oscillator for controlling the oscillatory frequency of said oscillator.
Claim 3
Dependent Claim
32 words
A phase synchronizing circuit claimed in claim 1, further comprising a clock pulse source; and n-samplers receiving clock pulses from said clock pulse source, and coupled, respectively, between said n-comparators and n-detectors.
Claim 4
Dependent Claim
31 words
The phase synchronizing circuit claimed in claim 1, in which n 2, and further comprising a phase shifter of pi /2 coupled between said oscillator and one of said phase detectors.
Claim 5
Dependent Claim
31 words
The phase synchronizing circuit claimed in claim 2, in which n 2, and further comprising a phase shifter of pi /2 coupled between said oscillator and one of said phase detectors.