Frequency and phase comparator

Claim 2

A frequency and phase comparator comprising: a. a reference signal oscillator, b. a voltage controlled oscillator producing a rectangular wave sIgnal, c. means for generating a sawtooth wave signal supplied with said rectangular wave signal, said sawtooth wave signal having the same frequency as that of said rectangular wave signal, d. a sampling and hold circuit supplied with said sawtooth wave signal and said reference signal and producing a DC signal proportional to the phase difference therebetween, said DC signal being supplied to said voltage controlled oscillator so as to phase lock its phase with respect to that of reference signal within a predetermined value, e. means for discriminating the frequency difference of said reference signal and said rectangular wave signal and producing an output signal when the frequency difference exceeds a predetermined range, f. control means supplied with said output signal so as to hold the amplitude of said sawtooth wave signal at its maximum or minimum values; whereby said frequency of said voltage controlled oscillator is controlled until the frequency difference falls within said predetermined frequency range.

Claim 3

A frequency and phase comparator according to claim 1, wherein said frequency discriminator comprises: a. a sawtooth wave signal generator receiving said rectangular wave signal from said voltage controlled oscillator, b. rectifying means receiving said sawtooth wave signal and producing a DC signal proportional to the frequency thereof, c. a DC voltage comparator receiving said DC signal and a reference DC signal, and d. switching means receiving an output signal of said DC voltage comparator and producing a control signal for controlling the amplitude of the sawtooth wave signal of said sawtooth wave signal generating means.

Claim 4

A frequency and phase comparator according to claim 2, wherein said DC voltage comparator includes a differential amplifier and said switching means includes a plurality of switching transistors.

Claim 5

A frequency and phase comparator according to claim 3, wherein said differential amplifier comprises first and second transistors with their base electrodes receiving said DC signal and said reference DC signal, the collector and emitter electrodes of said first and second transistors connected between ground and a voltage source through a common emitter resistor and collector loads, respectively, said switching transistors includes a third transistor whose base and emitter electrodes are connected between the collector electrode of one of said first and second transistors and the collector electrode of the other of said first and second transistors, respectively, and its collector electrode connected to one terminal of said voltage source through a collector load, and a fourth transistor whose base and emitter electrodes are connected between said collector electrode of said other one of first and second transistors and collector electrode of said one of said first and second transistors, respectively, and its collector electrode connected to said one terminal of said voltage source through a collector load whereby said control signal is produced across said collector loads of said third and fourth transistors.

Claim 6

A frequency and phase comparator according to claim 1, wherein said sampling and hold circuit comprises: a. a diode bridge circuit having at least four diodes which are connected with the same polarity to each other, and having an input terminal connected to a first connection point thereof and an output terminal connected to a second connection point thereof; said input terminal being supplied with said sawtooth wave signal, b. a pair of pulse transformers each having primary and secondary windings, with each secondary winding being connected between a third connection point of said diode bridge circuit and one terminal of a voltage source, and between a fourth connection point of said diode bridge circuit and the other terminal of said voltage source, respectively, a switching transistor, said each primary windings being connected across said teRminals of said voltage source through the collector and emitter electrodes of said switching transistor, said reference signal supplied to the base electrode of said switching transistor, c. a capacitor connected between said output terminal of said diode bridge circuit and a reference point; whereby said output terminal produces said DC signal proportional to the phase difference between said reference signal and said sawtooth wave signal.

Claim 7

A frequency and phase comparator circuit according to claim 5 including a field effect transistor with its gate connected to the output terminal of said diode bridge and its drain electrode connected to a voltage source, a load resistor connected between its source electrode and ground and an output terminal connected to said source for supplying said DC signal proportional to the phase difference between said reference signal and said sawtooth wave signal and supplied to said voltage controlled oscillator to control it.