JPH02124639A - Synthesized signal generator - Google Patents

Abstract

PURPOSE:To surely synchronize a frequency of an oscillator with a reference signal by keeping the output of a phase difference signal in a direction of decreasing an oscillated frequency till a difference component between an RF signal and the reference signal is within a prescribed frequency range. CONSTITUTION:A voltage controlled oscillator 6 whose oscillated frequency is changed in response to the voltage of an output signal of an integrator 5 and sending an RF signal is provided, and an identification circuit 9 keeps outputting a control signal to a phase comparator 5 to output a phase difference signal in a direction decreasing the oscillated frequency of the voltage controlled oscillator while the detector B8 cannot detect the output signal of the comparator 3. When the detector A7 detects the output signal of the converter 1 or the detector B8 detects the output signal of the comparator 3, the circuit 9 does not output a signal controlling the output of the comparator 4. The frequency of the oscillator is surely synchronized with the reference signal by pulling the output signal of the comparator 3 within a prescribed frequency range.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a synthesized signal generation device for use in devices that reliably synchronize the frequency of an RF output with a reference signal.

Prior Art FIG. 2 shows the configuration of a conventional synthesized signal generator. In FIG. 2, 1 is a frequency converter;
The RF multiplied signal and the reference signal A are combined and a signal of the component (RF signal multiplied reference signal A) is output to the low-pass filter 2.

A comparator 3 shapes the output signal of the low-pass filter 2 and outputs it to the phase comparator 4. 5 is an integrator which integrates the output signal of the phase comparator 4 and outputs it to the voltage controlled oscillator 6. The voltage controlled oscillator 6 outputs a frequency-controlled RF signal to the frequency converter 1 using the output signal of the integrator 5.

Next, the operation of the above conventional example will be explained. In FIG. 2, when the reference signals A and B are input, the frequency converter 1 outputs the sum of the RF multiplied signal and the reference signal A and the signal of the 3Bage difference component, and the low-pass filter 2 outputs the RF Only the signal of the difference component from the double signal reference signal A is taken out, and the comparator 3 shapes the waveform of the signal of the difference component from the RF double signal reference signal A. The phase comparator 4 has the above shaped R
The signal of the difference component from the F-fold signal reference signal A and the reference signal B are phase-compared and the phase difference signal is outputted, and the integrator 5 integrates this phase difference signal. Output as v-cho. At this time, by integrating the phase difference signal in the direction in which the oscillation frequency of the voltage controlled oscillator 6 approaches the sum of the reference signal A and the reference signal B, the RF ratio output frequency of the voltage controlled oscillator 6 is adjusted to the reference signal A and the reference signal B. It can be controlled to converge to signal B.

In this way, even with the conventional synthesized signal generator described above, the RF specific output frequency can be synchronized with the reference signal.

Problems to be Solved by the Invention However, in the conventional synthesized signal generation device described above, when the RF specific output frequency becomes higher than the frequency of the reference signal by a certain value or more, the (frequency converter ~ low pass filter) There was a problem in that the frequency-converted signal could not be detected due to the band limit, and the RF specific output frequency could not be synchronized with the reference signal.

The present invention solves these conventional problems, and aims to provide an excellent synthesized signal generator that can reliably synchronize the RF specific output frequency with the reference signal. be.

Means for Solving the Problems In order to achieve the above object, the present invention includes a detector for detecting the presence or absence of a signal at the output of the comparator 3 and the output of the frequency converter 1, respectively, and the output signal of the detector. An identification circuit is provided which converts the difference component from the RF multiplied signal reference signal A into an identification signal indicating whether or not it is within a certain frequency range and outputs the identification signal, and the output signal of this identification circuit controls the phase comparator, and the RF multiplied signal reference The phase difference signal 5 continues to be output in the direction of lowering the oscillation frequency of the voltage controlled oscillator 6 until the difference component from the signal A falls within a certain frequency range.

Therefore, according to the present invention, as described above, the frequency of the oscillator is decreased by continuing to output the phase difference signal in the direction of lowering the oscillation frequency until the difference component from the RF multiplied signal reference signal A falls within a certain frequency range. This has the effect of reliably synchronizing with the reference signal.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, blocks having the same functions as those of the conventional example are given the same numbers. A detector A 7 detects the output signal of the frequency converter 1 and outputs a detection signal to the identification circuit 9. A detector B 8 detects the output signal of the comparator 3 and outputs a detection signal to the identification circuit 9.

Next, the operation of the above embodiment will be explained. In the above embodiment, while the detector A7 cannot detect the output signal of the frequency converter 1, and at the same time the detector B8 cannot detect the output signal of the comparator 3, the identification port 6 and the page path 9 supply the phase comparator 4 with the voltage It continues to output a control signal that outputs a phase difference signal in the direction of lowering the oscillation frequency of the controlled oscillator 6. When the detector A7 detects the output signal of the frequency converter 1 or the detector B8 detects the output signal of the comparator 3, the identification circuit 9 stops outputting the signal for controlling the output of the phase comparator 4.

In this way, according to the above embodiment, the identification circuit 9 is connected to the phase comparator 4 until the detector A7 detects the output signal of the frequency converter 1 or the detector B8 detects the output signal of the comparator 3. , by continuing to output a control signal that outputs a phase difference signal in the direction of lowering the oscillation frequency of the voltage controlled oscillator 6 and pulling the output signal of the comparator 3 within a certain frequency range, the frequency of the oscillator is reliably synchronized with the reference signal. It has the effect of being able to

Effects of the Invention As is clear from the above embodiment, the present invention continues to output the phase difference signal 71\-7 in the direction of lowering the oscillation frequency until the difference component from the RF multiplied signal reference signal A falls within a certain frequency range. This has the effect that the frequency of the oscillator can be reliably synchronized with the reference signal.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a signal generator according to an embodiment of the present invention, and FIG. 2 is a schematic block diagram of a conventional signal generator. 1... Frequency converter, 2... Low pass filter, 3
... Comparator, 4... Phase comparator, 5... Integrator, 6... Voltage controlled oscillator, 7... Detector A, 8
...Detector B, 9...Identification circuit

Claims (1)

[Claims] a frequency converter that synthesizes the RF signal and the reference signal A;
From the output signal of this frequency converter, the RF signal and the reference signal A are
A low-pass filter that extracts only the signal of the difference component between the
A comparator shapes the output signal of this low-pass filter, and detects whether the difference component between the RF signal and the reference signal A is within a certain frequency range from the output signal of this comparator and the output signal of the frequency converter. an identification circuit that outputs an identification signal using the identification circuit; a phase comparator that compares the phase of the output signal of the comparator controlled by the output signal of the identification circuit with the reference signal B and outputs a phase difference signal; The RF
A synthesized signal generation device comprising a voltage controlled oscillator that sends out a signal.