JPH11237489A - Reference frequency generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate reference frequency signals in phase with the generation timing of absolute time of satellite wave, by providing a means imperatively synchronizing the output phase of an output frequency fout in absolute time of GPS time signal S1PPS. SOLUTION: The device is provided with a frequency converter A17b having a means receiving a reset pulse 51 from a phase reset controller 50 and resetting the output phase of the frequency converter A17b frequency-dividing an oscillation frequency of a voltage control oscillator 10 into a specific frequency ratio to the initial phase. The phase reset controller 50 receives the GPS time signal S1PPS in 1 second unit as an absolute reference timing and counts the time to be 1 hour, for example and resets the output phase of the frequency converter A17b in phase with the GPS time signal S1PPS after 1 hour elapsing to initial state. As the results, the phase of the output frequency fout is imperatively synchronized with the absolute time of satellite wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference frequency generator for receiving a radio wave from an artificial satellite having a built-in atomic frequency standard and generating a highly accurate reference frequency. The present invention relates to a reference frequency generator that can generate an output phase of a reference frequency generated and output by the reference frequency generator in synchronization.

[0002]

2. Description of the Related Art A conventional example will be described below with reference to an example of the configuration of a reference frequency generator shown in FIG. As a conventional known technique of a reference frequency generator that receives a radio wave from an artificial satellite and generates a highly accurate reference frequency, Japanese Patent Application Laid-Open
JP-A-6-314192 discloses a "reference frequency generator".

As one configuration of the reference frequency generating apparatus, as shown in FIG. 4, a satellite radio receiver 11, a time interval measuring unit 12, a frequency control arithmetic unit 13, a D / A converter 14, There is a configuration example including a frequency divider 15, a voltage controlled oscillator 10, a frequency converter A17, and a frequency converter B16.

According to the frequency control calculating means 13 having the above-described configuration, the GPS time signal S1pps based on the Coordinated Universal Time is determined by the long time constant and the feedback control corresponding to the digital PID control by the internal estimation calculating unit. A highly accurate and stable output frequency fou using a control algorithm that is not affected by disturbances imparted in the way or fluctuations caused by radio wave propagation.
Output t.

However, the phase difference data Tid between the GPS time signal S1pps on the satellite side and the internal time signal V1pps frequency-divided by the frequency divider 15 due to the aforementioned disturbance factors and other factors may not always converge to zero phase difference. is there. Alternatively, it takes a long time to converge to zero phase difference.

[0006]

As described above, in the conventional reference frequency generator, the GPS time signal S on the satellite side is used.
Regarding the phase difference relationship between 1 pps and the internal time signal V1 pps, there is a problem that the phase difference does not always converge to zero depending on the setting conditions of the digital filter having a long time constant.

As shown in FIG. 5, a plurality of two reference frequency generators are used at a distance of several tens of kilometers, and the plurality of reference frequency generators generate and output the output between fout1 and fout2. There is a use form in which it is required that the phases match. In such a use form, there is a problem that the output phases are not always synchronized due to the long time constant described above, and in such a use form, there is a practical difficulty.

It is an object of the present invention to provide a reference frequency generator capable of generating a reference frequency signal having a phase synchronized with the generation timing of the absolute time of the satellite radio wave.

[0009]

First, in order to solve the above-mentioned problems, according to the configuration of the present invention, a GPS time signal S1pp in units of one second, which is an absolute time signal upon receiving a GPS satellite radio wave, is provided.
A reference frequency generator, which includes a satellite radio receiver 11 for outputting s and outputs and outputs a high-precision output frequency fout gently following and synchronized with the GPS time signal S1pps,
The output phase of frequency conversion means (for example, frequency converter A17b) for receiving high-precision oscillation frequency 10f oscillating gently following PS time signal S1pps and generating and outputting output frequency fout divided by a predetermined frequency division ratio. For resetting to a constant phase state every predetermined time in synchronization with the pulse of the GPS time signal S1pps (for example, the phase reset control unit 5).
(0). According to the above invention, a reference enabling a reference frequency signal (output frequency fout) of a phase synchronized with the generation timing of the absolute time of the satellite wave to be generated between a plurality of reference frequency generators or a single reference frequency generator. A frequency generator can be realized.

FIG. 1 shows a solution according to the present invention. Second, in order to solve the above-mentioned problem, in the configuration of the present invention, the GPS satellite radio wave is received and the absolute time signal is 1
A satellite radio receiver 11 for outputting a GPS time signal S1pps in seconds; a time interval measuring unit 12, a frequency control operation unit 13, a D / A converter 14, a voltage controlled oscillator 10, a frequency converter A17b and the frequency converter B16
And a frequency divider 15 for generating and outputting a high-precision output frequency fout gently following and synchronized with the GPS time signal S1pps, and receives a reset pulse 51 from a phase reset control unit 50 described later. A frequency converter A17b having means for resetting the output phase of the frequency converter A17b for dividing the oscillation frequency of the voltage controlled oscillator 10 to a predetermined frequency division ratio to an initial phase;
Reference frequency generation, comprising: a phase reset control unit 50 that receives and counts the S time signal S1pps, initializes its own count value for each predetermined count value, and supplies a reset pulse 51 to the frequency converter A17b. There is a device.

FIG. 2 shows a solution related to the phase reset control section 50. The phase reset controller 50 receives and counts the GPS time signal S1pps,
It has a down counter 52 that sets its own count value to a predetermined count value when it reaches a zero value and repeatedly counts down. When a zero signal from the down counter 52 is received, it is reset at a timing synchronized with the GPS time signal S1pps. The reference frequency generator described above is provided with a reset pulse generator 56 that generates a pulse 51.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings together with embodiments.

FIG. 1 shows an example of the configuration of a reference frequency generator according to the present invention, which will be described below. This configuration is configured by adding a phase reset control unit 50 to a conventional component. However, it is assumed that the frequency converter A17b has a function of initializing and resetting the output phase.

As shown in FIG. 2, the internal configuration of the phase reset controller 50 includes a down counter 52 and a reset pulse generator 56. The corresponding frequency converter A
An example of the internal configuration of 17b is also shown. This frequency converter A
17b is an example constituted by a PLL circuit. In response to the oscillation frequency 10f output from the voltage controlled oscillator 10, the dividers 32, 33, and 37 divide the frequency into an M / P dividing ratio. This is a configuration example of outputting an output frequency fout that has passed only a fundamental wave component by a low-pass filter.
Here, P is the frequency division value of the frequency divider 32, and M is the frequency division value of the frequency divider 33.

The operation of the phase reset control unit 50 is a GPS time signal S1 in units of one second, which is an absolute reference time timing.
In response to the pps, the counting time which becomes a predetermined time interval, for example, one hour, is counted.
The output phase of the frequency converter A17b is reset to an initial state in synchronization with the time signal S1pps. As a result, the phase of the output frequency fout is forcibly synchronized with the absolute time of the satellite radio wave. However, the output frequency fout is disturbed at a time immediately after the output phase is forcibly set to the initial state. In this embodiment, however, the disturbance does not cause any trouble. Since the reference frequency generator itself has a high-precision oscillation frequency 10f that oscillates slowly following the GPS time signal S1pps, it is not necessary to frequently perform forced phase synchronization. Conversely, the GPS time signal S1pps itself has fluctuations or the like intentionally given in military terms. For this reason, it is better not to frequently perform the time interval for forcibly setting the output phase to the initial state, and practically, for example, a time interval of about one hour is preferable. Since two or more reference frequency generators located in remote locations are both receiving the same satellite radio wave, even if there is intentionally given fluctuation in military terms, the two The synchronization of the output phase between the reference frequency generators will not be lost.

The down counter 52 shown in FIG. 2 is a specific example using a preset down counter. Initially, a preset value 3600 corresponding to, for example, one hour is preset,
It counts down with the S time signal S1pps, supplies a count value zero signal to the reset pulse generator 56, and after itself presetting to a set value, starts counting down again repeatedly.

When the reset pulse generator 56 receives the zero signal from the down counter 52, the reset pulse generator 56 uses the clock of the oscillation frequency 10f output from the voltage
The reset pulse 51 having a timing synchronized with the time signal S1pps is generated and output once.

The frequency divider 37 in the frequency converter A17b
Is a frequency divider having a reset input terminal for determining the phase resolution of the output frequency fout to be output, and upon receiving the reset pulse 51, initializes and resets the value of the frequency dividing register to zero. As a result, the GPS time signal S1pps, ie,
As a result of being forcibly synchronized with the absolute time, a great advantage that the output frequency fout having the same output phase can be generated at any point in the remote place can be obtained.

The configuration of the present invention is not limited to the above embodiment. For example, in order to increase the phase resolution by the frequency divider 37, as shown in the configuration diagram of FIG. 3, the frequency conversion means 1 may be provided before the frequency converter A17c of FIG.
8, for example, the same PLL circuit or D
A synthesizer such as a DS (Direct Digital Synthesizer) or the like is inserted to output a frequency signal fout0 whose frequency has been converted to a target output frequency fout. The frequency converter A17c at the subsequent stage has a configuration in which the frequency divider 33 is omitted, and receives the frequency signal fout0. Therefore, an advantage that the frequency division ratio set value N of the frequency divider 37 can be increased is obtained. Further, the frequency converter A17b in FIG. 2 may be realized by a configuration using a synthesizer, a DDS, or the like having a function of receiving the reset pulse 51 and resetting the output phase.

[0020]

According to the present invention, the following effects can be obtained from the above description. As described above, the present invention sets the output phase of the output frequency fout to the GPS time signal S1p.
By providing a means for forcibly synchronizing with the absolute time of ps, it is possible to generate the output frequency fout having the same output phase at any point. As a result, it is possible to generate a plurality of reference frequencies at remote locations. There is a great advantage that the output phase of the output frequency fout of the reference frequency can be synchronized between the devices. Therefore, the technical effect of the present invention is great, and the industrial economic effect is also great.

[Brief description of the drawings]

FIG. 1 is a configuration example of a reference frequency generation device according to the present invention.

FIG. 2 is a configuration example illustrating a phase reset control unit of the present invention.

FIG. 3 is a configuration example illustrating another phase reset control unit of the present invention.

FIG. 4 is a configuration example of a conventional reference frequency generator.

FIG. 5 is an explanatory diagram of using two reference frequency generators between remote locations.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 voltage controlled oscillator 11 satellite radio receiver 12 time interval measuring unit 13 frequency control arithmetic unit 14 D / A converter 15, 32, 33, 37 frequency divider 16 frequency converter B 17, 17b, 17c frequency converter A 18 Frequency conversion means 50 Phase reset control unit 52 Down counter 56 Reset pulse generation unit

Claims (3)

[Claims] 1. A satellite radio receiver which receives a GPS satellite radio wave and outputs a GPS time signal in units of one second, which is an absolute time signal, comprises a high-precision output frequency fout which gently tracks and synchronizes with the GPS time signal. A reference frequency generator for generating and outputting an output of a frequency conversion means for receiving and outputting a high-precision oscillation frequency oscillating gently following the GPS time signal and generating and outputting an output frequency fout divided by a predetermined dividing ratio. A reference frequency generator comprising means for controlling the phase to a fixed phase state in synchronization with the pulse of the GPS time signal. 2. A satellite radio receiver which receives a GPS satellite radio wave and outputs a GPS time signal in units of one second, which is an absolute time signal, includes a time interval measuring unit, a frequency control arithmetic unit, and a D / A converter. , A voltage-controlled oscillator, a frequency converter A, a frequency converter B, and a frequency divider, and a high-precision output frequency fou gently following and synchronized with the GPS time signal.
A reference frequency generator that generates and outputs t, resets an output phase of a frequency converter A that divides an oscillation frequency of a voltage controlled oscillator to a predetermined division ratio in response to a reset pulse from a phase reset control unit to an initial phase. A frequency converter A having means for performing the following operations: a phase reset controller for receiving and counting the GPS time signal, initializing its own count value for each predetermined count value, and supplying a reset pulse to the frequency converter A; A reference frequency generator comprising: 3. A down-counter for receiving and decrementing the GPS time signal, setting its own count to a predetermined count when the GPS reset signal reaches a zero value, and repeatedly subtracting and counting. 3. The reference frequency generator according to claim 2, further comprising: a reset pulse generator that generates a reset pulse at a timing synchronized with a GPS time signal when a zero signal is received.