JPH03214069A - Phase measuring apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a phase measuring device that measures the phase difference between two alternating current signals.

(Prior Art) As a conventional phase measuring device of this type, there is one shown in FIG. In the figure, one of two alternating current signals (sine waves) whose phases are compared with each other is applied to a rectangular wave conversion circuit 1 as a reference input and the other as an input to be measured. The rectangular wave conversion circuit 1 converts each input AC signal waveform into rectangular wave signals a and b having the same phase as the AC signal waveform, and outputs the rectangular wave signals a and b. Among these, the rectangular wave signal a is applied to the frequency multiplier circuit 2. A phase-locked loop circuit is generally used as the frequency multiplier circuit 2, and outputs a clock signal with a frequency that is 360×10 times the frequency of the rectangular wave signal a. This clock signal f is applied to the phase measuring circuit 3 together with the aforementioned rectangular wave signals a and b. The phase measurement circuit 3 increments the clock signal f by 1 from a level change point of the rectangular wave signal a to a similar level change point of the rectangular wave signal A, and outputs a phase difference signal PH corresponding to the counted value.

In this case, by generating a clock signal f that is 360×1on times as large as the rectangular wave signal a and counting it, the phase Z can be measured in units of 0.1 degree, for example, if n-1.

(Three problems to be solved by the invention) In the conventional phase measuring device described above, since a phase-locked loop circuit is used as the frequency measuring circuit 2, the frequency nI variation range of the 01-frequency oscillator is Due to the limitations, the frequency range that can be multiplied by 1g is narrow, and the frequency range that can be measured is limited.

Incidentally, in a device that measures a phase difference at a midpoint of 0.1 degree using a commercial power source as a scorching phenomenon, the frequency range is limited to approximately 45 to 65 [Hzl].

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a phase measuring device that can expand the measurement frequency range.

[Structure of the invention]

(Means for Solving the Problems) For example, when measuring the phase difference between two alternating current signals, the present invention provides two inputs that serve as a reference input and an input to be measured, as shown in the block diagram of FIG. rectangular wave converting means 11 for converting alternating current signals into rectangular wave signals having the same phase, and frequency measuring means 12 for measuring the frequency of the alternating current signals;
A clock generating means 13 receives the frequency signal of the frequency measuring means 12 and generates a clock signal having a frequency of a predetermined magnification with respect to the measurement frequency, and one of the rectangular wave signals converted by the rectangular wave converting means 11. and a phase measuring means 14 for counting the clock signal of the clock generating means 13 from a level change point of the other rectangular wave signal to a similar level change point of the other rectangular wave signal to generate a phase difference signal.

(Function) In this invention, the frequency of the alternating current signal is measured by the frequency measuring means 12, and using the obtained frequency signal,
Since the clock generating means 13 generates a clock signal having a frequency that is a predetermined multiplier with respect to the measurement frequency, a rate multiplier circuit, for example, can be employed as the clock generating means 13, and the reference clock The range of measurement frequencies can be expanded simply by appropriately selecting the signal frequency.

(Embodiment) FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 3 indicate the same elements. A frequency measurement circuit 22 and a clock generation circuit 23 are used in place of the frequency multiplier circuit 2 in FIG. 3, and their configurations are shown in more detail. Here, the frequency measurement circuit 22
, an oscillator 221 that generates a clock signal, and a period measuring circuit 222 that counts the clock of the oscillator 221 from a level change point of the rectangular wave signal a to the next similar level change point to generate a digital period signal T. and periodic signal T
as an address, and the corresponding frequency in the form of N number of digital quantities; includes a storage element such as a self-memory ROM, and frequency data F corresponding to the periodic signal T (hereinafter, this F
(also used as a frequency value). Further, the clock generation circuit 23 generates a clock signal f. (hereinafter, this fo is also used as a frequency value) and this clock signal f. is one input, the frequency signal F is the other input, and the clock signal f is proportional to the product of these two inputs.
(hereinafter, this f is also used as a frequency value).

The operation of this embodiment configured as described above will be explained below.

First, two alternating currents f as a reference input and an input to be measured.
The rectangular wave conversion circuit 21 determines that the o number is “negative.

The "positive" part is converted into the rectangular wave signals a and b of rLJ. Square wave signal a corresponding to reference input
is input to the period measuring circuit 222.

This period measuring circuit 222 counts the clock signal of the oscillator 221 during the period from rise to rise or from fall to fall of the rectangular wave signal a, that is, measures the period of the alternating current signal and calculates the digital period 1. The signal T is output and added to the period/frequency conversion circuit 223. The period/frequency conversion circuit 223 uses the periodic signal T as an address to read frequency data from a storage element such as a ROM, outputs a frequency signal F corresponding to the periodic signal T, and converts it into a rate multiplier.
Add to circuit 232. Rate multiplier circuit 2
At 32, the frequency signal F and the output clock signal f of the oscillator 231. The following equation is calculated using .

f-f xF/10...(1) Here,
k is the maximum number of integer digits of the frequency value F, and f is the frequency value of the output signal of the rate multiplier circuit 232. The output signal f of the rate multiplier circuit 232 is input to the phase measuring means 24 as a clock signal for measuring the phase difference between the reference input and the input to be measured.

Rectangular wave signals a and b obtained by respectively converting the reference input and the input to be measured are also input to the phase measurement circuit 24 at the same time. Therefore, the phase measurement circuit 24 outputs the output of the rate multiplier circuit 232 during the period from the rise of the rectangular wave signal a to the rise of the rectangular wave signal S, or from the fall of the rectangular wave signal a to the fall of the rectangular wave signal S. The phase difference is measured by counting the clock signal f = [, and the phase difference signal P
Outputs H.

Here, the frequency value f of the clock signal for phase measurement and the frequency value f of the output of the oscillator 231. Explain the relationship between The phase measuring circuit 24 measures the phase difference in degrees.

To measure in units: f-360xlO' xF [Hz]
It must be, and if measured in units of 0.1 degree, the deviation is f
-3600xF [Hz]. Also,
Frequency values f and f. Since there is the relationship shown in equation (1) above, the frequency f! If the maximum number of digits k of the integer part of iF is 3, that is, the AC input signal frequency is less than 1.000 [Hz1, fo-3600x 10 -3,6 [MHz
It must be l.

Therefore, according to this embodiment, the frequency value f of the output of the oscillator 231. If is selected to be sufficiently high, it is possible to determine the phase difference between AC signals over a wide frequency range.

In the above embodiment, one reference input and one target 1N-
The phase difference with 1 constant input is J? Although we have explained the case where J is determined, when measuring the phase difference between two or more inputs to be measured with respect to one reference input, the square wave conversion circuit 21 and the phase measurement circuit 24 are connected according to the number of inputs to be measured. Just increase it.

Furthermore, in the above embodiment, the phase measuring device is constituted by independent circuits that can be roughly divided into four, but each of these functions can also be provided in a microcomputer.

〔Effect of the invention〕

As is clear from the above explanation, according to this invention,
Since the frequency of the AC signal is measured and a clock signal with a frequency that is a predetermined multiple of the measured frequency is generated, the only constraint on the input signal frequency is the reference clock signal, and the frequency of this reference clock is If it is selected to be sufficiently high, the effect is that the phase λ between AC signals can be measured over a wide frequency range.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram corresponding to the present invention, Fig. 2 is a block diagram showing the structure of an embodiment of the present invention, and Fig. 3 is a block diagram showing the structure of a conventional phase measuring device. be. 11... Rectangular wave conversion means, 12... Frequency measurement means, 13... Clock generation means, 14... Phase measurement means.

Claims (1)

[Claims] A phase measuring device for measuring a phase difference between a plurality of alternating current signals, comprising a rectangular wave converting means for converting each of the plurality of alternating current signals into rectangular wave signals having the same phase, and an alternating current signal serving as a reference among the alternating signals. a frequency measuring means for measuring the frequency; a clock generating means for inputting the frequency signal of the frequency measuring means and generating a clock signal having a frequency of a predetermined magnification with respect to the measured frequency; and converting by the rectangular wave converting means. and a phase measuring means for counting the clock signal of the clock generating means from a level change point of one of the rectangular wave signals to a similar level change point of the other rectangular wave signal to generate a phase difference signal. Characteristic phase measuring device.