JPS58148969A - Measuring device of alternating-current signal level - Google Patents

Abstract

PURPOSE:To measure levels of AC signals of low frequency and with frequency variation, by sampling and holding the AC signals only when they have specified potential differences between their rectification outputs and phase shift signals and specified rectification outputs. CONSTITUTION:When an AC signal E1 is applied from an AC signal source 11, a rectifying circuit 12 and a phase shifting circuit 15 generates the rectification output Ei1 and phase shift output Ei2 respectively. When the output Ei1 exceeds a prescribed value, a switch 14 is turned on through a checking circuit 13 and when the difference between the outputs Ei1 and Ei2 is within a prescribed range and below a prescribed value, a switch 17 is turned on through a sample timing signal generating circuit 16. Only when both those switches 14 and 17 are turned on, the charging and discharging of a memory capacitor 19 is so controlled that a charging voltage is equal to the sum output of the outputs Ei1 and Ei2 obtained by an adder 18, thus performing sampling and holding corresponding to variation of the signal Ei. Consequently, levels of even AC signals of low frequency and with frequency variation are measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an AC signal level measuring device for measuring the voltage or current magnitude of an AC signal with a 1M wave number change in a motor secondary circuit.

[Technical background of the invention]

Generally, when measuring the magnitude of alternating voltage or alternating current, a method is used in which the voltage to be measured is converted into direct current voltage using a filter such as a smoothing circuit.

Figure 1 is a block diagram showing an example of such a measurement method, in which 1 is an AC signal source, 2 is a rectifier that rectifies the input signal, 3 is a choke coil that smoothes the rectified output, 4 is a smoothing capacitor, 5 is a load resistance. In this way, a DC voltage Eo proportional to the voltage hi of the input signal 1 can be obtained across the load resistor 50, so that the AC voltage gi can be determined from this voltage EO.

[Problems with Background Art] However, in this type of device, as the frequency of the input signal decreases, the rhiznor content of the output voltage increases, making accurate voltage detection impossible. Furthermore, since the smoothing choke coil 3, capacitor 5, etc. are provided, there is a problem in that the response to sudden changes in input voltage becomes slow.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and it is possible to easily detect the level of low frequency, for example AC 16 of several Hz, or AC signals with frequency changes, which was difficult to detect using conventional methods. It is an object of the present invention to provide an AC signal level measuring device that is easy to detect.

[Summary of the invention]

The present invention uses the rectified output of a fixed signal as a reference, and only when the potential difference with respect to a signal arbitrarily phase-shifted from this is within a predetermined range and the rectified output is larger than a set value of correction, the rectified output can be adjusted. It is characterized by holding the rectified output and the phase-shifted signal.

[Embodiment of the Invention] Hereinafter, a block diagram of an embodiment of the present invention shown in FIG.
This will be explained in detail. In Fig. 2, 11 is an AC (i!1 source) that outputs the detected 1g signal to be added, 12 is a rectifier circuit that half-wave rectifies the input signal, and IS is fKl when the rectified output level glJ exceeds the set value Eml. switch 14
No. 1 is a phase shift circuit that gives an arbitrary O phase delay a (a) to the rectified output. And No. 16 is a phase shift circuit that gives an arbitrary O phase delay a (a) to the rectified output.
The above II flow circuit 11 (D output Ell and phase shift -
The switch 11 gives a ON signal to the second switch 11 only when the potential difference between the line 15 and the phase-shifted output EiJ is less than a predetermined value.
This is the timing signal generation path. Note that a rectified output and a phase-shifted output are provided to the first switch 14 via an X adder 11 made of a diode.
0 output through the second switch 1r?
Give it to 19 and photoelectrically. And the charging voltage of this memory controller/7''' pin 19 is the buffer 1 of the input impedance.
0 from the output terminal 11. Adder 1
A discharge resistor 22 is inserted in the output of the memory capacitor t19, and the charging voltage of the memory capacitor t19 is lll compared to the output voltage of the adder 180.
1, the difference is discharged via the discharge resistor 22\
, I try to do so.

With this configuration, when the 55th reciprocal signal (False 3rd figure) is given from the father's deviation signal source 11, the rectification @1; ), a phase shift output E12 (Fig. 3(b)) is output from the phase shifter IJ.
Only when the line output Ell exceeds the setting gEmJ, an ON signal (Channel 3 (C)) is applied to the agl switch 14 to turn on the sales switch 14. In addition, Il monkey output at1 and phase shift output E are input to the length timing signal generation circuit 16.
No. 17m (FIG. 3(d)) is applied to the second switch 11 to turn on the switch 11 only when the potential difference with iJ is smaller than the set value of the foot. and each of the eleventh and second switches J4. Memory controller f in the cabinet where J7 is on
``7t19 is discharged by the photoelectric or discharge resistor 22 so that the charging voltage of the adder 19 becomes equal to the output of the adder 18. Therefore, the photoelectric voltage Ec of the memory capacitor 19 (@
3 (·) corresponds to the change in the alternating current a signal El, and the photoelectric voltage Ea is outputted from the output terminal 21 via the buffer 20 as analog notes F, o.

〔Effect of the invention〕

Therefore, if the output of the output of the output of the princess of 1i (No. 1) and the phase-shifted output of 9 are within a predetermined potential difference, and the rectified output exceeds the predetermined voltage, the output of the output of the Ii and the phase-shifted output will only be 1. The added value is held in place.

Therefore, it operates reliably even when the alternating current signal has a very low number of waves or changes in frequency, and the structure is extremely simple.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional AC signal level leakage method, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a waveform diagram explaining the operation of the above embodiment. 11...AC & signal source, 12...** instrument, II...
・Detection inertia check circuit, switches 14...41,
DESCRIPTION OF SYMBOLS 15... Phase shifter, 16... Sungle tie construction/signal generation same circuit, 17... Second switch, 11... Adder, 19... Memory capacitor, 20... Buffer, 2: Output terminal, 22: Discharge resistor. Serving person Patent attorney Suzue Takehiko 1115 Figure 2

Claims (1)

[Claims] A rectifier that flows an alternating current signal Ii, a phase shifter that shifts the phase of the li output of this princess accent by a predetermined step, and a detection device that outputs an on signal when the li output of the princess accent is greater than the usage level. an eccentricity check circuit; a first switch that is supplied with the rectified output and the phase shift output of the phase shifter and is turned on by an on signal supplied from the Joki Ide No. 16 check circuit; and the rectified output and the phase shift output. a sander tying signal generation circuit that outputs an on signal when the potential difference between the
A second switch is supplied with the output of the first switch and is turned on at 16g supplied from the self-sandal timing signal generation circuit, and the second switch is photoconducted to nine potentials according to the level of the signal supplied from the second switch. The above connection a
An AC image level measuring device equipped with a memory capacitor that displays an analog signal corresponding to the mechanism of the m level.