JPH03190319A - Pulse waveform detection circuit - Google Patents

Abstract

PURPOSE:To insert the AC component of a pulse waveform accurately by providing a comparator comparing the output of an amplifier amplifying the output of an integration circuit integrating a voltage signal with a voltage signal, and outputting a pulse signal corresponding to a pulse wave shaped AC component. CONSTITUTION:Only an AC component of pulse shape with a high frequency is eliminated from a voltage signal wave by an integration circuit 7 comprising a low pass filter and the result is amplified by an amplifier 6 is inputted to the inverting input terminal of a comparator 1. In such a case, since a voltage signal wave enters as it is to a noninverting input terminal, when the voltage at the noninverting input terminal is higher than the voltage at the inverting input terminal, that is, a pulse signal is outputted from the comparator 1 corresponding to the input of the pulse shaped AC component. Thus, even when the DC component of the inputted signal wave and the AC component of pulse shape are subject to drift, an accurate pulse waveform is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse waveform detection circuit that detects a pulse wave-like alternating current component contained in a voltage signal.

[Conventional technology]

A conventional pulse waveform detection circuit is shown in FIG. 3, and input and output waveforms are shown in FIG. According to FIG. 3, the inverting input terminal and non-inverting input terminal of the comparator 1 are respectively configured to have an input signal voltage source 2 and a reference voltage 14 (constant voltage sources VRI and VH2 are switched by a switch 13) as shown. ) and connected to
The output of the comparator 1 is connected to ground by a load resistor 3. Note that comparator 1 outputs a 5V voltage when the voltage state of the input terminal is such that the inverting input voltage is higher than the voltage of the non-inverting input terminal, and outputs Ov when the non-inverting input terminal voltage is lower than the inverting input terminal voltage. Output. With the above operation, the output becomes a pulse output waveform for the input signal waveform 5.

According to this prior art, the reference voltage source 14 has a voltage source VRI.
, VR2, the number of output pulses differs depending on which one is selected. When the reference voltage source is VRI, the output from the circuit has a pulse waveform of 16, the number of pulses is 4, and the reference voltage source is VH.
2, the pulse waveform becomes 17, the number of pulses is 3, and the accuracy is 50 for the number of pulses that should actually be detected, 9.
% or less.

[Problem to be solved by the invention]

According to the circuit of the above-mentioned prior art, when a pulse is output by detecting the alternating current component 12 of the pulse carving superimposed on the direct current component 11 (see the waveform in FIG. 4), the accuracy is poor and the pulse is There was a problem in inserting the alternating current component of the shape.

An object of the present invention is to provide a highly accurate detection circuit that accurately extracts the alternating current component of the pulse waveform described above.

[Means to solve the problem]

In order to achieve the above purpose, a voltage signal wave is input to an integrating circuit to remove the pulse-shaped alternating current component, and the waveform is further amplified by an amplifier, and the voltage signal wave is input to a comparator. By inputting the signal, a pulse signal is output from the comparator in accordance with the AC component of the pulse shape.

[Effect]

According to the technology of the present invention, only a high-frequency pulse-shaped AC component is removed from the voltage signal wave by an integrating circuit configured with a low-pass filter at the inverting input terminal of the comparator, and is further amplified by an amplifier. The waveform is input. At this time, the voltage signal wave enters the non-inverting input terminal as it is, so when the non-inverting input terminal voltage is higher than the inverting input terminal voltage, that is, when a pulse-shaped AC component is input, the comparator A pulse signal is output from.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a circuit diagram of a pulse waveform detection circuit, and FIG. 2 shows input and output waveforms of the circuit of FIG. 1.

As shown in FIG. 1, the signal voltage source 2 is connected to the non-inverting input terminal of the comparator 1, and is
It constitutes a low pass filter of capacitor C9. )
is also connected. Further, the output of the integrating circuit 7 is input to the amplifier 6, and the output of the amplifier 6 is connected to the inverting input terminal of the comparator l. Note that a load resistor 3 is connected to the output terminal of the comparator 1 and grounded, so that the output from the comparator 1 is applied.

The operation of the above circuit will be explained using FIG.

The input signal wave 5 in FIG. 2 is input to the non-inverting input terminal of the comparator 1 in FIG. 1, and the input signal wave 5 in FIG.
The pulse-like AC component 12 of is removed by the integrating circuit 7 and the reference voltage waveform 4 is amplified by the amplifier 6.
is input. At this time, when the voltage value of the input signal wave exceeds the reference voltage value, the output voltage of the comparator 1 rises from Ov to 5V, and remains at 5V while the above conditions are met. Further, when the signal voltage value becomes less than the reference voltage value, the output decreases from 5V to Ov. The above operation is performed on the input signal wave 5, and its output becomes a pulsed output waveform 1o. Note that the pulse width is determined by the correlation between the AC component width of the input pulse shape and the reference voltage waveform 4, so its size can be adjusted by the amplifier 6, and the removal rate of the AC component of the pulse shape is determined by the integration circuit. This can be done by adjusting the time constant of

According to this embodiment, as shown in FIG. 2, the number of pulses in the output waveform 10 is nine for nine pulsed AC components in the input signal wave 5, which makes accurate detection possible. I can see it going. Furthermore, by adjusting the reference voltage output at any one point, subsequent input signals can be handled, which is effective in simplifying circuit adjustment.

The circuit of this embodiment uses an image processing binarization circuit and a plankton number as an analog-to-digital converter.

It can be applied to circuits used for measuring two diameters and body length.

〔Effect of the invention〕

According to the circuit of the present invention, the DC component of the input signal wave,
Even if the AC component of the pulse shape drifts, there is no problem with detection and an accurate pulse waveform can be output.

Furthermore, since there is no need for a circuit to store reference voltages in accordance with input signals, high-speed processing is possible.

[Brief explanation of drawings]

Fig. 1 shows an example of a circuit of the present invention, Fig. 2 shows an example of input/output waveforms of the circuit of the invention, Fig. 3 shows an example of a circuit of the prior art, and Fig. 4 shows an example of input/output waveforms of the circuit of the prior art. . DESCRIPTION OF SYMBOLS 1... Comparator, 4... Reference voltage waveform, S... Input signal voltage waveform, 6... Amplifier, 7... Integrating circuit, 1
0...Output waveform, 11...DC component, 12...Pulse-shaped AC cell λ Figure 4

Claims (1)

[Claims] 1. In a device for detecting an alternating current component of a pulse waveform included in a voltage signal, an integrating circuit that integrates the voltage signal;
It is characterized by comprising an amplifier that amplifies the output of the integrating circuit and a comparator that compares the output of the amplifier and the voltage signal and outputs a pulse signal corresponding to the current component of the pulse waveform. Pulse waveform detection circuit.