阅读说明：本技术 一种抗强光干扰的光脉冲接收电路 (Optical pulse receiving circuit capable of resisting strong light interference ) 是由 房红兵 马蕴骞 于 2020-04-26 设计创作，主要内容包括：本发明公开了一种抗强光干扰的光脉冲接收电路,包括光电转换单元、信号缓冲积分模块、差分放大模块与信号整形模块,所述光电转换单元用于将电流脉冲信号转化为电压脉冲信号；所述缓冲积分模块用于保存电压脉冲信号的直流分量；所述差分放大模块用于将电压脉冲信号与直流分量相减并放大；所述信号整形模块用于对相减放大后的信号进行整形。本发明适应性更强,鲁棒性高,误检率低。(The invention discloses an anti-strong light interference optical pulse receiving circuit, which comprises a photoelectric conversion unit, a signal buffering integration module, a differential amplification module and a signal shaping module, wherein the photoelectric conversion unit is used for converting a current pulse signal into a voltage pulse signal; the buffer integration module is used for storing the direct current component of the voltage pulse signal; the differential amplification module is used for subtracting the direct current component from the voltage pulse signal and amplifying the direct current component; and the signal shaping module is used for shaping the signals subjected to subtraction amplification. The method has the advantages of stronger adaptability, high robustness and low false detection rate.)

1. An optical pulse receiving circuit resisting strong light interference is characterized by comprising a photoelectric conversion unit, a signal buffering integration module, a differential amplification module and a signal shaping module, wherein the photoelectric conversion unit is used for converting a current pulse signal into a voltage pulse signal;

the buffer integration module is used for storing the direct current component of the voltage pulse signal;

the differential amplification module is used for subtracting the direct current component from the voltage pulse signal and amplifying the direct current component;

and the signal shaping module is used for shaping the signals subjected to subtraction amplification.

2. An optical pulse receiving circuit for resisting strong optical interference according to claim 1, wherein the photoelectric conversion unit comprises a PIN photodiode D1, an operational amplifier U3, a first resistor R1 and a first capacitor C1, wherein an anode of the first PIN photodiode D1 is connected to a-5V power supply, a cathode of the first PIN photodiode D1 is connected to an inverting input terminal of a first operational amplifier chip U3, the first resistor R1 and the first capacitor C1 are connected in parallel to the inverting input terminal and the output terminal of the first operational amplifier U3, and a non-inverting input terminal of the first operational amplifier U3 is connected to a ground line.

3. The circuit for receiving optical pulses with strong optical interference resistance according to claim 1, wherein the signal buffering and integrating module comprises a transistor Q1 and a second capacitor C2, the base of the first transistor Q1 is connected to the output terminal of the operational amplifier U3, the collector is connected to the 5V power supply, the emitter is connected to the positive electrode of the second capacitor C2, and the negative electrode of the second capacitor C2 is grounded.

4. The circuit for receiving optical pulses with strong optical interference resistance according to claim 1, wherein the differential amplification module comprises a differential amplifier U1 and a fifth resistor R5, a non-inverting input terminal IN + of the first differential amplifier U1 is connected to the output terminal of the photoelectric conversion unit, an inverting input terminal IN-of the first differential amplifier U1 is connected to the output terminal of the signal buffering integration module, and two ends of the fifth resistor R5 are connected to pin No. 1 and pin No. 8 of the first differential amplifier U1, respectively; the output OUT of the first differential amplifier U1 is connected to the input of the signal shaping module.

5. An optical pulse receiving circuit for resisting strong optical interference according to claim 1, comprising a first comparator U2, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first connector P1, wherein one end of each of the second resistor R2 and the third resistor R3 is connected to the inverting input terminal of the first comparator U2, the other end of each of the second resistor R2 and the third resistor R3 is connected to the ground line and the 5V power supply line, one end of the fourth resistor R4 is connected to the output terminal of the first comparator U2, the other end of the fourth resistor R4 is connected to the 5V power supply line, the output terminal of the first comparator U2 (connected to the first connector P1, and the non-inverting input terminal of the first comparator U2 is connected to the output terminal OUT of the first differential amplifier U1.

Technical Field

The invention belongs to the technical field of metering detection, and particularly relates to an optical pulse receiving circuit capable of resisting strong light interference.

Background

The flow meter is the basic instrument for flow measurement, and the rotor flow meter is the conventional flow meter for hydrology measurement. The current meter belongs to a rotor type current meter, and a water flow sensor is a propeller element. The water flow impacts the propeller to rotate, and the impact force of the water flow on the propeller leads to the rotating speed of the propeller to be fast and slow, so that the flow speed is measured. The rotor speed is typically measured using optics. However, the photoelectric sensor cannot work normally in the midday due to the influence of the sunlight intensity outdoors, so that the backlight resisting treatment is needed.

Most of the existing measures for resisting background light interference are to solve the problem from the angle of algorithms such as wavelet transformation and the like. And in addition, background interference is removed through subtraction after the background is collected by adding a sensor. Section 1.2 in the article, "a laser pulse correlation detection method for resisting background light interference" published in month 4 of 2012 by weiwaindong, sundawn spring, sundawn army mentions a design of removing background light interference by adding a photoelectric sensor to perform background light detection and then performing subtraction by a subtractor. But the above method is not applicable to simple pulse measurements requiring cost and volume control. In addition, a part of circuit designs adopt a capacitor to perform blocking processing on signals, however, the blocking processing and the inevitable differential processing on original signals make the weak pulse signals more difficult to distinguish.

Disclosure of Invention

The invention aims to provide an optical pulse receiving circuit which is resistant to strong light interference.

The technical solution for realizing the purpose of the invention is as follows: an optical pulse receiving circuit resisting strong light interference comprises a photoelectric conversion unit, a signal buffering integration module, a differential amplification module and a signal shaping module, wherein the photoelectric conversion unit is used for converting a current pulse signal into a voltage pulse signal;

the buffer integration module is used for storing the direct current component of the voltage pulse signal;

the differential amplification module is used for subtracting the direct current component from the voltage pulse signal and amplifying the direct current component;

and the signal shaping module is used for shaping the signals subjected to subtraction amplification.

Preferably, the photoelectric conversion unit comprises a PIN photodiode D1, an operational amplifier U3, a first resistor R1 and a first capacitor C1, wherein the anode of the first PIN photodiode D1 is connected to a-5V power supply, the cathode of the first PIN photodiode D1 is connected to the inverting input terminal of the first operational amplifier chip U3, the first resistor R1 and the first capacitor C1 are connected in parallel to the inverting input terminal and the output terminal of the first operational amplifier U3, and the non-inverting input terminal of the first operational amplifier U3 is connected to the ground.

Preferably, the signal buffering and integrating module comprises a transistor Q1 and a second capacitor C2, wherein the base of the first transistor Q1 is connected with the output end of the operational amplifier U3, the collector is connected with a 5V power supply, the emitter is connected with the anode of the second capacitor C2, and the cathode of the second capacitor C2 is grounded.

Preferably, the differential amplification module comprises a differential amplifier U1 and a fifth resistor R5, a non-inverting input terminal IN + of the first differential amplifier U1 is connected with the output terminal of the photoelectric conversion unit, an inverting input terminal IN-of the first differential amplifier U1 is connected with the output terminal of the signal buffering integration module, and two ends of the fifth resistor R5 are respectively connected with pin No. 1 and pin No. 8 of the first differential amplifier U1; the output OUT of the first differential amplifier U1 is connected to the input of the signal shaping module.

Preferably, the circuit comprises a first comparator U2, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first connector P1, wherein one end of each of the second resistor R2 and the third resistor R3 is connected with the inverting input end of the first comparator U2, the other end of each of the second resistor R2 and the third resistor R3 is connected with the ground line and the 5V power supply line respectively, one end of the fourth resistor R4 is connected with the output end of the first comparator U2, the other end of the fourth resistor R4 is connected with the 5V power supply line, and the output end of the first comparator U2 (connected with the first connector P1, and the non-inverting input end of the first comparator U2 is connected with the output end OUT of the first differential amplifier U1.

Compared with the prior art, the invention has the following remarkable advantages: according to the invention, through integration, pulses in original signals are attenuated, only signals brought by background light are retained, and pulse signals are extracted in a lossless manner through subtraction operation; the method has the advantages of stronger adaptability, high robustness and low false detection rate.

The present invention is described in further detail below with reference to the attached drawings.

Drawings

Fig. 1 is a schematic diagram of the present invention.

Fig. 2 is a schematic structural diagram of the present invention.

Detailed Description

An optical pulse receiving circuit resisting strong light interference comprises a photoelectric conversion unit, a signal buffering integration module, a differential amplification module and a signal shaping module, wherein the output end of the photoelectric conversion unit is respectively connected with the input end of the buffering integration module and the non-inverting input end of the differential amplification module, and the output end of the buffering integration module is connected with the inverting input end of the differential amplification module; and the output end of the differential amplification module is connected with the input end of the signal shaping module.

The photoelectric conversion unit is used for converting the current pulse signal into a voltage pulse signal;

the buffer integration module is used for storing the direct current component of the voltage pulse signal;

the differential amplification module is used for subtracting the direct current component from the voltage pulse signal and amplifying the direct current component;

and the signal shaping module is used for shaping the signals subjected to subtraction amplification.

In a further embodiment, the photoelectric conversion unit includes a PIN photodiode D1, an operational amplifier U3, a first resistor R1, and a first capacitor C1, an anode of the first PIN photodiode D1 is connected to a-5V power supply, a cathode of the first PIN photodiode D1 is connected to an inverting input terminal of the first operational amplifier chip U3, the first resistor R1 and the first capacitor C1 are connected in parallel to the inverting input terminal and the output terminal of the first operational amplifier U3, and a non-inverting input terminal of the first operational amplifier U3 is connected to a ground line.

In a further embodiment, the signal buffering integration module comprises a transistor Q1 and a second capacitor C2, wherein a base of the first transistor Q1 is connected to an output terminal of the operational amplifier U3, a collector of the first transistor Q1 is connected to a 5V power supply, an emitter of the first transistor Q1 is connected to an anode of the second capacitor C2, and a cathode of the second capacitor C2 is grounded.

The differential amplification module comprises a differential amplifier U1 and a fifth resistor R5, wherein the non-inverting input end IN + of the first differential amplifier U1 is connected with the output end of the operational amplifier U3, and the inverting input end IN-of the first differential amplifier U1 is connected with the emitter of the first triode Q1. Two ends of the fifth resistor R5 are respectively connected with the No. 1 pin and the No. 8 pin of the first differential amplifier U1. The output OUT of the first differential amplifier U1 is connected to an input of the signal shaping module.

The signal shaping module comprises a first comparator U2, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first connector P1, wherein the second resistor R2 and the third resistor R3 are direct-current bias resistors, one end of each direct-current bias resistor is connected with the inverted input end (No. 2 pin) of the first comparator U2, and the other end of each direct-current bias resistor is connected to a ground wire and a 5V power supply wire respectively. The fourth resistor R4 is a pull-up resistor, one end of the fourth resistor R4 is connected with the output end (pin No. 1) of the first comparator U2, and the other end of the fourth resistor R4 is connected to a 5V power supply line. The output end (pin 1) of the first comparator U2 is connected with the first connector P1, and outputs signals. The non-inverting input of the first comparator U2 is connected to the output OUT of the first differential amplifier U1.

The working principle of the invention is as follows:

the PIN photodiode D1 converts the current pulse signal into a voltage pulse signal through an operational amplifier after receiving the signal, then the voltage pulse signal is divided into two paths, one path is directly connected to the non-inverting input end of the differential amplification module, the other path is connected to a buffer integration module formed by a triode and a capacitor, the buffer integration module is used for storing the direct current component of the pulse signal, namely the electric signal generated by background light, when the differential amplification module core is actually used, an instrument amplifier is selected to realize the subtraction and the amplification of the original signal and the direct current component, so that the interference caused by the background light is eliminated, the subtracted signal is connected to a signal shaping module for shaping, and the signal is converted into TT L level which can be read by a controller and is output.