CN206673918U - Pyroelectricity signal amplification circuit filter - Google Patents

Abstract

A pyroelectric signal amplification and filtering circuit belongs to the technical field of pyroelectric signal filtering. The utility model aims to solve the problem that the existing pyroelectric sensor cannot effectively distinguish the signals of human heat source and non-human heat source. It performs high-pass filtering on the signal through the high-pass filter circuit composed of resistor R1 and capacitor C1 to filter out the influence of low-frequency signals; The second-order low-pass filter circuit is formed to remove the high-frequency signal generated by non-human heat sources, and perform a signal amplification; after filtering by the capacitor C4, the filtered signal enters the dual operational amplifier U2, resistor R6, resistor R7, resistor The inverting amplifying circuit composed of R8, resistor R10, capacitor C5 and sliding rheostat R9 performs second signal amplification, changing the resistance value of sliding rheostat R9 can change the amplification factor of the inverting amplifying circuit. The utility model is used for amplification and filtering of pyroelectric signals.

Description

Pyroelectric signal amplification filter circuit

technical field

The utility model relates to a pyroelectric signal amplification filter circuit, which belongs to the technical field of pyroelectric signal filtering.

Background technique

The pyroelectric infrared sensor can detect the infrared radiation emitted by the human body. If the relevant characteristic information is extracted from the detected infrared radiation signal and analyzed and processed, the approximate position information of the human target can be obtained. However, since the human body or other heat sources may generate spontaneous infrared radiation and emit electromagnetic waves, when the human body is in a complex external environment, the positioning judgment of the human body is easily interfered by signals from other heat sources. Therefore, it is necessary to take effective measures to eliminate Non-human heat source, thereby improving the accuracy of human body positioning.

After receiving the infrared signal, the existing pyroelectric sensor neither amplifies the effective signal nor effectively filters the interference signal to eliminate the interference, so that it cannot effectively distinguish the human heat source signal from the non-human heat source signal.

Contents of the invention

The purpose of the utility model is to solve the problem that the existing pyroelectric sensor cannot effectively distinguish the signals of human heat sources and non-human heat sources, and provides a pyroelectric signal amplification and filtering circuit.

The pyroelectric signal amplification and filtering circuit described in the utility model includes resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, sliding rheostat R9, resistance R10, capacitance C1, capacitance C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, polar capacitor C7, dual operational amplifier U1 and dual operational amplifier U2,

The resistor R1 is connected between the source S and the gate G of the pyroelectric infrared sensor U3, the gate G is grounded, and the drain D is connected to the +5V power supply; the source S of the pyroelectric infrared sensor U3 is connected to the dual operational amplifier U1 Connect capacitor C1, resistor R2 and resistor R3 in sequence between the inverting input terminals, one end of capacitor C2 is connected between resistor R2 and resistor R3, and the other end of capacitor C2 is grounded;

The non-inverting input terminal of the dual operational amplifier U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is grounded; the inverting input terminal and the output terminal of the dual operational amplifier U1 are connected to the resistor R5, and the capacitor C3 is connected in parallel with the resistor R5;

A capacitor C4 and a resistor R6 are sequentially connected between the output terminal of the dual operational amplifier U1 and the inverting input terminal of the dual operational amplifier U2, the non-inverting input terminal of the dual operational amplifier U2 is connected to one end of the resistor R10, and the other end of the resistor R10 is grounded; The non-inverting input terminal of the operational amplifier U2 is connected to one end of the resistor R7, and the other terminal of the resistor R7 is connected to the +5V power supply; the inverting input terminal and the output terminal of the dual operational amplifier U2 are connected to the capacitor C5, and the resistor R8 and the sliding rheostat R9 are connected in series with the The capacitor C5 is connected in parallel, and the sliding end of the sliding rheostat R9 is connected to the output end of the dual operational amplifier U2; the output end of the dual operational amplifier U2 is used as the output end of the filter circuit;

The positive electrode of the polar capacitor C7 is connected to the +5V power supply, the negative electrode of the polar capacitor C7 is grounded, and the capacitor C6 is connected in parallel with the polar capacitor C7.

The advantages of the utility model: the utility model is used for the amplification and filtering of the human body perception positioning signal. It performs high-pass filtering on the signal collected by the pyroelectric infrared sensor through the high-pass filter circuit formed by the resistance R1 and the capacitor C1, and filters out the low-frequency signal. influences. Then, through the second-order low-pass filter circuit composed of dual operational amplifier U1, resistor R2, resistor R3, capacitor C2, capacitor C3, resistor R4, and resistor R5, the second-order filter is used to remove high-frequency signals generated by non-human heat sources , and perform a signal amplification. After the second-order low-pass filtering, the signal is filtered again by capacitor C4, and the filtered signal will enter the circuit composed of dual operational amplifier U2, resistor R6, resistor R7, resistor R8, resistor R10, capacitor C5 and sliding rheostat R9. The inverting amplifying circuit performs second signal amplification, wherein the amplification factor of the inverting amplifying circuit is changed by changing the resistance value of the sliding rheostat R9. The utility model ensures that the polarity of the final output signal remains unchanged through two inverting amplifying and filtering circuits, and successfully filters out low-frequency signals that interfere with the circuit and high-frequency signals that interfere with identifying human heat sources and non-human heat sources, ensuring The signal passes through, and the auxiliary pyroelectric infrared sensor correctly identifies the heat source of the human body and the heat source of the non-human body.

Description of drawings

Fig. 1 is a schematic circuit diagram of the pyroelectric signal amplification and filtering circuit described in the present invention.

detailed description

Specific Embodiment 1: The following describes this embodiment in conjunction with FIG. 1 . The pyroelectric signal amplification and filtering circuit described in this embodiment includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, Resistor R8, sliding rheostat R9, resistor R10, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, polar capacitor C7, dual operational amplifier U1 and dual operational amplifier U2,

The resistor R1 is connected between the source S and the gate G of the pyroelectric infrared sensor U3, the gate G is grounded, and the drain D is connected to the +5V power supply; the source S of the pyroelectric infrared sensor U3 is connected to the dual operational amplifier U1 Connect capacitor C1, resistor R2 and resistor R3 in sequence between the inverting input terminals, one end of capacitor C2 is connected between resistor R2 and resistor R3, and the other end of capacitor C2 is grounded;

The non-inverting input terminal of the dual operational amplifier U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is grounded; the inverting input terminal and the output terminal of the dual operational amplifier U1 are connected to the resistor R5, and the capacitor C3 is connected in parallel with the resistor R5;

A capacitor C4 and a resistor R6 are sequentially connected between the output terminal of the dual operational amplifier U1 and the inverting input terminal of the dual operational amplifier U2, the non-inverting input terminal of the dual operational amplifier U2 is connected to one end of the resistor R10, and the other end of the resistor R10 is grounded; The non-inverting input terminal of the operational amplifier U2 is connected to one end of the resistor R7, and the other terminal of the resistor R7 is connected to the +5V power supply; the inverting input terminal and the output terminal of the dual operational amplifier U2 are connected to the capacitor C5, and the resistor R8 and the sliding rheostat R9 are connected in series with the The capacitor C5 is connected in parallel, and the sliding end of the sliding rheostat R9 is connected to the output end of the dual operational amplifier U2; the output end of the dual operational amplifier U2 is used as the output end Out of the filter circuit;

The positive electrode of the polar capacitor C7 is connected to the +5V power supply, the negative electrode of the polar capacitor C7 is grounded, and the capacitor C6 is connected in parallel with the polar capacitor C7.

In this embodiment, the polar capacitor C7 and the capacitor C6 are connected in parallel to form a filter circuit, which is used to filter out the fluctuations generated in the overall circuit to ensure that the power supply is not disturbed; the drain D of the pyroelectric infrared sensor U3 uses + The 5V power supply provides electric energy, and the source S sends out its identification information in the form of a voltage signal; the resistor R1 and the non-polar capacitor C1 form a high-pass filter circuit to filter the voltage signal output by the source S; the dual operational amplifier U1 and Resistor R2, resistor R3, capacitor C2, capacitor C3, resistor R4 and resistor R5 constitute a second-order low-pass filter circuit, which performs second-order low-pass filtering on the received signal and amplifies the signal; capacitor C4 acts as a filter capacitor for dual The output signal of operational amplifier U1 is filtered; the inverting amplification low-pass filter circuit composed of dual operational amplifier U2, resistor R6, resistor R7, resistor R8, resistor R10, capacitor C5 and sliding rheostat R9 identifies pyroelectric infrared sensor U3 The signal is amplified and filtered twice, and the second amplification factor can be modified by changing the value of the sliding rheostat R9.

Specific embodiment two: the present embodiment is described below in conjunction with Fig. 1, and this embodiment is further described to embodiment one, and double operational amplifier U1 and double operational amplifier U2 are LM358 chip, and No. 8 pins of LM358 chip are connected +5V power supply, Pin 4 is grounded.

Claims (2)

1. a kind of pyroelectricity signal amplification circuit filter, it is characterised in that it includes resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, slide rheostat R9, resistance R10, electric capacity C1, electric capacity C2, electric capacity C3, electric capacity C4, electric capacity C5, electric capacity C6, polar capacitor C7, dual operational amplifier U1 and dual operational amplifier U2,

Resistance R1 is connected between pyroelectric infrared sensor U3 source S and grid G, grid G ground connection, drain D connection+5V electricity Source；Electric capacity C1, electricity are sequentially connected between pyroelectric infrared sensor U3 source S and dual operational amplifier U1 inverting input R2 and resistance R3 is hindered, electric capacity C2 one end is connected between resistance R2 and resistance R3, electric capacity C2 other end ground connection；

Dual operational amplifier U1 in-phase input end connection resistance R4 one end, resistance R4 other end ground connection；Double operation amplifiers Resistance R5 is connected between device U1 inverting input and output end, electric capacity C3 is in parallel with resistance R5；

Electric capacity C4 and electricity are sequentially connected between dual operational amplifier U1 output end and dual operational amplifier U2 inverting input Hinder R6, dual operational amplifier U2 in-phase input end connection resistance R10 one end, resistance R10 other end ground connection；Double computings are put Big device U2 in-phase input end connection resistance R7 one end, resistance R7 another termination+5V power supplys；Dual operational amplifier U2's is anti- In parallel with electric capacity C5 after electric capacity C5, resistance R8 and slide rheostat R9 connect, slip change is connected between phase input and output end Hinder device R9 sliding end connection dual operational amplifier U2 output end；Dual operational amplifier U2 output end is as filter circuit Output end；

Polar capacitor C7 positive pole connection+5V power supplys, polar capacitor C7 negative pole ground connection, electric capacity C6 are in parallel with polar capacitor C7.

2. pyroelectricity signal amplification circuit filter according to claim 1, it is characterised in that dual operational amplifier U1 and double Operational amplifier U2 is LM358 chips, No. 8 pin connection+5V power supplys of LM358 chips, No. 4 pins ground connection.