CN115683350A - Weak signal acquisition circuit applied to single-channel lead salt photoelectric detector - Google Patents
Weak signal acquisition circuit applied to single-channel lead salt photoelectric detector Download PDFInfo
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- CN115683350A CN115683350A CN202211331297.0A CN202211331297A CN115683350A CN 115683350 A CN115683350 A CN 115683350A CN 202211331297 A CN202211331297 A CN 202211331297A CN 115683350 A CN115683350 A CN 115683350A
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Abstract
The invention belongs to the technical field of infrared photoelectric signal acquisition, and mainly relates to a weak signal acquisition circuit system applied to a single-channel lead salt photoelectric detector, which is used for acquiring signals of the lead salt infrared photoelectric detector. It includes: the device comprises a partial pressure matching resistance unit module, a blocking filter circuit unit module, a signal amplification circuit unit module, an analog-to-digital conversion unit module and a digital signal acquisition and processing unit module. The invention provides a low-noise weak signal acquisition circuit applicable to a single-channel infrared photoelectric detector on the basis of the prior art. After the weak photoelectric signal is filtered and amplified, the photoelectric signal is prevented from being interfered by various large noises and even submerged. Therefore, the photoelectric signal can be better collected and analyzed by adopting the signal collecting circuit system, and the precision and the signal-to-noise ratio of the signal are finally improved.
Description
Technical Field
The invention belongs to the technical field of infrared photoelectric signal acquisition, and mainly relates to a weak signal acquisition circuit system applied to a single-channel lead salt photoelectric detector, which is used for acquiring signals of the lead salt infrared photoelectric detector.
Background
With the continuous development of modern industrial technology, especially the arrival of the industrial 4.0 era, more and more fields are inaccessible to the sense of the human body. Therefore, there is a strong need for a device that is accessible in these areas, and thus probes have come to be in force. Currently, infrared photodetectors are gradually widely used in civil and military applications. However, the output of the infrared photodetector is an analog signal, and a signal acquisition system is needed to convert the analog signal into a digital signal. The signal acquisition circuit provided by the invention can realize conversion between analog-digital signals and is more convenient to acquire and analyze the signals.
The signal output by the infrared photodetector is very weak, but various noises, such as thermal noise, exist in the surrounding environment. Then the noise will interfere with the weak signal we need and even be drowned out. Therefore, it is very important to process these weak signals. Most of lead salt infrared photoelectric detectors and signal acquisition and processing circuits in the current market are imported, and can only be matched with part of infrared photoelectric detectors to achieve a better effect. Meanwhile, the purchase of such products is complicated and the price is extremely high, and the products are inconvenient to maintain in the later period and the like.
Disclosure of Invention
Aiming at the problems, the invention provides a low-noise weak signal acquisition circuit applicable to a single-channel infrared photoelectric detector on the basis of the prior art after overcoming the defects of the prior art. After the weak photoelectric signal is filtered and amplified, the photoelectric signal is prevented from being interfered by various large noises and even submerged. Therefore, the photoelectric signal can be better collected and analyzed by adopting the signal collecting circuit system, and the precision and the signal-to-noise ratio of the signal are finally improved.
The technical scheme of the invention is as follows:
a weak signal acquisition circuit system applied to a single-channel infrared photoelectric detector comprises: the device comprises a partial pressure matching resistance unit module, a blocking filter circuit unit module, a signal amplification circuit unit module, an analog-to-digital conversion unit module and a digital signal acquisition and processing unit module.
The voltage division matching resistance unit module is used for matching signal voltage; the blocking filter circuit unit module is used for primary filtering processing of the generated signals; the signal amplification circuit unit module is used for amplifying the acquired signals; the analog-to-digital conversion unit module is used for converting the analog signal amplified by the amplifying circuit into a digital signal; and the digital signal acquisition and processing unit module is used for acquiring and processing the converted digital signals.
By using the technical scheme, the circuit structure can be simplified, and the cost is reduced; secondly, weak signals generated by the infrared photoelectric detector can be acquired and processed, and finally circuit system optimization is achieved.
The technical scheme can be further optimized as follows: the blocking filter circuit unit module comprises a blocking capacitor C1 and a resistor R3 to form an RC filter circuit, and the output end of the RC filter circuit is electrically connected with the positive input electrode of the amplifier OP chip.
The technical scheme can be further optimized as follows: the signal amplification circuit unit module comprises an amplifier OP chip, a feedback resistor R1, a capacitor C2 and a resistor R2. Wherein:
the positive input electrode of the amplifier OP chip is connected in series with an RC circuit in the blocking filter circuit, and the negative input electrode of the amplifier OP chip is connected in series with a resistor R2 and then grounded to GND;
the feedback resistor R1 is connected with the capacitor C2 in parallel to form an RC parallel circuit; one end of the parallel RC is connected with the negative input electrode of the amplifier OP chip, and the other end of the parallel RC is connected with the signal output end OUT of the amplifier OP chip;
the positive voltage end of the amplifier OP chip is connected with a resistor R0 in series and then connected with a power supply VCC, and the negative voltage end is grounded GND; and the signal output end OUT of the amplifier OP chip is electrically connected with the No. 1 pin of the U2 in the analog-to-digital conversion unit module.
The technical scheme can be further optimized as follows: the analog-to-digital conversion unit module comprises a processor U2, a capacitor C7, a resistor R6 and a resistor R7, wherein:
the No. 1 pin of the processor U2 is connected with the signal output end OUT of the amplifier OP chip, and the No. 5, no. 6, no. 7 and No. 8 pins are grounded together;
one end of the capacitor C7 is connected with pins 14 and 16 of the processor U2 and then connected with a 5V power supply, and the other end of the capacitor C7 is connected with pins 12 and 13 of the processor U2 and then connected with GND;
one end of the resistor R6 is connected with a pin 9 of the processor U2 and then connected with a pin 17 of the U1 in the digital signal acquisition and processing unit module in parallel, and the other end of the resistor R is connected with a 5V power supply;
one end of the resistor R7 is connected with a No. 10 pin of the processor U2 and then connected with a No. 16 pin of the U1 in the digital signal acquisition and processing unit module, and the other end of the resistor R7 is connected with a 5V power supply;
the technical scheme can be further optimized as follows: and the processor U2 in the analog-to-digital conversion unit module is a PCF8591 chip.
The technical scheme can be further optimized as follows: the digital signal acquisition and processing unit module comprises a processor U1, a reset circuit unit and a crystal oscillator circuit unit. Wherein:
the reset circuit unit is electrically connected with the No. 9 pin of the processor U1; the crystal oscillator circuit unit is electrically connected with pins 18 and 19 of the processor U1 respectively.
The technical scheme can be further optimized as follows: and a processor U1 in the digital signal acquisition and processing unit module is an STC89C52 chip.
To sum up, the beneficial effect of this application is: compared with a circuit in the prior art, the circuit adopts a modular design, the reliability of the circuit is improved, the circuit structure is optimized, the cost performance of selected elements and chips is high, and the use cost is greatly reduced. Compared with an imported signal acquisition circuit with high price, the modularized design is convenient for interchange, and the later-stage circuit maintenance cost is reduced. Finally, the circuit in the application is more suitable for short-wavelength and low-frequency infrared photoelectric detectors, reduces noise influence and improves signal accuracy.
Drawings
FIG. 1 is a schematic diagram of an RC filter circuit of a photodetector;
FIG. 2 is a schematic circuit diagram of a signal amplification unit of the photodetector;
FIG. 3 is a schematic circuit diagram of an analog-to-digital conversion unit of the photodetector;
FIG. 4 is a schematic diagram of a digital signal acquisition and processing main control circuit of the photodetector;
Detailed Description
The technical solutions in the embodiments of the present application will be further described with reference to the drawings and the detailed description in the specification. The following are only some of the embodiments in the present application, and other technical personnel may make some technical solution changes based on the embodiments in the present application and all belong to the scope of the embodiments in the present application.
The invention relates to a weak signal acquisition circuit system applied to a single-channel lead salt photoelectric detector, which is mainly used for short-wave infrared lead salt detectors such as PbSe, pbS and the like to realize the conversion between target infrared signals and electric signals. The system mainly comprises: the device comprises a partial pressure matching resistance unit module, a blocking filter circuit unit module, a signal amplification circuit unit module, an analog-to-digital conversion unit module and a digital signal acquisition and processing unit module.
The signal acquisition process mainly comprises the following steps: analog signals output by the lead salt photoelectric detector pass through the partial pressure matching resistor unit module, the blocking and filtering circuit unit module, the signal amplifying circuit unit module and the analog-to-digital conversion unit module and then enter the digital signal acquisition and processing unit module, and digital filtering processing is carried out on the converted digital signals by the single chip microcomputer.
The voltage division matching resistance unit module comprises a detector chip and a matching resistor; the blocking filter circuit unit module mainly comprises a resistor R and a capacitor C which are connected in parallel to form a filter RC circuit; an amplifier OP chip in the signal amplification circuit unit module adopts an OPA333 chip; a PCF8591 chip is adopted by a processor U2 in the analog-to-digital conversion unit module; a processor U1 in the digital signal acquisition and processing unit module adopts an STC89C52 chip;
the voltage division matching resistance unit module includes: a detector r and a matching resistor RL;
the detector r in the voltage division matching resistance unit module adopts a lead salt photoelectric detector as a signal source to generate a required analog signal. The D end of the detector r is connected with a 5V power supply, the S end is connected with the matching resistor RL, and the GND end is connected with the other end of the RL and then grounded; wherein, adopt the precision to be 5%, the resistance RL that the resistance matches with the dark resistance of detector r, the purpose is in order to let the signal more stable.
As shown in fig. 1, a capacitor C1 in the dc blocking filter circuit unit module is a patch capacitor, the precision of which is ± 20%, and is used for blocking and dividing a dc voltage portion in a signal; the resistor R3 is a chip resistor with the precision of 5 percent and is connected with the capacitor C1 in parallel to form an RC circuit, and the purpose is to filter partial noise in 5V bias voltage.
One end of a capacitor C1 is used as an input end of a signal and is connected with the S end of a detector R, the signal generated by the detector R is received, a direct current part and partial noise IN the signal are filtered, and the other end of the capacitor C1 is connected with a resistor R3 and an OPA333 chip IN + positive input end; the other end of the resistor R3 is connected to GND.
The signal amplification circuit unit module comprises an OPA333 amplifier chip, a feedback resistor R1, a capacitor C2 and a resistor R2.
As shown in fig. 2, the amplifier OP chip in the signal amplification circuit unit module is a low-power-consumption and precise operational amplifier OPA333 chip of texas instruments, which can provide an extremely low offset voltage and realize a drift close to zero with the passage of time and the change of ambient temperature; the IN-negative input end of an OPA333 chip is electrically connected with a feedback resistor R1, a resistor R2 and a capacitor C2, the OUT serving as the signal output end of the precision operational amplifier is connected with the feedback resistor R1, the capacitor C2 and the AIN0 end of the signal input end of a PCF8591 chip IN the analog-to-digital conversion unit module, and analog signals are sent into the PCF8591 chip and converted into digital signals; the positive electrode V + is connected with the resistor R0, and the negative electrode V-is connected with GND; the other end of the resistor R0 is connected to a power supply VCC.
The feedback resistor R1 is a chip resistor with the precision of 5% and is connected between the reverse input end IN-and the signal output end OUT of the OPA333 chip; the resistor R2 is a chip resistor with the precision of 5%, one end of the resistor R2 is connected with the resistor R1 and the reverse input end IN-of the OPA333 chip, and the other end of the resistor R2 is connected with GND.
The analog-to-digital conversion unit module comprises: PCF8591 chip, resistor R6, resistor R7, and capacitor C7;
specifically, as shown in fig. 3, the PCF8591 chip is a typical analog-to-digital conversion chip, and has 4 input ports, 8 bits, 16 pins in total, AIN0 to AIN3 are 4 analog signal input ports, A0 to A2 are 3 pin address ports, and are grounded after being connected to VSS in the circuit, and SCL and SDA are I2C bus serial input/output and I2C clock lines, respectively;
an AIN0 end (pin No. 1) of a PCF8591 chip is used as an input end of an analog signal and is connected with an OUT end of an OPA333 chip in an amplifier circuit unit module, and then the analog signal is converted into a digital signal; the A0 end (pin No. 5) is connected with the A1 end (pin No. 6), the A2 end (pin No. 7) and the VSS end (pin No. 8) and then is connected with GND; of SDA terminal (pin 9), resistor R6 and STC89C52 chips
Connected with SCL terminal (pin No. 10) and resistor R7 and STC89C52 chip
The SCL port and the SDA port are communicated with a single chip microcomputer STC89C52 chip in the digital signal acquisition processing unit in an I2C bus mode so as to realize signal intercommunication; an EXT end (No. 12 pin) is connected with an AGND end (No. 13 pin) and then connected with GND, and a VDD end (No. 16 pin) and a VREF end (No. 14 pin) are connected with a capacitor C7 and 5V voltage; the other end of the capacitor C7 is connected with GND; wherein, the resistor R6 is a chip resistor with the precision of 5 percent, and the capacitor C7 is a chip capacitor with the precision of +/-20 percent.
As shown in fig. 4, the digital signal acquisition processing unit module includes a processor U1, a reset circuit unit, a crystal oscillator circuit unit, and a switching power supply unit. Wherein:
the reset circuit unit is electrically connected with a No. 9 pin of the processor U1; the crystal oscillator circuit unit is respectively electrically connected with pins 18 and 19 of the processor U1; after the polar capacitor C6 and the chip capacitor C12 in the switch power supply unit are connected in parallel, one end of the polar capacitor C6 is connected with VCC (pin No. 40) of the processor U1 and is connected with the switch S2, and the other end of the polar capacitor C6 is connected with GND (pin No. 20) of the processor U1; the other end of the switch S2 is connected with a 5V power supply. A processor U1 in the digital signal acquisition processing unit module adopts an STC89C52 chip, and Keil software and C language are used for writing related control programs to realize circuit control, signal acquisition, signal processing and digital filtering.
Claims (7)
1. A weak signal acquisition circuit applied to a single-channel lead salt photoelectric detector is used for a short-wave infrared lead salt detector and realizes the conversion of a target infrared signal and an electric signal, and is characterized in that the weak signal acquisition circuit comprises a voltage division matching resistance unit module, a blocking filter circuit unit module, a signal amplification circuit unit module, an analog-to-digital conversion unit module and a digital signal acquisition processing unit module; the voltage division matching resistance unit module is used for matching signal voltage; the blocking filter circuit unit module is used for primary filtering processing of the generated signals; the signal amplification circuit unit module is used for amplifying the acquired signals; the analog-to-digital conversion unit module is used for converting the analog signal amplified by the amplifying circuit into a digital signal; the digital signal acquisition and processing unit module is used for acquiring and processing the converted digital signals;
the blocking filter circuit unit module comprises a blocking capacitor C1 and a resistor R3 to form an RC filter circuit, and the output end of the RC filter circuit is electrically connected with the positive input electrode of the amplifier OP chip;
the signal amplification circuit unit module comprises an amplifier OP chip, a feedback resistor R1, a capacitor C2 and a resistor R2, wherein:
a positive input electrode of the amplifier OP chip is connected in series with an RC circuit in the blocking filter circuit, and a negative input electrode of the amplifier OP chip is connected in series with a resistor R2 and then grounded to GND;
the feedback resistor R1 is connected with the capacitor C2 in parallel to form an RC parallel circuit; one end of the parallel RC is connected with the negative input electrode of the amplifier OP chip, and the other end of the parallel RC is connected with the signal output end OUT of the amplifier OP chip;
the positive voltage end of the amplifier OP chip is connected with a resistor R0 in series and then is connected with a power supply VCC, and the negative voltage end is grounded GND; the signal output end OUT of the amplifier OP chip is electrically connected with the No. 1 pin of the U2 in the analog-to-digital conversion unit module;
the analog-to-digital conversion unit module comprises a processor U2, a capacitor C7, a resistor R6 and a resistor R7, wherein:
the No. 1 pin of the processor U2 is connected with the signal output end OUT of the amplifier OP chip, and the No. 5, no. 6, no. 7 and No. 8 pins are grounded together;
one end of the capacitor C7 is connected with pins 14 and 16 of the processor U2 and then connected with a 5V power supply, and the other end of the capacitor C7 is connected with pins 12 and 13 of the processor U2 and then connected with GND;
one end of the resistor R6 is connected with a pin 9 of the processor U2 and then connected with a pin 17 of the processor U1 in the digital signal acquisition and processing unit module in parallel, and the other end of the resistor R is connected with a 5V power supply;
one end of the resistor R7 is connected with a pin No. 10 of the processor U2 and then connected with a pin No. 16 of the processor U1 in the digital signal acquisition and processing unit module in parallel, and the other end of the resistor R is connected with a 5V power supply;
the digital signal acquisition and processing unit module comprises a processor U1, a reset circuit unit and a crystal oscillator circuit unit, wherein:
the reset circuit unit is electrically connected with the No. 9 pin of the processor U1; the crystal oscillator circuit unit is electrically connected with pins 18 and 19 of the processor U1 respectively.
2. The weak signal acquisition circuit applied to the single-channel lead salt photoelectric detector as claimed in claim 1, wherein the processor U2 in the analog-to-digital conversion unit module is a PCF8591 chip.
3. The weak signal acquisition circuit applied to the single-channel lead salt photoelectric detector as claimed in claim 1, wherein the processor U1 in the digital signal acquisition processing unit module is an STC89C52 chip.
4. The weak signal acquisition circuit applied to the single-channel lead salt photoelectric detector as claimed in claim 1, wherein the voltage-dividing matching resistance unit module comprises: a detector r and a matching resistor RL; a detector r in the partial voltage matching resistance unit module adopts a lead salt photoelectric detector as a signal source to generate a required analog signal; the D end of the detector r is connected with a 5V power supply, the S end is connected with the matching resistor RL, and the GND end is connected with the other end of the RL and then grounded; wherein, adopt the precision to be 5%, resistance RL that the resistance matches with the dark resistance of detector r, the purpose is in order to let the signal more stable.
5. The weak signal acquisition circuit applied to the single-channel lead salt photoelectric detector as claimed in claim 1, wherein the capacitor C1 in the dc blocking filter circuit unit module is a patch capacitor with a precision of ± 20% and is used for blocking off a dc voltage part in a signal; the resistor R3 is a chip resistor with the precision of 5 percent and is connected with the capacitor C1 in parallel to form an RC circuit, and the purpose is to filter partial noise in 5V bias voltage.
6. The weak signal acquisition circuit applied to the single-channel lead salt photoelectric detector as claimed IN claim 1, wherein the feedback resistor R1 IN the signal amplification circuit unit module is a chip resistor with a precision of 5% and is connected between the inverting input terminal IN-and the signal output terminal OUT of the amplifier OP chip; the resistor R2 is a chip resistor with the precision of 5%, one end of the resistor R2 is connected with the resistor R1 and the reverse input end IN-of the amplifier OP chip, and the other end of the resistor R2 is connected with GND.
7. The weak signal acquisition circuit applied to the single-channel lead salt photoelectric detector as claimed in claim 1, wherein the resistor R6 in the analog-to-digital conversion unit module is a patch resistor with an accuracy of 5%, and the capacitor C7 is a patch capacitor with an accuracy of ± 20%.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211331297.0A CN115683350A (en) | 2022-10-28 | 2022-10-28 | Weak signal acquisition circuit applied to single-channel lead salt photoelectric detector |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211331297.0A CN115683350A (en) | 2022-10-28 | 2022-10-28 | Weak signal acquisition circuit applied to single-channel lead salt photoelectric detector |
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| CN115683350A true CN115683350A (en) | 2023-02-03 |
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| CN202211331297.0A Pending CN115683350A (en) | 2022-10-28 | 2022-10-28 | Weak signal acquisition circuit applied to single-channel lead salt photoelectric detector |
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| CN (1) | CN115683350A (en) |
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- 2022-10-28 CN CN202211331297.0A patent/CN115683350A/en active Pending
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