Water quality PH value detection circuit based on stochastic resonance system

Abstract

The utility model provides a water quality PH value detection circuit based on a stochastic resonance system, the circuit comprises a signal processing circuit and a signal application circuit, the signal processing circuit comprises a four-dimensional double-potential-well stochastic resonance circuit and a low-pass filter circuit; the signal application circuit comprises an analog-to-digital conversion circuit, a minimum system circuit, a display circuit, a key circuit and an alarm circuit; the four-dimensional double-potential-well stochastic resonance circuit, the low-pass filter circuit and the analog-to-digital conversion circuit are sequentially connected in series, and the analog-to-digital conversion circuit, the display circuit, the key circuit and the alarm circuit are connected with an AT89C51 chip pin of the single-chip microcomputer AT89C51 minimum system. The circuit can carry out noise reduction and filtering processing on a to-be-processed signal detected by the PH sensor, the processed signal is displayed on the LCD screen after analog-to-digital conversion and processing, the upper limit alarm threshold value and the lower limit alarm threshold value of the PH value can be adjusted through the key, and if the threshold values are exceeded, the alarm function can be triggered.

Description

TECHNICAL FIELD

[0001] The utility model relates to signal processing and electronic equipment field, specifically provide a kind of water quality PH value detection circuit based on random resonance system. BACKGROUND

[0002] At present, people pay more and more attention to water quality pollution of water environment, especially in the treatment of industrial wastewater, and a series of consequences caused by non-compliance of industrial wastewater discharge are frequently reported by media, and the water quality PH value detection of industrial wastewater is one of important conditions to reach discharge standard. Although the water quality PH value detection of industrial wastewater is increasingly perfect, when using PH sensor to detect water quality PH value, due to the interference of internal circuit noise of sensor, electromagnetic interference noise in surrounding environment, electrochemical reaction noise during detection and the like, the signal measured by PH sensor often has certain noise. The past signal processing method usually uses low-pass, high-pass, band-pass, band-stop and the like filter circuit to achieve the purpose of noise reduction, but this process may cause some characteristics of signal to be weakened, and the noise reduction effect is not very good.

[0003] Based on the above problems, the utility model designs a kind of water quality PH value detection circuit based on random resonance system, which can not only achieve better noise suppression effect, but also can adjust the upper and lower threshold values of alarm PH value through key according to the different discharge standard PH value ranges of different types of industrial wastewater, if not within the range of water quality PH value, remind that the water quality is not up to standard, and it is suitable for detecting whether the water quality PH value of different types of industrial wastewater meets the standard. SUMMARY

[0004] The utility model is based on above background art, designs a kind of water quality PH value detection circuit based on random resonance system, and this circuit includes: signal processing circuit and signal application circuit;Wherein signal processing circuit includes four-dimensional double potential well random resonance circuit (101), low-pass filter circuit (102);Signal application circuit includes analog-digital conversion circuit (201), minimum system circuit (202), display circuit (203), keying circuit (204), alarm circuit (205);A kind of water quality PH value detection circuit based on random resonance system can carry out noise reduction and filtering processing to the signal to be handled detected by PH sensor;The signal after processing can be displayed on LCD screen by analog-digital conversion and data processing;PH alarm threshold can be adjusted by key, if exceeding threshold buzzer will emit sound and LED lamp will bright red light, to realize alarm function.

[0005] In order to realize the above target, the utility model provides the following technical scheme.

[0006] The signal processing circuit includes a four-dimensional double potential well random resonance circuit (101) and a low-pass filter circuit (102); the signal processing circuit can perform noise reduction and filtering processing on the signal to be processed detected by the PH sensor. The input signal is input into the y-dimension circuit of the four-dimensional double potential well random resonance circuit (101), and the y-dimension signal is output as an output signal after system noise reduction amplification; the signal to be processed detected by the PH sensor is input into the x-dimension circuit of the four-dimensional double potential well random resonance circuit (101). The relationship between the y-dimension output signal and the x-dimension signal to be processed detected by the PH sensor is When data processing is performed in the signal application circuit, the size of the y-dimension signal can be calculated by The size of the signal to be processed detected by the PH sensor is calculated and applied to a display circuit (203) and an alarm circuit (205).

[0007] The input end of the four-dimensional double potential well random resonance circuit (101) is connected with the output end of the PH sensor, and the output end is connected with the input end of the low-pass filter circuit (102); the circuit includes multipliers A1, A2 and A3, operational amplifiers U1, U2, U3, U4, U5, U6, U7, U8, U9, U10, U11, U12, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25 and R26, and capacitors C1, C2, C3 and C4.

[0008] Further, in the x-dimension circuit of the four-dimensional double potential well random resonance circuit (101), one end of the resistor R1 is connected with the output end of the operational amplifier U5, and the other end is connected with the reverse input end of the operational amplifier U1 and one end of the resistor R3; one end of the resistor R2 is connected with the output end of the operational amplifier U3, and the other end is connected with the reverse input end of the operational amplifier U1 and one end of the resistor R3; one end of the resistor R3 is connected with the reverse input end of the operational amplifier U1, and the other end is connected with the output end of the operational amplifier U1 and one end of the resistor R4; one end of the resistor R4 is connected with the output end of the operational amplifier U1, and the other end is connected with the reverse input end of the operational amplifier U2 and one end of the capacitor C1; one end of the capacitor C1 is connected with the reverse input end of the operational amplifier U2, and the other end is connected with the output end of the operational amplifier U2 and one end of the resistor R5; one end of the resistor R5 is connected with the output end of the operational amplifier U2, and the other end is connected with the reverse input end of the operational amplifier U3 and one end of the resistor R6; one end of the resistor R6 is connected with the reverse input end of the operational amplifier U3, and the other end is connected with the output end of the operational amplifier U3; and the positive input ends of the operational amplifiers U1, U2 and U3 are grounded.

[0009] In the y-dimension circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), one end of resistor R7 is connected to the output terminal of the PH sensor, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one end of resistor R8 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one input terminal of multiplier A1 is connected to the output terminal of operational amplifier U3, and the other input terminal is connected to the output terminal of operational amplifier U8; one end of resistor R9 is connected to the output terminal of multiplier A1, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one input terminal of multiplier A2 is connected to the output terminal of operational amplifier U8, and the other input terminal is connected to the output terminal of operational amplifier U11; one end of resistor R10 is connected to the output terminal of multiplier A2, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one end of resistor R11 is connected to the inverting input terminal of operational amplifier U4, and the other end is connected to the output terminal of operational amplifier U4 and one end of resistor R12; one end of resistor R12 is connected to the output terminal of operational amplifier U4, and the other end is connected to the inverting input terminal of operational amplifier U5 and one end of capacitor C2; one end of capacitor C2 is connected to the inverting input terminal of operational amplifier U5, and the other end is connected to the output terminal of operational amplifier U5 and one end of resistor R13; one end of resistor R13 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U6 and one end of resistor R14; one end of resistor R14 is connected to the inverting input terminal of operational amplifier U6, and the other end is connected to the output terminal of operational amplifier U6; the non-inverting input terminals of operational amplifiers U4, U5 and U6 are connected to ground.

[0010] In the z-dimension circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), two input terminals of the multiplier A3 are connected to the output terminal of the operational amplifier U5; one end of the resistor R15 is connected to the output terminal of the multiplier A3, and the other end is connected to the inverting input terminal of the operational amplifier U7 and one end of the resistor R17; one end of the resistor R16 is connected to the output terminal of the operational amplifier U9, and the other end is connected to the inverting input terminal of the operational amplifier U7 and one end of the resistor R17; one end of the resistor R17 is connected to the inverting input terminal of the operational amplifier U7, and the other end is connected to the output terminal of the operational amplifier U7 and one end of the resistor R18; one end of the resistor R18 is connected to the output terminal of the operational amplifier U7, and the other end is connected to the inverting input terminal of the operational amplifier U8 and one end of the capacitor C3; one end of the capacitor C3 is connected to the inverting input terminal of the operational amplifier U8, and the other end is connected to the output terminal of the operational amplifier U8 and one end of the resistor R19; one end of the resistor R19 is connected to the output terminal of the operational amplifier U8, and the other end is connected to the inverting input terminal of the operational amplifier U9 and one end of the resistor R20; one end of the resistor R20 is connected to the inverting input terminal of the operational amplifier U9, and the other end is connected to the output terminal of the operational amplifier U9; the non-inverting input terminals of the operational amplifiers U7, U8 and U9 are grounded.

[0011] In the w-dimension circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), one end of the resistor R21 is connected to the output terminal of the operational amplifier U5, and the other end is connected to the inverting input terminal of the operational amplifier U10 and one end of the resistor R23; one end of the resistor R22 is connected to the output terminal of the operational amplifier U12, and the other end is connected to the inverting input terminal of the operational amplifier U10 and one end of the resistor R23; one end of the resistor R23 is connected to the inverting input terminal of the operational amplifier U10, and the other end is connected to the output terminal of the operational amplifier U10 and one end of the resistor R24; one end of the resistor R24 is connected to the output terminal of the operational amplifier U10, and the other end is connected to the inverting input terminal of the operational amplifier U11 and one end of the capacitor C4; one end of the capacitor C4 is connected to the inverting input terminal of the operational amplifier U11, and the other end is connected to the output terminal of the operational amplifier U11 and one end of the resistor R25; one end of the resistor R25 is connected to the output terminal of the operational amplifier U11, and the other end is connected to the inverting input terminal of the operational amplifier U12 and one end of the resistor R26; one end of the resistor R26 is connected to the inverting input terminal of the operational amplifier U12, and the other end is connected to the output terminal of the operational amplifier U12; the non-inverting input terminals of the operational amplifiers U10, U11 and U12 are grounded.

[0012] One end of the resistor R27 in the low-pass filter circuit (102) is connected to the output terminal of the operational amplifier U5, and the other end of the resistor R27 is connected to the resistor R28 and the capacitor C5; one end of the capacitor C5 is connected to the resistor R27 and the resistor R28, and the other end is grounded; one end of the resistor R28 is connected to the resistor R27 and the capacitor C5, and the other end is connected to the resistor R29, the capacitor C6, and the inverting input terminal of the operational amplifier U13; one end of the resistor R29 is connected to the inverting input terminal of the operational amplifier U13, and the other end is connected to the output terminal of the operational amplifier U13 and the resistor R31; one end of the capacitor C6 is connected to the inverting input terminal of the operational amplifier U13, and the other end is connected to the output terminal of the operational amplifier U13 and the resistor R31; one end of the resistor R30 is connected to the non-inverting input terminal of the operational amplifier U13, and the other end is grounded; one end of the resistor R31 is connected to the output terminal of the operational amplifier U13, and the other end is connected to the inverting input terminal of the operational amplifier U14 and the resistor R32; one end of the resistor R32 is connected to the inverting input terminal of the operational amplifier U14, and the other end is connected to the output terminal of the operational amplifier U14; and the non-inverting input terminal of the operational amplifier U14 is grounded.

[0013] The low-pass filter circuit (102) includes a second-order inverting filter circuit and an inverting amplification circuit. The second-order inverting filter circuit can suppress high-frequency noise generated in the process of collecting and transmitting the electrical signal by the PH sensor, and can also smooth the y-dimensional signal output by the four-dimensional double-potential well random resonance circuit. The amplification factor is , and the cutoff frequency is . The purpose of the inverting amplification circuit is to change the amplitude of the electrical signal from a negative value to a positive value. The amplification factor is . Substituting the specific numerical value , we get , , and , that is, the amplitude of the electrical signal does not change after passing through the low-pass filter circuit (102).

[0014] Further, the input end of the low-pass filter circuit (102) is connected with the output end of the four-dimensional double-potential well stochastic resonance circuit (101), and the output end is connected with the input end of the analog-digital conversion circuit (201); the circuit comprises: one end of a resistor R27 is connected with the output end of an operational amplifier U5, the other end of the resistor R27 is connected with a resistor R28, a resistor R29 and a capacitor C5; one end of the capacitor C5 is connected with the resistor R27, the resistor R28 and the resistor R29, and the other end is grounded; one end of the resistor R28 is connected with the resistor R27, the resistor R29 and the capacitor C5, and the other end is connected with a capacitor C6 and the reverse input end of the operational amplifier U13; one end of the resistor R29 is connected with the resistor R27, the resistor R28 and the capacitor C5, and the other end is connected with the output end of the operational amplifier U13 and a resistor R31; one end of the capacitor C6 is connected with the reverse input end of the operational amplifier U13, and the other end is connected with the output end of the operational amplifier U13 and the resistor R31; one end of a resistor R30 is connected with the forward input end of the operational amplifier U13, and the other end is grounded; one end of the resistor R31 is connected with the output end of the operational amplifier U13, and the other end is connected with the reverse input end of an operational amplifier U14 and a resistor R32; one end of the resistor R32 is connected with the reverse input end of the operational amplifier U14, and the other end is connected with the output end of the operational amplifier U14; the forward input end of the operational amplifier U14 is grounded.

[0015] The signal application circuit comprises: an analog-digital conversion circuit (201) composed of a power supply, an ADC0832 chip U15, an AT89C51 chip U16, a display screen U17, a resistor U18, keys B1, B2, B3, B4, B5, a crystal oscillator X1, a polarity capacitor C7, a PNP triode, a buzzer, light-emitting diodes D1 and D2, resistors R33, R34, R35 and R36, capacitors C8 and C9, a minimum system circuit (202), a display circuit (203), a key circuit (204) and an alarm circuit (205); the signal application circuit can display the processed signal on the LCD screen through analog-digital conversion and data processing, and adjust the alarm threshold value of PH through the keys, and trigger the alarm function if the threshold value is exceeded.

[0016] In the signal application circuit, the analog-digital conversion circuit is connected with the 5th pin, the 6th pin, the 7th pin and the 8th pin of the chip AT89C51 of the minimum system circuit (202); the display circuit is connected with the 21st pin, the 22nd pin, the 23rd pin, the 32nd pin, the 33rd pin, the 34th pin, the 35th pin, the 36th pin, the 37th pin and the 38th pin of the chip AT89C51 of the minimum system circuit (202); the key circuit is connected with the 10th pin, the 11th pin, the 12th pin and the 13th pin of the chip AT89C51 of the minimum system circuit (202); and the alarm circuit is connected with the 24th pin, the 25th pin and the 26th pin of the chip AT89C51 of the minimum system circuit (202).

[0017] The analog-digital conversion circuit (201) can convert analog signals into corresponding digital signals and send them to the single-chip microcomputer for corresponding data processing.

[0018] Further, the input end of the analog-digital conversion circuit (201) is connected with the output end of the low-pass filter circuit (102); the 1 pin of the chip U15 is connected with the 8 pin of the chip U16; the 3 pin of the chip U15 is connected with the output end of the operational amplifier U14; the GND pin is grounded; the VCC pin is connected with the power supply; the 7 pin of the chip U15 is connected with the 5 pin of the chip U16; the 5 pin of the chip U15 is connected with the 6 pin of the chip U16; and the 6 pin of the chip U15 is connected with the 7 pin of the chip U16.

[0019] The minimum system circuit (202) is connected with the analog-digital conversion circuit (201), the display circuit (203), the key circuit (204) and the alarm circuit (205) and can process data information as the main control center.

[0020] Further, one end of the polarity capacitor C7 in the minimum system circuit (202) is connected with the power supply and the button B1, and the other end of the polarity capacitor C7 is connected with the resistor R33, the button B1 and the 9th pin of the chip U16; the button B1 is connected with the polarity capacitor C7 in parallel, one end of the button B1 is connected with one end of the polarity capacitor C7, and the other end of the button B1 is connected with the other end of the polarity capacitor C7; one end of the resistor R33 is connected with the 9th pin of the chip U16, and the other end of the resistor R33 is grounded; one end of the capacitor C8 is connected with one end of the capacitor C9, and the other end of the capacitor C8 is connected with the crystal oscillator X1 and the 19th pin of the chip U16; one end of the capacitor C9 is connected with one end of the capacitor C8, and the other end of the capacitor C9 is connected with the crystal oscillator X1 and the 18th pin of the chip U16; one end of the capacitor C8 and the capacitor C9 connected directly is grounded; one end of the crystal oscillator X1 is connected with the capacitor C8 and the 19th pin of the chip U16, and the other end of the crystal oscillator X1 is connected with the capacitor C9 and the 18th pin of the chip U16; the 31st pin of the chip U16 is connected with the power supply; the 5th pin, the 6th pin, the 7th pin and the 8th pin of the chip U16 of the minimum system circuit (202) are connected with the 7th pin, the 5th pin, the 6th pin and the 1st pin of the chip U15 of the analog-digital conversion circuit (201) respectively; the 4th pin, the 5th pin, the 6th pin, the 14th pin, the 13th pin, the 12th pin, the 12th pin, the 10th pin, the 9th pin, the 8th pin and the 7th pin of U17 of the display circuit (203) are connected with the 21st pin, the 22nd pin, the 23rd pin, the 31st pin, the 32nd pin, the 33rd pin, the 34th pin, the 35th pin, the 36th pin, the 37th pin and the 38th pin of the minimum system circuit (202) respectively; one end of the buttons B2, B3, B4 and B5 of the button circuit (204) is connected with the 10th pin, the 11th pin, the 12th pin and the 13th pin of the single-chip microcomputer respectively; one end of the resistor R23, D1 and D2 of the alarm circuit (205) is connected with the 24th pin, the 25th pin and the 26th pin of the single-chip microcomputer respectively.

[0021] The display circuit (203) can display the data detected by the PH sensor on the LCD screen.

[0022] Further, the input end of the display circuit (203) is connected with the 21st pin, 22nd pin, 23rd pin, 31st pin, 32nd pin, 33rd pin, 34th pin, 35th pin, 36th pin, 37th pin, 38th pin and 39th pin of the minimum system circuit (202); the connection route of the circuit is that the pin VSS of the display screen U17 in the display circuit (203) is grounded, the pin VDD of the display screen U17 is connected with the power supply, the 4th pin of the display screen U17 is connected with the 21st pin of the chip U16, the 5th pin of the display screen U17 is connected with the 22nd pin of the chip U16, the 6th pin of the display screen U17 is connected with the 23rd pin of the chip U16, the 7th pin of the display screen U17 is connected with the 39th pin of the chip U16, the 8th pin of the display screen U17 is connected with the 38th pin of the chip U16, the 9th pin of the display screen U17 is connected with the 37th pin of the chip U16, the 10th pin of the display screen U17 is connected with the 36th pin of the chip U16, the 11th pin of the display screen U17 is connected with the 35th pin of the chip U16, the 12th pin of the display screen U17 is connected with the 34th pin of the chip U16, the 7th pin of the display screen U13 is connected with the 33rd pin of the chip U16, the 14th pin of the display screen U17 is connected with the 32nd pin of the chip U16; the 1st pin of the row resistor U18 is connected with the power supply, the 2nd pin of the row resistor U18 is connected with the 7th pin of the display screen U17 and the 39th pin of the chip U16, the 3rd pin of the row resistor U18 is connected with the 8th pin of the display screen U17 and the 38th pin of the chip U16, the 4th pin of the row resistor U18 is connected with the 9th pin of the display screen U17 and the 37th pin of the chip U16, the 5th pin of the row resistor U18 is connected with the 10th pin of the display screen U17 and the 36th pin of the chip U16, the 6th pin of the row resistor U18 is connected with the 11th pin of the display screen U17 and the 35th pin of the chip U16, the 7th pin of the row resistor U18 is connected with the 12th pin of the display screen U17 and the 34th pin of the chip U16, the 8th pin of the row resistor U18 is connected with the 13th pin of the display screen U17 and the 33rd pin of the chip U16, the 9th pin of the row resistor U18 is connected with the 14th pin of the display screen U17 and the 32nd pin of the chip U16.

[0023] The key circuit (204) can control the upper and lower threshold values of PH, the key B2 can increase the lower limit value of PH, the key B3 can decrease the lower limit value of PH, the key B4 can increase the upper limit value of PH, and the key B5 can decrease the upper limit value of PH.

[0024] Further, the output end of the key circuit (204) is connected with the 10 pin, 11 pin, 12 pin and 13 pin of the single-chip microcomputer; the circuit comprises: one end of the key B2 is connected with the 10 pin of the chip U16; one end of the key B3 is connected with the 11 pin of the chip U16; one end of the key B4 is connected with the 12 pin of the chip U16; one end of the key B5 is connected with the 13 pin of the chip U16; the other end of the keys B2, B3, B4 and B5 is grounded.

[0025] The alarm circuit (205) is divided into light alarm and buzzer alarm, if the finally displayed PH value is in the set threshold range, the green light is bright, if the threshold is exceeded, the red light is bright and the buzzer emits sound.

[0026] Further, the input end of the alarm circuit (205) is connected with the 24 pin, 25 pin and 26 pin of the single-chip microcomputer; the circuit comprises: one end of the resistor R34 is connected with the 24 pin of the chip U16, and the other end is connected with the base of the PNP triode; the emitter of the PNP triode is connected with the power supply, the base of the PNP triode is connected with the resistor R34, the collector of the PNP triode is connected with the buzzer BUZZER; one end of the buzzer is connected with the collector of the PNP triode, and the other end is grounded; one end of the light emitting diode D1 is connected with the 25 pin of the chip U16, and the other end is connected with the resistor R35; one end of the resistor R35 is connected with D1, and the other end is connected with the power supply and the resistor R36; one end of the light emitting diode D2 is connected with the 26 pin of the chip U16, and the other end is connected with the resistor R36; one end of the resistor R36 is connected with D2, and the other end is connected with the power supply and the resistor R35.

[0027] The utility model brings the beneficial effect that:

[0028] The utility model discloses a four-dimensional double potential well random resonance circuit (101) is set up, and the signal processing circuit is connected with the four-dimensional double potential well random resonance circuit (101), the signal processing circuit comprises: the input end of the signal processing circuit is connected with the output end of the four-dimensional double potential well random resonance circuit (101), and the output end of the signal processing circuit is connected with the input end of the low pass filter circuit (102), and the low pass filter circuit (102) comprises: the input end of the low pass filter circuit (102) is connected with the output end of the signal processing circuit, and the output end of the low pass filter circuit (102) is connected with the input end of the analog-digital conversion circuit (201).

[0029] Compared with the prior signal processing circuit, the water quality PH value detection circuit based on the random resonance system can not only realize better noise suppression effect, but also can adjust the upper and lower threshold values of the alarm PH value through the key according to the different PH value ranges of the discharge standards corresponding to different types of industrial wastewater, and if the water quality PH value is not in the range, the water quality is not up to standard, and the water quality PH value of different types of industrial wastewater is detected. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a kind of water quality PH value detection circuit based on the overall framework diagram of random resonance system.

[0031] Figure 2 It is a kind of water quality PH value detection circuit based on the flow chart of random resonance system.

[0032] Figure 3 It is a kind of signal processing circuit diagram.

[0033] Figure 4 It is a kind of signal application circuit diagram.

[0034] Figure 5 It is a kind of water quality PH value detection circuit based on the overall diagram of random resonance system. DETAILED DESCRIPTION

[0035] In order to clearly describe the purpose, technical scheme and advantages of the utility model, the utility model will be more complete and clear in the following with the help of drawings.

[0036] As shown in Figure 1 It is a kind of water quality PH value detection circuit based on the overall framework diagram of random resonance system. The circuit is divided into signal processing circuit and signal application circuit, wherein the signal processing circuit includes four-dimensional double potential well random resonance circuit (101), low-pass filter circuit (102);Signal application circuit includes analog-digital conversion circuit (201), minimum system circuit (202), display circuit (203), keying circuit (204), alarm circuit (205).

[0037] As shown in Figure 2 It is a kind of water quality PH value detection circuit based on the flow chart of random resonance system, and its flow is as follows:

[0038] S1, the noise reduction and filtering processing of PH sensor detected signal to be processed;In signal processing circuit, the PH sensor detected signal to be processed enters the circuit, is first input to four-dimensional double potential well random resonance circuit (101) and is subjected to noise reduction processing, then is input to low-pass filter circuit (102) to make the signal further smooth processing;

[0039] S2, the processed signal is displayed on the LCD screen through analog-to-digital conversion and data processing, and the alarm threshold of PH is adjusted through the button, and the alarm function is triggered if the threshold is exceeded; in the signal application circuit, the smoothed signal enters the analog-to-digital conversion circuit (201), the analog signal is converted into a digital signal, and the PH value is displayed on the LCD screen of the display circuit after data processing by the single-chip microcomputer, and the upper and lower threshold values can be adjusted through the button circuit (204), and in the alarm circuit, if the PH value is within the range, the green light is on, and the buzzer does not sound, and if the threshold range is exceeded, the red light is on, and the buzzer sounds.

[0040] As Figure 3 shown, it is a signal processing circuit diagram, the signal processing circuit can perform noise reduction and filtering processing on the signal to be processed detected by the PH sensor, and the circuit includes: a four-dimensional double potential well random resonance circuit (101) and a low-pass filter circuit (102); the connection of the signal processing circuit is: the input end of the four-dimensional double potential well random resonance circuit (101) is connected with the output end of the PH sensor, the output end of the four-dimensional double potential well random resonance circuit (101) is connected with the input end of the low-pass filter circuit (102); the input end of the low-pass filter circuit (102) is connected with the output end of the four-dimensional double potential well random resonance circuit (101), and the output end of the low-pass filter circuit (102) is connected with the input end of the analog-to-digital conversion circuit (201); the signal processing circuit includes: multipliers A1, A2, A3, operational amplifiers U1, U2, U3, U4, U5, U6, U7, U8, U9, U10, U11, U12, U13, U14, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, R30, R31, R32, capacitors C1, C2, C3, C4, C5, C6.

[0041] As Figure 3 shown in 101, it is a four-dimensional double potential well random resonance circuit (101) diagram, in which the IN interface of the PH sensor collects external signals, the OUT interface of the PH sensor is connected with the second-dimensional circuit of the four-dimensional double potential well random resonance circuit (101), the signal to be processed detected by the PH sensor enters the signal processing circuit through this, and the four-dimensional double potential well random resonance circuit (101) can perform noise reduction processing on the signal; wherein the input signal is input in the y-dimensional circuit of the four-dimensional double potential well random resonance circuit (101), and after system noise reduction and amplification, the y-dimensional signal is taken as the output signal; the signal to be processed detected by the PH sensor in the four-dimensional double potential well random resonance circuit (101) has a relationship with the output signal of the y-dimensional In the signal application circuit, the size of the y-dimension signal can be calculated by The size of the signal detected by the PH sensor is calculated and applied to the display circuit (203) and the alarm circuit (205).

[0042] In the x-dimension circuit of the four-dimension double-potential well random resonance circuit (101), one end of the resistor R1 is connected to the output terminal of the operational amplifier U5, and the other end is connected to the reverse input terminal of the operational amplifier U1 and one end of the resistor R3; one end of the resistor R2 is connected to the output terminal of the operational amplifier U3, and the other end is connected to the reverse input terminal of the operational amplifier U1 and one end of the resistor R3; one end of the resistor R3 is connected to the reverse input terminal of the operational amplifier U1, and the other end is connected to the output terminal of the operational amplifier U1 and one end of the resistor R4; one end of the resistor R4 is connected to the output terminal of the operational amplifier U1, and the other end is connected to the reverse input terminal of the operational amplifier U2 and one end of the capacitor C1; one end of the capacitor C1 is connected to the reverse input terminal of the operational amplifier U2, and the other end is connected to the output terminal of the operational amplifier U2 and one end of the resistor R5; one end of the resistor R5 is connected to the output terminal of the operational amplifier U2, and the other end is connected to the reverse input terminal of the operational amplifier U3 and one end of the resistor R6; one end of the resistor R6 is connected to the reverse input terminal of the operational amplifier U3, and the other end is connected to the output terminal of the operational amplifier U3; the positive input terminals of the operational amplifiers U1, U2 and U3 are grounded.

[0043] In the y-dimension circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), one end of resistor R7 is connected to the output terminal of the PH sensor, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one end of resistor R8 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one input terminal of multiplier A1 is connected to the output terminal of operational amplifier U3, and the other input terminal is connected to the output terminal of operational amplifier U8; one end of resistor R9 is connected to the output terminal of multiplier A1, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one input terminal of multiplier A2 is connected to the output terminal of operational amplifier U8, and the other input terminal is connected to the output terminal of operational amplifier U11; one end of resistor R10 is connected to the output terminal of multiplier A2, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one end of resistor R11 is connected to the inverting input terminal of operational amplifier U4, and the other end is connected to the output terminal of operational amplifier U4 and one end of resistor R12; one end of resistor R12 is connected to the output terminal of operational amplifier U4, and the other end is connected to the inverting input terminal of operational amplifier U5 and one end of capacitor C2; one end of capacitor C2 is connected to the inverting input terminal of operational amplifier U5, and the other end is connected to the output terminal of operational amplifier U5 and one end of resistor R13; one end of resistor R13 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U6 and one end of resistor R14; one end of resistor R14 is connected to the inverting input terminal of operational amplifier U6, and the other end is connected to the output terminal of operational amplifier U6; the non-inverting input terminals of operational amplifiers U4, U5 and U6 are connected to ground.

[0044] In the z-dimensional circuit of the four-dimensional double-potential-well random resonant circuit (101): both input terminals of multiplier A3 are connected to the output terminals of operational amplifier U5; one end of resistor R15 is connected to the output terminal of multiplier A3, and the other end is connected to the inverting input terminal of operational amplifier U7 and one end of resistor R17; one end of resistor R16 is connected to the output terminal of operational amplifier U9, and the other end is connected to the inverting input terminal of operational amplifier U7 and one end of resistor R17; one end of resistor R17 is connected to the inverting input terminal of operational amplifier U7, and the other end is connected to the output terminal of operational amplifier U7 and one end of resistor R18; the resistor R18 One end is connected to the output of operational amplifier U7, and the other end is connected to the inverting input of operational amplifier U8 and one end of capacitor C3; one end of capacitor C3 is connected to the inverting input of operational amplifier U8, and the other end is connected to the output of operational amplifier U8 and one end of resistor R19; one end of resistor R19 is connected to the output of operational amplifier U8, and the other end is connected to the inverting input of operational amplifier U9 and one end of resistor R20; one end of resistor R20 is connected to the inverting input of operational amplifier U9, and the other end is connected to the output of operational amplifier U9; the non-inverting inputs of operational amplifiers U7, U8, and U9 are grounded.

[0045] In the w-dimensional circuit of the four-dimensional double-potential-well random resonant circuit (101): one end of resistor R21 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U10 and one end of resistor R23; one end of resistor R22 is connected to the output terminal of operational amplifier U12, and the other end is connected to the inverting input terminal of operational amplifier U10 and one end of resistor R23; one end of resistor R23 is connected to the inverting input terminal of operational amplifier U10, and the other end is connected to the output terminal of operational amplifier U10 and one end of resistor R24; one end of resistor R24 ​​is connected to the output of operational amplifier U10. One end of the capacitor is connected to the inverting input of operational amplifier U11 and one end of capacitor C4; one end of capacitor C4 is connected to the inverting input of operational amplifier U11, and the other end is connected to the output of operational amplifier U11 and one end of resistor R25; one end of resistor R25 is connected to the output of operational amplifier U11, and the other end is connected to the inverting input of operational amplifier U12 and one end of resistor R26; one end of resistor R26 is connected to the inverting input of operational amplifier U12, and the other end is connected to the output of operational amplifier U12; the non-inverting inputs of operational amplifiers U10, U11, and U12 are grounded.

[0046] like Figure 3 As shown in Figure 102, the low-pass filter circuit (102) includes a second-order inverting filter circuit and an inverting amplifier circuit. The second-order inverting filter circuit can suppress high-frequency noise generated during the acquisition and transmission of electrical signals by the PH sensor, and can also smooth the y-dimensional signal output by the four-dimensional double-potential-well random resonant circuit (101). The amplification factor is [missing value]. , the cut-off frequency is ; the purpose of the inverting amplifier circuit is to change the amplitude of the electrical signal from negative to positive, and the amplification factor is ; by substituting the specific values , we can get , , then , that is, the amplitude of the electrical signal does not change after passing through the low-pass filter circuit (102); the circuit includes: operational amplifiers U13, U14, resistors R27, R28, R29, R30, R31, R32, capacitors C5, C6.

[0047] In the low-pass filter circuit (102), one end of the resistor R27 is connected to the output terminal of the operational amplifier U5, and the other end of the resistor R27 is connected to the resistor R28, the resistor R29, and the capacitor C5; one end of the capacitor C5 is connected to the resistor R27, the resistor R28, and the resistor R29, and the other end is grounded; one end of the resistor R28 is connected to the resistor R27, the resistor R29, and the capacitor C5, and the other end is connected to the capacitor C6 and the inverting input terminal of the operational amplifier U13; one end of the resistor R29 is connected to the resistor R27, the resistor R28, and the capacitor C5, and the other end is connected to the output terminal of the operational amplifier U13 and the resistor R31; one end of the capacitor C6 is connected to the inverting input terminal of the operational amplifier U13, and the other end is connected to the output terminal of the operational amplifier U13 and the resistor R31; one end of the resistor R30 is connected to the positive input terminal of the operational amplifier U13, and the other end is grounded; one end of the resistor R31 is connected to the output terminal of the operational amplifier U13, and the other end is connected to the inverting input terminal of the operational amplifier U14 and the resistor R32; one end of the resistor R32 is connected to the inverting input terminal of the operational amplifier U14, and the other end is connected to the output terminal of the operational amplifier U14; the positive input terminal of the operational amplifier U14 is grounded.

[0048] As shown in Figure 4 , it is a signal application circuit diagram, which includes: an analog-to-digital conversion circuit (201) composed of a power supply, an ADC0832 chip U15, an AT89C51 chip U16, a display screen U17, a resistor U18, keys B1, B2, B3, B4, B5, a crystal oscillator X1, a polar capacitor C7, a PNP triode, a buzzer, light-emitting diodes D1, D2, resistors R33, R34, R35, R36, capacitors C8, C9, a minimum system circuit (202), a display circuit (203), a key circuit (204), and an alarm circuit (205); the signal application circuit can display the processed signal on the LCD screen through analog-to-digital conversion and data processing, and adjust the alarm threshold of PH through the keys, and if the threshold is exceeded, the alarm function will be triggered.

[0049] In the signal application circuit, the analog-to-digital conversion circuit is connected to pins 5, 6, 7, and 8 of the AT89C51 chip in the minimum system circuit (202); the display circuit is connected to pins 21, 22, 23, 32, 33, 34, 35, 36, 37, 38, and 39 of the AT89C51 chip in the minimum system circuit (202); the button circuit is connected to pins 10, 11, 12, and 13 of the AT89C51 chip in the minimum system circuit (202); and the alarm circuit is connected to pins 24, 25, and 26 of the AT89C51 chip in the minimum system circuit (202).

[0050] like Figure 4 As shown in 201, the ADC0832 chip in the analog-to-digital converter circuit (201) has the characteristics of low power consumption, high performance and strong stability. It can convert analog signals into corresponding 8-bit digital signals through steps such as clock control, input signal sampling, start conversion signal, successive approximation conversion and conversion result output. The analog-to-digital converter circuit (201) can convert analog signals into corresponding digital signals and send them to the microcontroller for corresponding data processing.

[0051] In the analog-to-digital converter circuit (201), pin 1 of chip U15 is connected to pin 8 of chip U16; pin 3 of chip U15 is connected to the output of operational amplifier U14; the GND pin is grounded; the VCC pin is connected to the power supply; pin 7 of chip U15 is connected to pin 5 of chip U16; pin 5 of chip U15 is connected to pin 6 of chip U16; and pin 6 of chip U15 is connected to pin 7 of chip U16.

[0052] like Figure 4 As shown in 202, the reset circuit in the minimum system circuit (202) can restore the system to its initial state when a fault or error occurs. The minimum system circuit (202) is connected to the analog-to-digital conversion circuit (201), the display circuit (203), the key circuit (204), and the alarm circuit (205), and can process data as the main control center.

[0053] In the minimum system circuit (202), one end of polarized capacitor C7 is connected to the power supply and button B1, and the other end of polarized capacitor C7 is connected to resistor R33, button B1, and pin 9 of chip U16; button B1 is connected in parallel with polarized capacitor C7, one end of button B1 is connected to one end of polarized capacitor C7, and the other end of button B1 is connected to the other end of polarized capacitor C7; one end of resistor R33 is connected to pin 9 of chip U16, and the other end of resistor R33 is grounded; one end of capacitor C8 is connected to one end of capacitor C9, and the other end of capacitor C8 is connected to crystal oscillator X1 and pin 19 of chip U16; one end of capacitor C9 is connected to one end of capacitor C8, and the other end of capacitor C9 is connected to crystal oscillator X1 and pin 18 of chip U16; the end of capacitor C8 directly connected to capacitor C9 is grounded; one end of crystal oscillator X1 is connected to capacitor C8 and pin 19 of chip U16, and the other end is connected to capacitor C9 and pin 18 of chip U16; pin 31 of chip U16... The pins are connected to the power supply; pins 5, 6, 7, and 8 of chip U16 in the minimum system circuit (202) are connected to pins 7, 5, 6, and 1 of chip U15 in the analog-to-digital conversion circuit (201), respectively; pins 4, 5, 6, 14, 13, 12, 12, 10, 9, 8, and 7 of U17 in the display circuit (203) are connected to pin 21 of chip U15 in the minimum system circuit (202), respectively. Pins 22, 23, 31, 32, 33, 34, 35, 36, 37, 38, and 39 are connected; one end of buttons B2, B3, B4, and B5 of the button circuit (204) is connected to pins 10, 11, 12, and 13 of the microcontroller, respectively; one end of resistors R23, D1, and D2 of the alarm circuit (205) is connected to pins 24, 25, and 26 of the microcontroller, respectively.

[0054] like Figure 4 As shown in Figure 203, the LCD1602 liquid crystal display module in the display circuit (203) can be divided into two stages: write mode and display mode. In the write mode stage, the microcontroller chip sends data and instructions to the display module, which are transmitted to the driver via pins. The driver sends the data and instructions to the liquid crystal screen through different pins, such as the RS pin used to distinguish data and instructions, the RW pin used to control the read and write mode, and the E pin used to control the transmission of data. In the display mode stage, according to the data and instructions sent by the driver, different pixels on the liquid crystal screen can display the required information by presenting a bright or dark display through the different arrangement states of liquid crystal molecules. The display circuit (203) can display the data detected by the PH sensor on the LCD screen.

[0055] In the display circuit (203), the VSS and VEE pins of display screen U17 are grounded, the VDD pin of display screen U17 is connected to the power supply, the 4th pin of display screen U17 is connected to the 21st pin of chip U16, the 5th pin of display screen U17 is connected to the 22nd pin of chip U16, the 6th pin of display screen U17 is connected to the 23rd pin of chip U16, the 7th pin of display screen U17 is connected to the 39th pin of chip U16, the 8th pin of display screen U17 is connected to the 38th pin of chip U16, the 9th pin of display screen U17 is connected to the 37th pin of chip U16, the 10th pin of display screen U17 is connected to the 36th pin of chip U16, the 11th pin of display screen U17 is connected to the 35th pin of chip U16, the 12th pin of display screen U17 is connected to the 34th pin of chip U16, the 7th pin of display screen U13 is connected to the 33rd pin of chip U16, and the 14th pin of display screen U17 is connected to the power supply. Pin 32 of chip U16 is connected; pin 1 of resistor array U18 is connected to the power supply; pin 2 of resistor array U18 is connected to pin 7 of display U17 and pin 39 of chip U16; pin 3 of resistor array U18 is connected to pin 8 of display U17 and pin 38 of chip U16; pin 4 of resistor array U18 is connected to pin 9 of display U17 and pin 37 of chip U16; pin 5 of resistor array U18 is connected to pin 10 of display U17 and pin 36 of chip U16; pin 6 of resistor array U18 is connected to pin 11 of display U17 and pin 35 of chip U16; pin 7 of resistor array U18 is connected to pin 12 of display U17 and pin 34 of chip U16; pin 8 of resistor array U18 is connected to pin 13 of display U17 and pin 33 of chip U16; and pin 9 of resistor array U18 is connected to pin 14 of display U17 and pin 32 of chip U16.

[0056] like Figure 4 As shown in 204, the circuit configuration of the button circuit (204) is such that buttons B2, B3, B4, and B5 are all grounded, and the other ends of the four buttons are connected to pins 10, 11, 12, and 13 of chip U16. When a button is pressed, the circuit is turned on, and the pin reads a low level; when the button is released, the circuit is turned off, and the pin reads a high level. The button circuit (204) can control the upper and lower threshold values ​​of pH, and the alarm circuit (205) will show a corresponding response. Button B2 can increase the lower limit value of pH, button B3 can decrease the lower limit value of pH, button B4 can increase the upper limit value of pH, and button B5 can decrease the upper limit value of pH.

[0057] The output end of the key circuit (204) is connected with the 10th pin, 11th pin, 12th pin and 13th pin of the single-chip microcomputer; the circuit comprises: one end of the key B2 is connected with the 10th pin of the chip U16; one end of the key B3 is connected with the 11th pin of the chip U16; one end of the key B4 is connected with the 12th pin of the chip U16; one end of the key B5 is connected with the 13th pin of the chip U16; the other end of the keys B2, B3, B4 and B5 is grounded.

[0058] As shown in Figure 4 As shown in Fig. 205, when the light-emitting diode in the alarm circuit (205) is in a forward working state, i.e. the current flows from the anode to the cathode of the LED, the light-emitting diode emits light, the PNP triode is used for amplifying the current to provide the start of driving the buzzer, and the switching of the buzzer is controlled by the program of the single-chip microcomputer; the alarm circuit (205) comprises a buzzer circuit and an LED lamp circuit; if the finally displayed PH value is within the set threshold range, the green light is on, and if the threshold is exceeded, the red light is on and the buzzer emits sound.

[0059] The input end of the alarm circuit (205) is connected with the 24th pin, 25th pin and 26th pin of the single-chip microcomputer; the circuit comprises: one end of the resistor R34 is connected with the 24th pin of the chip U16, and the other end is connected with the base of the PNP triode; the emitter of the PNP triode is connected with the power supply, the base of the PNP triode is connected with the resistor R34, and the collector of the PNP triode is connected with the buzzer BUZZER; one end of the buzzer is connected with the collector of the PNP triode, and the other end is grounded; one end of the light-emitting diode D1 is connected with the 25th pin of the chip U16, and the other end is connected with the resistor R35; one end of the resistor R35 is connected with D1, and the other end is connected with the power supply and the resistor R36; one end of the light-emitting diode D2 is connected with the 26th pin of the chip U16, and the other end is connected with the resistor R36; one end of the resistor R36 is connected with D2, and the other end is connected with the power supply and the resistor R35.

[0060] As shown in Figure 5 As shown in Fig. 205, when the light-emitting diode in the alarm circuit (205) is in a forward working state, i.e. the current flows from the anode to the cathode of the LED, the light-emitting diode emits light, the PNP triode is used for amplifying the current to provide the start of driving the buzzer, and the switching of the buzzer is controlled by the program of the single-chip microcomputer; the alarm circuit (205) comprises a buzzer circuit and an LED lamp circuit; if the finally displayed PH value is within the set threshold range, the green light is on, and if the threshold is exceeded, the red light is on and the buzzer emits sound.

Claims

1. A water quality PH value detection circuit based on a stochastic resonance system, characterized in that, The circuit is divided into signal processing circuit and signal application circuit, wherein the signal processing circuit comprises four-dimensional double potential well random resonance circuit (101) and low pass filter circuit (102); the signal application circuit comprises analog-digital conversion circuit (201), minimum system circuit (202), display circuit (203), key circuit (204) and alarm circuit (205); In the signal processing circuit, the input end of the four-dimensional double potential well random resonance circuit (101) is connected with the output end of the PH sensor, and the output end of the four-dimensional double potential well random resonance circuit (101) is connected with the input end of the low pass filter circuit (102); the input end of the low pass filter circuit (102) is connected with the output end of the four-dimensional double potential well random resonance circuit (101), and the output end of the low pass filter circuit (102) is connected with the input end of the analog-digital conversion circuit (201); In the signal application circuit, the input end of the analog-digital conversion circuit (201) is connected with the output end of the low pass filter circuit (102), the output end of the analog-digital conversion circuit (201) is connected with the 5th pin, 6th pin, 7th pin and 8th pin of the single-chip microcomputer; the input end of the display circuit (203) is connected with the 21st pin, 22nd pin, 23rd pin, 32nd pin, 33rd pin, 34th pin, 35th pin, 36th pin, 37th pin, 38th pin and 39th pin of the minimum system circuit (202); the output end of the key circuit (204) is connected with the 10th pin, 11th pin, 12th pin and 13th pin of the single-chip microcomputer; the input end of the alarm circuit (205) is connected with the 24th pin, 25th pin and 26th pin of the single-chip microcomputer.

2. The water quality PH value detection circuit based on a stochastic resonance system according to claim 1, characterized in that, The signal processing circuit comprises four-dimensional double potential well random resonance circuit (101) and low pass filter circuit (102); In the x-dimensional circuit of the four-dimensional double potential well random resonance circuit (101), one end of the resistor R1 is connected with the output end of the operational amplifier U5, and the other end is connected with the reverse input end of the operational amplifier U1 and one end of the resistor R3; one end of the resistor R2 is connected with the output end of the operational amplifier U3, and the other end is connected with the reverse input end of the operational amplifier U1 and one end of the resistor R3; one end of the resistor R3 is connected with the reverse input end of the operational amplifier U1, and the other end is connected with the output end of the operational amplifier U1 and one end of the resistor R4; one end of the resistor R4 is connected with the output end of the operational amplifier U1, and the other end is connected with the reverse input end of the operational amplifier U2 and one end of the capacitor C1; one end of the capacitor C1 is connected with the reverse input end of the operational amplifier U2, and the other end is connected with the output end of the operational amplifier U2 and one end of the resistor R5; one end of the resistor R5 is connected with the output end of the operational amplifier U2, and the other end is connected with the reverse input end of the operational amplifier U3 and one end of the resistor R6; one end of the resistor R6 is connected with the reverse input end of the operational amplifier U3, and the other end is connected with the output end of the operational amplifier U3; the positive input ends of the operational amplifiers U1, U2 and U3 are grounded; In the y-dimension circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), one end of resistor R7 is connected to the output terminal of the PH sensor, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one end of resistor R8 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one input terminal of multiplier A1 is connected to the output terminal of operational amplifier U3, and the other input terminal is connected to the output terminal of operational amplifier U8; one end of resistor R9 is connected to the output terminal of multiplier A1, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one input terminal of multiplier A2 is connected to the output terminal of operational amplifier U8, and the other input terminal is connected to the output terminal of operational amplifier U11; one end of resistor R10 is connected to the output terminal of multiplier A2, and the other end is connected to the inverting input terminal of operational amplifier U4 and one end of resistor R11; one end of resistor R11 is connected to the inverting input terminal of operational amplifier U4, and the other end is connected to the output terminal of operational amplifier U4 and one end of resistor R12; one end of resistor R12 is connected to the output terminal of operational amplifier U4, and the other end is connected to the inverting input terminal of operational amplifier U5 and one end of capacitor C2; one end of capacitor C2 is connected to the inverting input terminal of operational amplifier U5, and the other end is connected to the output terminal of operational amplifier U5 and one end of resistor R13; one end of resistor R13 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U6 and one end of resistor R14; one end of resistor R14 is connected to the inverting input terminal of operational amplifier U6, and the other end is connected to the output terminal of operational amplifier U6; the non-inverting input terminals of operational amplifiers U4, U5, and U6 are grounded; In the z-dimension circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), both input terminals of multiplier A3 are connected to the output terminal of operational amplifier U5; one end of resistor R15 is connected to the output terminal of multiplier A3, and the other end is connected to the inverting input terminal of operational amplifier U7 and one end of resistor R17; one end of resistor R16 is connected to the output terminal of operational amplifier U9, and the other end is connected to the inverting input terminal of operational amplifier U7 and one end of resistor R17; one end of resistor R17 is connected to the inverting input terminal of operational amplifier U7, and the other end is connected to the output terminal of operational amplifier U7 and one end of resistor R18; one end of resistor R18 is connected to the output terminal of operational amplifier U7, and the other end is connected to the inverting input terminal of operational amplifier U8 and one end of capacitor C3; one end of capacitor C3 is connected to the inverting input terminal of operational amplifier U8, and the other end is connected to the output terminal of operational amplifier U8 and one end of resistor R19; one end of resistor R19 is connected to the output terminal of operational amplifier U8, and the other end is connected to the inverting input terminal of operational amplifier U9 and one end of resistor R20; one end of resistor R20 is connected to the inverting input terminal of operational amplifier U9, and the other end is connected to the output terminal of operational amplifier U9; the non-inverting input terminals of operational amplifiers U7, U8, and U9 are grounded; In the w-dimensional circuit of the four-dimensional double-potential-well stochastic resonance circuit (101), one end of resistor R21 is connected to the output terminal of operational amplifier U5, and the other end is connected to the inverting input terminal of operational amplifier U10 and one end of resistor R23; one end of resistor R22 is connected to the output terminal of operational amplifier U12, and the other end is connected to the inverting input terminal of operational amplifier U10 and one end of resistor R23; one end of resistor R23 is connected to the inverting input terminal of operational amplifier U10, and the other end is connected to the output terminal of operational amplifier U10 and one end of resistor R24; one end of resistor R24 is connected to the output terminal of operational amplifier U10, and the other end is connected to the inverting input terminal of operational amplifier U11 and one end of capacitor C4; one end of capacitor C4 is connected to the inverting input terminal of operational amplifier U11, and the other end is connected to the output terminal of operational amplifier U11 and one end of resistor R25; one end of resistor R25 is connected to the output terminal of operational amplifier U11, and the other end is connected to the inverting input terminal of operational amplifier U12 and one end of resistor R26; one end of resistor R26 is connected to the inverting input terminal of operational amplifier U12, and the other end is connected to the output terminal of operational amplifier U12; the non-inverting input terminals of operational amplifiers U10, U11 and U12 are grounded. In the low-pass filter circuit (102), one end of resistor R27 is connected to the output terminal of operational amplifier U5, and the other end of resistor R27 is connected to resistor R28, resistor R29 and capacitor C5; one end of capacitor C5 is connected to resistor R27, resistor R28 and resistor R29, and the other end is grounded; one end of resistor R28 is connected to resistor R27, resistor R29 and capacitor C5, and the other end is connected to capacitor C6 and the inverting input terminal of operational amplifier U13; one end of resistor R29 is connected to resistor R27, resistor R28 and capacitor C5, and the other end is connected to the output terminal of operational amplifier U13 and resistor R31; one end of capacitor C6 is connected to the inverting input terminal of operational amplifier U13, and the other end is connected to the output terminal of operational amplifier U13 and resistor R31; one end of resistor R30 is connected to the non-inverting input terminal of operational amplifier U13, and the other end is grounded; one end of resistor R31 is connected to the output terminal of operational amplifier U13, and the other end is connected to the inverting input terminal of operational amplifier U14 and resistor R32; one end of resistor R32 is connected to the inverting input terminal of operational amplifier U14, and the other end is connected to the output terminal of operational amplifier U14; the non-inverting input terminal of operational amplifier U14 is grounded.

3. The water quality PH value detection circuit based on a stochastic resonance system according to claim 1, characterized in that The signal application circuit includes an analog-to-digital conversion circuit (201), a minimum system circuit (202), a display circuit (203), a key circuit (204), an alarm circuit (205); In the signal application circuit, the analog-digital conversion circuit is connected with the 5th pin, the 6th pin, the 7th pin and the 8th pin of the chip AT89C51 of the minimum system circuit (202); the display circuit is connected with the 21st pin, the 22nd pin, the 23rd pin, the 32nd pin, the 33rd pin, the 34th pin, the 35th pin, the 36th pin, the 37th pin, the 38th pin and the 39th pin of the chip AT89C51 of the minimum system circuit (202); the key circuit is connected with the 10th pin, the 11th pin, the 12th pin and the 13th pin of the chip AT89C51 of the minimum system circuit (202); and the alarm circuit is connected with the 24th pin, the 25th pin and the 26th pin of the chip AT89C51 of the minimum system circuit (202).

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