CN212748734U - Water dissolved oxygen detection circuit based on time domain-to-frequency domain - Google Patents
Water dissolved oxygen detection circuit based on time domain-to-frequency domain Download PDFInfo
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- CN212748734U CN212748734U CN202020231811.3U CN202020231811U CN212748734U CN 212748734 U CN212748734 U CN 212748734U CN 202020231811 U CN202020231811 U CN 202020231811U CN 212748734 U CN212748734 U CN 212748734U
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Abstract
The utility model provides an aquatic dissolved oxygen detection circuitry based on time domain changes frequency domain, it includes consecutive photoelectric conversion module that is used for converting light signal into the signal of telecommunication, the time domain that is used for converting the data that the time domain detected into the square wave signal of frequency domain changes frequency domain module, phase place acquisition circuit that gathers the phase place change of frequency domain signal and phase place signal that phase place signal conversion becomes voltage signal changes voltage signal module; the time domain to frequency domain based detection circuit for dissolved oxygen in water in the scheme adopts the operational amplifier U2A, the operational amplifier U3A, the voltage comparator U4A and the operational amplifier U9B which are not high-speed processing chips, so that the cost of the whole acquisition circuit is reduced, and meanwhile, due to low-frequency acquisition, the requirements on circuit board wiring and plates of the whole acquisition circuit are reduced.
Description
Technical Field
The utility model relates to an integrated circuit technical field, concretely relates to aquatic dissolved oxygen detection circuitry based on time domain changes frequency domain.
Background
Dissolved oxygen in water is one of five most important parameters in water quality monitoring, and industries such as aquaculture, environment-friendly water quality monitoring, electronic power and the like need to monitor the dissolved oxygen of corresponding water quality, so that the safety and reliability of the used water quality are ensured. At present, two methods, namely a polarography method and a fluorescence method, are mainstream for detecting the dissolved oxygen in water, the polarography method has higher requirement on water quality, is generally used under the condition of ug/L-level dissolved oxygen detection, is suitable for industries with high requirements such as industry, military use and the like, and is generally expensive. The polarography is not suitable for popularization and use because the polarography is particularly expensive and has high precision, and the cost of the polarography is difficult to bear for general enterprises. The fluorescence detection is generated because the fluorescence method is used for detecting the dissolved oxygen, is low in price and simple to use, and is commonly used in the market at present. The fluorescence dissolved oxygen detection method also has two detection methods, one is a light intensity method for detecting dissolved oxygen, and the other is a fluorescence lifetime method for detecting dissolved oxygen.
The principle of detecting the dissolved oxygen by the light intensity method is that light with a specific wavelength is irradiated on a fluorescent film, after the medicinal powder on the fluorescent film is irradiated by the light with the specific wavelength, the medicinal powder on the fluorescent film emits exciting light with the specific wavelength when the electronic transition is recovered to the original state of the fluorescent film, and the intensity of the emitted light and the content of the dissolved oxygen in water are in a certain proportional relation, so that the detection of the dissolved oxygen in the water can be carried out by utilizing the principle.
The principle of detecting the dissolved oxygen by using the fluorescence lifetime method is that the fluorescent film is irradiated by light with a specific wavelength, the medicinal powder on the fluorescent film emits exciting light with the specific wavelength when the electronic transition is recovered to the original state of the fluorescent film after being irradiated by the light with the specific wavelength, and the lifetime of the exciting light and the content of the dissolved oxygen in water form a certain proportional relation, so that the detection of the dissolved oxygen in the water can be carried out by using the principle.
The light intensity method detection is influenced by the light intensity of the fluorescent film, so that the service cycle is short, but the fluorescence lifetime method detection greatly increases the service cycle because the dependence on the light intensity is reduced. However, the fluorescence life method is used for detecting the content of dissolved oxygen in water, at present, a time domain detection method is used for many circuits, the whole period of fluorescence is collected and monitored, the detection can be completed only by using a high-speed operational amplifier, a high-speed AD conversion module and a high-speed data processing chip, the circuit cost is overhigh, the design is excessively complex, the high-frequency circuit has extremely high requirements on the wiring of the whole circuit board, the layout is more difficult in the debugging process, and the problem elimination is more time-consuming and labor-consuming.
Disclosure of Invention
To the defect that exists among the prior art, the utility model aims to provide an aquatic dissolved oxygen detection circuitry based on time domain changes frequency domain, its low cost of this dissolved oxygen detection circuitry, the consumption is little and detect precision and stability can effectively be ensured.
In order to achieve the above object, the utility model adopts the following technical scheme:
a water dissolved oxygen detection circuit based on a time domain to frequency domain comprises a photoelectric conversion module for converting an optical signal into an electric signal, a time domain to frequency domain module for converting data detected by the time domain into a square wave signal of the frequency domain, a phase acquisition circuit for acquiring phase change of the frequency domain signal and a phase signal to voltage signal module for converting the phase signal into a voltage signal, wherein the photoelectric conversion module comprises a photodiode D1, an operational amplifier U2A and an operational amplifier U3A, the cathode end of the photodiode D1 is grounded, the anode end of the photodiode D1 is filtered by capacitors C7 and C8 with different capacities and then connected with the reverse input end of the operational amplifier U2A, the reverse input end of the operational amplifier U2A is connected with the output end of the operational amplifier U2A by a resistor R8 and a capacitor C13 which are connected in parallel, the same-direction input end of the operational amplifier U2A is grounded, the output end of the operational amplifier U2A is connected with a capacitor C14 and a resistor R9 which are arranged in series and then is connected with the reverse input end of the operational amplifier U3A, the same-direction input end of the operational amplifier U3A is connected with a constant voltage of 2.5V through a resistor R4, the reverse input end of the operational amplifier U3A is connected with the output end of the operational amplifier U3A through a resistor R10 and a capacitor C16 which are connected in parallel, and the output end of the operational amplifier U3A is connected with the time domain to frequency domain module and used for outputting a converted photoelectric conversion signal.
Further, the time domain to frequency domain module includes a voltage comparator U4A, wherein an output terminal of the operational amplifier U3A is connected to a same-direction input terminal of the voltage comparator U4A through a resistor R5, an inverting input terminal of the voltage comparator U4A is connected to a comparison voltage DAC _1 through a filter resistor R11 and a capacitor C17 connected in parallel, and an output terminal of the voltage comparator U4A is connected to the phase acquisition circuit through a pull-up resistor R3 to pull up an output signal OUT _ 2.
Further, the phase acquisition circuit comprises a nand gate chip U5A and a not gate chip U6A, wherein an output signal OUT _2 is connected to a first input port of the nand gate chip U5A, an input pin of the not gate chip U6A is connected to a signal OUT _1 which has the same frequency and phase as the optical signal, an output pin of the not gate chip U6A is connected to a second input port of the nand gate chip U5, and an output port of the nand gate chip U5A is connected to the phase signal to voltage signal conversion module, and is configured to output the phase signal acquired after conversion.
Further, the operational amplifier U9B of the phase signal to voltage signal module, the output port of the nand gate chip U5A is connected to the inverting input terminal of the operational amplifier U9B through a low pass filter circuit formed by a resistor R6 and a capacitor C12 and a series resistor R7, the inverting input terminal of the operational amplifier U9B is connected to the resistor R1, the other end of the resistor R1 is grounded, the inverting input terminal of the operational amplifier U9B is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the output terminal of the operational amplifier, so as to form a signal amplification circuit for amplifying the converted signal.
The scheme has the beneficial technical effects that: it is through adopting operational amplifier U2A, operational amplifier U3A, voltage comparator U4A and operational amplifier U9B, it is not the high-speed processing chip all, therefore whole acquisition circuit's cost has been reduced to it is not the in this scheme aquatic dissolved oxygen detection circuit based on time domain frequency domain, simultaneously owing to be low frequency collection, therefore circuit board wiring and panel requirement to whole acquisition circuit reduce, in addition owing to be low frequency acquisition signal, therefore it is more controllable to receive external interference, the circuit is more stable, overall cost is cheaper, the consumption is lower.
Drawings
FIG. 1 is a schematic block diagram of a dissolved oxygen detection circuit according to the present invention;
FIG. 2 is a schematic diagram of a dissolved oxygen detection circuit according to the present invention;
fig. 3 is a functional schematic diagram of the dissolved oxygen detection circuit of the present invention.
In the figure:
the device comprises a 1-photoelectric conversion module, a 2-time domain to frequency domain module, a 3-phase acquisition circuit and a 4-phase signal to voltage signal conversion module.
Detailed Description
The present invention will be described in further detail with reference to the drawings and the following detailed description.
Referring to fig. 1 to 2, the circuit for detecting dissolved oxygen in water based on time domain to frequency domain in this embodiment includes a photoelectric conversion module 1 for converting an optical signal of a laser valve into an electrical signal, a time domain to frequency domain module 2 for converting data detected in the time domain into a square wave signal in the frequency domain, a phase acquisition circuit 3 for acquiring a phase change of the frequency domain signal, and a phase signal to voltage signal module 4 for converting the phase signal into a voltage signal, which are connected in sequence.
The photoelectric conversion module 1 converts an optical signal into an electric signal using the photodiode D1 and the operational amplifiers U2A and U3A, and amplifies the electric signal to a voltage range that can be collected.
Referring to fig. 3, the time domain to frequency domain module 2 uses a voltage comparator U4A to compare the signal obtained from the previous stage with a given voltage signal, so as to obtain a square wave signal. At the moment, the method that the whole waveform can be described only by acquiring a lot of data originally is converted into the method that the square wave signal is only acquired, then the subsequent phase acquisition circuit 3 is utilized to acquire the obtained phase offset, and the size of the phase offset is in a certain proportional relation with the content of the oxygen dissolved in the water.
The phase acquisition circuit 3 inputs the square wave signal of the laser method and the acquired square wave signal into the NAND gate chip U5A circuit through the NOT gate chip U6A at the same time for phase acquisition.
The phase signal to voltage signal module 4 is configured to convert the collected phase square wave signal into a direct current voltage signal after passing through a low-pass filter circuit formed by a resistor R6 and a capacitor C12, and then amplify and output the obtained direct current voltage signal through an operational amplifier U9B.
Specifically, referring to fig. 2, the circuit modules will be described in detail:
the photoelectric conversion module 1 comprises a photodiode D1, an operational amplifier U2A and an operational amplifier U3A, wherein the cathode terminal of the photodiode D1 is grounded, the anode terminal of the photodiode D1 is filtered by capacitors C7 and C8 with different capacities, and then is connected with the reverse input terminal of the operational amplifier U2A, the reverse input terminal of the operational amplifier U2A is connected with the output terminal of the operational amplifier U2A through a resistor R8 and a capacitor C13 which are connected in parallel, the same-direction input terminal of the operational amplifier U2A is grounded, the output terminal of the operational amplifier U2A is connected with the reverse input terminal of the operational amplifier U3A after being connected with the capacitor C14 and the resistor R9 which are arranged in parallel, the same-direction input terminal of the operational amplifier U3A is connected with the rated voltage of 2.5V through a resistor R4, the reverse input terminal of the operational amplifier U3A is connected with the output terminal of the operational amplifier U3A through a resistor R10 and a capacitor C16, the output end of the operational amplifier U3A is connected to the time domain to frequency domain module 2, and is used for outputting the converted photoelectric conversion signal.
The time domain to frequency domain module 2 comprises a voltage comparator U4A, wherein an output end of the operational amplifier U3A is connected with a same-direction input end of the voltage comparator U4A through a resistor R5, an inverting input end of the voltage comparator U4A is connected with a comparison voltage DAC _1 through a filter resistor R11 and a capacitor C17 which are connected in parallel, and an output end of the voltage comparator U4A is connected with the phase acquisition circuit 3 through an output signal OUT _2 which is processed by pulling up the output end of the voltage comparator U4A through a pull-up resistor R3.
The phase acquisition circuit 3 comprises a nand gate chip U5A and a not-gate chip U6A, wherein an output signal OUT _2 is connected with a first input port of the nand gate chip U5A, an input pin of the not-gate chip U6A is connected with a signal OUT _1 which has the same frequency and phase as the optical signal, an output pin of the not-gate chip U6A is connected with a second input port of the nand gate chip U5A, and an output port of the nand gate chip U5A is connected with the phase signal to voltage signal conversion module 4 for outputting the phase signal acquired after conversion.
The phase signal-to-voltage signal module 4 is an operational amplifier U9B, an output port of the nand gate chip U5A is connected with a homodromous input terminal of the operational amplifier U9B through a low-pass filter circuit composed of a resistor R6 and a capacitor C12, and a series resistor R7, an inverting input terminal of the operational amplifier U9B is connected with the resistor R1, the other end of the resistor R1 is grounded, an inverting input terminal of the operational amplifier U9B is connected with one end of the resistor R2, and the other end of the resistor R2 is connected with an output terminal of the operational amplifier to form a signal amplification circuit for amplifying the converted signal, so far, the whole circuit is described completely.
In summary, the time-domain to frequency-domain-based detection circuit for dissolved oxygen in water in the embodiment adopts the operational amplifier U2A, the operational amplifier U3A, the voltage comparator U4A and the operational amplifier U9B, which are not high-speed processing chips, so that the cost of the whole acquisition circuit is reduced, meanwhile, due to low-frequency acquisition, the requirements on the circuit board wiring and the board of the whole acquisition circuit are reduced, and in addition, due to low-frequency acquisition signals, the received external interference is more controllable, the circuit is more stable, the overall cost is lower, and the power consumption is lower.
It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalent technologies, the present invention is also intended to include such modifications and variations.
Claims (4)
1. The utility model provides an aquatic dissolved oxygen detection circuitry based on time domain changes frequency domain which characterized in that: the dissolved oxygen detection circuit comprises a photoelectric conversion module for converting an optical signal into an electric signal, a time domain-to-frequency domain module for converting data detected in a time domain into a square wave signal in a frequency domain, a phase acquisition circuit for acquiring phase change of the frequency domain signal, and a phase signal-to-voltage signal module for converting the phase signal into a voltage signal, wherein the photoelectric conversion module comprises a photodiode D1, an operational amplifier U2A, and an operational amplifier U3A, wherein a cathode end of the photodiode D1 is grounded, an anode end of the photodiode D1 is connected with an inverted input end of the operational amplifier U2A after being filtered by capacitors C7 and C8 with different capacities, the inverted input end of the operational amplifier U2A is connected with an output end of the operational amplifier U2A through a resistor R8 and a capacitor C13 which are connected in parallel, and an equidirectional input end of the operational amplifier U2A is grounded, the output end of the operational amplifier U2A is connected in series with a capacitor C14 and a resistor R9 which are arranged and then connected with the reverse input end of the operational amplifier U3A, the same-direction input end of the operational amplifier U3A is connected with the rated voltage of 2.5V through a resistor R4, the reverse input end of the operational amplifier U3A is connected with the output end of the operational amplifier U3A through a resistor R10 and a capacitor C16 which are connected in parallel, and the output end of the operational amplifier U3A is connected with the time domain to frequency domain module and used for outputting the converted photoelectric conversion signal.
2. The circuit for detecting the dissolved oxygen in water based on the time domain to frequency domain as claimed in claim 1, wherein: the time domain to frequency domain module comprises a voltage comparator U4A, wherein the output end of the operational amplifier U3A is connected with the homodromous input end of the voltage comparator U4A through a resistor R5, the reverse input end of the voltage comparator U4A is connected with a comparison voltage DAC _1 through a filter resistor R11 and a capacitor C17 which are connected in parallel, and the output end of the voltage comparator U4A is connected with the phase acquisition circuit through an output signal OUT _2 which is processed by pulling up the output end of the voltage comparator U4A through a pull-up resistor R3.
3. The circuit for detecting the dissolved oxygen in water based on the time domain to frequency domain as claimed in claim 2, wherein: the phase acquisition circuit comprises a NAND gate chip U5A and a NOT gate chip U6A, wherein an output signal OUT _2 is connected with a first input port of the NAND gate chip U5A, an input pin of the NOT gate chip U6A is connected with a signal OUT _1 which has the same frequency and the same phase as an optical signal, an output pin of the NOT gate chip U6A is connected with a second input port of the NAND gate chip U5A, and an output port of the NAND gate chip U5A is connected with the phase signal voltage conversion signal module and is used for outputting a phase signal acquired after conversion.
4. The circuit for detecting dissolved oxygen in water based on time domain to frequency domain as claimed in claim 3, wherein: the phase signal-to-voltage signal conversion module operational amplifier U9B is characterized in that an output port of the NAND gate chip U5A is connected with a homodromous input end of the operational amplifier U9B through a low-pass filter circuit formed by a resistor R6 and a capacitor C12 and a series resistor R7, an inverting input end of the operational amplifier U9B is connected with the resistor R1, the other end of the resistor R1 is grounded, an inverting input end of the operational amplifier U9B is connected with one end of the resistor R2, and the other end of the resistor R2 is connected with an output end of the operational amplifier to form a signal amplification circuit for amplifying the converted signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020231811.3U CN212748734U (en) | 2020-02-28 | 2020-02-28 | Water dissolved oxygen detection circuit based on time domain-to-frequency domain |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020231811.3U CN212748734U (en) | 2020-02-28 | 2020-02-28 | Water dissolved oxygen detection circuit based on time domain-to-frequency domain |
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| Publication Number | Publication Date |
|---|---|
| CN212748734U true CN212748734U (en) | 2021-03-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020231811.3U Active CN212748734U (en) | 2020-02-28 | 2020-02-28 | Water dissolved oxygen detection circuit based on time domain-to-frequency domain |
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| CN (1) | CN212748734U (en) |
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- 2020-02-28 CN CN202020231811.3U patent/CN212748734U/en active Active
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Inventor after: Hua Yajun Inventor after: Liu Haibo Inventor after: Bian Baoli Inventor after: Wang Honglu Inventor after: Zhao Youpeng Inventor after: Zhang Yuzhen Inventor after: Fu Yu Inventor after: Gou Yan Inventor after: Liu Jianhua Inventor before: Hua Yajun Inventor before: Wang Honglu Inventor before: Zhao Youpeng Inventor before: Zhang Yuzhen Inventor before: Fu Yu Inventor before: Gou Yan Inventor before: Liu Jianhua Inventor before: Liu Haibo Inventor before: Bian Baoli |
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