CN202994625U - Weak optical signal detection circuit of liquid particle counter - Google Patents
Weak optical signal detection circuit of liquid particle counter Download PDFInfo
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- CN202994625U CN202994625U CN 201220664431 CN201220664431U CN202994625U CN 202994625 U CN202994625 U CN 202994625U CN 201220664431 CN201220664431 CN 201220664431 CN 201220664431 U CN201220664431 U CN 201220664431U CN 202994625 U CN202994625 U CN 202994625U
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Abstract
The utility model relates to a weak optical signal detection circuit of a liquid particle counter. The weak optical signal detection circuit is connected with a sensor of the liquid particle counter and is used for processing signals which are output by the sensor to extract useful signals. The detection circuit comprises a drive circuit which is connected with the sensor and outputs drive signals to drive the sensor, a pre-amplifying circuit which is connected with the sensor and is used for amplifying output signals of the sensor, and a demodulator circuit which is used for performing coherent demodulation on the amplified output signals. An input terminal of the demodulator circuit is connected with the drive circuit and the pre-amplifying circuit respectively and an output terminal of the demodulator circuit outputs signals which are demodulated. According to the detection circuit disclosed by the utility model, the principle of coherent demodulation is adopted to extract useful signals related to particle information from strong background noise, so that the capability of extracting signals is enhanced, the signal to noise ratio is well improved and the stability and the resolution ratio of signal detection are improved.
Description
Technical field
The utility model relates to a kind of Optic-Electric Detecting Circuit for weak signal of liquid particle counter, specifically, relates to a kind of testing circuit that extracts useful signal in the ground unrest of complexity.
Background technology
Liquid particle counter is for detection of the small insoluble particle pollutant in liquid, and it has in fields such as parenteral solution detection, water quality detection, fluid detection, semiconductor technology controls very widely uses.Light blockage method laser liquid particle collector utilizes fine particle to scattering of light and stops and realize particle counting and measurement according to light scattering theory.
In at present general liquid particle counter signal processing circuit, laser instrument sends light beam, enter sample cell after processing through optical module, when particle process sample cell, because particle produces the photoresistance effect to light, this time will produce pulse signal through after photoelectric conversion component, and the pulse height of this signal depends on the size of grain diameter, and this signal includes the noise signal that particle pulse signal, laser noise signal and parasitic light produce.Be noise decrease, all adopt the amplification of normal mode, filtering to process in traditional liquid particle counter signal processing circuit, to extract the pulse signal that is directly proportional to grain diameter.Shown in accompanying drawing 1, traditional signal processing circuit comprises subtraction circuit 104, and an one input end is connected with Laser Driven 101, and another input end is connected with pre-amplification circuit 103.After the signal of sensor 102 amplifies through pre-amplification circuit 103 in input subtraction circuit 104, monitoring pin MD signal and the signal process subtraction circuit 104 that contains particle information with Laser Driven 101, reaching the purpose of eliminating noise, then through low-pass filter circuit 105 and secondary amplifying circuit 106 with the noise that the improves signal subsequent drive ability of signal processing circuit when.
In above-mentioned signal processing model, by taking laser instrument MD signal, really squelch is played a role, but do not consider herein the problem of noise phase, therefore signal may be introduced new noise through after subtracter, increases the intractability of signal.In addition for improving signal to noise ratio (S/N ratio), to laser drive part divide, the laser instrument parasitic light processes and proposed very high requirement.
Summary of the invention
It is higher that the purpose of this utility model is to provide a kind of extraction signal capabilities, and anti-interference is the Optic-Electric Detecting Circuit for weak signal of liquid particle counter preferably.
For achieving the above object, the technical solution adopted in the utility model is:
a kind of Optic-Electric Detecting Circuit for weak signal of liquid particle counter, be connected with the sensor of liquid particle counter and the signal that described sensor is exported is processed to extract useful signal, it comprise be connected with described sensor and output drive signal to drive the driving circuit of the laser instrument in described sensor, the pre-amplification circuit that is connected with described sensor and the output signal of described sensor is amplified, it also comprises the demodulator circuit that the output signal after amplifying is carried out coherent demodulation, the input end of described demodulator circuit is connected with described pre-amplification circuit with described driving circuit respectively, described demodulator circuit output grain diameter signal to be measured.
Preferably, described demodulator circuit comprises
Phase-shift circuit, the input end of described phase-shift circuit is connected with the output terminal of described driving circuit;
Multiplier, an input end of described multiplier is connected with the output terminal of described pre-amplification circuit, and another input end is connected with the output terminal of described phase-shift circuit;
Filtering circuit, the input end of described filtering circuit is connected with the output terminal of described multiplier, and the output terminal output of described filtering circuit is through the grain diameter signal described to be measured of demodulation.
Preferably, described filtering circuit is bandwidth-limited circuit.
Preferably, described driving circuit is laser drive circuit.
Preferably, described laser drive circuit is the high-frequency oscillating circuits of the high-frequency oscillation signal of output square wave or sine wave.
The utility model principle of work is: sensor is worked under the driving of driving circuit and output signal, this output signal is inputted in demodulator circuit after amplifying through pre-amplification circuit, and the signal of driving circuit also is input in demodulator circuit as the reference signal simultaneously, demodulator circuit is according to the principle of coherent demodulation, by extracting useful signal in sensor output and amplifying signal.
Because technique scheme is used, the utility model compared with prior art has following advantages: the principle that adopts coherent demodulation, the useful signal of relevant particle information is extracted from stronger ground unrest, improved the ability of signal extraction, better improve signal to noise ratio (S/N ratio), strengthened stability and the resolution of input.
Description of drawings
Accompanying drawing 1 is the theory diagram of the signal deteching circuit of existing liquid particle counter.
Accompanying drawing 2 is the theory diagram of the Optic-Electric Detecting Circuit for weak signal of a kind of liquid particle counter of the present utility model.
Accompanying drawing 3 is the signal transformation diagram of the Optic-Electric Detecting Circuit for weak signal of a kind of liquid particle counter of the present utility model.
In above accompanying drawing: 101, Laser Driven; 102, sensor; 103, pre-amplification circuit; 104, subtraction circuit; 105, low-pass filter circuit; 106, secondary amplifying circuit;
201, driving circuit; 202, sensor; 203, pre-amplification circuit; 204, phase-shift circuit; 205, multiplier; 206, filtering circuit; 207, secondary amplifying circuit.
Embodiment
Below in conjunction with embodiment shown in the drawings, the utility model is further described.
Embodiment one: shown in accompanying drawing 2 and accompanying drawing 3.A kind of Optic-Electric Detecting Circuit for weak signal of liquid particle counter is connected with the sensor 202 of liquid particle counter and the signal that sensor 202 is exported is processed to extract useful signal.
This Optic-Electric Detecting Circuit for weak signal comprise be connected with sensor 202 and output drive signal with the driving circuit 201 of driving sensor 202, be connected with sensor 202 and pre-amplification circuit 203 that the output signal of sensor 202 is amplified, the output signal after amplification carried out the secondary amplifying circuit 207 that coherent demodulation obtains the demodulator circuit of grain diameter signal to be measured, is connected with the output terminal of demodulator circuit and grain diameter signal to be measured is amplified.
The input end of demodulator circuit is connected with pre-amplification circuit 203 with driving circuit 201 respectively, and it comprises phase-shift circuit 204, multiplier 205, filtering circuit 206.
The input end of phase-shift circuit 204 is connected with the output terminal of driving circuit 201.An input end of multiplier 205 is connected with the output terminal of pre-amplification circuit 203, and another input end is connected with the output terminal of phase-shift circuit 204.The input end of filtering circuit 206 is connected with the output terminal of multiplier 205, the output terminal output grain diameter signal to be measured of filtering circuit 206.This filtering circuit 206 is bandwidth-limited circuit.
In multiplier 205 as one road signal input demodulator circuit after the output signal of sensor 202 is amplified through pre-amplification circuit 203, and the high-frequency oscillation signal a that driving circuit 201 is exported became the signal consistent with signal b phase place and inputted in multiplier 205 as another road signal after advancing phase-shift circuit 204.Above-mentioned two paths of signals obtains only comprising the signal c of particle information after multiplier 205 and bandwidth-limited circuit 206.Can obtain the signal that size adapts to the subsequent conditioning circuit needs at this moment, then through the secondary amplifying circuit 207 that is formed by general amplifier.
This Optic-Electric Detecting Circuit for weak signal adopts the principle of coherent demodulation to carry out the detection of particle collector feeble signal, laser high frequency noise, circuit low-frequency noise and external interference noise had extremely strong inhibiting effect, not only improved the ability of extracting feeble signal from strong background noise, and also be enhanced aspect anti-interference, also reduced simultaneously the requirement to laser instrument and relevant light paths.This circuit is not only applicable to liquid particle counter, and other faint optics input are also had same reference role.
Above-described embodiment only is explanation technical conceive of the present utility model and characteristics, and its purpose is to allow person skilled in the art scholar can understand content of the present utility model and implement according to this, can not limit protection domain of the present utility model with this.All equivalences of doing according to the utility model Spirit Essence change or modify, within all should being encompassed in protection domain of the present utility model.
Claims (5)
1. the Optic-Electric Detecting Circuit for weak signal of a liquid particle counter, be connected with the sensor of liquid particle counter and the signal that described sensor is exported is processed to extract useful signal, it comprise be connected with described sensor and output drive signal to drive the driving circuit of the laser instrument in described sensor, the pre-amplification circuit that is connected with described sensor and the output signal of described sensor is amplified, it is characterized in that: it also comprises the demodulator circuit that the output signal after amplifying is carried out coherent demodulation, the input end of described demodulator circuit is connected with described pre-amplification circuit with described driving circuit respectively, described demodulator circuit output grain diameter signal to be measured.
2. the Optic-Electric Detecting Circuit for weak signal of a kind of liquid particle counter according to claim 1, it is characterized in that: described demodulator circuit comprises
Phase-shift circuit, the input end of described phase-shift circuit is connected with the output terminal of described driving circuit;
Multiplier, an input end of described multiplier is connected with the output terminal of described pre-amplification circuit, and another input end is connected with the output terminal of described phase-shift circuit;
Filtering circuit, the input end of described filtering circuit is connected with the output terminal of described multiplier, and the output terminal output of described filtering circuit is through the grain diameter signal described to be measured of demodulation.
3. the Optic-Electric Detecting Circuit for weak signal of a kind of liquid particle counter according to claim 2, it is characterized in that: described filtering circuit is bandwidth-limited circuit.
4. the Optic-Electric Detecting Circuit for weak signal of a kind of liquid particle counter according to claim 1, it is characterized in that: described driving circuit is laser drive circuit.
5. the Optic-Electric Detecting Circuit for weak signal of a kind of liquid particle counter according to claim 4 is characterized in that: described laser drive circuit is the high-frequency oscillating circuits of output square wave or sinusoidal wave high-frequency oscillation signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220664431 CN202994625U (en) | 2012-12-06 | 2012-12-06 | Weak optical signal detection circuit of liquid particle counter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220664431 CN202994625U (en) | 2012-12-06 | 2012-12-06 | Weak optical signal detection circuit of liquid particle counter |
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| Publication Number | Publication Date |
|---|---|
| CN202994625U true CN202994625U (en) | 2013-06-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220664431 Expired - Lifetime CN202994625U (en) | 2012-12-06 | 2012-12-06 | Weak optical signal detection circuit of liquid particle counter |
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| CN (1) | CN202994625U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106990163A (en) * | 2016-01-20 | 2017-07-28 | 宝山钢铁股份有限公司 | Detection circuit and system for Inner Defect Testing |
| CN114413935A (en) * | 2022-01-26 | 2022-04-29 | 西安交通大学 | Noise suppression system and method of Fabry-Perot sensor |
-
2012
- 2012-12-06 CN CN 201220664431 patent/CN202994625U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106990163A (en) * | 2016-01-20 | 2017-07-28 | 宝山钢铁股份有限公司 | Detection circuit and system for Inner Defect Testing |
| CN114413935A (en) * | 2022-01-26 | 2022-04-29 | 西安交通大学 | Noise suppression system and method of Fabry-Perot sensor |
| CN114413935B (en) * | 2022-01-26 | 2023-08-22 | 西安交通大学 | Noise suppression system and method for Fabry-Perot sensor |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130612 |
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| CX01 | Expiry of patent term |