CN206740645U - Laser methane monochromatic light road harmonic measurement device based on FPGA - Google Patents
Laser methane monochromatic light road harmonic measurement device based on FPGA Download PDFInfo
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- CN206740645U CN206740645U CN201720492830.XU CN201720492830U CN206740645U CN 206740645 U CN206740645 U CN 206740645U CN 201720492830 U CN201720492830 U CN 201720492830U CN 206740645 U CN206740645 U CN 206740645U
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Abstract
The utility model discloses a kind of laser methane monochromatic light road harmonic measurement device based on FPGA, device includes FPGA, thermistor, PID temperature control circuit, thermistor is arranged on low-frequency sweep current feedback circuit, and it is connected with FPGA, FPGA temperature control signals output end is connected with PID temperature control circuit, methane adsorption point constant temperature on the low-frequency sweep electric current of control low-frequency sweep current feedback circuit output；The output end of low-frequency sweep current feedback circuit does not absorb a signal input part for substrate harmonic noise Acquisition Circuit with methane adsorption point harmonic signal Acquisition Circuit, methane respectively and is connected, and methane adsorption point harmonic signal Acquisition Circuit, methane do not absorb an output end for substrate harmonic noise Acquisition Circuit and is connected respectively with FPGA input.The utility model need not carry out zero point adjustment, improve CH_4 detection precision, easy to use suitable for various environment, have a good application prospect.
Description
Technical field
It the utility model is related to CH_4 detection technical field, and in particular to a kind of laser methane monochromatic light road based on FPGA is humorous
Ripple detection means.
Background technology
T unable filter, i.e. the spectral detection skill based on DFB (distributed Feedback) laser
Art, it is widely used in gas detection industry because it has the characteristics that high s/n ratio and fast response time.In detection process
Laser modulates the light intensity and wavelength of laser output laser simultaneously by way of current-modulation.But laser diode current is adjusted
There is many noises during system, such as：Photodiode dark current, light path pollution, temperature change, lock phase interpolator arithmetic noise
With laser ground noise etc..If these noises, which are dealt with improperly, will have a strong impact on detection sensitivity, such as：Laser methane sensor
Zero point can influence zero point, low-concentration methane signal is in external environmental change because the external condition such as light intensity and temperature shifts
Under can be submerged in ground noise, or ground noise be less than the original record of sensor zero point value, so as to influence accuracy of detection.
In order to overcome the problem of above-mentioned, Traditional solutions are the progress zero point calibrations in scheduling and planning, and this method
It is preferable to be based only on external environment（Noise is low）Under conditions of, if null offset situation occurs under severe electric circumstance, i.e.,
Ground noise changes, moreover, Traditional solutions are the zero point calibrations by normal temperature and high/low temperature, it is necessary in different temperatures
The lower record zero point value of point, and this process needs to occupy certain manpower, financial resources, and the production cycle increases.
Because laser methane sensor can carry out concentration fitting according to the zero point of record in the measurements, so when environment changes
When causing the noise to change, laser methane sensor can not carry out real-time response, can not can only analyze depositing for interference
Therefore, it is automatic to be badly in need of a kind of laser methane sensor that can record ground noise in real time under conditions of measurement is not influenceed
Balancing controls and method.
Utility model content
The purpose of this utility model is overcome in the prior art when environment, which changes, causes noise to change, laser methane
Sensor can not carry out real-time response, can not can only analyze the problem of interference is present.It is of the present utility model to be based on FPGA
Laser methane monochromatic light road harmonic measurement device, by FPGA will absorb point harmonic signal, do not absorb a substrate harmonic noise
Signal synchronously after amplification, after subtracting each other, obtains methane signal value, without carrying out zero point adjustment, improves CH_4 detection precision, is applied to
Various environment, it is easy to use, have a good application prospect.
In order to achieve the above object, technical scheme is used by the utility model：
A kind of laser methane monochromatic light road harmonic measurement device based on FPGA, including FPGA, thermistor, PID temperature control
Circuit processed, low-frequency sweep current feedback circuit, methane adsorption point harmonic signal Acquisition Circuit, methane do not absorb a substrate harmonic noise
Acquisition Circuit,
The thermistor is arranged on low-frequency sweep current feedback circuit, and is connected with FPGA, the temperature of the FPGA
Control signal output is connected with PID temperature control circuit, the low-frequency sweep electricity of control low-frequency sweep current feedback circuit output
Methane adsorption point constant temperature on stream；
The output end of the low-frequency sweep current feedback circuit respectively with methane adsorption point harmonic signal Acquisition Circuit, methane not
The signal input part for absorbing point substrate harmonic noise Acquisition Circuit is connected, the methane adsorption point harmonic signal Acquisition Circuit,
Methane does not absorb an output end for substrate harmonic noise Acquisition Circuit and is connected respectively with FPGA input,
Subtracter and two groups of phaselocked loop amplifying units, the methane adsorption point harmonic signal collection are provided with the FPGA
Circuit, methane do not absorb an output end for substrate harmonic noise Acquisition Circuit the input with one group of phaselocked loop amplifying unit respectively
It is connected, the output end of two groups of phaselocked loop amplifying units exports methane signal value by subtracter.
The foregoing laser methane monochromatic light road harmonic measurement device based on FPGA, the low-frequency sweep current feedback circuit output
Low-frequency sweep current signal be triangular wave, the center of the triangular wave is methane adsorption point, the both ends of the triangular wave
Position is that methane does not absorb a little.
The foregoing laser methane monochromatic light road harmonic measurement device based on FPGA, the control low-frequency sweep current feedback circuit
Methane adsorption point constant temperature on the low-frequency sweep electric current of output, ensure that absorbing point changes in amplitude is less than 0.1mA.
The foregoing laser methane monochromatic light road harmonic measurement device based on FPGA, the low-frequency sweep current signal is using just
String ripple is high-frequency modulation signal.
The beneficial effects of the utility model are：Laser methane monochromatic light road harmonic detecting dress of the present utility model based on FPGA
Put, after absorbing the harmonic signal put by FPGA, not absorb a substrate harmonic noise signals synchronization amplification, after subtracting each other, obtain
Methane signal value, without carrying out zero point adjustment, CH_4 detection precision is improved, constant temperature at methane adsorption point is controlled, is applied to
Various environment, it is easy to use, have a good application prospect.
Brief description of the drawings
Fig. 1 is the system block diagram of the laser methane monochromatic light road harmonic measurement device of the present utility model based on FPGA.
Fig. 2 is the oscillogram of low-frequency sweep current signal of the present utility model.
Embodiment
Below in conjunction with Figure of description, the utility model is further described.
As shown in Fig. 1, the laser methane monochromatic light road harmonic measurement device based on FPGA, including FPGA, thermistor, PID
Temperature-control circuit, low-frequency sweep current feedback circuit, methane adsorption point harmonic signal Acquisition Circuit, that methane does not absorb a substrate is humorous
Ripple Noise Acquisition circuit,
The thermistor is arranged on low-frequency sweep current feedback circuit, and is connected with FPGA, the temperature of the FPGA
Control signal output is connected with PID temperature control circuit, the low-frequency sweep electricity of control low-frequency sweep current feedback circuit output
Methane adsorption point constant temperature on stream；
The output end of the low-frequency sweep current feedback circuit respectively with methane adsorption point harmonic signal Acquisition Circuit, methane not
The signal input part for absorbing point substrate harmonic noise Acquisition Circuit is connected, the methane adsorption point harmonic signal Acquisition Circuit,
Methane does not absorb an output end for substrate harmonic noise Acquisition Circuit and is connected respectively with FPGA input,
Subtracter and two groups of phaselocked loop amplifying units, the methane adsorption point harmonic signal collection are provided with the FPGA
Circuit, methane do not absorb an output end for substrate harmonic noise Acquisition Circuit the input with one group of phaselocked loop amplifying unit respectively
It is connected, the output end of two groups of phaselocked loop amplifying units exports methane signal value by subtracter.
As shown in Fig. 2 the low-frequency sweep current signal of the low-frequency sweep current feedback circuit output is triangular wave, described three
The center of angle ripple is methane adsorption point, and the end positions of the triangular wave do not absorb a little for methane, low-frequency sweep electric current letter
Number sine wave is used as high-frequency modulation signal
Methane adsorption point constant temperature on the low-frequency sweep electric current of the control low-frequency sweep current feedback circuit output, ensures to absorb
Point changes in amplitude is less than 0.1mA, ensures the reliability of harmonic signal gathered at methane adsorption point, improves detection accuracy.
Laser methane monochromatic light road harmonic measurement device of the present utility model based on FPGA, operation principle include following step
Suddenly,
Step（A）, the low-frequency sweep current signal after low-frequency sweep current feedback circuit output detection methane, the low frequency sweeps
It is triangular wave to retouch current signal, and uses sine wave as high-frequency modulation signal；
Step（B）, the temperature on low-frequency sweep electric current at methane adsorption point is gathered by thermistor, is sent to FPGA,
And by FPGA Control PID temperature-control circuits, ensure methane adsorption point constant temperature on low-frequency sweep electric current, absorb point changes in amplitude
Less than 0.1mA；
Step（C）, a substrate harmonic noise is not absorbed by methane adsorption point harmonic signal Acquisition Circuit, methane and gathers electricity
Road gathers the harmonic signal of the absorption point on low-frequency sweep current signal, does not absorb a substrate harmonic noise signals respectively, respectively
The phaselocked loop amplifying unit being sent in FPGA；
Step（D）, by phaselocked loop amplifying unit to absorbing the harmonic signal of point, not absorbing a substrate harmonic noise signals
Synchronize and enhanced processing after, the subtracter that is sent in FPGA；
Step（F）, by subtracter, the harmonic signal value for absorbing point is subtracted and does not absorb a substrate harmonic noise signals
Value, obtains methane signal value.
In summary, the laser methane monochromatic light road harmonic measurement device of the present utility model based on FPGA, will by FPGA
The harmonic signal of absorption point, after not absorbing a substrate harmonic noise signals synchronization amplification, after subtracting each other, methane signal value is obtained, nothing
Zero point adjustment need to be carried out, improves CH_4 detection precision, controls constant temperature at methane adsorption point, suitable for various environment, is used
It is convenient, have a good application prospect.
General principle of the present utility model, main features and advantages have been shown and described above.The technical staff of the industry
It should be appreciated that the utility model is not restricted to the described embodiments, the simply explanation described in above-described embodiment and specification is originally
The principle of utility model, on the premise of the spirit and scope of the utility model is not departed from, the utility model also has various change
And improvement, these changes and improvements are both fallen within claimed the scope of the utility model.The utility model requires protection scope
By appended claims and its equivalent thereof.
Claims (4)
1. the laser methane monochromatic light road harmonic measurement device based on FPGA, it is characterised in that：Including FPGA, thermistor, PID temperature
Degree control circuit, low-frequency sweep current feedback circuit, methane adsorption point harmonic signal Acquisition Circuit, methane do not absorb a substrate harmonic wave
Noise Acquisition circuit,
The thermistor is arranged on low-frequency sweep current feedback circuit, and is connected with FPGA, the temperature control of the FPGA
Signal output part is connected with PID temperature control circuit, on the low-frequency sweep electric current of control low-frequency sweep current feedback circuit output
Methane adsorption point constant temperature；
The output end of the low-frequency sweep current feedback circuit does not absorb with methane adsorption point harmonic signal Acquisition Circuit, methane respectively
The signal input part of point substrate harmonic noise Acquisition Circuit is connected, the methane adsorption point harmonic signal Acquisition Circuit, methane
An output end for substrate harmonic noise Acquisition Circuit is not absorbed respectively with FPGA input to be connected,
Subtracter and two groups of phaselocked loop amplifying units, the methane adsorption point harmonic signal collection electricity are provided with the FPGA
Road, methane do not absorb an output end for substrate harmonic noise Acquisition Circuit the input phase with one group of phaselocked loop amplifying unit respectively
Connection, the output end of two groups of phaselocked loop amplifying units export methane signal value by subtracter.
2. the laser methane monochromatic light road harmonic measurement device according to claim 1 based on FPGA, it is characterised in that：It is described
The low-frequency sweep current signal of low-frequency sweep current feedback circuit output is triangular wave, and the center of the triangular wave is inhaled for methane
Sink, the end positions of the triangular wave do not absorb a little for methane.
3. the laser methane monochromatic light road harmonic measurement device according to claim 1 based on FPGA, it is characterised in that：It is described
Methane adsorption point constant temperature on the low-frequency sweep electric current of low-frequency sweep current feedback circuit output is controlled, ensures that absorption point changes in amplitude is small
In 0.1mA.
4. the laser methane monochromatic light road harmonic measurement device according to claim 2 based on FPGA, it is characterised in that：It is described
Low-frequency sweep current signal uses sine wave as high-frequency modulation signal.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106908413A (en) * | 2017-05-05 | 2017-06-30 | 江苏三恒科技股份有限公司 | Laser methane monochromatic light road harmonic measurement device and method based on FPGA |
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2017
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106908413A (en) * | 2017-05-05 | 2017-06-30 | 江苏三恒科技股份有限公司 | Laser methane monochromatic light road harmonic measurement device and method based on FPGA |
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