CN85105064B - Infrared spectrum analyser gauging mechamism - Google Patents
Infrared spectrum analyser gauging mechamism Download PDFInfo
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- CN85105064B CN85105064B CN85105064A CN85105064A CN85105064B CN 85105064 B CN85105064 B CN 85105064B CN 85105064 A CN85105064 A CN 85105064A CN 85105064 A CN85105064 A CN 85105064A CN 85105064 B CN85105064 B CN 85105064B
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- CN
- China
- Prior art keywords
- infrared spectrum
- amplifier
- signal
- scale
- spectrum analyser
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Abstract
The present invention relates to an amplifying circuit used for amplifying the output of a wavelength detector. The amplifying circuit is composed of a preamplifier and a signal measuring amplifier arranged on the output end of the preamplifier, wherein the signal measuring amplifier is provided with an input resistor, a feedback resistor, a variable resistor and a normally open switch connected with the signal measuring amplifier in series; the variable resistor is connected with a series branch of the normally open switch and the feedback resistor in parallel. In this way, the gain of the signal measuring amplifier can be changed.
Description
The present invention relates to the calibrating device of infrared spectrum analyser.
Generally speaking, all to carry out scale to infrared spectrum analyser school zero and with the normal space.So far, high-ranking officers' zero gas is introduced measuring cell with predetermined flow velocity, and after indication is stable, regulates zero point; Then scale gas is introduced measuring cell with predetermined flow velocity, and after indication is stable, regulate scale.Here, used the gas scaling method.Yet this gas scaling method exists a problem, promptly regulates the expensive gases that scale all needs a kind of rigorous examination to cross at every turn.Demarcation expense like this will increase.
In contrast, people have attempted a kind of mechanical scaling method, method according to this, need not used gas usually, need only by means of dimmer (as a sheet metal, a dim light optical filter or a liquid crystal cell) luminous flux that reduces by measuring cell projects the luminous flux of detecting device with change, just can demarcate at an easy rate.Yet, according to this mechanical scaling method (wherein utilizing a sheet metal), because moving and similar factor of sheet metal insertion position can produce trickle influence, and then can produce error as the luminous flux annihilator.In addition, when utilizing dim light optical filter and liquid crystal cell,, can change the degree that weakens of luminous flux owing to spot, the similar factor of scar and luminous flux annihilator self as the luminous flux annihilator.As mentioned above, in this mechanical scaling method, be difficult to keep high precision.Moreover mechanical scaling method has a shortcoming, promptly because it comprises movable part, so be easy to produce fault.
The purpose of this invention is to provide a kind of can be easy, demarcate exactly, and need not constantly to use the calibrating device of the infrared spectrum analyser of school scale gas.
According to infrared spectrum analyser of the present invention, can take out measuring-signal and reference signal respectively and amplify, then the difference of two signals is sent as output signal, be characterized in and carry out scale by change in order to the gain of the amplifying circuit of measurement by magnification signal.
According to the present invention and since the adjusting of scale just the gain of the amplifying circuit by changing the measurement by magnification signal carry out, therefore, do not need constantly to use expensive scale gas.In addition, owing to the aging scale skew that causes of light source, the spot in pond and similar factor just can check out that the demarcation expense can reduce significantly.In addition, because different with mechanical scaling method, calibrating device of the present invention does not comprise movable parts such as luminous flux annihilator, therefore, except reducing significantly the calibration cost, can produce other fault hardly, and then, can easy and accurately demarcate.
Fig. 1 is the circuit diagram according to a kind of optimum implementation of the present invention.
Fig. 2 is a part block scheme of explanation function.
Optimum implementation of the present invention is described below with reference to the accompanying drawings.Referring to Fig. 1, this is the structure sketch map of " single light source-single pond type " infrared spectrum analyser, (10) be the pond that has sample gas inlet (11) and outlet (12), (20) be to place the end in pond (10) to be used for the light source of infrared radiation, (30) be the test section that places the other end in pond (10), (40) are the modulation choppers that places between pond (10) and light source (20).
Test section (30) is made up of a reference wavelength detecting device (31) and a measurement wavelength detecting (32), and said measurement wavelength detecting has a bandpass filter (32 ').The infrared ray of wavelength in the specific absorption bandwidth range that is absorbed by special component passes through this wave filter as the object that will determine in the sample gas, and produces a measuring-signal Vs.Reference wavelength detecting device (31) is equipped with bandpass filter (31 '), and the bandwidth range not infrared ray in above-mentioned special component absorption region or have only is seldom measured the infrared ray that absorbed by above-mentioned special component by this bandpass filter, and exports a reference signal V
R(50), (60) are prime amplifiers.(70) be the reference signal amplifier that places prime amplifier (50) output terminal, it has an input resistance (71) and a feedback resistance (72), is used for amplifying through prime amplifier (56) and the reference signal V of the reference wavelength detecting device (31) that comes with predetermined gain
R, subtracter (90) is coupled in the output of this reference signal amplifier
Input end.(80) expression places the measure signal amplifier of prime amplifier (60) output terminal, it has an input resistance (81) and a feedback resistance (82), is used for amplifying through prime amplifier (60) and the measuring-signal V of the measurement wavelength detecting (32) that comes with predetermined gain
S, the Θ input end of subtracter (90) is coupled in the output of this measure signal amplifier.In addition, it is in parallel after variable resistor (83) is connected with normally closed switch (84) with feedback resistance (82).So just constitute a feedback circuit FB, thereby the gain of measure signal amplifier (80) can change freely.But resistance (83) is not must be variable resistor, can be the resistance of a fixed resistance value yet.(100) expression places the amplifier of subtracter (90) output terminal, (101) expression range adjuster, and C represents output.
When the concentration of measuring samples gas, normally closed switch (84) for the condition that disconnects under, sample gas is introduced pond (10), the infrared radiation of being sent by power supply (20) is to sample gas, and modulates by chopper (40).By measuring the detected measuring-signal V of wavelength detecting (32)
SWith by the detected reference signal V of reference wavelength detecting device (31)
RSuitably amplified, from measuring-signal, deducted reference signal then, just obtained a concentration signal C.
Below, also will describe with reference to the scale adjustment of the infrared spectrum analyser in 2 pairs of preceding methods of figure.
Referring to Fig. 1,1
0Representative is by the full gain of prime amplifier (50) to the reference electric system R of reference signal amplifier (70) output terminal; 1
1Representative is by the full gain of prime amplifier (60) to the measurement electric system S of measure signal amplifier (80) output terminal; K
1Represent the gain of in-phase amplifier (100).In addition, referring to Fig. 2, I
ORThe ultrared energy that table is given off by light source (20) with reference wavelength; I
OSRepresentative is by the ultrared energy of measuring wavelength that has of light source (20) radiation; I
1RRepresentative through pond (10) and bandpass filter (31 ') after, the ultrared energy with reference wavelength, I
1SRepresentative through pond (10) and bandpass filter (32 ') after, have the ultrared energy of measuring wavelength.
Concentration signal C from amplifier (100) is represented by following equation (1):
C＝K
1（1
0V
R-1
1V
S）……（1）
Suppose, with the proportional constant of detection sensitivity of reference wavelength detecting device (31) be a
1, with the proportional constant of measurement sensitivity of measuring wavelength detecting (32) be a
2, reference signal V then
RWith measuring-signal V
SBe expressed as follows:
V
R＝a
1I
1RV
S＝a
2I
1S
Flow through at the school zero gas under the condition of pond (10), regulate full gain 1 with reference to electric system R
0With the full gain 1 of measuring electric system S
1, then following formula is suitable for:
K
1（1
0V
RZ-1
1V
SZ）＝0，
In the formula, V
RZAnd V
SZRepresent respectively at the school zero gas and flow through under the condition of pond (10), the output signal of reference wavelength detecting device (31) and measurement wavelength detecting (32).
Therefore, I
1SAnd I
1RThe variation of ratio represent with the form of zero point drift.On the other hand, has only the I of working as
1SAnd I
1RDuring with same rate of change, or, just can produce the scale drift when pond length with when measuring the wavelength departure optimum value.With regard to scale gas does not flow,, can check the former correction by flowing of school zero gas although be difficult to check the latter's correction.
When the scale gas flow, C by under establish an equation (2) expression:
C＝K
1（1
0V
RS-1
1V
SS）……（2）
In the formula, V
RSAnd V
SSBe respectively reference wavelength detecting device (31) and the output signal of measuring wavelength detecting (32).
But, because V
RSAlmost with V
RZEquate, so equation (2) can be represented by following equation (3):
C＝K
1（1
0V
RZ-1
1V
SS）……（3）
In the scale adjustment process, by Closing Switch (84), reduce total feedback resistance value, the value of gain m of feedback circuit FB that makes measure signal amplifier (86) is less than 1.Make relational expression V if regulate
SS=mV
SZSet up, then above-mentioned equation (3) can be represented by following equation (4):
C＝K
1（1
0V
RZ-ml
1V
SZ）……（4）
Therefore, in the scale adjustment process, if gain m=V
SS/ V
SZInvest V
SZ, then under the condition that the school zero gas flows, can obtain the signal identical with the signal that under the condition of scale gas flow, obtains.
Suppose I
1RAnd I
1SChange with same ratio a, then concentration signal C can be represented by following equation (5):
C＝K
1（1
0aV
RS-1
1aV
SS）
＝aK
1（1
0V
RS-1
1V
SS）……（5）
On the other hand, because the right value of scale should be K
1(1
0V
RS-1
1V
RS), with the right value of the right of above-mentioned equation (5) and scale more as can be seen, the former be the latter a doubly, that is to say to have produced the scale drift.
To illustrate that below this scale drift can be regulated according to the present invention.Suppose, at I
1RAnd I
1SUnder the condition with same ratio a variation, check I
1RAnd I
1S, then establish an equation down (6) adapt to:
C′＝K
1（1
0a
1V
RZ-m1
1aV
SZ）
＝aK
1（1
0V
RZ-m1
1V
SZ）
＝aK
1（1
0V
RS-1
1V
SS）……（6）
Equation (6) is consistent with above-mentioned equation (5).In other words, can need not to make the scale gas flow by the gain that only changes measure signal amplifier (80), just can regain with scale gas flow situation under the identical state of state that obtains.If by means of range adjuster (101) minimizing owing to the aging luminous flux that causes of power supply (20) is compensated (just can make a=1 like this) with this understanding, then can obtain the right value of scale.
An example of practical adjustments will be described below.
At first, when the school zero gas is flowed, regulate range adjuster (105), (106) carry out school zero, and the semaphore with reference to electric system R can equate with the semaphore of measuring electric system S like this, and the output of detecting device (90) becomes zero.Then, when making the scale gas flow of concentration known, regulate range adjuster (101) so that the output of measuring instrument becomes this concentration.With this understanding, promptly under the condition that school zero-sum scale is all finished, the school zero gas is flowed, treat that indication is stable after, closed normally closed switch (84).At this moment, indicated value is write down.Because resistance (83) is variable resistor, so, change resistance (83) and just can make indicated value become an appropriate value.
Making regular check in the process afterwards, just the school is zero but the school zero gas is flowed, and then, along with the closed normal open switch (84) that constantly flows of school zero gas is regulated range adjuster (101), indicated value just can become above-mentioned memory value like this.
Though " single light source-single pond " type infrared spectrum analyser illustrates that the present invention is not limited thereto in above-mentioned optimum implementation.For example, the present invention also can be applicable to " two pond " type infrared spectrum analyser, and is wherein arranged side by side with the sample test pond, settling a reference cell.In addition, the present invention also can be used for " multivariate analysis instrument ".In a word, the present invention can be used for the analyser of any this type.Promptly reference signal and measuring-signal take out respectively in instrument, and their difference is used as concentration signal output.
Claims (2)
1, a kind of calibrating device of infrared spectrum analyser comprises: measure the test section that wavelength detecting (32) is formed by a reference wavelength detecting device (31) and one, reference signal amplifier (70) and measure signal amplifier (80) place above-mentioned reference wavelength detecting device (31) respectively and measure the output terminal of wavelength detecting (32), carry out school zero by range adjuster (105), (106), and amplify the signal that comes self-detector (31), (32) respectively; The output signal of subtracter (90) reception amplifier (70), (80), and with its difference output; Amplifier (100) places the output terminal of subtracter (90), demarcates by range adjuster 101; The calibrating device of this infrared spectrum analyser is characterised in that: one is carried out the circuit of easy scale with gain-adjusted, and it places the feedback circuit (FB) of above-mentioned measure signal amplifier (80).
2, the calibrating device of infrared spectrum analyser as claimed in claim 1, it is characterized in that the circuit that carries out easy scale with gain-adjusted comprises the variable resistor (83) of connecting with normal open switch (84), and feedback resistance (82), because this circuit places the feedback circuit of measure signal amplifier (80), so can compensate well because the scale drift that photosystem causes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85105064A CN85105064B (en) | 1984-07-09 | 1985-07-03 | Infrared spectrum analyser gauging mechamism |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59143169A JPS6120840A (en) | 1984-07-09 | 1984-07-09 | Calibrating mechanism of infrared analyzer |
| CN85105064A CN85105064B (en) | 1984-07-09 | 1985-07-03 | Infrared spectrum analyser gauging mechamism |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85105064A CN85105064A (en) | 1987-03-04 |
| CN85105064B true CN85105064B (en) | 1987-04-08 |
Family
ID=25741835
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN85105064A Expired CN85105064B (en) | 1984-07-09 | 1985-07-03 | Infrared spectrum analyser gauging mechamism |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN85105064B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102607615A (en) * | 2012-03-29 | 2012-07-25 | 天津大学 | Gain self-compensating method for linear array CCD (Charge-coupled Device) pixel level signal and compensating circuit |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104883141A (en) * | 2015-06-02 | 2015-09-02 | 中国科学院上海技术物理研究所 | Bridge type input resistance negative feedback CMOS (Complementary Metal Oxide Semiconductor) pre-amplifying circuit |
-
1985
- 1985-07-03 CN CN85105064A patent/CN85105064B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102607615A (en) * | 2012-03-29 | 2012-07-25 | 天津大学 | Gain self-compensating method for linear array CCD (Charge-coupled Device) pixel level signal and compensating circuit |
| CN102607615B (en) * | 2012-03-29 | 2015-01-21 | 天津大学 | Gain self-compensating method for linear array CCD (Charge-coupled Device) pixel level signal and compensating circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN85105064A (en) | 1987-03-04 |
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Applicant after: Shandong Xinhua Pharmaceutical Group Co., Ltd. Applicant before: Xinhua Parmaceutical Factory |
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| COR | Change of bibliographic data |
Free format text: CORRECT: APPLICANT; FROM: SHANDONG XINHUA PHARMACEUTICAL FACTORY TO: XINHUA PHARMACY GROUP CO., LTD., SHANDONG PROV. |