CN201007707Y - Non-linear correction circuit for infrared spectrometer - Google Patents
Non-linear correction circuit for infrared spectrometer Download PDFInfo
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- CN201007707Y CN201007707Y CNU2006200473307U CN200620047330U CN201007707Y CN 201007707 Y CN201007707 Y CN 201007707Y CN U2006200473307 U CNU2006200473307 U CN U2006200473307U CN 200620047330 U CN200620047330 U CN 200620047330U CN 201007707 Y CN201007707 Y CN 201007707Y
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- operational amplifier
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- potentiometer
- integrated operational
- correction circuit
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Abstract
A non-linear correction circuit for infrared spectrometer is connected between a zero/ sensibility correction module of the infrared spectrometer and a current output module, comprising an analogs multiplier, a first integral operational amplifier, a potentiometer and a second integral operational amplifier. The analogs multiplier is connected to the zero/ sensibility correction module via inlet connection. The first integral operational amplifier and an inlet end are connected to the analogs multiplier. An outlet end of the first integral operational amplifier is connected to an inverted input end of the first integral operational amplifier after voltage division. A first end of the potentiometer in connected to the output of the first integral operational amplifier and is back coupled to the analogs multiplier by a whip. A second end of the potentiometer is connected to a reference voltage. The output of the first integral operational amplifier passes through a whip of a second potentiometer and is output to a non-inverting input end of the second integral operational amplifier after voltage division. An output of the second integral operational amplifier is used as an output of the non-linear correction circuit and output of the second integral operational amplifier is back coupled to an inverted input end of the second integral operational amplifier. According to service use, the non-linear correction circuit is provided with good correction capability.
Description
Technical Field
The utility model relates to an infrared spectroscopy analysis appearance's nonlinear correction technique, more specifically say, relate to an infrared spectroscopy analysis appearance nonlinear correction circuit.
Background
An infrared spectroscopic analysis instrument is an instrument which utilizes the absorption characteristic of infrared light when the infrared light penetrates through a medium, and because the attenuation of the infrared light in the gas to be analyzed follows an exponential law, the output characteristic of the instrument presents an exponential characteristic. When the infrared spectroscopic analyzer is used for micro or micro/constant analysis, the nonlinearity is not so severe and satisfactory results can be obtained by parabolic correction. The parabola correction needs three correction points (zero point, full-scale point and half-scale point), so that two correction parameters exist, the required parameter values are difficult to find out on the plane of the two parameters, and the adjustment of each parameter influences the output of the half-scale point and the full-scale point.
Thus, there is a need for a technique that can correct for non-linearity in infrared spectrometers.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a simple and easy approximate parabola nonlinear correction technique, it only needs a correction parameter, is suitable for analog circuit, and its mathematical model also is suitable for the singlechip circuit.
According to the utility model discloses, a be connected to between infrared spectrometer's zero point/sensitivity correction module and the current output module, include for infrared spectrometer nonlinear correction circuit: the output signal of the zero/sensitivity correction module is used as an input voltage and is connected to a first input end of the analog multiplier; the output end of the analog multiplier is connected to the non-inverting input end of the first integrated operational amplifier, and the output of the first integrated operational amplifier is connected to the inverting input end of the first integrated operational amplifier after being divided by a resistor R1 and a resistor R2; the output of the first integrated operational amplifier is connected to a first end of the potentiometer, and is fed back to a second input end of the analog multiplier through a movable arm of the potentiometer, and a second end of the potentiometer is connected to a reference voltage; and the output of the first integrated operational amplifier is divided by a second potentiometer and a resistor R3 and is input to the non-inverting input end of the integrated operational amplifier through a movable arm of the second potentiometer, the output of the second integrated operational amplifier is used as the output of the nonlinear correction circuit, and the output of the second integrated operational amplifier is fed back to the inverting input end of the second integrated operational amplifier.
According to the utility model discloses an embodiment, the second integrated operational amplifier constitutes closed loop gain and is 1 cophase amplifier circuit.
According to the utility model discloses an embodiment, first operational amplifier realizes 2 cophase enlargiments.
The utility model discloses among the technical scheme who adopts, adopted simple circuit just can realize just correcting micro or micro/constant, in the correction, simplified the nonlinear correction process, hardly found required parameter value on the plane of two parameters in having overcome traditional nonlinear parabola and having rectified to and all can influence the shortcoming of the output of half-range point and full-range point when adjusting every parameter. Practical use shows, the utility model discloses a nonlinear correction circuit has good correction ability to it is accurate to rectify.
Drawings
In the present invention, like reference numerals refer to like features throughout, wherein,
fig. 1 is a circuit diagram of a non-linearity correction circuit according to an embodiment of the present invention;
fig. 2 is a normalized input-output characteristic diagram of the nonlinear correction circuit of the above embodiment.
Detailed Description
The technical scheme of the invention is further explained by combining the drawings and the embodiment.
The utility model provides a simple and easy approximate parabola nonlinear correction technique, it only needs a correction parameter, is suitable for analog circuit, also is suitable for the single chip microcomputer circuit.
Assume that the meter has performed zero-point correction at the zero-point/sensitivity correction module. The mathematical model of the inserted non-linearity correction module is:
in the formula
m is a nonlinear correction coefficient and is between 0 and 1, because m and x are less than 1
y＝(1-m)(x+mx 2 +m 2 x 3 +......)
And removing the high-order terms with the power of more than 3 to obtain the parabolic nonlinear correction. In the above equation, vi is the input of the nonlinear correction module, V o Vfs is the input-output full-scale value (5V) for the output of the non-linear correction module.
As can be seen from the formula, no matter what value of m is between 0 and 1, the input/output characteristics of the correction module pass through two points of (0,0) and (1,1), so that the value of m is increased, and the curvature of the input/output characteristics is increased. When m =0, there is no non-linearity correction.
Based on the above principle, the present invention firstly provides a non-linear correction circuit for infrared spectrometer, referring to fig. 1, fig. 1 shows a circuit diagram of the non-linear correction circuit,
as shown in fig. 1, the non-linear correction circuit for an infrared spectrometer is connected between a zero point/sensitivity correction module (not shown) and a current output module (not shown) of the infrared spectrometer, and typically, the current output module is a 4/20mA current output module, and the non-linear correction circuit includes:
the analog multiplier 102 is used for connecting an output signal of the zero/sensitivity correction module serving as an input voltage Vi to a first input end X of the analog multiplier and serving as an input voltage Vx of the first input end X;
the output end Z of the analog multiplier 102 is connected to the non-inverting input end of the first integrated operational amplifier 202, the output voltage Vz1 of the Z end is used as the input of the non-inverting input end of the first integrated operational amplifier 202, the output of the first integrated operational amplifier 202 is divided by a resistor R1 (204) and a resistor R2 (206) and then connected to the inverting input end of the first integrated operational amplifier 202; the first operational amplifier 202 realizes 2 times of in-phase amplification;
a potentiometer 104, wherein the output of the first integrated operational amplifier 202 is connected to a first end a of the potentiometer 104, and is fed back to a second input end Y of the analog multiplier 102 through a boom 106 of the potentiometer 104 as an input voltage Vy of the second input end Y, and a second end b of the potentiometer 104 is connected to a reference voltage Vref, and in the embodiment, the reference voltage Vref is +5V;
and a second integrated operational amplifier 208, wherein the output Vz of the first integrated operational amplifier 202 is divided by a second potentiometer 210 and a resistor R3 (212), and is input to the non-inverting input terminal of the integrated operational amplifier 208 through a movable arm 214 of the second potentiometer 210, the output of the second integrated operational amplifier 208 is used as the output of the non-linear correction circuit, and the output of the second integrated operational amplifier 208 is fed back to the inverting input terminal of the second integrated operational amplifier 208, and the second integrated operational amplifier 208 constitutes a non-inverting amplifier circuit with a closed-loop gain of 1.
In the embodiment shown in fig. 1, the analog multiplier 102 is of the AD633 type and the first and second integrated operational amplifiers 202 and 208 are of the OP-07 type.
Referring to fig. 1, the total resistance of the potentiometer 104 is RW, and the resistance from the boom 106 to the end b is mRW, so the input voltage Vy of the second input terminal Y of the analog multiplier 102 is:
V Y ＝mV Z +(1-m)·5＝mV Z +(1-m)V fs
the input-output relationship of the AD633 type analog multiplier is as follows:
thus:
solving the equation yields the output of the first integrated operational amplifier 202 as:
because: v X ＝V i ，V 0 ＝V Z
The mathematical model of the nonlinear correction module is
The normalized input-output characteristic of the nonlinear correction module is shown in fig. 2, and fig. 2 is a graph of the normalized input-output characteristic of the nonlinear correction circuit.
According to the utility model discloses, infrared spectrometer's correction step does:
(1) Introducing zero gas, adjusting zero correction of the instrument to ensure that V is i ＝0；
(2) Introducing full-range standard gas, adjusting the sensitivity of the instrument, and correcting to obtain V i =5V, the boom 214 of the second potentiometer is adjusted to the maximum position, when V is present o Also equal to 5V;
(3) Introducing half-range standard gas, adjusting a movable arm 106 of the potentiometer 104 to enable V o And 2.5V, completing the nonlinear correction.
The calibration steps of this circuit should be noted, in addition to the steps described above: in the general case of the above-mentioned,full-range calibration of infrared spectrometerThe concentration of gas is about 85-95% of the full range value instead of the full range value. This is taken into account by introducing a circuit of the second integrated operational amplifier 208, the second potentiometer 210 and the resistor R3 (212). When full range calibration is performed, the sensitivity of the instrument is adjusted to correct V Z =5V (see fig. 1), and then the boom 214 of the second potentiometer 210 is adjusted so that V is set O Equal to the corresponding output of the full-scale calibration gas (e.g., 90% of full-scale calibration gas, the second potentiometer 210 is adjusted to make V 0 ＝5×90％＝4.5V)。
The utility model discloses among the technical scheme who adopts, adopted simple circuit just can realize just correcting micro or micro/constant, in the correction, simplified the nonlinear correction process, hardly found required parameter value on the plane of two parameters in having overcome traditional nonlinear parabola and having rectified to and all can influence the shortcoming of the output of half range point and full range point when adjusting every parameter. Practical use shows, the utility model discloses a nonlinear correction circuit has good correction ability to it is accurate to rectify.
Claims (3)
1. A non-linear correction circuit of an infrared spectrometer is connected between a zero point/sensitivity correction module and a current output module of the infrared spectrometer, and comprises:
an analog multiplier (102) to whose first input (X) the output signal of the zero/sensitivity correction module is connected as an input voltage (Vi);
the output end (Z) of the analog multiplier (102) is connected to the non-inverting input end of the first integrated operational amplifier (202), the output of the first integrated operational amplifier (202) is connected to the inverting input end of the first integrated operational amplifier (202) after being divided by a resistor R1 (204) and a resistor R2 (206);
a potentiometer (104), wherein the output of the first integrated operational amplifier (202) is connected to a first end (a) of the potentiometer (104), the output is fed back to a second input end (Y) of the analog multiplier (102) through a movable arm (106) of the potentiometer (104), and a second end (b) of the potentiometer (104) is connected to a reference voltage (Vref);
and a second integrated operational amplifier (208), wherein the output of the first integrated operational amplifier (202) is divided by a second potentiometer (210) and a resistor R3 (212), the divided voltage is input to the non-inverting input end of the integrated operational amplifier (208) through a movable arm (214) of the second potentiometer (210), the output of the second integrated operational amplifier (208) is used as the output of the nonlinear correction circuit, and the output of the second integrated operational amplifier (208) is fed back to the inverting input end of the second integrated operational amplifier (208).
2. The non-linearity correction circuit of claim 1,
the second integrated operational amplifier (208) forms a non-inverting amplifier circuit with a closed-loop gain of 1.
3. The non-linearity correction circuit of claim 1,
the first operational amplifier (202) achieves 2 times in-phase amplification.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006200473307U CN201007707Y (en) | 2006-10-31 | 2006-10-31 | Non-linear correction circuit for infrared spectrometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006200473307U CN201007707Y (en) | 2006-10-31 | 2006-10-31 | Non-linear correction circuit for infrared spectrometer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201007707Y true CN201007707Y (en) | 2008-01-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2006200473307U Expired - Fee Related CN201007707Y (en) | 2006-10-31 | 2006-10-31 | Non-linear correction circuit for infrared spectrometer |
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| CN (1) | CN201007707Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103493366A (en) * | 2011-04-25 | 2014-01-01 | 西铁城控股株式会社 | Analog multiplier circuit, variable gain amplifier, detector circuit, and physical quantity sensor |
-
2006
- 2006-10-31 CN CNU2006200473307U patent/CN201007707Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103493366A (en) * | 2011-04-25 | 2014-01-01 | 西铁城控股株式会社 | Analog multiplier circuit, variable gain amplifier, detector circuit, and physical quantity sensor |
| US9396362B2 (en) | 2011-04-25 | 2016-07-19 | Citizen Holdings Co., Ltd. | Analog multiplier circuit, variable gain amplifier, detector circuit, and physical quantity sensor |
| CN103493366B (en) * | 2011-04-25 | 2016-08-24 | 西铁城控股株式会社 | Analog multiplication circuit, variable gain amplifier, detecting circuit and physical quantity transducer |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080116 Termination date: 20151031 |
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| EXPY | Termination of patent right or utility model |