CN106405248A - Resistance measurement circuit of raising preset level triangular wave excitation - Google Patents
Resistance measurement circuit of raising preset level triangular wave excitation Download PDFInfo
- Publication number
- CN106405248A CN106405248A CN201610914636.6A CN201610914636A CN106405248A CN 106405248 A CN106405248 A CN 106405248A CN 201610914636 A CN201610914636 A CN 201610914636A CN 106405248 A CN106405248 A CN 106405248A
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- signal
- analog
- predetermined level
- triangular
- raising
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/14—Measuring resistance by measuring current or voltage obtained from a reference source
Abstract
The invention discloses a resistance measurement circuit of raising preset level triangular wave excitation, and relates to the field of resistance measurement. The resistance measurement circuit comprises a microcontroller which controls a digital-to-analog converter to output raising preset level triangular wave voltage signals of which the positive and negative cycles are symmetric. The raising preset level triangular wave voltage signals are converted into raising preset current value triangular wave current signals through a voltage and current converter. The raising preset current value triangular wave current signals excite the measured resistor to generate voltage signals. The voltage signals are inputted to an analog-to-digital converter through amplification of an amplifier, and the analog-to-digital converter inputs the conversion result to the microcontroller. The microcontroller enables the result of accumulation and subtraction of the respective data of the positive and negative half cycles of the raising preset level triangular waves to be proportional to the measured resistor so as to calculate the resistance value of the measured resistor. The complexity of a constant current source circuit and a subsequent measurement circuit can be reduced and the accuracy of resistance measurement can be enhanced.
Description
Technical field
The present invention relates to resistance measurement field, more particularly, to a kind of resistance measurement electricity raising predetermined level triangle wave excitation
Road.
Background technology
The measurement of resistance is very universal, and in various resistance measurement methods, voltammetry is again commonly used with high precision.Volt
Peace method is by using Ohm's law：R=U/I is measuring resistance value.Driving voltage (constant pressure source electricity known to measured resistance is applied
Road), the then electric current in measurement measured resistance, or to exciting current (constant-current source circuit) known to measured resistance applying, then survey
Voltage in amount measured resistance, can calculate the resistance of unknown resistance.
In order to improve the acquisition quality of signal, notification number of the prior art is CN 104808063A, and the day for announcing is 2015
The patent application in July 29 in year improves the quality of resistance measurement by the use of triangular wave as pumping signal.
Inventor, during realizing the present invention, finds at least to suffer from the drawback that in above-mentioned prior art and not enough：
Because existing measuring circuit is bar none all using analog-digital converter, analog-digital converter is near input limits
Exist significantly non-linear when (maximum or minimum amplitude), the analog signal level of particularly input analog-to-digital converter is lower, obtains
The uncertainty of the digital conversion results arriving is bigger.
Therefore, using pure triangular wave as pumping signal when, the data signal obtaining in the low level part of triangular wave
Signal to noise ratio just very low, thus have impact on the acquisition precision of signal.
Content of the invention
The invention provides a kind of resistance measuring circuit raising predetermined level triangle wave excitation, the present invention passes through triangle
Ripple is adjusted to the triangular wave raising predetermined level, improves the certainty of measurement of resistance, described below：
A kind of resistance measuring circuit raising predetermined level triangle wave excitation, including：Microcontroller, with described microcontroller
The digital to analog converter of connection, analog-digital converter；Described digital to analog converter connects voltage current adapter, described Voltage to current transducer
It is additionally provided with amplifier between device and described analog-digital converter,
Described in described microprocessor control, the positive and negative periodic symmetry of digital to analog converter output raises predetermined level triangular wave electricity
Pressure signal, described predetermined level triangle wave voltage signal of raising is converted into raising predetermined current through described voltage current adapter
Value triangular current signal, described pre-set current value triangular current signal excitation measured resistance of raising produces voltage signal；
Described voltage signal is input to described analog-digital converter via described amplifier after amplifying, described analog-digital converter will
Transformation result is input to described microcontroller；
During analog-digital converter conversion, noise level does not change, but as the triangular signal driving
Due to having raised predetermined level, in the low level part of triangular signal, data signal is improved substantially compared to noise, thus carrying
High in triangular signal low level section, get the signal to noise ratio of data signal, and then improve the number being input in microprocessor
The precision of word signal；
By raising positive and negative half period of predetermined level triangular wave, each data cumulative and subtracting each other obtains described microcontroller
Result be proportional to measured resistance, calculate the resistance of described measured resistance.
Wherein, as the triangular signal driving due to having raised predetermined level, in the high level part of triangular signal,
Improve the signal to noise ratio getting data signal.
Wherein, the value of predetermined level is that more than half is optimal for the dynamic range of data signal.
A kind of resistance measuring circuit raising predetermined level triangle wave excitation, including：Microcontroller, with described microcontroller
The current D-A conveter of connection, analog-digital converter；Also set up between described current D-A conveter and described analog-digital converter
There is amplifier,
Described in described microprocessor control, the positive and negative periodic symmetry of current D-A conveter output raises pre-set current value three
Angle signal wave current, described pre-set current value triangular current signal excitation measured resistance of raising produces voltage signal；
Described voltage signal is input to described analog-digital converter via described amplifier after amplifying, described analog-digital converter will
Transformation result is input to described microcontroller；
During analog-digital converter conversion, noise level does not change, but as the triangular signal driving
Due to having raised predetermined level, in the low level part of triangular signal, data signal is improved substantially compared to noise, thus carrying
High in triangular signal low level section, get the signal to noise ratio of data signal, and then improve the number being input in microprocessor
The precision of word signal；
By raising positive and negative half period of predetermined level triangular wave, each data cumulative and subtracting each other obtains described microcontroller
Result be proportional to measured resistance, calculate the resistance of described measured resistance.
Wherein, as the triangular signal driving due to having raised predetermined level, in the high level part of triangular signal,
Improve the signal to noise ratio getting data signal.
Wherein, the value of predetermined level is that more than half is optimal for the dynamic range of data signal.
The beneficial effect of technical scheme that the present invention provides is：The present invention will raise predetermined level triangle by microcontroller
Each data cumulative and subtract each other the result obtaining and be proportional to measured resistance of the positive and negative half period of ripple, calculates measured resistance
Resistance；The present invention is CN 104808063A compared to the notification number in background technology, and the day for announcing is the special of July 29 in 2015
Profit application, invention significantly increases the precision of data signal, and then improve the data signal being input in microprocessor
Precision so that microcontroller calculates the measured resistance of degree of precision.Present invention achieves high speed, the high accuracy of big information
Measurement, and have that structure and circuit be simple, device and technological requirement is low, debugging easily, high reliability.
Brief description
Fig. 1 is a kind of structural representation of resistance measuring circuit raising predetermined level triangle wave excitation of embodiment 1；
Fig. 2 raises predetermined level triangle wave voltage signal schematic representation for embodiment 1；
Fig. 3 is a kind of structural representation of resistance measuring circuit raising predetermined level triangle wave excitation of embodiment 2；
Fig. 4 raises pre-set current value triangular current signal schematic representation for embodiment 2；
In accompanying drawing, the list of parts representated by each label is as follows：
MCU：Microcontroller； DAC：Digital to analog converter；
VCC：Voltage current adapter； A：Amplifier；
ADC：Analog-digital converter； Zx：Measured resistance；
IDAC：Current D-A conveter； Ii：Raise pre-set current value triangular current signal；
Vi：Raise predetermined level triangle wave voltage signal.
Specific embodiment
For making the object, technical solutions and advantages of the present invention clearer, below embodiment of the present invention is made further
Ground describes in detail.
Embodiment 1
Referring to Fig. 1, a kind of resistance measuring circuit raising predetermined level triangle wave excitation, including：Microcontroller, number
Weighted-voltage D/A converter DAC, voltage current adapter VCC, amplifier A, analog-digital converter ADC；
What microcontroller controlled digital to analog converter DAC output positive and negative periodic symmetry as shown in Figure 2 raises predetermined level
Triangle wave voltage signal, raise predetermined level triangle wave voltage signal be converted into raising through voltage current adapter VCC default
Current value triangular current signal Ii, raise pre-set current value triangular current signal IiExcitation measured resistance Zx, produce voltage letter
Number Vi=IiZx, voltage signal is input to analog-digital converter ADC via after amplifier A amplification, and analog-digital converter ADC is by Change-over knot
Fruit is input to microcontroller, and by the positive and negative half period of triangular wave, each data cumulative and subtracting each other obtains microcontroller
Result be proportional to measured resistance Zx, measured resistance Z can be calculatedx.
After the embodiment of the present invention raises predetermined level, after voltage signal is via amplifier A amplification, it is input to analog-to-digital conversion
During device ADC, noise level does not change, but as the triangular signal driving due to having raised predetermined level,
In the low level part of triangular signal, triangular signal improves substantially compared to noise, thus improve in triangular signal
The signal to noise ratio of the data signal of low level section；It is CN 104808063A compared to the notification number in background technology, the day for announcing is
July 29 in 2015, the embodiment of the present invention considerably improved in triangle using pure triangular wave as the patent application of pumping signal
The signal to noise ratio of the data signal of ripple signal low level section, and then improve the precision of the transformation result being input in microcontroller.
Further, since raising predetermined level, noise level is not changed in, in the high level part of triangular signal, triangle
Ripple signal also has some improvement compared to noise, improves the signal to noise ratio of the data signal in triangular signal high level section.
Transformation result precision due to analog-digital converter ADC is improved, and then improves and be input in microcontroller
The precision of data signal, microprocessor is processed to data signal, can calculate measured resistance Zx.
Wherein, the value of predetermined level preferred analog-digital converter ADC conversion data signal dynamic range more than half, when
During more than or equal to 1/2 dynamic range, the distortion raising the triangular signal of predetermined level is minimum, is adopted by analog-digital converter ADC
The digital signal quality highest collecting.
That is, by sampled value v of the positive half period of each triangular wave in certain time (integer triangle period of wave)iTired
Plus obtain adding up and sampled value v of the negative half period of each triangular wavejCumulative obtain cumulative and, this two are cumulative and subtract each other,
The result (the actual area for triangular wave) obtaining is proportional to measured resistance Zx, measured resistance Z can be calculatedx, derive as follows：
Taking a cycle as a example calculate the area of triangular wave, each periodic sampling 2k time, first k time cumulative cumulative with latter k time：
Within a triangle period of wave, the mean value of sampled value is：
In the area of triangle interior triangular period of wave it is：
When sampling in positive half period, sampled value v is vi；When sampling in negative half period, sampled value v is vj.
That is,
Previous item：When calculate positive half period, latter：Calculate negative half-cycle.
Note before and after's twoIt is identical value, butAnd vj＞ 0, so
For x, value is sampled to amplitude, if within the regular hour uniform sampling N (>>1) put and carry out average, obtain
Mean value be
Wherein, [x] is that analog-digital converter quantifies to x, namely the positive integer that round off rounding obtains.xiIt is
The amplitude of i point, [xi] it is analog-digital converter to xiQuantified, namely the positive integer that round off rounding obtains.
(6) formula shows, the signal sampling that is compared with " clean " repeatedly carries out averagely, to improve its precision, institute
The error of the mean value obtaining is identical with the error of unitary sampling, is Δ xi.
If sawtooth waveforms is sampled for x to amplitude, equally within the regular hour uniform sampling N (>>1) put and carry out
Averagely, the mean value obtaining is
Wherein, xi=mi+Δxi, mi=[xi].That is to say that rounding obtains positive integer, but lose after being rounded
" random " error.
(7) formula can obtain further with arithmetic series sum formula：
(8) the previous item in formula is value after quantifying although less than the result of (6) formula half, but according to error theory,
The precision of one data does not change because being multiplied by a fixing non-zero constant.But it is the random number of zero-mean in one next,
Compare will reduce in (6) formulaTimes, therefore, sawtooth waveforms or triangular wave pumping signal are carried out equally can obtaining after over-sampling
To putting forward high-precision effect, and do not need in addition to increase frequency disturbing signal.
To the model of each device in addition to doing specified otherwise, the model of other devices is not limited the embodiment of the present invention,
As long as the device of above-mentioned functions can be completed.
In sum, because the embodiment of the present invention is with respect to the application documents in background technology, considerably improve three
The signal to noise ratio of the data signal of angle ripple low level section, and also improve the noise of the data signal in triangular signal high level section
Than, and then improve the precision of the data signal being input in microcontroller, microprocessor is processed to data signal, permissible
Calculate measured resistance Zx.
Embodiment 2
Referring to Fig. 3, a kind of resistance measuring circuit raising predetermined level triangle wave excitation, including：Microcontroller, electricity
Fluxion weighted-voltage D/A converter IDAC, amplifier A, analog-digital converter ADC；
The triangular wave of microcontroller control electric current digital to analog converter IDAC output positive and negative periodic symmetry as shown in Figure 4
Current signal Ii, triangular current signal IiExcitation measured resistance Zx, produce voltage signal Vi=IiZx, voltage signal is via amplification
Device A is input to analog-digital converter ADC after amplifying, and transformation result is input to microcontroller, microcontroller by analog-digital converter ADC
Device MCU is by each data cumulative and subtract each other the result obtaining and be proportional to measured resistance Z of the positive and negative half period of triangular wavex, can
To calculate measured resistance Zx.
Wherein, the microcontroller in the present embodiment is by each data cumulative and subtracting each other of the positive and negative half period of triangular wave
The result obtaining is proportional to measured resistance ZxDetailed operating procedures same as Example 1, therefore not to repeat here.
To the model of each device in addition to doing specified otherwise, the model of other devices is not limited the embodiment of the present invention,
As long as the device of above-mentioned functions can be completed.
In sum, because the embodiment of the present invention is with respect to the application documents in background technology, considerably improve three
The signal to noise ratio of the data signal of angle ripple low level section, and also improve the noise of the data signal in triangular signal high level section
Than, and then improve the precision of the data signal being input in microcontroller, microprocessor is processed to data signal, permissible
Calculate measured resistance Zx.
It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the embodiments of the present invention
Sequence number is for illustration only, does not represent the quality of embodiment.
The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all spirit in the present invention and
Within principle, any modification, equivalent substitution and improvement made etc., should be included within the scope of the present invention.
Claims (6)
1. a kind of resistance measuring circuit raising predetermined level triangle wave excitation, including：Microcontroller, with described microcontroller even
The digital to analog converter that connects, analog-digital converter；Described digital to analog converter connects voltage current adapter, described voltage current adapter
Be additionally provided with amplifier and described analog-digital converter between it is characterised in that；
The predetermined level triangle wave voltage of raising that digital to analog converter described in described microprocessor control exports positive and negative periodic symmetry is believed
Number, described predetermined level triangle wave voltage signal of raising is converted into raising pre-set current value three through described voltage current adapter
Angle signal wave current, described pre-set current value triangular current signal excitation measured resistance of raising produces voltage signal；
Described voltage signal is input to described analog-digital converter via described amplifier after amplifying, described analog-digital converter will be changed
Result is input to described microcontroller；
Analog-digital converter conversion during, noise level does not change, but as driving triangular signal due to
Raise predetermined level, in the low level part of triangular signal, data signal is improved substantially compared to noise, thus improve
In triangular signal low level section, get the signal to noise ratio of data signal, and then improve the numeral letter being input in microprocessor
Number precision；
Described microcontroller will raise positive and negative half period of predetermined level triangular wave each data cumulative and subtract each other the knot obtaining
Fruit is proportional to measured resistance, calculates the resistance of described measured resistance.
2. a kind of resistance measuring circuit raising predetermined level triangle wave excitation according to claim 1 it is characterised in that
As the triangular signal driving due to having raised predetermined level, in the high level part of triangular signal, improve and get
The signal to noise ratio of data signal.
3. a kind of resistance measuring circuit raising predetermined level triangle wave excitation according to claim 1 it is characterised in that
The value of predetermined level is that more than half is optimal for the dynamic range of data signal.
4. a kind of resistance measuring circuit raising predetermined level triangle wave excitation, including：Microcontroller, with described microcontroller even
The current D-A conveter that connects, analog-digital converter；It is additionally provided between described current D-A conveter and described analog-digital converter
Amplifier it is characterised in that；
Described in described microprocessor control, the positive and negative periodic symmetry of current D-A conveter output raises pre-set current value triangular wave
Current signal, described pre-set current value triangular current signal excitation measured resistance of raising produces voltage signal；
Described voltage signal is input to described analog-digital converter via described amplifier after amplifying, described analog-digital converter will be changed
Result is input to described microcontroller；
Analog-digital converter conversion during, noise level does not change, but as driving triangular signal due to
Raise predetermined level, in the low level part of triangular signal, data signal is improved substantially compared to noise, thus improve
In triangular signal low level section, get the signal to noise ratio of data signal, and then improve the numeral letter being input in microprocessor
Number precision；
Described microcontroller will raise positive and negative half period of predetermined level triangular wave each data cumulative and subtract each other the knot obtaining
Fruit is proportional to measured resistance, calculates the resistance of described measured resistance.
5. a kind of resistance measuring circuit raising predetermined level triangle wave excitation according to claim 4 it is characterised in that
As the triangular signal driving due to having raised predetermined level, in the high level part of triangular signal, improve and get
The signal to noise ratio of data signal.
6. a kind of resistance measuring circuit raising predetermined level triangle wave excitation according to claim 4 it is characterised in that
The value of predetermined level is that more than half is optimal for the dynamic range of data signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610914636.6A CN106405248A (en) | 2016-10-20 | 2016-10-20 | Resistance measurement circuit of raising preset level triangular wave excitation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610914636.6A CN106405248A (en) | 2016-10-20 | 2016-10-20 | Resistance measurement circuit of raising preset level triangular wave excitation |
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| CN106405248A true CN106405248A (en) | 2017-02-15 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2579052A1 (en) * | 2010-05-25 | 2013-04-10 | Zoomlion Heavy Industry Science and Technology Co., Ltd. | Method for measuring resistance value of conversion resistance of current mode analog /digital converter |
| CN103944540A (en) * | 2014-05-08 | 2014-07-23 | 成都雷电微力科技有限公司 | Triangular wave signal generator |
| CN203970383U (en) * | 2014-05-04 | 2014-12-03 | 山东中医药大学 | A kind of electrocardiogram signal acquisition device |
| CN104360165A (en) * | 2014-11-26 | 2015-02-18 | 上海斐讯数据通信技术有限公司 | Multichannel resistance measuring device |
| CN104808063A (en) * | 2015-04-23 | 2015-07-29 | 天津大学 | Triangular wave excited impedance measurement circuit |
| CN205286367U (en) * | 2016-01-08 | 2016-06-08 | 方华 | Medical treatment oxyhemoglobin saturation measurement system |
-
2016
- 2016-10-20 CN CN201610914636.6A patent/CN106405248A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2579052A1 (en) * | 2010-05-25 | 2013-04-10 | Zoomlion Heavy Industry Science and Technology Co., Ltd. | Method for measuring resistance value of conversion resistance of current mode analog /digital converter |
| CN203970383U (en) * | 2014-05-04 | 2014-12-03 | 山东中医药大学 | A kind of electrocardiogram signal acquisition device |
| CN103944540A (en) * | 2014-05-08 | 2014-07-23 | 成都雷电微力科技有限公司 | Triangular wave signal generator |
| CN104360165A (en) * | 2014-11-26 | 2015-02-18 | 上海斐讯数据通信技术有限公司 | Multichannel resistance measuring device |
| CN104808063A (en) * | 2015-04-23 | 2015-07-29 | 天津大学 | Triangular wave excited impedance measurement circuit |
| CN205286367U (en) * | 2016-01-08 | 2016-06-08 | 方华 | Medical treatment oxyhemoglobin saturation measurement system |
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Application publication date: 20170215 |