DK177939B1 - A method for linearization of the output of an analog-to-digital converter and measuring instruments using such method - Google Patents
A method for linearization of the output of an analog-to-digital converter and measuring instruments using such method Download PDFInfo
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- DK177939B1 DK177939B1 DK201270791A DKPA201270791A DK177939B1 DK 177939 B1 DK177939 B1 DK 177939B1 DK 201270791 A DK201270791 A DK 201270791A DK PA201270791 A DKPA201270791 A DK PA201270791A DK 177939 B1 DK177939 B1 DK 177939B1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K17/00—Measuring quantity of heat
- G01K17/06—Measuring quantity of heat conveyed by flowing media, e.g. in heating systems e.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device
- G01K17/08—Measuring quantity of heat conveyed by flowing media, e.g. in heating systems e.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device based upon measurement of temperature difference or of a temperature
- G01K17/10—Measuring quantity of heat conveyed by flowing media, e.g. in heating systems e.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device based upon measurement of temperature difference or of a temperature between an inlet and an outlet point, combined with measurement of rate of flow of the medium if such, by integration during a certain time-interval
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
- H03M1/0617—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence
- H03M1/0634—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale
- H03M1/0636—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the amplitude domain
- H03M1/0639—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the amplitude domain using dither, e.g. using triangular or sawtooth waveforms
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/124—Sampling or signal conditioning arrangements specially adapted for A/D converters
- H03M1/1245—Details of sampling arrangements or methods
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K2219/00—Thermometers with dedicated analog to digital converters
Description
A METHOD FOR LINEARIZATION OF THE OUTPUT OF AN ANALOG-TO-DIGITAL CONVERTER AND MEASURING INSTRUMENTS USING SUCH METHOD
The present invention relates to a method for linearization of the output of an analog-to-digital converter, a temperature sensor using such method and a heat consumption meter comprising such temperature sensors.
Background of the invention
It is well-known within the art to use analog-to-digital converters (ADCs) to convert input in the form of a continuous physical quantity, such as an electric voltage, to a digital number that represents the amplitude of this quantity. Since the conversion involves quantization of the input, it introduces a small amount of error. Instead of doing a single conversion, an ADC often performs the conversions ("samples" the input) periodically. The result is a sequence of digital values that have converted a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal.
The quantization error of the ADC depends on its resolution, i.e. on the number of discrete values it can produce over the range of analog values which, in turn, is decided by the number of bits used by the ADC for representing each digital value.
In practice, however, the resolution of an ADC may be improved significantly using well-known methods, such as oversampling of the analog signal and dithering.
Dither, as known in the art, is a very small amount of random noise (typically white noise), which is added to the input before conversion. Its effect is to cause the state of the least significant bit (LSB) of the ADC output to randomly oscillate between 0 and 1 in the presence of very low levels of input, rather than sticking at a fixed value.
Rather than the signal simply getting cut off altogether at this low level (which is only being quantized to a resolution of 1 bit), it extends the effective range of signals that the ADC can convert, at the expense of a slight increase in noise. Effectively, the quantization error is diffused across a series of noise values. The result is an accurate representation of the signal over time. A suitable filter at the output of the system can thus recover this small signal variation. Thus, the dithering produces results that are more exact than the LSB of the ADC.
All ADCs suffer from non-linearity errors caused by their physical imperfections, causing their output to deviate from a linear function. These errors are typically taken care of through calibration of the systems using the ADCs.
It is important to note that a small amount of dither, as known in the art, can only increase the resolution of an ADC. It cannot improve the integral linearity of the ADC, and thus the absolute accuracy does not necessarily improve. US 2012/0013494 A1 discloses a method of reducing nonlinear distortion of an ADC used to process analog radio frequency AC input signals, where an analog dither-signal is added to the input signal before conversion, and removed in the digital domain by a dither-signal removal module.
Brief description of the invention
It is an object of the present invention to provide a method for linearization of the output of an ADC so that the need for calibration of the system using the ADC is reduced or even eliminated.
The present invention relates to a method for linearization of the output of an analog-to-digital converter (ADC), said method comprising the steps of creating an analog ADC input signal by combining a substantially constant voltage to be measured with an analog dithering signal, feeding the analog ADC input signal to the ADC for converting it into a sequence of digital signal values, and using the sequence of digital signal values for calculating a single resulting digital value representing the voltage to be measured, wherein the analog dithering signal is arranged so that the analog ADC input signal fed to the ADC causes the output of the ADC to vary over at least 50 %, preferably over at least 70 %, most preferred over at least 80 %, of the full output range of the ADC.
It should be noted that by the expression "substantially constant voltage to be measured" is to be understood that the voltage can be considered constant during the time it takes to perform a measurement and obtain a single resulting digital value representing the voltage to be measured, whereas the voltage may vary from one measurement to another.
By letting the ADC input signal vary over most of the output range of the ADC, the non-linearity of the ADC is substantially eliminated. If measurements are performed over a narrow output range only, as is the case in ADC systems known in the art, the non-linearity error overlaying the resulting digital signal value depends on the position of the narrow range within the full output range of the ADC. With the present invention using very broad output ranges, on the other hand, the non-linearity errors accumulated over most of the full output range are substantially the same for each measurement, resulting in an offset of the single resulting digital value, which does not depend on the voltage to be measured.
In an embodiment of the invention, the sequence of digital signal values for calculating a single resulting digital value comprises at least 100 values, preferably at least 500 values, most preferred at least 1000 values. A large number of digital signal values (or samples) is needed in order to be able to get the necessary information from the signal for obtaining a significant improvement of the resolution due to the dithering, such as for instance a 16 bit resolution from a 12 bit ADC.
In an embodiment, the analogue dithering signal consists of at least half a period of a substantially sinusoidal signal.
In an embodiment, the frequency of the substantially sinusoidal signal is between 50 Hz and 20 kHz, preferably between 200 Hz and 10 kHz, most preferred between 500 Hz and 4 kHz.
The use of sinusoidal signals, especially with frequencies within the specified ranges, has shown to result in a very high degree of linearity of the relation between the voltages to be measured and the single resulting digital values representing these voltages.
In an embodiment of the invention, the analog ADC input signal is created either by adding the analog dithering signal to the voltage to be measured or by subtracting the analog dithering signal from the voltage to be measured.
The preferred method for creating the analog ADC input signal from the voltage to be measured and the analog dithering signal may depend on the type and characteristics of the amplifier circuit used for combining the two signals.
In an embodiment of the invention, the calculation of the resulting digital value representing the voltage to be measured includes an averaging of the sequence of digital signal values from the ADC.
If the analog dithering signal is arranged appropriately, the resulting digital value can be calculated through a simple averaging of the values in the sequence of digital signal values from the ADC.
In an embodiment of the invention, the analog dithering signal is produced using a digital-to-analog converter (DAC).
In an embodiment of the invention, the ADC and the DAC are both arranged within a single common electronic microcontroller circuit.
Many modem microcontroller circuits comprise not only an ADC but also one or more DACs within the same circuit, which is advantageous for obtaining cost-and space-efficient solutions.
In an embodiment of the invention, the microcontroller circuit further comprises a direct memory access module (DMA) arranged to feed data from an electronic memory to the DAC for creation of the analog dithering signal during measurement.
In order to utilize the capacity of the microcontroller optimally, it is advantageous if some of the core functions of the microcontroller can be switched off during measurement. This can be obtained using a DMA module, which is able to feed data from an electronic memory to the DAC even when such core functions are switched off.
In an aspect of the invention, it relates to a temperature sensor comprising an analog-to-digital converter (ADC) and being arranged to establish a linearized output of the analog-to-digital converter (ADC) for representing outputs from one or more temperature-dependent electronic components, the temperature sensor being arranged to create an analog ADC input signal (ADCis) by combining a substantially constant voltage (Vm) to be measured with an analog dithering signal (ds), the analog ADC input signal being fed to the ADC for converting it into a sequence of digital signal values, and the temperature sensor further being arranged to calculate a single resulting digital value representing the voltage to be measured from the sequence of digital signal values, wherein the analog dithering signal is arranged so that the analog ADC input signal fed to the ADC causes the output (Org) of the ADC to vary over at least 50 %, preferably over at least 70 %, most preferred over at least 80 %, of the full output range of the ADC.
In an embodiment of the invention, the temperature-dependent electronic components include at least one positive temperature coefficient (PTC) resistor and the output therefrom is the voltage across the PTC resistor when a constant and well-defined current runs through the PTC resistor.
Using PTC resistors, such as platinum elements, is advantageous, because there is a very high degree of linearity between the temperature and the voltage across such a resistor with a given current running through the resistor.
In an embodiment of the invention, the resistance of the PTC resistor representing the temperature is calculated from the resulting digital value by linear interpolation between two digital reference values, which reference values are found using the method described above for representing the voltage across two resistors, respectively, each of which has a well-defined resistance and using the same constant and well-defined current as used for measuring the voltage across the PTC resistor.
By finding reference values through measurement across two well-defined resistances just before or after each temperature measurement, it is obtained that no calibration of the temperature sensor is needed, and that the well-defined current only has to be constant during one cycle of finding reference values and the temperature measurement.
It should be noted that, in order to avoid any contribution from the analog dithering signal when making the linear interpolation, it is important that the analog dithering signal is exactly the same for each of the three measurements performed during the same cycle when finding a digital output value of the ADC for the voltages across the two reference resistors and the positive temperature coefficient resistor, respectively.
In an aspect of the invention, it relates to a heat consumption meter comprising one or more temperature sensors as described above and a flow meter, in which heat consumption meter the heat energy extracted from a flow of a fluid, such as district heating water, is calculated from the flow of the fluid and the difference between the temperatures of the incoming fluid and the outgoing fluid, respectively.
In an embodiment of the invention, the flow meter is an ultrasonic flow meter measuring the difference between the transit times of ultrasonic pulses propagating in and against the flow direction, respectively.
Figures
In the following, a few exemplary embodiments of the invention is described in more detail with reference to the figures, of which
Fig. 1 illustrates schematically the non-linearity of an ADC and the consequences thereof when using systems known in the art,
Fig. 2 illustrates schematically the missing consequences of such linearity for a system using a method according to an embodiment of the invention,
Fig. 3 illustrates schematically the configuration of a temperature sensor according to an embodiment of the invention,
Fig. 4 illustrates how the resistance of a temperature dependent resistor can be found by linear interpolation, and
Fig. 5 illustrates schematically the configuration of a heat consumption meter according to an embodiment of the invention.
Detailed description of the invention
Fig. 1 illustrates schematically the consequences of the non-linearity of an ADC.
With the input on the horizontal input axis and the output on the vertical axis, a linear output curve Ol and a non-linear output curve Onl are shown. The figure illustrates, how the non-linearity means that a first input voltage Vi results in an output Onli, which is different from the output Oli that would have been the output of a linear ADC. Similarly, a second input voltage V2 results in an output Onl2, which is different from the output Ol2 that would have been the output of a linear ADC.
The relations between the actual output values Onli, Onl2 and the ideal output values Oli, Ol2 are relative simple, as the actual output values Onli, Onl2 are the sums of the ideal output values Oli, Ol2 and non-linearity error values C\n, C\i2:
(1) (2)
What should be noted is that the non-linearity error values cnli, C\l2 depend on the input voltages Vi, V2. Thus for input voltages in a close range around Vi, for instance due to dithering with a small amount of white noise for increasing the resolution as known in the art, the non-linearity error value Cnli is relatively large and positive, whereas for input voltages in a close range around V2, the non-linearity error value Cnli is relatively small and negative. This means that calibration of the system is needed for taking into account the different non-linearity error values e\n, Cnl2 at different input voltages Vi, V2.
If, on the other hand, as illustrated schematically in Fig. 2, a dithering signal of much larger amplitude than the variations of the input voltage Yin is added to or subtracted from the input signal I to form an analog ADC input signal ADQS so that the output range Org corresponding to the analog ADC input signal ADQS covers most of the output range of the ADC, the non-linearity errors are accumulated over most of the full output range of the ADC resulting in substantially the same offset added to the output of the ADC for each measurement independent of the input voltage Vin.
Fig. 3 illustrates schematically the configuration of a temperature sensor TS according to an embodiment of the invention. A constant current generator Ig generates an electric current which, through a switching unit SU can be directed through either a first reference resistor Ri, through a second reference resistor R2 or through a positive temperature coefficient resistor Rpic-
The input voltage Yin to be converted by the ADC is measured across the resistor Ri, R2, Rptc through which this currents runs. Before the input voltage Vin is fed to the ADC, however, an analog dithering signal ds with a large amplitude compared to the variations in the input voltage Vin as described above is subtracted from the input voltage Vin whereby the analog ADC input signal ADQS is created.
The analog dithering signal ds, which makes the output from the ADC substantially linear as described above, is created by a digital-to-analog converter DAC, the data for which is provided by a direct memory access module (DMA). The use of a DMA module allows for feeding data to the DAC even when core parts of a microcontroller pC of which the ADC, the DAC and the DMA module are all parts are put out of function. It is advantageous to put those core parts out of function when measuring using the ADC in order to utilize the capacity of the microcontroller pC optimally. Preferably, the dithering signal ds consists of at least half a period of a sinusoidal signal.
The output from the ADC is forwarded to a CPU, which is part of the same microcontroller pC as is the ADC, the DAC and the DMA module, for further processing and calculations. In preferred embodiments, however, a microcontroller pC with an ADC, which is able to perform an averaging of a sequence of samples without involving the CPU, is used. In that case, the whole measuring process can be carried out without any active current consumption by the CPU.
The relation between the resistance of the positive temperature coefficient resistor Rptc of the platinum element type and the temperature follows the "Callendar - Van Dusen" equation.
The simpler form of this equation is generally valid only over the temperature range between 0 °C and 661 °C and is given as:
(3)
In equation (3), the constants A and B are derived from experimentally determined parameters using resistance measurements made at different temperatures.
Solving this simple quadratic equation results in the following value of t:
(4)
Thus, if the actual resistance QPTc of Rptc (corresponding to R in equation (4)) is known, the temperature can be calculated from this equation.
Due to the offset added to the output from the ADC because of the use of the dithering signal ds as described above, the simple linear relation between the current running from the constant current generator Ig through the positive temperature coefficient resistor Rptc and the output from the ADC according to Ohm's Law is no longer valid.
However, taking the substantial linearity of the ADC into account, the actual resistance Qptc of Rptc can be calculated by simple linear interpolation if the two reference resistors Ri and R2 are chosen to have resistances just outside the resistance range of the positive temperature coefficient resistor Rpic corresponding to the relevant temperature range. Making three subsequent measurements with the three resistors Ri, R2 and Rpic, respectively, using the same value of the current from the constant current generator Ig results in three output values Ori, Or2 og Optc, respectively, from the ADC, the latter being between the two first ones as illustrated in Fig. 4.
If Qri, Qr2 og Qptc denote the resistances of the three resistors Ri, R2 and Rptc, respectively, the resistance QPTc of the positive temperature coefficient resistor RPTc can be found using the following equation:
(5) and the temperature can be calculated using equation (4) by substituting QPTc for the value R therein.
In some embodiments, the temperature sensor TS comprises more than one positive temperature coefficient resistor Rptc and, optionally, also more than one set of reference resistors Ri. R2 so that temperatures at different positions can be measured using the same microcontroller pC.
The configuration of a heat consumption meter HCM comprising one or more such temperature sensors TS is illustrated schematically in Fig. 5.
The illustrated heat consumption meter HCM calculates the heat consumption of a heat exchanger HE in a domestic household connected to a district heating system from repeated measurements of the temperatures Tin and Tout of the incoming and outgoing district heating water, respectively, and of the flow of district heating water through the system. The two temperatures Tm, Tout are preferably measured using a temperature sensor TS with two positive temperature coefficient resistors Rptc as described above, whereas the flow of district heating water can be measured using an appropriate flow meter FM, such as an ultrasonic flow meter.
The formulas used by the heat consumption meter HCM for calculating the heat consumption from a sequence of such measured temperature and flow values are well-known within the art and are defined by recognized standards and recommendations relating to heat consumption meters, such as for instance the OIML R 75 recommendation issued by the OIML (International Organization of Legal Metrology).
List of reference numbers ADC. Analog-to-digital converter ADCis. Analog ADC input signal CPU. Central processing unit DAC. Digital-to-analog converter DMA. Direct memory access module ds. Dithering signal eNLi. Error value due to non-linearity at a first input voltage eNL2. Error value due to non-linearity at a second input voltage FM. Flow meter HCM. Heat consumption meter HE. Heat exchanger
Ig. Constant current generator
Ol. Linear output curve
Oli. Ideal output for a first input voltage
Ol2- Ideal output for a second input voltage
Onl- Non-linear output curve
Onli. Actual output for a first input voltage
Onl2- Actual output for a second input voltage Οριο- Output using PTC resistor
Ori. Output using first reference resistor
Or2. Output using second reference resistor
Org. Output range corresponding to analog ADC input signal
Ri. First re ference resistor R2. Second reference resistor
Rptc. Positive temperature coefficient resistor SU. Switching unit
Tin. Temperature of incoming district heating water TS. Temperature sensor
Tout. Temperature of outgoing district heating water
Vin. Input voltage
Vi. First input voltage V2. Second input voltage
QpTc- Resistance of PTC resistor
Qri. Resistance of first reference resistor
Qr2. Resistance of second reference resistor iiC. Electronic microcontroller
Claims (12)
1. Fremgangsmåde til linearisering af outputtet fra en analog-til-digital-konverter (ADC), hvilken fremgangsmåde omfatter trinnene: skabelse af et analogt ADC-indgangssignal (ADCis) ved at kombinere en spænding (Vin), som skal måles, med et analogt dithering-signal (ds), og - tilførsel af det analoge ADC-indgangssignal til ADC'en til konvertering af det til en sekvens af digitale signalværdier, kendetegnet ved, at fremgangsmåden endvidere omfatter trinnet: anvendelse af sekvensen af digitale signalværdier til beregning af en enkelt resulterende digital værdi, som repræsenterer den spænding, der skal måles, og hvor den spænding (Vin), som skal måles, er i det væsentlige konstant, og hvor det analoge dithering-signal er indrettet således, at det analoge ADC-indgangssignal, som tilføres ADC'en, får outputtet (Org) fra ADC'en til at variere over mindst 50 %, fortrinsvis over mindst 70 %, især foretrukket over mindst 80 %, af ADC’ens fulde outputområde.
2. Fremgangsmåde ifølge krav 1, hvor sekvensen af digitale signalværdier til beregning af en enkelt resulterende digital værdi omfatter mindst 100 værdier, fortrinsvis mindst 500 værdier, især foretrukket mindst 1000 værdier.
3. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor det analoge ADC-indgangssignal skabes enten ved at addere det analoge dithering- signal til den spænding, som skal måles, eller ved at subtrahere det analoge dithering-signal fra den spænding, som skal måles.
4. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor beregningen af den resulterende digitale værdi, som repræsenterer den spænding, der skal måles, indbefatter en gennemsnitsbestemmelse af sekvensen af digitale signalværdier fra ADC'en.
5. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor det analoge dithering-signal frembringes under anvendelse af en digital-til-analog-konverter (DAC).
6. Fremgangsmåde ifølge krav 5, hvor ADC'en og DAC'en begge er anbragt i et enkelt fælles elektronisk mikrocontro lierkreds løb (pC).
7. Fremgangsmåde ifølge krav 6, hvor mikrocontrollerkredsløbet yderligere omfatter et direkte hukommelsesadgangsmodul (DMA), som er indrettet til at tilføre data fra en elektronisk hukommelse til DAC'en til skabelse af det analoge dithering-signal under måling.
8. Temperatursensor (TS), som omfatter en analog-til-digital-konverter (ADC) og er indrettet til at etablere et lineariseret output fra analog-til-digital-konverteren (ADC) til repræsentation af output fra en eller flere temperaturafhængige elektroniske komponenter, idet temperatursensoren er indrettet til at skabe et analogt ADC-indgangssignal (ADCis) ved at kombinere en i det væsentlige konstant spænding (Vin), som skal måles, med et analogt dithering-signal (ds), idet det analoge ADC-indgangssignal tilføres til ADC'en til konvertering af det til en sekvens af digitale signalværdier, og idet temperatursensoren yderligere er indrettet til at beregne en enkelt resulterende digital værdi, som repræsenterer spændingen, der skal måles, ud fra sekvensen af digitale signalværdier, hvor det analoge dithering-signal er indrettet således, at det analoge ADC-indgangssignal, som tilføres ADC'en, får outputtet (Org) fra ADC'en til at variere over mindst 50 %, fortrinsvis over mindst 70 %, især foretrukket over mindst 80 %, af ADC'ens fulde outputområde.
9. Temperatursensor ifølge krav 8, hvor de temperaturafhængige elektroniske komponenter indbefatter mindst én positivtemperaturkoefficientsmodstand (Rptc), og outputtet derfra er spændingen på tværs af PTC-modstanden, når en konstant og veldefineret strøm løber gennem PTC-modstanden.
10. Temperatursensor ifølge krav 9, hvor PTC-modstandens modstand (ΩΡΤο), som repræsenterer temperaturen, beregnes ud fra den resulterende digitale værdi ved hjælp af lineær interpolation mellem to digitale referenceværdier (Qri, Qr2), hvilke referenceværdier findes under anvendelse af fremgangsmåden ifølge et hvilket som helst af kravene 1-9 til repræsentation af spændingen på tværs af henholdsvis to modstande (Ri, R2), som hver har en veldefineret modstand, og under anvendelse af den samme konstante og veldefinerede strøm, som anvendes til måling af spændingen på tværs af PTC-modstanden.
11. Varmeforbrugsmåler (HCM), som omfatter en eller flere temperatursensorer ifølge et hvilket som helst af kravene 8-10 og en flowmåler (FM), i hvilken varmeforbrugsmåler den varmeenergi, som ekstraheres fra en fluidstrøm, såsom fjernvarmevand, beregnes ud fra fluidstrømmen og forskellen mellem temperaturerne (Tin, Tout) på henholdsvis det indgående fluid og det udgående fluid.
12. Varmeforbrugsmåler ifølge krav 11, hvor flowmåleren er en ultrasonisk flowmåler, som måler forskellen mellem løbetiderne for ultrasoniske impulser, som udbreder sig henholdsvis i og mod strømningsretningen.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DK201270791A DK177939B1 (en) | 2012-12-18 | 2012-12-18 | A method for linearization of the output of an analog-to-digital converter and measuring instruments using such method |
| PCT/DK2013/050160 WO2014094775A1 (en) | 2012-12-18 | 2013-05-28 | A method for linearization of the output of an analog-to-digital converter and measuring instruments using such method |
| EP13727800.8A EP2936685A1 (en) | 2012-12-18 | 2013-05-28 | A method for linearization of the output of an analog-to-digital converter and measuring instruments using such method |
| US14/653,695 US20150333762A1 (en) | 2012-12-18 | 2013-05-28 | Method For Linearization Of The Output Of An Analog-To-Digital Converter And Measuring Instruments Using Such Method |
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| Application Number | Priority Date | Filing Date | Title |
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| DK201270791 | 2012-12-18 | ||
| DK201270791A DK177939B1 (en) | 2012-12-18 | 2012-12-18 | A method for linearization of the output of an analog-to-digital converter and measuring instruments using such method |
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| Publication Number | Publication Date |
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| DK201270791A1 DK201270791A1 (en) | 2014-06-19 |
| DK177939B1 true DK177939B1 (en) | 2015-01-19 |
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| Country | Link |
|---|---|
| US (1) | US20150333762A1 (da) |
| EP (1) | EP2936685A1 (da) |
| DK (1) | DK177939B1 (da) |
| WO (1) | WO2014094775A1 (da) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9903766B2 (en) | 2015-11-30 | 2018-02-27 | Infineon Technologies Ag | Remote temperature sensing |
| CN105953938A (zh) * | 2016-04-22 | 2016-09-21 | 安徽京师方圆信息技术有限公司 | 一种测量机箱温度的方法 |
| US9848152B1 (en) * | 2016-09-27 | 2017-12-19 | Omnivision Technologies, Inc. | Analog dithering to reduce vertical fixed pattern noise in image sensors |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120013494A1 (en) * | 2010-07-19 | 2012-01-19 | Massachusetts Institute Of Technology | Time Varying Quantization-based Linearity Enhancement of Signal Converters and Mixed-signal Systems |
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| US4710747A (en) * | 1984-03-09 | 1987-12-01 | Fairchild Semiconductor Corporation | Method and apparatus for improving the accuracy and resolution of an analog-to-digital converter (ADC) |
| US5030849A (en) * | 1989-06-30 | 1991-07-09 | Analog Devices, Inc. | Monolithic ratiometric temperature measurement circuit |
| DE4238084A1 (en) * | 1991-11-15 | 1993-05-19 | Hewlett Packard Co | Analogue measurement value converter for real=time transformation into engineering unit - uses high value binary number bits to address stored coefficients, and lower value bits to perform correction using coefficients |
| US5493298A (en) * | 1993-03-01 | 1996-02-20 | Hewlett-Packard Company | Dithered analog-to-digital converter |
| US5525984A (en) * | 1993-08-06 | 1996-06-11 | Adc Telecommunications, Inc. | Optimization of weighted signal-to-noise ratio for a digital video encoder |
| JP3396512B2 (ja) * | 1993-08-31 | 2003-04-14 | パイオニア株式会社 | ディザ生成装置 |
| US5835038A (en) * | 1997-05-08 | 1998-11-10 | Burr-Brown Corporation | DC dither circuitry and method for delta-sigma modulator |
| US5963157A (en) * | 1997-06-23 | 1999-10-05 | Motorola, Inc. | Method and apparatus for the addition and removal of a dither signal |
| US6268814B1 (en) * | 2000-03-14 | 2001-07-31 | Lucent Technologies Inc. | Carrier-dependent dithering for analog-to-digital conversion |
| US6577257B2 (en) * | 2000-09-11 | 2003-06-10 | Broadcom Corporation | Methods and systems for digital dither |
| US7233746B2 (en) * | 2002-01-30 | 2007-06-19 | Blake James N | Wide dynamic range sensor signal processing method & circuitry for analog and digital information signals |
| US7369290B1 (en) * | 2003-03-19 | 2008-05-06 | Photonic Systems, Inc. | Modulator bias control |
| SE530417C2 (sv) * | 2005-11-02 | 2008-05-27 | Kimmo Yliniemi | En anordning för mätning av energiåtgång fär att värma upp tappvatten |
| US7286075B2 (en) * | 2005-11-14 | 2007-10-23 | Analog Devices, Inc. | Analog to digital converter with dither |
| US7548177B2 (en) * | 2006-08-14 | 2009-06-16 | Agilent Technologies, Inc. | Multiple FM dither |
| US7486213B2 (en) * | 2007-03-20 | 2009-02-03 | Broadcom Corporation | Method and system for increasing resolution and accuracy of an analog to digital converter |
| EP2000788A1 (en) * | 2007-06-06 | 2008-12-10 | Kamstrup A/S | Energy Calculator with Installation Error Detection |
| DE102008003793A1 (de) * | 2008-01-10 | 2009-07-16 | BSH Bosch und Siemens Hausgeräte GmbH | Sensor-Aktor-System |
| DE102008054902B4 (de) * | 2008-12-18 | 2011-11-10 | BSH Bosch und Siemens Hausgeräte GmbH | Kochgeschirr mit Temperaturmessschaltung |
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| US8340531B2 (en) * | 2009-12-18 | 2012-12-25 | General Instrument Corporation | Method and apparatus for improved SBS suppression in optical fiber communication systems |
| US8543010B2 (en) * | 2010-02-24 | 2013-09-24 | Jds Uniphase Corporation | Bias control in an optical modulator and transmitter |
| US8672542B2 (en) * | 2010-05-26 | 2014-03-18 | Honeywell International Inc. | High resolution measurement of thermistor thermometry signals with wide dynamic range |
| JP5546020B2 (ja) * | 2011-03-28 | 2014-07-09 | パナソニック株式会社 | Ａｄ変換装置 |
| US8970409B2 (en) * | 2012-03-22 | 2015-03-03 | Hittite Microwave Corporation | Dynamic dithering method and apparatus for analog-to-digital converters |
| US9281833B2 (en) * | 2012-05-28 | 2016-03-08 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Analog-to-digital converter with power supply-based reference |
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- 2013-05-28 WO PCT/DK2013/050160 patent/WO2014094775A1/en active Application Filing
- 2013-05-28 EP EP13727800.8A patent/EP2936685A1/en not_active Withdrawn
- 2013-05-28 US US14/653,695 patent/US20150333762A1/en not_active Abandoned
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120013494A1 (en) * | 2010-07-19 | 2012-01-19 | Massachusetts Institute Of Technology | Time Varying Quantization-based Linearity Enhancement of Signal Converters and Mixed-signal Systems |
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| Publication number | Publication date |
|---|---|
| WO2014094775A1 (en) | 2014-06-26 |
| EP2936685A1 (en) | 2015-10-28 |
| US20150333762A1 (en) | 2015-11-19 |
| DK201270791A1 (en) | 2014-06-19 |
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