A temperature measurement method based on gaussian noise

Abstract

The application discloses a temperature measuring method based on Gaussian noise in the technical field of temperature measurement, and comprises the following steps: mixing a voltage signal output by a thermistor in a circuit with a Gaussian noise signal to obtain a mixed signal, amplifying the mixed signal through an amplifier, and dividing the mixed signal into two paths to obtain a first signal and a second signal which are completely same; the first signal is compared with a first threshold voltage through a first comparator, and the second signal is compared with a second threshold voltage through a second comparator; signals output by the comparators are sent to a digital circuit for sampling through flip-flops or latches, and then temperature values are obtained by calculation or table lookup in the digital circuit. The method superimposes Gaussian noise on the output signal of the thermistor, and then carries out code value probability statistics on the single-bit sampled data, so that the temperature measurement is realized, high-precision ADC is not needed, and the precision of temperature measurement can be improved by controlling the sampling frequency and sampling time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of temperature measurement, and particularly relates to a temperature measurement method based on Gaussian noise. BACKGROUND

[0002] Temperature is a physical quantity representing the degree of coldness or hotness of an object, and is one of the basic detection parameters in the fields of instruments and meters, manufacturing, and automation industry. With the progress of society and the improvement of science and technology, the accuracy of temperature measurement in these fields is also increasingly required. For example, in the fields of instruments and meters and automation industry, people need to automatically and accurately detect and control the temperature of various instruments. If the change of temperature is not detected in time, some instruments may be damaged or materials may be destroyed. For example, in the manufacturing field, the casting temperature has a great influence on the mechanical properties, crack tendency, and surface quality of ingots. For products with different properties, the temperature needs to be controlled within different ranges. Therefore, high-precision temperature measurement is an important technology.

[0003] Since the resistance of a thermistor changes with temperature, a common temperature measurement method is to convert the resistance of the thermistor into a voltage signal, amplify the voltage through an amplifier circuit, and then convert the amplified signal into a digital quantity by using a high-precision ADC (analog-to-digital converter). After computer processing, the temperature data can be obtained. However, this method requires the use of a high-precision ADC, and since the accuracy of the ADC is fixed, the accuracy of temperature measurement is limited within a certain range, and it is not possible to further improve the accuracy during the measurement process as needed. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a temperature measurement method based on Gaussian noise to solve the problems raised in the background.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A temperature measurement method based on Gaussian noise, comprising the following steps:

[0007] Mixing the voltage signal output by the thermistor in the circuit with a Gaussian noise signal to obtain a mixed signal, and amplifying the mixed signal through an amplifier to obtain a secondary signal;

[0008] Then, the secondary signal is divided into two paths to obtain a first signal and a second signal which are identical. The first signal is compared with a first threshold voltage through a first comparator, and the second signal is compared with a second threshold voltage through a second comparator;

[0009] The signal outputted by the comparator is sent to the digital circuit to be sampled by a flip-flop or a latch, and then the temperature value is calculated or looked up in the digital circuit.

[0010] Preferably, the probability density functions of the voltage amplitude distribution of the first signal and the second signal are as follows:

[0011]

[0012]

[0013] In the formula, x1 is the voltage deviation between the voltage value of the first signal and the threshold value of the first comparator, x2 is the voltage deviation between the voltage value of the second signal and the threshold value of the second comparator; μ1 is the voltage deviation between the mean value of the first signal and the threshold value of the first comparator, μ2 is the voltage deviation between the mean value of the second signal and the threshold value of the second comparator; σ1 is the standard deviation of the voltage of the first signal, and σ2 is the standard deviation of the voltage of the second signal.

[0014] Preferably, the data sampled in the digital circuit by the signals outputted by the first comparator and the second comparator can obtain the probabilities P(1) and P(2) that the respective code values are 1, and the accuracy of the probability statistics value can be improved by increasing the number of the sampled data.

[0015] Preferably, the first signal and the second signal are the same, so σ1 and σ2 are the same, and σ can be used to replace them, and the formula is as follows:

[0016]

[0017]

[0018]

[0019] In the formula, TH1 is the first threshold voltage, and TH2 is the second threshold voltage, and TH1 and TH2 are not equal.

[0020] Preferably, if the probabilities P'(1) and P'(2) that the respective code values of the first comparator and the second comparator are 0 are calculated, the formula is as follows:

[0021]

[0022]

[0023] Preferably, by solving the formula (3) (4) (5) or (5) (6) (7), the voltage of the thermistor output is TH1+μ1 or TH2+μ2, then according to the voltage value of VCC, the resistance value of the first resistor and the second resistor, the resistance value of the thermistor is obtained, and then the temperature value can be obtained by using the relationship between the resistance value of the thermistor and the temperature value.

[0024] Preferably, the amplifier can be removed, and when the comparator has a latching function, the sampling function can be completed at the same time of making the amplitude comparison, and then the obtained single-bit data is sent to the digital circuit.

[0025] The beneficial effects of the present application are:

[0026] The method of the present application realizes the measurement of temperature by superimposing Gaussian noise on the output signal of the thermistor and then performing code value probability statistics on the single-bit sampled data, without using high-precision ADC, and the precision of temperature measurement can be improved by controlling the sampling frequency and sampling time. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor.

[0028] Figure 1 is the flow chart of the method in the embodiment of the present application;

[0029] Figure 2 is the flow chart when using platinum resistance in the embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0031] Please refer to Figure 1 The embodiment provides a temperature measurement method based on Gaussian noise, in order to make the temperature measurement no longer need to use high-precision ADC, and the measurement precision of temperature can be improved according to the needs, and the method steps are as follows:

[0032] The voltage signal outputted by the thermistor in the circuit is mixed with a Gaussian noise signal to obtain a mixed signal, the mixed signal is amplified by an amplifier to obtain a secondary signal, and then the secondary signal is divided into two paths to obtain a first signal and a second signal which are completely same. The first signal is compared with a threshold voltage 1 (TH1) by a comparator 1 (first comparator), and the second signal is compared with a threshold voltage 2 (TH2) by a comparator 2 (second comparator). The signals outputted by the comparators are sent to a digital circuit for sampling by a flip-flop or a latch, and then the temperature value is obtained by calculation or table lookup in the digital circuit. The amplifier is not necessary, and the sampled data can also be sent to other computing devices for calculation or table lookup to obtain the temperature value, for example, sent to a remote computer through optical fiber communication for temperature calculation. In addition, according to the needs, a comparator with a latch function can also be used to directly complete the sampling and quantization of the signal, and then the single-bit data obtained is sent to the digital circuit.

[0033] The principle of the present application is as follows: the signal outputted by the comparator can obtain single-bit data after sampling, and the probability of code value 0 or code value 1 is counted, which is related to the waveform characteristics of the first signal and the second signal. Since the first signal and the second signal are both Gaussian noise, the probability density function of the voltage amplitude distribution is as follows:

[0034]

[0035]

[0036] In the formula, x1 is the voltage deviation between the voltage value of the first signal and the threshold value of the first comparator, x2 is the voltage deviation between the voltage value of the second signal and the threshold value of the second comparator; μ1 is the voltage deviation between the mean value of the first signal and the threshold value of the first comparator, μ2 is the voltage deviation between the mean value of the second signal and the threshold value of the second comparator; σ1 is the standard deviation of the voltage of the first signal, and σ2 is the standard deviation of the voltage of the second signal.

[0037] The data sampled in the digital circuit by the signals outputted by the first comparator and the second comparator can obtain the probabilities P(1) and P(2) of the respective code value 1, and the accuracy of the probability statistics value can be improved by increasing the number of sampled data. Since the first signal and the second signal are the same, σ1 and σ2 are the same, and σ can be used instead, and the following formula is obtained:

[0038]

[0039]

[0040]

[0041] If the statistical results are the probabilities P'(1) and P'(2) that the code values ​​of the first and second comparators are both 0, then formulas (3) and (4) can be changed to the following formulas:

[0042]

[0043]

[0044] Using formulas (3)(4)(5) or (5)(6)(7), the parameters μ1, μ2 and σ can be solved, and the output voltage of the thermistor can be obtained as TH1+μ1 or TH2+μ2. Since the voltage value of VCC, the resistance values ​​of resistor 1 (first resistor) and resistor 2 (second resistor) are known, the resistance value of the thermistor can be obtained. Then, the temperature can be calculated by using the relationship between the resistance value of the thermistor and the temperature. Alternatively, the relationship between probability and temperature can be made into a lookup table and stored in the digital circuit, so that the temperature value can be obtained directly by looking up the table.

[0045] In summary, by superimposing Gaussian noise onto the output signal of the thermistor and then performing code value probability statistics on the single-bit sampled data, temperature measurement can be achieved.

[0046] Using the above method, accuracy can be improved as needed by controlling the sampling frequency and sampling time without using a high-precision ADC.

[0047] To verify the effectiveness of the method, a platinum resistance thermometer (Pt100) was used for testing. Please refer to [link to relevant documentation]. Figure 2 As shown, the voltage signal output by the platinum resistance thermometer (Pt100) is mixed with Gaussian noise to obtain a mixed signal. The mixed signal is then split into two paths to obtain the same first signal. Figure 2 V1) and second signal ( Figure 2 In the middle (V2), the first signal is compared with the threshold voltage through the positive input terminal of comparator 1. The second signal is compared with the threshold voltage through the positive input terminal of comparator 2. Comparison, among which and The voltage is obtained by dividing the voltage between a 200-ohm resistor and two 100-ohm resistors. The comparator output signal is then sent to the FPGA (Field Programmable Gate Array) chip for sampling. The sampled data is processed by the embedded CPU to obtain the temperature value.

[0048] The embedded CPU's data processing method is as follows:

[0049] After the FPGA samples the signals of comparator 1 and comparator 2, the obtained single-bit data are respectively statistically analyzed to obtain the probabilities P(1) and P(2) that their respective code values are 1. Since the first signal and the second signal are Gaussian distributed, the relationships between P(1), P(2) and the signal probability density function can be obtained by using formulas (1) and (2) as follows:

[0050]

[0051]

[0052]

[0053] In the formula, x1 is the voltage deviation between the first signal voltage value and TH1, x2 is the voltage deviation between the voltage value of the second signal and TH2; μ1 is the voltage deviation between the mean value of the first signal and TH1, μ2 is the voltage deviation between the mean value of the second signal and TH2; σ is the standard deviation of the signal voltage.

[0054] By using formulas (8), (9) and (10), μ1, μ2 and σ can be obtained, and then the voltage output by Pt100 is TH1 + μ1 or TH2 + μ2. And since the voltage value of VCC, the resistances of resistor 1 and resistor 2 are all known, according to the voltage division principle of the circuit, the resistance value of Pt100 can be calculated, and the relationship between the resistance value of Pt100 and the temperature can be described by the following formula:

[0055] When -200°C < T < 0°C

[0056] R T = R0[1 + AT + BT 2 + C(T - 100)T 3 (11)

[0057] When 0°C < T < 850°C

[0058] R T = R0[1 + AT + BT[[ID=(36]] 2 (12)

[0059] In the formula, R T is the resistance value at temperature T; R0 is the corresponding resistance value at temperature T0 (usually T0 = 0°C); A = 3.9083×10 -3 , B = -5.775×10 -7 , C = -4.183×10 -12 .

[0060] The temperature value can be calculated by using the resistance value of Pt100 through formula (11) and / or formula (12).

[0061] In the description of the specification, reference to "one embodiment", "an example", "certain examples" etc. means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment" or "an example", "in certain embodiments" or "certain examples" in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0062] Those skilled in the art will appreciate that embodiments of the application can be devised for a method, a system, or a computer program product. Accordingly, the application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product on one or more computer readable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code thereon.

[0063] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks or in conjunction with the flowcharts described above. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks or in conjunction with the flowcharts described above.

[0064] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks or in conjunction with the flowcharts described above. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks or in conjunction with the flowcharts described above.

[0065] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks or in conjunction with the flowcharts described above. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks or in conjunction with the flowcharts described above.

[0066] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or equivalent replacement should be covered within the protection scope of the claims of the present application.

Claims

1. A method of temperature measurement based on Gaussian noise, characterized in that, The method comprises the following steps: The voltage signal outputted by the thermistor in the circuit is mixed with a Gaussian noise signal to obtain a mixed signal, and the mixed signal is amplified by an amplifier to obtain a secondary signal; The secondary signal is then divided into two paths to obtain a first signal and a second signal which are identical, the first signal is compared with a first threshold voltage by a first comparator, and the second signal is compared with a second threshold voltage by a second comparator, wherein the first threshold voltage and the second threshold voltage are not equal and are obtained by dividing a power voltage Vcc of the circuit; The signals outputted by the comparators are sampled by flip-flops or latches in a digital circuit, and then a temperature value is obtained by calculation or table lookup in the digital circuit.

2. The method of claim 1, wherein, The probability density functions of the voltage amplitude distribution of the first signal and the second signal are as follows: (1) (2) wherein is a voltage deviation between the voltage value of the first signal and the threshold value of the first comparator, is a voltage deviation between the voltage value of the second signal and the threshold value of the second comparator; is a voltage deviation between the mean value of the first signal and the threshold value of the first comparator, is a voltage deviation between the mean value of the second signal and the threshold value of the second comparator; is a standard deviation of the voltage of the first signal, is a standard deviation of the voltage of the second signal.

3. The method of claim 2, wherein, The data obtained by sampling the signals outputted by the first comparator and the second comparator in the digital circuit are used to obtain probabilities P(1) and P(2) of respective code values being 1, and the accuracy of the probability statistics values is improved by increasing the number of the sampled data.

4. The method of claim 3, wherein, The first signal and the second signal are identical, so The same, instead of The formula is as follows: (3) (4) (5) In the formula, TH1 is the first threshold voltage, TH2 is the second threshold voltage, and TH1 is not equal to TH2.

5. The method of claim 4, wherein, As is counted is the probability that each of the first and second comparators has a code value of 0 (1), , the formula is as follows: (6) (7) 。 6. The method of claim 5, wherein, Solving the formula (3) (4) (5) or (5) (6) (7) obtains , and , the voltage of the thermistor output is or , then according to the voltage value of VCC, the first resistance and the second resistance, the resistance value of the thermistor is obtained, and the temperature value is obtained by using the relationship between the resistance value of the thermistor and the temperature value.

7. The method of claim 1, wherein, The amplifier can be removed, the comparators can have a latching function, and the sampling function can be completed at the same time as the amplitude comparison, and then the obtained single-bit data is sent to the digital circuit. 8.A computer readable storage medium storing program codes, the program codes, when executed by a processor, implement the method according to any one of claims 1-7. 9.A computing device comprising a processor and a storage medium storing program codes, the program codes, when executed by the processor, implement the method according to any one of claims 1-7.

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