CN117040533A - Remote self-calibration method and system for analog-to-digital conversion - Google Patents
Remote self-calibration method and system for analog-to-digital conversion Download PDFInfo
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- H—ELECTRICITY
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- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
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- H03M1/46—Analogue value compared with reference values sequentially only, e.g. successive approximation type with digital/analogue converter for supplying reference values to converter
- H03M1/466—Analogue value compared with reference values sequentially only, e.g. successive approximation type with digital/analogue converter for supplying reference values to converter using switched capacitors
- H03M1/468—Analogue value compared with reference values sequentially only, e.g. successive approximation type with digital/analogue converter for supplying reference values to converter using switched capacitors in which the input S/H circuit is merged with the feedback DAC array
Abstract
The application belongs to the field of electrical metering calibration, and discloses a remote self-calibration method and a system for analog-to-digital conversion, wherein the remote self-calibration method comprises the following steps: an analog-to-digital converter and a remote self-calibration module connected with the analog-to-digital converter; the remote self-calibration module includes: the system comprises a singlechip MCU, a time setting unit, a remote control computer, a calibrated end data acquisition unit and a calibrated end data acquisition unit; the calibrated end data acquisition unit and the calibrated end data acquisition unit are connected with the satellite; the calibrated end data acquisition unit is also respectively connected with the analog-digital converter and the singlechip MCU; the time setting unit is respectively connected with the analog-digital converter, the singlechip MCU and the calibration end data acquisition unit; the calibration end data acquisition unit is also connected with the remote control computer; the singlechip MCU is in communication connection with the remote control computer. The technical scheme of the application has the advantages of improving quality and efficiency and ensuring accuracy.
Description
Technical Field
The application belongs to the field of electrical metering calibration, and particularly relates to a remote self-calibration method and system for analog-to-digital conversion.
Background
Conventional self-calibration methods typically require that the calibration operation be performed at the start-up or regular intervals of the ADC. This may take up some time and resources, resulting in a delay in the response time of the system or increased power consumption; second, a reference signal or a specific input signal is generally required to be acquired in advance for performing a calibration operation, which means that the ADC may not be able to perform an accurate measurement immediately before performing the calibration, which may cause a delay in the measurement result; attenuation or instability may also occur over prolonged use. For example, calibration parameters may fail due to changes in environmental conditions, device aging, or other factors, resulting in unreliable calibration results; finally, some conventional self-calibration methods may require additional hardware circuitry or design considerations to support the calibration operation. This may increase the complexity and cost of the system.
Disclosure of Invention
The application aims to provide a remote self-calibration method and a system for analog-to-digital conversion, which are used for solving the problems in the prior art.
In order to achieve the above object, according to one aspect, the present application provides a remote self-calibration system for analog-to-digital conversion, comprising:
an analog-to-digital converter and a remote self-calibration module connected with the analog-to-digital converter;
the remote self-calibration module includes: the system comprises a singlechip MCU, a time setting unit, a remote control computer, a calibrated end data acquisition unit and a calibrated end data acquisition unit; the calibrated end data acquisition unit and the calibration end data acquisition unit are connected with a satellite; the calibrated end data acquisition unit is also respectively connected with the analog-digital converter and the singlechip MCU; the time setting unit is respectively connected with the analog-digital converter, the singlechip MCU and the calibration end data acquisition unit; the calibration end data acquisition unit is also connected with the remote control computer; the singlechip MCU is in communication connection with the remote control computer.
Optionally, the analog-to-digital converter specifically includes: the device comprises a sampling and holding unit, a time sequence control unit, a comparator, an SAR logic circuit module and an N-bit DAC circuit module;
the input end of the sampling and holding unit is used for inputting an analog signal, and the output end of the sampling and holding unit is connected with the negative electrode input end of the comparator; the input end of the time sequence control unit is used for inputting a reset signal and a clock signal, and the output end of the time sequence control unit is connected with the input ends of the SAR logic circuit and the sampling hold unit;
the input end of the SAR logic circuit module is also connected with the output end of the comparator, and the output end of the SAR logic circuit module is connected with the N-bit DAC circuit module;
the input end of the N-bit DAC circuit module is used for inputting reference voltage, and the output end of the N-bit DAC circuit module is connected with the positive electrode input end of the comparator.
Optionally, the time setting unit specifically includes: a memory and a timer/counter;
the input end of the memory is connected with the MCU, and the output end of the memory is connected with the input end of the timer/counter; the output end of the timer/counter is respectively connected with the analog-digital converter and the calibrated end data acquisition unit.
Optionally, the calibrated end data acquisition unit specifically includes: the system comprises a first satellite common view receiver, a first conversion module and a first time-frequency counter;
one end of the first satellite common view receiver is in communication connection with the satellite, the other end of the first satellite common view receiver is connected with the input end of a first time frequency counter, the input end of the first time frequency counter is also respectively connected with one end of the first conversion module and the time setting unit, the output end of the first time frequency counter is connected with the singlechip MCU, and the other end of the first conversion module is connected with the analog-digital converter.
Optionally, the calibration end data acquisition unit includes: the second conversion module, the second time-frequency counter, the second satellite common-view receiver and the standard source;
the second conversion module, the second time-frequency counter, the second satellite common view receiver and the standard source
The remote control computer is connected with one end of the second conversion module through the standard source, the input end of the second time-frequency counter is respectively connected with the output end of the second conversion module and the signal output end of the second satellite common-view receiver, the output end of the second time-frequency counter is connected with the remote computer, and the input end of the second satellite common-view receiver is connected with the satellite in a communication mode.
In order to achieve the above object, the present application provides a remote self-calibration method of the remote self-calibration system, including:
step one: initializing each module in a remote self-calibration system, and automatically detecting whether each instrument in the remote self-calibration system is normally started or not;
step two: detecting the power-on state of the analog-to-digital converter;
step three: the timer/counter and the first time-frequency counter are paired based on the related parameter data of the analog-digital converter;
step four: setting sampling time and detection points, transmitting a calibration instruction through a singlechip MCU and a remote control computer, acquiring initial data of the standard source and the analog-digital converter based on the calibration instruction, and further storing the initial data;
step five: acquiring a time difference of the same satellite pulse signal between the standard source and the analog-digital converter;
step six: acquiring voltage difference data between the standard source and the analog-digital converter based on the time difference, and calibrating initial data based on the voltage difference data to obtain the calibrated output voltage of the analog-digital converter;
optionally, the initial data specifically includes: initial voltage value data of the standard source, initial reference voltage data of the analog-to-digital converter, and initial quantization level data of the analog-to-digital converter.
Optionally, acquiring a time difference between acquiring the same satellite pulse signal between the standard source and the analog-digital converter specifically includes:
the first satellite common view receiver and the second GPS common view receiver in the remote self-calibration system simultaneously acquire the same satellite pulse signal, and the time of acquiring the same satellite pulse signal by each common view receiver is subjected to difference to obtain the time difference of acquiring the same satellite pulse signal between the standard source and the analog-digital converter;
optionally, acquiring voltage difference data between the standard source and the analog-digital converter based on the time difference specifically includes:
Δt AGPS ＝t A -t GPS
Δt BGPS ＝t B -t GPS
Δt ABi ＝Δt AGPS -Δt BGPS ＝t A -t B
wherein t is A 、t B Clock time, Δt, of the standard source and the analog-to-digital converter, respectively AGPS 、Δt BGPS Time difference delta t between atomic clock second pulse and GPS second pulse of the clocks of the standard source and the analog-digital converter respectively ABi A time difference between the standard source and the analog-to-digital converter;
acquiring frequency difference data of the standard source and the analog-to-digital converter:
wherein f A 、f B The frequencies of the standard source and the analog-digital converter are respectively obtained by converting corresponding voltages by conversion modules; τ is the average time interval;
and reversely pushing the frequency difference data to obtain the input end voltage difference data.
The application has the technical effects that:
the remote self-calibration method and system for analog-to-digital conversion provided by the application have the following effects:
(1) Ensuring accuracy: the primary purpose of metrology calibration is to verify and confirm the accuracy of the measurement device. By comparison with known standards, the bias and error of the ADC module can be determined and corrected. Thus, the accuracy of the measurement results can be ensured, so that reliable data can be obtained in the fields of scientific research, industrial production, medical diagnosis and the like.
(2) Improving traceability: another important purpose of metrology calibration is to ensure traceability of the measurement results. Traceability means that the measurement results can be traced back to international or national standard units. By comparison and calibration with known standards, a traceable measurement chain can be established, thereby ensuring consistency and comparability of the measurement results. This is critical to ensure consistency of measurement results between different laboratories or equipment.
(3) Meets the requirements of rules and standards: many industries and fields have stringent requirements for the accuracy and traceability of ADC modules. By performing a metering calibration, it is ensured that the device meets the requirements of regulations and standards. This is important for obtaining certification, compliance and quality control.
(4) Maintenance of equipment performance: the metrology calibration may help detect and correct problems with drift, aging, and malfunction of the measurement ADC module. Periodic calibration can keep the performance of the device stable and discover and solve potential problems in time to ensure reliability and consistency of measurement results.
(5) Quality and efficiency are improved: by accurate and traceable measurement results, the quality of the product and service can be improved. Qualified metering calibration can help optimize the process, reduce errors and variations, and improve production efficiency and product consistency.
(6) The labor cost is reduced: the remote metering does not need personnel to perform data acquisition and recording in real time, and can greatly reduce the labor cost. The metering data can be acquired and transmitted in real time through an automation system and a remote monitoring platform, so that the workload of personnel and the requirement of manual operation are reduced.
(7) The safety is improved: some metering sites present hazardous environments such as high temperatures, high pressures, hazardous gases, and the like. The remote metering technology can be far away from the dangerous environments, and metering equipment is arranged in a safe place for data acquisition, so that the safety of personnel and the safety of working environments are improved.
(8) Real-time monitoring and feedback: the remote calibration ADC module can realize real-time monitoring and remote control of the ADC equipment. Through the remote monitoring platform, metering data can be acquired at any time, analyzed and judged, abnormal conditions can be found timely, and corresponding measures can be taken. This helps to improve the efficiency of fault detection and troubleshooting, reducing downtime and losses.
(9) Accuracy and traceability: remote metering systems typically employ digital technology for data acquisition and processing, self-calibration of the ADC, providing greater accuracy and traceability thereto. The acquisition and transmission of the digitized signals reduces the possibility of interference of the analog signals, thereby improving the accuracy and reliability of the data.
(10) Cross-region and remote operation: the remote metering technology can realize unified management and operation of metering equipment distributed in different regions. No matter where the equipment is located, remote operation, monitoring and data acquisition can be performed as long as the network connection is provided, and equipment management and maintenance are facilitated.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 is a schematic diagram of a system architecture in an embodiment of the present application;
FIG. 2 is a flow chart of an embodiment of the present application;
FIG. 3 is a block diagram of an analog to digital converter apparatus in accordance with an embodiment of the present application;
FIG. 4 is a flow chart of obtaining the output voltage of the analog-to-digital converter after calibration according to an embodiment of the present application;
fig. 5 is a flowchart of an ADC conversion process according to an embodiment of the application.
Detailed Description
Various exemplary embodiments of the application will now be described in detail, which should not be considered as limiting the application, but rather as more detailed descriptions of certain aspects, features and embodiments of the application.
It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the application. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although the application has been described with reference to a preferred method, any method similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methodologies associated with the documents. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the application described herein without departing from the scope or spirit of the application. Other embodiments will be apparent to those skilled in the art from consideration of the specification of the present application. The specification and examples of the present application are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
Example 1
As shown in fig. 1-5, the present embodiment provides a remote self-calibration system for analog-to-digital conversion, which includes:
a remote self-calibration system for analog-to-digital conversion, comprising:
an analog-to-digital converter and a remote self-calibration module connected with the analog-to-digital converter;
the remote self-calibration module includes: the system comprises a singlechip MCU, a time setting unit, a remote control computer, a calibrated end data acquisition unit and a calibrated end data acquisition unit; the calibrated end data acquisition unit and the calibration end data acquisition unit are connected with a satellite; the calibrated end data acquisition unit is also respectively connected with the analog-digital converter and the singlechip MCU; the time setting unit is respectively connected with the analog-digital converter, the singlechip MCU and the calibration end data acquisition unit; the calibration end data acquisition unit is also connected with the remote control computer; the singlechip MCU is in communication connection with the remote control computer.
A remote self-calibration method comprising:
initializing each module in a remote self-calibration system, and automatically detecting whether each instrument in the remote self-calibration system is normally started or not;
detecting the power-on state of the analog-to-digital converter;
the timer/counter and the first time-frequency counter are paired based on the related parameter data of the analog-digital converter;
setting sampling time and detection points, transmitting a calibration instruction through a singlechip MCU and a remote control computer, acquiring initial data of the standard source and the analog-digital converter based on the calibration instruction, and further storing the initial data;
acquiring a time difference of the same satellite pulse signal between the standard source and the analog-digital converter;
acquiring voltage difference data between the standard source and the analog-digital converter based on the time difference, and calibrating initial data based on the voltage difference data to obtain the calibrated output voltage of the analog-digital converter;
in this embodiment, the system hardware mainly comprises a calibrated device, a standard source device, a voltage-to-frequency converter, a time-to-frequency counter, and a satellite synchronous clock source. The control computer acquires the data information of the laboratory end time interval counter and the pulse counter through a standard interface, acquires the pulse frequency of the calibrated end in real time by using a data remote transmission technology, detects the reference voltage of the ADC module in real time, calculates a new quantization unit, and completes self-calibration calculation.
Analog-to-digital conversion, analog-to-Digital Converter, commonly referred to as ADC, refers to a device that converts a continuously variable Analog signal into a discrete digital signal.
ADC processing: the ADC process typically goes through four steps of sampling, holding, quantizing and encoding, as shown in fig. 5:
(1) sample and hold: sampling is the conversion of a signal that varies continuously in time into a signal that is discrete in time, i.e. the conversion of an analog quantity that varies continuously in time into a series of equally spaced pulses whose amplitude depends on the input analog quantity. The sampling is performed by following the sampling theorem that the sampled value does not distort the original analog signal when the sampling frequency is greater than twice the highest frequency component of the analog signal.
The analog signal is sampled to obtain a series of sample pulses, the sampling pulse width is generally short, and the amplitude of the sample pulse obtained should be temporarily maintained for conversion before the next sampling pulse arrives. Therefore, a hold circuit is added after the sampling circuit.
(2) Quantization and coding: the input analog signal voltage is subjected to sample and hold to obtain a step wave. The step wave is still an analog quantity which can be continuously valued. But the n-bit digital quantity can only be kept 2 n A number of values. Thus, the use of digital quantities to represent continuously varying analog quantities has an approximation problem similar to rounding. The sampled sample pulse level is normalized to a discrete level close to it, a process called quantization. Designated discrete level is called quantization level U q The difference between the two quantization levels is called quantization unit Δv, and the more the number of bits, the finer the quantization level, the smaller Δv.
FSR full scale voltage; the number of bits in the N digital output; 2 N A state number; Δv resolution.
Unquantized U after sample and hold 0 Value and quantization level U q The values are usually unequal, the difference being referred to as quantization error epsilon, i.e. epsilon=u 0 -U q . There are generally two methods of quantization: only the rounding and rounding methods are omitted.
Only the method of entering is not carried out: when U is 0 When the mantissa of (2) is less than DeltaV, the tail is rounded off. The method has positive epsilon and positive epsilon max Let the variation range of the input signal be 0-1V, let Δv=1/2, taking 3-bit ADC as an example 3 In the quantization, the partial rejection of the insufficient quantization unit is performed, the analog voltage having a value of 0 to 1/8V is denoted by 0 Δv, the binary number 000 is denoted by 1 Δv, the analog voltage having a value of 1/8 to 2/8V is denoted by 1 Δv, the binary number 001 is denoted by 7 Δv, and the analog voltage having a value of 7/8 to 8/8V is denoted by binary number 111;
rounding when U 0 When the mantissa of (2) is less than DeltaV/2, the tail is rounded off. When U is 0 When the mantissa of (2) is greater than DeltaV/2, the tail is cut into whole. This method ε may be positive or negative, but ε max It can be seen that its error is small, |=Δv/2. Still taking a 3-bit ADC as an example, if the variation range of the input signal is 0-1V, Δv/2=1/2 3 In the quantization, the partial rejection of the insufficient quantization unit is performed, the analog voltage with the value between 0 and 1/16V is denoted as 0 Δv by binary number 000, and the analog voltage with the value between 1/16 and 3/16V is denoted as 1 Δv by binary number 001;
for an N-bit ADC, the reference voltage is known, and the quantization method is determined, so that the encoding can be performed.
(3) Full scale voltage (FSR) and reference voltage (V) ref ) Relation of (2)
FSR and V of ADC ref There is a direct relationship between them. FSR represents the maximum input voltage range that the ADC can measure, and V ref Is the reference voltage used by the ADC. In general, fsr=v ref . That is, when the reference voltage is equal to the full scale voltage, the input voltage range of the ADC will match the reference voltage. In this case, the ADC may map the input voltage entirely into its quantization range.
In a satellite view angle, atomic clocks at two places at a long distance can perform time-frequency comparison through clock signals of satellites received at the same time. And the satellite common-view receivers at the two ends of the calibration laboratory and the calibrated laboratory receive the same satellite signal at the same moment under the same common-view time table, and the time difference between the satellite atomic clock second pulse and the local atomic clock second pulse is measured through a time interval counter. The calibration laboratory and the calibrated end can carry out data transmission through the Internet, and the time difference data at the two ends are differenced, so that the time deviation between the two atomic clocks can be obtained. Setting the time of atomic clocks at the calibrated end and the calibrated end as t respectively A And t B Atomic clock time t GPS The time difference between the atomic clock second pulse and the satellite second pulse at two ends is delta t AGPS And Deltat BGPS The following steps are:
Δt AGPS ＝t A -t GPS
Δt BGPS ＝t B -t GPS
Δt AGPS -Δt BGPS ＝t A -t B ＝Δt AB
multiple measurements are carried out to obtain multiple groups of two-end time deviation values delta t ABi The average relative frequency deviation of atomic clocks at two ends can be obtained
Wherein f A ，f B The frequencies of atomic clocks at the calibrated end and the calibrated end, respectively, τ being the average time interval.
(2) ADC self-calibration principle based on reference voltage
1) Relationship between ADC output voltage and reference voltage: the ADC samples an analog signal to provide a quantized digital code representing the input signal. The digital output code is post-processed and the results can be reported to an operator who uses the information to make decisions and take action. It is therefore important that the digital codes are correctly associated with the analog signals they represent.
u o For output voltage, D is the output decimal code (machine output is binary), Δv is the resolution (step size of the least significant bit LSB). In general, the ADC input voltage is related to the output code by a simple relationship:
u o ＝D×ΔV
after the ADC conversion is completed, the decimal value of the output code is multiplied by the LSB size to calculate the input voltage. Knowing the LSB size is critical for switching between code and voltage.
Note the FSR of the ADC used, as different ADCs have different FSRs. The FSR is always proportional to the reference voltage, possibly also depending on any internal gain:
it can be seen that the stability and accuracy of the reference voltage are particularly important for the final output.
When the reference voltage is deviated during the operation of the ADC, the full scale voltage of the ADC is affected, and if the quantization unit (LSB) calculated using the ideal data is not measured, an additional error of the output result is caused.
2) Reference voltage calibration of ADC: the D/a converter will convert the generated digital quantity into analog quantity according to the reference voltage, and a reference voltage is needed during conversion, which is the reference voltage of our AD module, and if the reference voltage is unstable, the converted analog quantity will not be stable. According to the application, based on calibration of the reference voltage, when the reference voltage is introduced with errors, the remote calibration module is utilized to realize interval sampling of the reference voltage, and new full-scale voltage and LSB step length are calculated, so that the accuracy of identification of unknown sampling signals and final output results is ensured.
(1) Initializing a system: and starting a client calibration program, sending an initialization instruction to system hardware by a device management module of the system, and recording parameter information of a standard device and an ADC module to be tested and the like.
(2) Initializing self-checking: and initializing a system homepage, and initializing last detection data to avoid interference.
(3) Calibrating homepage parameter setting: and selecting and setting ADC reference voltage calibration points, corresponding models of the calibration points, acquisition time and other related parameters on a main page of the calibration system, and automatically detecting whether a remote calibration instrument is started normally.
(4) Detecting the power-on state of the chip: and (5) remotely monitoring whether the chip is powered up or not, and determining whether to start self-calibration of the chip or not.
(5) The timer is paired with a time-frequency counter: firstly, a timer for controlling a time sequence circuit of an ADC module is paired with a satellite clock, so that related errors are reduced on time reference point settings of a subsequent acquisition rate and a conversion rate. The timer can improve the control precision of the time sequence circuit by timing;
(6) Transmitting a calibration command and collecting initial reference voltage data: the calibration control module of the system sends a calibration start instruction, reads the set detection point, collects data such as standard end and reference voltage to be detected, quantization unit, calibration duration and the like, and stores the data in a corresponding path.
(7) And (3) periodically collecting new reference voltages: and sampling the reference voltage on time according to the sampling time point set by the parameter of the calibration homepage, comparing whether deviation occurs with the initial reference voltage, and calculating a new quantization unit in real time.
(8) Calibration data processing and report generation: and when each detection period of the system is finished, recording, calculating errors and evaluating uncertainty of data in the analog-to-digital converter after calibration is finished, and generating a report.
Fig. 3 is a block diagram of an analog-to-digital converter device, in which an ADC module, a voltage-to-frequency conversion module, a time-to-frequency counter, a wireless communication module, and a display module are integrally developed. When the ADC module starts to work, the time counter receives the time synchronization of the satellite common-view receiver through the wireless transmission module, the time sequence control circuit of the ADC is adjusted, the voltage frequency module converts the reference voltage value into the frequency value, the frequency value is counted by the time frequency counter, the frequency value is transmitted to the laboratory end and the satellite common-view receiver through the wireless communication module, the time difference is calculated, and the calibration of the reference voltage is completed.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims (9)
1. A remote self-calibration system for analog-to-digital conversion, comprising:
an analog-to-digital converter and a remote self-calibration module connected with the analog-to-digital converter;
the remote self-calibration module includes: the system comprises a singlechip MCU, a time setting unit, a remote control computer, a calibrated end data acquisition unit and a calibrated end data acquisition unit; the calibrated end data acquisition unit and the calibration end data acquisition unit are connected with a satellite; the calibrated end data acquisition unit is also respectively connected with the analog-digital converter and the singlechip MCU; the time setting unit is respectively connected with the analog-digital converter, the singlechip MCU and the calibration end data acquisition unit; the calibration end data acquisition unit is also connected with the remote control computer; the singlechip MCU is in communication connection with the remote control computer.
2. A remote self-calibration system for analog to digital conversion as recited in claim 1, wherein,
the analog-to-digital converter specifically comprises: the device comprises a sampling and holding unit, a time sequence control unit, a comparator, an SAR logic circuit module and an N-bit DAC circuit module;
the input end of the sampling and holding unit is used for inputting an analog signal, and the output end of the sampling and holding unit is connected with the negative electrode input end of the comparator; the input end of the time sequence control unit is used for inputting a reset signal and a clock signal, and the output end of the time sequence control unit is connected with the input ends of the SAR logic circuit and the sampling hold unit;
the input end of the SAR logic circuit module is also connected with the output end of the comparator, and the output end of the SAR logic circuit module is connected with the N-bit DAC circuit module;
the input end of the N-bit DAC circuit module is used for inputting reference voltage, and the output end of the N-bit DAC circuit module is connected with the positive electrode input end of the comparator.
3. A remote self-calibration system for analog to digital conversion as recited in claim 1, wherein,
the time setting unit specifically comprises: a memory and a timer/counter;
the input end of the memory is connected with the MCU, and the output end of the memory is connected with the input end of the timer/counter; the output end of the timer/counter is respectively connected with the analog-digital converter and the calibrated end data acquisition unit.
4. A remote self-calibration system for analog to digital conversion as recited in claim 1, wherein,
the calibrated end data acquisition unit specifically comprises: the system comprises a first satellite common view receiver, a first conversion module and a first time-frequency counter;
one end of the first satellite common view receiver is in communication connection with the satellite, the other end of the first satellite common view receiver is connected with the input end of a first time frequency counter, the input end of the first time frequency counter is also respectively connected with one end of the first conversion module and the time setting unit, the output end of the first time frequency counter is connected with the singlechip MCU, and the other end of the first conversion module is connected with the analog-digital converter.
5. A remote self-calibration system for analog to digital conversion as recited in claim 1, wherein,
the calibration end data acquisition unit comprises: the second conversion module, the second time-frequency counter, the second satellite common-view receiver and the standard source;
the second conversion module, the second time-frequency counter, the second satellite common view receiver and the standard source
The remote control computer is connected with one end of the second conversion module through the standard source, the input end of the second time-frequency counter is respectively connected with the output end of the second conversion module and the signal output end of the second satellite common-view receiver, the output end of the second time-frequency counter is connected with the remote computer, and the input end of the second satellite common-view receiver is connected with the satellite in a communication mode.
6. The remote self-calibration method of a remote self-calibration system according to any one of claims 1 to 5, comprising:
step one: initializing each module in a remote self-calibration system, and automatically detecting whether each instrument in the remote self-calibration system is normally started or not;
step two: detecting the power-on state of the analog-to-digital converter;
step three: the timer/counter and the first time-frequency counter are paired based on the related parameter data of the analog-digital converter;
step four: setting sampling time and detection points, transmitting a calibration instruction through a singlechip MCU and a remote control computer, acquiring initial data of the standard source and the analog-digital converter based on the calibration instruction, and further storing the initial data;
step five: acquiring a time difference of the same satellite pulse signal between the standard source and the analog-digital converter;
step six: and acquiring voltage difference data between the standard source and the analog-digital converter based on the time difference, and calibrating initial data based on the voltage difference data to obtain the calibrated output voltage of the analog-digital converter.
7. The remote self-calibration method according to claim 6, wherein the initial data specifically comprises: initial voltage value data of the standard source, initial reference voltage data of the analog-to-digital converter, and initial quantization level data of the analog-to-digital converter.
8. The method of claim 6, wherein obtaining the time difference between the standard source and the adc for obtaining the same satellite pulse signal, comprises:
and enabling the first satellite common-view receiver and the second GPS common-view receiver in the remote self-calibration system to simultaneously acquire the same satellite pulse signal, and performing difference on the time of acquiring the same satellite pulse signal by each common-view receiver to acquire the time difference of acquiring the same satellite pulse signal between the standard source and the analog-digital converter.
9. The remote self-calibration method according to claim 6, wherein obtaining the voltage difference data between the standard source and the analog-to-digital converter based on the time difference, comprises:
Δt AGPS ＝t A -t GPS
Δt BGPS ＝t B -t GPS
Δt ABi ＝Δt AGPS -Δt BGPS ＝t A -t B
wherein t is A 、t B Clock time, Δt, of the standard source and the analog-to-digital converter, respectively AGPS 、Δt BGPS Time difference delta t between atomic clock second pulse and GPS second pulse of the clocks of the standard source and the analog-digital converter respectively ABi A time difference between the standard source and the analog-to-digital converter;
acquiring frequency difference data of the standard source and the analog-to-digital converter:
wherein f A 、f B The frequencies of the standard source and the analog-digital converter are respectively obtained by converting corresponding voltages by conversion modules; τ is the average time interval;
and reversely pushing the frequency difference data to obtain the input end voltage difference data.
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