CN102510284A - Methods and devices for calibrating alternating-current voltage signal and alternating current signal - Google Patents

Abstract

The invention provides methods and devices for calibrating an alternating-current voltage signal and an alternating current signal. The method for calibrating the alternating-current voltage signal comprises the following steps of: firstly, taking an average value of N-point sampling data within a last sampling period as a zero-point parameter of the current sampling period; secondly, carrying out zero-point correction on the sampling data according to the zero-point parameter; thirdly, respectively calculating an effective value of the voltage according to the sampling data subjected to the zero-point correction; fourthly, receiving standard data of the voltage; fifthly, calculating an amplitude parameter of the voltage according to the standard data and the effective value of the voltage; and sixthly, correcting the calculated effective value of the voltage by using the amplitude parameter to obtain an original data value of the sampling signal. According to the methods provided by the invention, the design cost is greatly reduced and a design circuit is simplified; and the difference between the precision of an integrated circuit and the precision of an electronic element is eliminated, so that the reliability of hardware is increased, the time required for calibrating the parameters in the batch-production process is shortened, human errors introduced into the calibration are greatly reduced and the accuracy of the sampling data is increased.

Description

The calibration steps of a kind of ac voltage signal and ac current signal and device thereof

Technical field

The present invention relates to the calibration steps of a kind of ac voltage signal and ac current signal.

Background technology

Voltage in AC system or current sample at first will pass through signal transducer, convert ac small signal into, deliver to microprocessor through modulate circuit again and carry out analog-to-digital conversion, and data sampling and processing obtain target data.In the prior art; Convert in the process of target data at voltage signal or electric current AC signal; In order to obtain target data more accurately, use high-precision electronic device (such as precision resister, high-operational amplifier) and scalable device (scalable precision resistance, adjustable condenser).Because these devices are to use the adjustment means manual adjustments, and only allow before dispatching from the factory, to regulate once, can not regulate again after dispatching from the factory, like this, not only increased hardware cost, and introduced human error in the test process easily, reduced reliability.

Summary of the invention

Technical problem to be solved by this invention provides the calibration steps of a kind of ac voltage signal and ac current signal, the problem that the calibration that need not use high-precision electronic device and scalable device can solve above-mentioned AC signal exists.

In order to solve the problems of the technologies described above, the present invention provides a kind of ac voltage signal calibration steps: comprise the steps:

Step 1, with the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Step 2, according to above-mentioned zero point parameter sampled data carried out zero point revise;

Step 3, according to revised sampled data at zero point calculating voltage effective value respectively;

Step 4, reception voltage standard data;

Step 5, according to the amplitude parameter of voltage standard data and voltage effective value calculating voltage;

Step 6, use amplitude parameter are revised the data value of the high-voltage AC signal that obtains importing to the voltage effective value after calculating.

Further, also comprise the steps:

The input ac voltage signal changes into ac small signal with the alternating voltage circulation;

The adjustment ac voltage signal, but the voltage analog signal that the ac high-voltage signal is changed into Direct Sampling is got N sampled point to the voltage analog signal of input and is sampled in one-period;

Further, step 4 also comprises the reception calibration command.

Further, the step that also comprises the amplitude parameter of storage voltage.

Simultaneously, the present invention also provides a kind of ac voltage signal calibrating installation, comprising:

Zero point, parameter extraction module was used for the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Data correcting module at zero point, according to above-mentioned zero point parameter to sampled data carry out revising zero point the voltage effective value computing module, according to revised sampled data at zero point calculating voltage effective value respectively

Receiver module, reception voltage standard data

The amplitude parameter calculating module, according to the amplitude parameter of voltage standard data and voltage effective value calculating voltage;

Data correction module, use amplitude parameter are revised the voltage effective value after calculating, and are the raw value of sampled signal.

Further, also comprise:

Voltage sensor is used for the ac high-voltage signal is changed into the AC low-tension signal;

Signal conditioning circuit is used to adjust ac voltage signal, but the ac high-voltage signal is changed into the voltage analog signal of Direct Sampling;

Sample circuit, the voltage analog signal of input is got N sampled point and sampled in one-period;

Further, the alternating voltage calibrating installation also comprises:

The amplitude parameter of memory module, storage voltage.

Simultaneously, the present invention also provides a kind of alternating current calibration steps, it is characterized in that, comprises the steps:

Step 1, with the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Step 2, according to above-mentioned zero point parameter sampled data carried out zero point revise;

Step 3, according to zero point revised sampled data calculate current effective value respectively;

Step 4, received current normal data;

Step 5, calculate the amplitude parameter of electric current according to current standard data and current effective value;

Step 6, use amplitude parameter are revised the three-phase current effective value after calculating, and are the raw value of sampled signal.

Further, before step 1, also comprise the steps:

The input AC current signal changes into the little current signal of interchange with the AC great current signal;

Adjust ac current signal, but change into the voltage analog signal of Direct Sampling;

The current analog signal of input is got N sampled point in one-period sample;

Further, the step that after step 6, also comprises the amplitude parameter of storaging current.

Simultaneously, the present invention also provides a kind of calibrating installation of alternating current, comprises

Zero point, parameter extraction module was used for the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Data correcting module at zero point, according to above-mentioned zero point parameter sampled data carried out zero point revise;

The current effective value computing module, according to zero point revised sampled data calculate current effective value respectively

Receiver module, received current normal data

The amplitude parameter calculating module, calculate the amplitude parameter of electric current according to current standard data and current effective value;

Data correction module, use amplitude parameter are revised the current effective value after calculating, and are the raw value of sampled signal.

Further, the calibrating installation of alternating current of the present invention also comprises:

Current sensor is used for ac current signal is changed into the alternating current small-signal;

Signal conditioning circuit is used to adjust ac current signal, but ac current signal is changed into the voltage analog signal of Direct Sampling;

Sample circuit, the voltage analog signal of input is got N sampled point and sampled in one-period;

Further, the calibrating installation of alternating current of the present invention is characterized in that, also comprises: the amplitude parameter of memory module, storaging current.

Adopt alternating voltage calibration steps of the present invention and alternating current calibration steps; To greatly reduce design cost, simplify design circuit, overcome the difference of integrated circuit and electronic component precision; Improved hardware reliability; Shorten the needed time of parametric calibration in the batch production process, greatly reduced the human error of introducing in the calibration, improved the accuracy of sampled data.

Description of drawings

Fig. 1 is an alternating voltage calibrating principle block diagram

Fig. 2 is an alternating voltage calibration software flow chart

Fig. 3 is alternating current calibrating principle figure

Fig. 4 is an alternating current calibration software flow chart

Embodiment

In order to make the object of the invention, technical scheme and advantage more clear, below in conjunction with accompanying drawing and embodiment, further set forth the present invention, instantiation described herein is only in order to explaining the present invention, and is not used in qualification the present invention.

Calibration steps in conjunction with the alternating voltage calibrating principle block diagram illustrations ac voltage signal of the present invention of Fig. 1 comprises the steps:

1, input ac voltage signal changes into the AC low-tension signal with the ac high-voltage signal;

2, adjust ac voltage signal, but the AC low-tension signal is changed into the voltage analog signal of Direct Sampling

3, the voltage analog signal of input being got N sampled point in one-period samples;

4, with the mean value of up-sampling N point sampling data in the cycle parameter at zero point as the next sampling period;

5, according to above-mentioned zero point parameter sampled data carried out zero point revise; Revise the sampling edge limit zero point and revise, need use same zero point parameter to revise each sampled point.

6, according to zero point revised sampled data calculate the voltage in three phases effective value respectively

7, microprocessor receives voltage standard data and calibration command

8, calculate the amplitude parameter of three-phase voltage according to voltage standard data and voltage effective value

9, use the amplitude parameter that the voltage effective value after calculating is revised the data value of the high-voltage AC signal that obtains importing.

10, the amplitude parameter of storage three-phase voltage, the parameter at zero point of not storing three-phase voltage.

Likewise, the calibrating installation of ac voltage signal of the present invention comprises:

Voltage sensor is used for the ac high voltage signal is changed into the interchange low voltage signal;

Signal conditioning circuit; Be used to adjust ac voltage signal, but the ac high-voltage signal is changed into the voltage analog signal of Direct Sampling, it comprises: the current potential that comprises the DC component that superposes promotes circuit; Amplifying circuit, filter circuit and clamp circuit, and microprocessor carries the AD sample port.Because signal conditioning circuit is a prior art, repeats no more at this.

Sample circuit, to the three-phase voltage analog signal N point of in one-period, sampling respectively of input;

Every phase parameter extraction module at zero point, be used for the mean value of up-sampling every phase N point sampling data in the cycle parameter at zero point as the next sampling period;

Data correcting module at zero point, be used for according to above-mentioned zero point parameter sampled data carried out zero point revise; Revise the sampling edge limit zero point and revise, need use same zero point parameter to revise each sampled point of every phase.

The voltage effective value computing module, according to zero point revised sampled data calculate the voltage in three phases effective value respectively;

Receiver module, be used to receive voltage standard data and calibration command;

The amplitude parameter calculating module, calculate the amplitude parameter of three-phase voltage according to voltage standard data and voltage effective value;

The data correction module uses the amplitude parameter that the voltage effective value after calculating is revised, and is the raw value of sampled signal.

The amplitude parameter of memory module, storage three-phase voltage, and the parameter at zero point of not storing three-phase voltage.

Alternating voltage calibration software flow chart in conjunction with Fig. 2 is carefully explained concrete work of the present invention and computational process:

Microprocessor carries out discrete sampling to the three-phase voltage analog signal of direct entering AD sample port in one-period; Each sampling period is a N sampled point; The sample numerical value that obtains in the one-period leaves DVa [N], DVb [N], DVc [N] in, and revise the back zero point is DVa [N]-ZVa, DVb [N]-ZVb, DVc [N]-ZVc, uses revised data DVa at zero point [N]-ZVa, DVb [N]-ZVb, DVc [N]-ZVc to calculate A, B, C voltage in three phases effective value Va, Vb, Vc; Wherein calculate A; B, C three-phase voltage effective value uses the root mean square calculation formula, and computational process is following:

$\mathrm{Va}=\sqrt{\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\left(\mathrm{DVa}\right[i]-\mathrm{ZVa})*\left(\mathrm{DVa}\right[i]-\mathrm{ZVa})}{N}}$

$\mathrm{Vb}=\sqrt{\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\left(\mathrm{DVb}\right[i]-\mathrm{ZVb})*\left(\mathrm{DVb}\right[i]-\mathrm{ZVb})}{N}}$

$\mathrm{Vc}=\sqrt{\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\left(\mathrm{DVc}\right[i]-\mathrm{ZVc})*\left(\mathrm{DVc}\right[i]-\mathrm{ZVc})}{N}})$

Use data DVa [N], DVb [N], DVc [N] behind the discrete sampling to calculate the mean value of three-phase voltage data N point sampling data in this sampling period respectively as the parameter Z Va1 at zero point in next sampling period, ZVb1, ZVc1.Zero point the CALCULATION OF PARAMETERS formula, computational process is following: $\mathrm{ZVa}1=\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\mathrm{DVa}\left[i\right]}{N};$ $\mathrm{ZVb}1=\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\mathrm{DVb}\left[i\right]}{N};$ $\mathrm{ZVc}1=\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\mathrm{DVc}\left[i\right]}{N}$ Microprocessor receives calibration A, B, C three-phase normal voltage data Vstd_a; Vstd_b, behind Vstd_c and the calibration command, the amplitude parameter that microprocessor calculates A, B, C three-phase voltage respectively is respectively KVa=Vstd_a/Va; KVb=Vstd_b/Vb, KVc=Vstd_c/Vc.The error problem that brings ratio to amplify in the signal condition process that used the amplitude parametric compensation uses the voltage data after the calibration parameter calculating to be Ua=Va*KVa; Ub=Vb*KVb; Uc=Vc*KVc, the Va in this formula wherein, Vb, Vc are a that calculates after the sampled data in current sampling period carries out revising zero point, b, the effective value data of c three-phase voltage.KVa, KVb, KVc are a of the last calibration, b, the amplitude parameter of c three-phase voltage.Ua, Ub, Uc is for having carried out the correction at zero point, and effective value calculates, a after the amplitude correction, b, the end product of c three-phase voltage.At last, the amplitude parameter of storage three-phase voltage.This calibration steps adopts two-point method, is the parameter at zero point a bit, and another point is the amplitude parameter, and calibration finishes the back only needs storage amplitude parameter in the non-volatile power down memory of main control unit.

Calibration steps in conjunction with the alternating current calibrating principle block diagram illustrations ac current signal of the present invention of Fig. 3:

1, input AC current signal changes into the electric current small-signal with the AC great current signal;

2, adjust ac current signal, but change into the voltage analog signal of Direct Sampling;

3, to the current analog signal N point of in one-period, sampling of input;

4, with the mean value of up-sampling N point sampling data in the cycle parameter at zero point as the next sampling period;

5, according to above-mentioned zero point parameter sampled data carried out zero point revise; Revise the sampling edge limit zero point and revise, need use same zero point parameter to revise each sampled point in this cycle.

6, according to zero point revised sampled data calculate current effective value respectively

7, microprocessor received current normal data and calibration command

8, calculate the amplitude parameter of electric current according to current standard data and current effective value

9, use the amplitude parameter that the current effective value after calculating is revised, be the raw value of sampled signal.

10, the amplitude parameter of storaging current.

Likewise, the calibrating installation of ac current signal of the present invention comprises:

Current sensor is used for the AC great current signal is changed into the little current signal of interchange;

Signal conditioning circuit; Be used to adjust ac current signal; But ac current signal is changed into the voltage analog signal of Direct Sampling; It comprises: electric current promotes circuit to the change-over circuit of voltage, the current potential of stack DC component, amplifying circuit, filter circuit and clamp circuit, and microprocessor carries the AD sample port.Because signal conditioning circuit is a prior art, repeats no more at this.

Sample circuit, the three-phase current analog signal of input is got N sampled point and sampled in one-period;

Zero point parameter extraction module, be used for the mean value of up-sampling N point sampling data in the cycle parameter at zero point as the next sampling period;

Data correcting module at zero point, be used for according to above-mentioned zero point parameter sampled data carried out zero point revise; Revise the sampling edge limit zero point and revise, need use same zero point parameter to revise each sampled point;

The current effective value computing module, according to zero point revised sampled data calculate current effective value;

Receiver module, be used for received current normal data and calibration command;

The amplitude parameter calculating module, calculate the amplitude parameter of electric current according to current standard data and current effective value;

The data correction module uses the amplitude parameter that the current effective value after calculating is revised, and is the raw value of sampled signal;

The amplitude parameter of memory module, storage three-phase current.

Alternating current calibration software flow chart in conjunction with Fig. 4 is carefully explained concrete work of the present invention and computational process, and the calibration steps with a phase current in this specific embodiment is an example.

Microprocessor carries out discrete sampling to the alternating current analog signal of direct entering AD sample port in one-period; Each sampling period is a N sampled point numerical value sum; The sample numerical value that obtains in the one-period leaves DIa [N] (calibration process of plain telegram stream so that a is example mutually in addition) in; Revise the back zero point is DIa [N]-ZIa, uses revised data DIa at zero point [N]-ZIa to calculate alternating current effective value Ia in this sampling period, and the formula that calculates Ia is: $\mathrm{Ia}=\sqrt{\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\left(\mathrm{DIa}\right[i]-\mathrm{ZIa})*\left(\mathrm{DIa}\right[i]-\mathrm{ZIa})}{N}}$ Data DIa [N] calculating mean value behind the use discrete sampling is as the parameter Z Ia1 at zero point in next sampling period, and calculating CALCULATION OF PARAMETERS formula at zero point is: $\mathrm{ZIa}1=\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\mathrm{DIa}\left[i\right]}{N},$ In order not influence the computational speed of this periodicity certificate, use the sampled value in the parameter revised version cycle at zero point of previous sampling period calculating.After microprocessor received normalized current data I std_a and calibration command, the amplitude parameter that microprocessor calculates alternating current was KIa=Istd_a/Ia, had compensated the problem of bringing ratio to amplify in the signal condition process, was second parameter.Use the current data after calibration parameter calculates to be Ia '=Ia*KIa; Wherein the sampled data in the current sampling period of Ia in this formula is carried out a phase current effective value data that calculate after the correction zero point.KIa is the amplitude parameter of a phase current of the last calibration.Ia ' is for having carried out the correction at zero point, and effective value calculates, the end product of the electric current after the amplitude correction.More than be to be example with a phase current, b, the calibration steps of c phase current is consistent with a phase current, is not giving unnecessary details at this.This calibration steps adopts two-point method, is the parameter at zero point a bit, and another point is the amplitude parameter, and calibration finishes the back only needs storage amplitude parameter in the non-volatile power down memory of main control unit.

In alternating-current system main control unit and branching unit exchange three-phase voltage input signal, alternating current input signal all used calibration steps of the present invention.

At AC power distribution cabinet/AC distribution panel, the alternating voltage and the ac current signal that exchange in the output counter system all can use calibration Fang Fafa of the present invention.

On basis of the present invention, certain road ac voltage signal and ac current signal are carried out software calibration respectively; Voltage calibration parameter that calculates and correcting current parameter; Can be used for revising the active power of this road signal, reactive power, data such as active electrical degree, idle electric degree.And the amplitude corrected parameter of power and electric degree need not be stored in the nonvolatile memory along with the calibration parameter of voltage and current upgrades automatically.

The above only is a preferred implementation of the present invention, should be pointed out that the engineer in any present technique field, not breaking away under the prerequisite of the present invention, also possibly improve and retouch, and these improvement and retouching all are regarded as protection scope of the present invention.

Claims (20)

1. the calibration steps of an ac voltage signal is characterized in that, comprises the steps:

Step 1, with the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Step 2, according to above-mentioned zero point parameter sampled data carried out zero point revise;

Step 3, according to revised sampled data at zero point calculating voltage effective value respectively;

Step 4, reception voltage standard data;

Step 5, according to the amplitude parameter of voltage standard data and voltage effective value calculating voltage;

Step 6, use amplitude parameter are revised the data value of the high-voltage AC signal that obtains importing to the voltage effective value after calculating.

2. the calibration steps of alternating voltage according to claim 1 is characterized in that, before step 1, also comprises the steps:

The input ac voltage signal changes into ac small signal with alternating voltage;

Adjust ac voltage signal, but the ac high-voltage signal is changed into the voltage analog signal of Direct Sampling;

The voltage analog signal of input is got N sampled point in one-period sample.

3. the calibration steps of alternating voltage according to claim 1 is characterized in that, step 4 also comprises the reception calibration command.

4. the calibration steps of alternating voltage according to claim 1 is characterized in that, after step 6, also comprises the step of the amplitude parameter of storage voltage.

5. the calibration steps of alternating voltage according to claim 1 is characterized in that, the computational methods of said voltage effective value are:

$V=\sqrt{\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\left(\mathrm{DV}\right[i]-\mathrm{ZV})*\left(\mathrm{DV}\right[i]-\mathrm{ZV})}{N}}$

Wherein, V is the effective value of voltage, and ZV is the parameter at zero point, and DV [N]-ZV is a revised sampled data at zero point.

6. the calibration steps of alternating voltage according to claim 5 is characterized in that, said amplitude CALCULATION OF PARAMETERS method is: KV=Vstd/V, and wherein KV is the amplitude parameter, and Vstd is the normal voltage data, and V is the effective value of voltage.

7. the calibration steps of alternating voltage according to claim 5; It is characterized in that; Revised voltage effective value is respectively: U=V*KV; Wherein, V is the effective value data of the voltage that calculates after the sampled data in current sampling period carries out revising zero point, and KV be the amplitude parameter of the last voltage of calibrating.

8. an ac voltage signal calibrating installation is characterized in that, comprising:

Zero point, parameter extraction module was used for the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Data correcting module at zero point, according to above-mentioned zero point parameter sampled data carried out zero point revise;

The voltage effective value computing module, according to revised sampled data calculating voltage effective value at zero point;

Receiver module, reception voltage standard data;

The amplitude parameter calculating module, according to the amplitude parameter of voltage standard data and voltage effective value calculating voltage;

Data correction module, use amplitude parameter are revised the data value of the high-voltage AC signal that obtains importing to the voltage effective value after calculating.

9. a kind of ac voltage signal calibrating installation according to claim 8 is characterized in that, also comprises:

Voltage sensor is used for the ac high voltage signal is changed into the AC low-tension signal;

Signal conditioning circuit; Be used to adjust ac voltage signal, but the ac high-voltage signal is changed into the voltage analog signal of Direct Sampling, it comprises the change-over circuit of high-voltage signal; Amplifying circuit, filter circuit and clamp circuit, and microprocessor carries the AD sample port;

Sample circuit, the voltage analog signal of input is got N sampled point and sampled in one-period.

10. a kind of ac voltage signal calibrating installation according to claim 9 is characterized in that, also comprises:

The amplitude parameter of memory module, storage voltage.

11. an alternating current calibration steps is characterized in that, comprises the steps:

Step 1, with the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Step 2, according to above-mentioned zero point parameter sampled data carried out zero point revise;

Step 3, according to zero point revised sampled data calculate current effective value;

Step 4, received current normal data;

Step 5, calculate the amplitude parameter of electric current according to current standard data and current effective value;

Step 6, use amplitude parameter are revised the data value of the high-voltage AC signal that obtains importing to the current effective value after calculating.

12. alternating current calibration steps according to claim 11 is characterized in that, before step 1, also comprises the steps:

The input AC current signal changes into ac small signal with ac current signal;

Adjust ac current signal, but change into the voltage analog signal of Direct Sampling;

The current analog signal of input is got N sampled point in one-period sample.

13. alternating current calibration steps according to claim 12 is characterized in that described step 4 also comprises the step that receives calibration command.

14. alternating current calibration steps according to claim 13 is characterized in that, after step 6, also comprises the step of the amplitude parameter of storaging current.

15. alternating current calibration steps according to claim 11 is characterized in that, the computational methods of current effective value are:

$I=\sqrt{\frac{\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}\left(\mathrm{DI}\right[i]-\mathrm{ZI})*\left(\mathrm{DI}\right[i]-\mathrm{ZI})}{N}}$

Wherein, ZI is the corrected parameter at zero point, and DI [N]-ZI is a revised sampled data at zero point.

16. alternating current calibration steps according to claim 15 is characterized in that: the current amplitude parameter be KI=Istd/I wherein Istd be the normalized current data, I is a current effective value.

17. alternating current calibration steps according to claim 16 is characterized in that, revised current data is I '=I*KI; Wherein, I is a current effective value, and KI is the amplitude parameter that changes electric current into of the last calibration.

18. the calibrating installation of an alternating current is characterized in that, comprising:

Zero point, parameter extraction module was used for the mean value of up-sampling N point sampling data in the cycle parameter at zero point as this sampling period;

Data correcting module at zero point, according to above-mentioned zero point parameter sampled data carried out zero point revise;

The current effective value computing module, according to zero point revised sampled data calculate current effective value respectively;

Receiver module, received current normal data;

The amplitude parameter calculating module, calculate the amplitude parameter of electric current according to current standard data and current effective value;

Data correction module, use amplitude parameter are revised the current effective value after calculating, and obtain the data value of input current.

19. the calibrating installation of alternating current according to claim 18 is characterized in that, also comprises:

Current sensor is used for ac current signal is changed into the alternating voltage small-signal;

Signal conditioning circuit is used to adjust ac voltage signal, but the AC great current signal is changed into the voltage analog signal of Direct Sampling;

Sample circuit, the voltage analog signal of input is got N sampled point and sampled in one-period.

20. the calibrating installation of alternating current according to claim 19 is characterized in that, also comprises:

The amplitude parameter of memory module, storaging current signal.

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