JP4721919B2 - Correction method and correction apparatus - Google Patents

Description

  The present invention relates to a correction method and a correction apparatus. In particular, the present invention relates to a correction method and a correction apparatus for correcting frequency characteristics of a signal generator and a digitizer used in a test apparatus for testing a device under test.

  A test apparatus for testing AC characteristics of a device under test such as a semiconductor device includes a signal generator that generates an analog signal to be supplied to the device under test, and a digitizer that acquires an analog output signal from the device under test. Is provided. It is desirable that the signal generator and digitizer provided in the test apparatus have a small variation in frequency characteristics and can be measured with high reproducibility.

  Conventionally, the frequency characteristics of the signal generator and the digitizer have been measured and adjusted in order to reduce the variation in the frequency characteristics of the signal generator and the digitizer of the test apparatus. In addition, for the purpose of reducing variation in the frequency characteristics of the signal generator and digitizer of the test apparatus, the S-parameter is calculated by loop-connecting the analog path of the signal generator or the analog path of the digitizer and the network analyzer, In some cases, the signal waveform is corrected by the calculated S parameter.

  In addition, since the presence of a prior art document is not recognized at present, description regarding the prior art document is omitted.

  However, the method of measuring and adjusting the frequency characteristics is time consuming and troublesome. Further, in the method of calculating the S parameter using the network analyzer, the network analyzer must be connected manually or a switching circuit must be provided in advance in the signal generator and the digitizer. In addition, since the network analyzer analyzes the analog path in the method of calculating the S parameter using the network analyzer, the frequency characteristics of the digital / analog converter and the analog / digital converter cannot be corrected.

  Accordingly, an object of the present invention is to provide a correction method and a correction apparatus that can solve the above-described problems. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.

  In order to solve the above problems, in the first embodiment of the present invention, a signal generator for generating an input signal to a device under test and an output signal of the device under test are used in a test apparatus for testing the device under test. A correction method for correcting a frequency characteristic of a digitizer that measures a reference signal generation stage in which a reference signal generator having a known frequency characteristic generates a predetermined reference signal, and a reference signal is input to the digitizer. The first characteristic acquisition stage for acquiring the frequency characteristic of the measurement signal output by the digitizer according to the reference signal, the frequency characteristic of the reference signal and the frequency characteristic of the measurement signal are compared, and the frequency of the digitizer is determined based on the comparison result. A digitizer correction stage for correcting the characteristics and a signal generator for correcting the frequency characteristics to generate a signal under measurement having the same pattern as the reference signal. A constant signal generation stage, a second characteristic acquisition stage in which the signal under measurement is input to a digitizer whose frequency characteristic has been corrected in the digitizer correction stage, and the frequency characteristic of the measurement signal output according to the signal under measurement by the digitizer is acquired; A signal generator correction stage that compares the frequency characteristic of the measurement signal acquired in the second characteristic acquisition stage with the frequency characteristic of the reference signal generator, and corrects the frequency characteristic of the signal generator based on the comparison result. A correction method is provided.

  In the correction method, a reference signal having signal components at a plurality of predetermined frequencies is generated in a reference signal generation stage, and a signal component of the measurement signal at a plurality of predetermined frequencies is acquired in a first characteristic acquisition stage. In the correction stage, the signal component of the reference signal and the signal component of the measurement signal may be compared for each frequency, and a correction coefficient for correcting the frequency characteristics of the digitizer may be calculated for each frequency.

  The correction method is to cause the signal generator to generate a signal under measurement having signal components at a plurality of predetermined frequencies at the measurement signal generation stage, and at a second characteristic acquisition stage, at a predetermined plurality of frequencies of the measurement signal. The signal component is acquired, and at the signal generator correction stage, the signal component of the measurement signal is compared with the frequency characteristic component of the reference signal generator for each frequency, and the frequency characteristics of the signal generator for each frequency A correction coefficient for correcting the above may be calculated.

  In the correction method, a plurality of signal generators whose frequency characteristics are to be corrected are sequentially generated in a measured signal generation stage, and a measured signal having the same pattern as the reference signal is sequentially generated. The measurement signal is sequentially input to the digitizer whose frequency characteristic has been corrected in the digitizer correction stage, and the digitizer sequentially acquires the frequency characteristic of the measurement signal output in accordance with each signal under measurement, and in the signal generator correction stage, The frequency characteristics of each measurement signal acquired sequentially in the second characteristic acquisition stage are sequentially compared with the frequency characteristics of the reference signal generator, and the frequency characteristics of the corresponding signal generator are sequentially corrected based on the comparison results. You can do it.

  The digitizer receives the reference signal output from the reference signal generator and transmits it to the subsequent circuit, the analog-digital converter that converts the signal transmitted by the input analog circuit into a digital measurement signal, and the analog-digital converter An input data memory for storing a measurement signal to be output and a first correction memory for storing a correction coefficient for correcting the measurement signal stored in the input data memory, and the measurement signal stored in the data memory in the first characteristic acquisition stage The frequency characteristics of the measurement signal may be calculated based on

  In the correction method, at the digitizer correction stage, a correction coefficient may be generated based on the comparison result and stored in the first correction memory.

  The signal generator includes an output data memory for storing waveform data of a signal to be generated, a second correction memory for storing a correction coefficient for correcting the waveform data stored in the output data memory, and waveform data stored in the output data memory Is converted into an analog signal under test, and a signal under test output from the digital analog converter is received and output to a digitizer. The signal generator is corrected based on the comparison result. A correction coefficient may be generated and stored in the second correction memory.

  In the second embodiment of the present invention, the frequency characteristics of the signal generator that generates an input signal to the device under test and the digitizer that measures the output signal of the device under test are used in a test apparatus that tests the device under test. A correction method for correcting, wherein a reference signal generation stage for causing a signal generator to generate a predetermined reference signal, and a reference signal input to a reference digitizer having a known frequency characteristic, the reference digitizer responding to the reference signal The first characteristic acquisition stage for acquiring the frequency characteristic of the measurement signal to be output in comparison, the frequency characteristic of the measurement signal and the frequency characteristic of the reference digitizer, and a signal for correcting the frequency characteristic of the signal generator based on the comparison result A signal under measurement having the same pattern as the reference signal is generated in the signal generator whose frequency characteristics have been corrected in the generator correction stage and the signal generator correction stage. A measured signal generation stage, a second characteristic acquisition stage for inputting the measured signal to a digitizer whose frequency characteristics are to be corrected, and acquiring a frequency characteristic of the measurement signal output by the digitizer according to the measured signal; Provided is a correction method comprising a digitizer correction step of comparing the frequency characteristic of a measurement signal acquired in the two-characteristic acquisition stage with the frequency characteristic of a reference digitizer and correcting the frequency characteristic of the digitizer based on the comparison result.

  In the third aspect of the present invention, the frequency characteristics of a signal generator that generates an input signal to the device under test and a digitizer that measures the output signal of the device under test are used in a test apparatus that tests the device under test. A correction device for correcting, a reference signal generator having a known frequency characteristic, a reference signal generator for generating a predetermined reference signal, and a reference signal input to the digitizer, the digitizer responding to the reference signal A first characteristic acquisition unit that acquires a frequency characteristic of the measurement signal to be output; a digitizer correction unit that compares the frequency characteristic of the reference signal and the frequency characteristic of the measurement signal and corrects the frequency characteristic of the digitizer based on the comparison result; A signal generator to be measured that causes the signal generator to correct frequency characteristics to generate a signal under measurement having the same pattern as the reference signal, and a signal under measurement, A second characteristic acquisition unit that inputs to the digitizer whose frequency characteristic is corrected by the digitizer correction unit and acquires the frequency characteristic of the measurement signal that the digitizer outputs according to the signal under measurement, and the measurement signal acquired by the second characteristic acquisition unit And a signal generator correction unit that compares the frequency characteristic of the reference signal generator with the frequency characteristic of the reference signal generator and corrects the frequency characteristic of the signal generator based on the comparison result.

  In the fourth embodiment of the present invention, the frequency characteristics of a signal generator that generates an input signal to the device under test and a digitizer that measures the output signal of the device under test are used in a test apparatus that tests the device under test. A correction device for correcting a reference signal generation unit that generates a predetermined reference signal in a signal generator and a reference digitizer having a known frequency characteristic, and the reference digitizer responds to the reference signal. A signal for correcting the frequency characteristics of the signal generator based on the comparison result, comparing the frequency characteristics of the measurement signal and the reference digitizer with the first characteristic acquisition unit for acquiring the frequency characteristics of the measurement signal to be output A generator correction unit and a signal generator whose frequency characteristics are corrected by the signal generator correction unit are configured to generate a signal under measurement having the same pattern as the reference signal. A second signal acquisition unit that inputs a signal under measurement to a constant signal generation unit, a digitizer whose frequency characteristic is to be corrected, and acquires a frequency characteristic of the measurement signal output by the digitizer according to the signal under measurement; There is provided a correction device including a digitizer correction unit that compares a frequency characteristic of a measurement signal acquired by an acquisition unit with a frequency characteristic of a reference digitizer and corrects the frequency characteristic of the digitizer based on a comparison result.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  According to the present invention, the inherent frequency characteristics of the signal generator and the digitizer can be corrected.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

  FIG. 1 shows the configuration of the signal generator 20 and the digitizer 30 and the reference signal generator 40 together with the configuration of the correction apparatus 10 according to the present embodiment. The correction apparatus 10 according to the present embodiment corrects the frequency characteristics of the signal generator 20 and the digitizer 30 used in a test apparatus that tests a device under test using a reference signal generator 40 whose frequency characteristics are known. The correction device 10 includes a reference signal generation unit 11, a first characteristic acquisition unit 12, a digitizer correction unit 13, a measured signal generation unit 14, a second characteristic acquisition unit 15, and a signal generator correction unit 16. Prepare.

  The reference signal generator 11 causes the reference signal generator 40 to generate a predetermined reference signal. The first characteristic acquisition unit 12 inputs the reference signal to the digitizer 30 and acquires the frequency characteristic of the measurement signal output by the digitizer 30 according to the reference signal. The digitizer correction unit 13 compares the frequency characteristic of the reference signal and the frequency characteristic of the measurement signal, and corrects the frequency characteristic of the digitizer 30 based on the comparison result.

  The signal under measurement generating unit 14 causes the signal generator 20 whose frequency characteristics are to be corrected to generate a signal under measurement having the same pattern as the reference signal. The second characteristic acquisition unit 15 inputs the signal under measurement to the digitizer 30 whose frequency characteristic has been corrected by the digitizer correction unit 13, and acquires the frequency characteristic of the measurement signal output by the digitizer 30 according to the signal under measurement. The signal generator correction unit 16 compares the frequency characteristic of the measurement signal acquired by the second characteristic acquisition unit 15 with the frequency characteristic of the reference signal generator 40, and determines the frequency characteristic of the signal generator 20 based on the comparison result. to correct.

  The signal generator 20 generates an input signal to the device under test. As an example, the signal generator 20 includes an output data memory 21, a second correction memory 22, a digital analog converter 23, and an output analog circuit 24. The output data memory 21 stores waveform data of signals to be generated. The second correction memory 22 stores a correction coefficient for correcting the waveform data stored in the output data memory 21. The correction coefficient stored in the second correction memory 22 is used to correct the waveform data stored in the output data memory 21 when a signal is generated. That is, the output data memory 21 corrects the stored waveform data with the correction coefficient stored in the second correction memory 22 and outputs the corrected waveform data to the digital / analog converter 23. The digital / analog converter 23 converts the waveform data stored in the output data memory 21 into an analog signal under measurement. The output analog circuit 24 receives the signal under measurement output from the digital analog converter 23 and outputs it to the digitizer 30.

  The digitizer 30 measures the output signal of the device under test. As an example, the digitizer 30 includes an input analog circuit 31, an analog-digital converter 32, an input data memory 33, and a first correction memory 34. The input analog circuit 31 receives the reference signal output from the reference signal generator 40 and transmits it to the subsequent circuit. The analog-digital converter 32 converts the signal transmitted by the input analog circuit 31 into a digital measurement signal. The input data memory 33 stores the measurement signal output from the analog / digital converter 32. The first correction memory 34 stores a correction coefficient for correcting the measurement signal stored in the input data memory 33. The correction coefficient stored in the first correction memory 34 is used to correct the waveform data stored in the input data memory 33 at the time of signal acquisition. That is, the input data memory 33 corrects the stored waveform data with the correction coefficient stored in the first correction memory 34, and outputs it to the outside.

  The reference signal generator 40 is a signal generator whose accuracy is compensated by a standard device, for example. The reference signal generator 40 and the signal generator 20 are connected to the digitizer 30 by, for example, a user during each use.

  FIG. 2 shows a processing flow of the correction apparatus 10 according to the present embodiment. First, in step S11, the reference signal generator 11 causes the reference signal generator 40 to generate a predetermined reference signal. Here, the reference signal generation unit 11 may generate a reference signal having signal components at a plurality of predetermined frequencies.

  Next, in step S12, the first characteristic acquisition unit 12 inputs the reference signal to the digitizer 30 to be corrected, and acquires the frequency characteristic of the measurement signal that the digitizer 30 outputs according to the reference signal. When the reference signal includes a plurality of frequency components, the first characteristic acquisition unit 12 may acquire signal components at a plurality of predetermined frequencies of the measurement signal. The first characteristic acquisition unit 12 may calculate the frequency characteristic of the measurement signal based on the measurement signal stored in the input data memory 33.

  Next, in step S13, the digitizer correction unit 13 compares the frequency characteristic of the reference signal with the frequency characteristic of the measurement signal, and corrects the frequency characteristic of the digitizer 30 based on the comparison result. For example, the digitizer correction unit 13 may correct the frequency characteristic of the digitizer 30 by generating a correction coefficient based on the comparison result and storing it in the first correction memory 34. In this case, the input data memory 33 corrects the stored waveform data with the correction coefficient stored in the first correction memory 34 and outputs the corrected waveform data. When the reference signal includes a plurality of frequency components, the digitizer correction unit 13 compares the signal component of the reference signal and the signal component of the measurement signal for each frequency, Alternatively, a correction coefficient for correcting the frequency characteristic of the digitizer 30 may be calculated.

  In step S13, for example, the digitizer correction unit 13 represents the frequency characteristic as Wd (f) in response to the input of the reference signal whose frequency characteristic is represented as Wm (f) to the digitizer 30. When the measurement signal is stored in the input data memory 33, a value {Wd (f) / Wm (f)} obtained by normalizing Wd (f) with Wm (f) is used as a correction coefficient for correcting the frequency characteristics of the digitizer 30. As good as Thus, the digitizer 30 removes the frequency characteristic components of the input analog circuit 31 and the analog-digital converter 32 from the waveform data stored in the input data memory 33, and outputs the same waveform data as the waveform of the original input signal. can do.

For example, it is assumed that the digitizer 30 receives an arbitrary input signal (frequency characteristic Wi (f)) and, as a result, acquires an acquisition signal having a frequency characteristic Wdi (f). Further, it is assumed that the frequency characteristic of the input analog circuit 31 is ad (f) and the frequency characteristic of the analog-digital converter 32 is ac (f). In this case, the relationship between the input signal Wi (f) and the acquired signal Wdi (f) is as shown in Expression (1).
Wdi (f) = Wi (f) · ad (f) · ac (f) (1)

Here, when the value {Wd (f) / Wm (f)} obtained by normalizing Wd (f) with Wm (f) is used as the correction coefficient, the correction device 10 is represented by the following equation (2). In addition, correction is performed by dividing the acquired signal (Wdi (f)) by the correction coefficient.
Wdi (f) / {Wd (f) / Wm (f)}
= Wi (f) · ad (f) · ac (f) / {Wd (f) / Wm (f)} (2)

The relationship between Wd (f) and Wm (f) is as shown in equation (3).
Wd (f) = Wm (f) · ad (f) · ac (f) (3)
Substituting equation (3) into equation (2) gives the following equation (4).
Wdi (f) / {Wd (f) / Wm (f)}
= Wi (f) .ad (f) .ac (f) / {Wm (f) .ad (f) .ac (f) / Wm (f)}
= Wi (f) (4)

  As shown in the equation (4), the digitizer correction unit 13 sets a value {Wd (f) / Wm (f)} obtained by normalizing Wd (f) by Wm (f) as a correction coefficient. The digitizer 30 can correctly acquire waveform data for an arbitrary input signal Wi (f). Therefore, the correction device 10 can correct the frequency characteristics of the input analog circuit 31 and the analog-digital converter 32 in the digitizer 30 by using {Wd (f) / Wm (f)} as a correction coefficient.

  Next, in step S14, the measured signal generation unit 14 causes the signal generator 20 whose frequency characteristics are to be corrected to generate a measured signal having the same pattern as the reference signal. For example, when the reference signal includes a plurality of frequency components, the measured signal generation unit 14 may cause the signal generator 20 to generate a measured signal having signal components at a plurality of predetermined frequencies. .

  Next, in step S15, the second characteristic acquisition unit 15 inputs the signal under measurement to the digitizer 30 whose frequency characteristic has been corrected by the digitizer correction unit 13 in step S13, and the digitizer 30 outputs it according to the signal under measurement. Get the frequency characteristics of the measurement signal. When the signal under measurement includes a plurality of frequency components, the second characteristic acquisition unit 15 may acquire signal components at a plurality of predetermined frequencies of the measurement signal.

  Next, in step S16, the signal generator correction unit 16 compares the frequency characteristic of the measurement signal acquired by the second characteristic acquisition unit 15 in step S15 with the frequency characteristic of the reference signal generator 40, and determines the comparison result. Based on this, the frequency characteristic of the signal generator 20 is corrected. For example, the signal generator correction unit 16 may correct the frequency characteristics of the signal generator 20 by generating a correction coefficient based on the comparison result and storing the correction coefficient in the second correction memory 22. In this case, the output data memory 21 corrects and outputs the stored waveform data with the correction coefficient stored in the second correction memory 22. In addition, when the signal under measurement includes a plurality of frequency components, the signal generator correction unit 16 determines the signal component of the measurement signal and the frequency characteristic component of the reference signal generator 40 for each frequency. And a correction coefficient for correcting the frequency characteristics of the signal generator 20 may be calculated for each frequency.

  For example, the signal generator correction unit 16 has an input whose frequency characteristic is represented by Wg (f) in response to the signal generator 20 generating a signal under measurement whose frequency characteristic is represented by Wm (f). When a signal is input to the digitizer 30, a value {Wg (f) / Wm (f)} obtained by normalizing Wg (f) with Wm (f) may be used as a correction coefficient for correcting the frequency characteristics of the signal generator 20. . Thus, the signal generator 20 removes in advance the frequency characteristic components of the digital analog converter 23 and the output analog circuit 24 from the waveform data stored in the output data memory 21, and the waveform stored in the output data memory 21. Can output a signal with the same waveform.

For example, the signal generator 20 generates an arbitrary output signal (frequency characteristic Wo (f)), and as a result, the corrected digitizer 30 acquires an acquisition signal having a frequency characteristic of Wgo (f). . Further, it is assumed that the frequency characteristic of the digital analog converter 23 is ag (f) and the frequency characteristic of the output analog circuit 24 is da (f). In this case, the relationship between the arbitrary output signal Wo (f) and the acquired signal Wgo (f) is as shown in Expression (5).
Wgo (f) = Wo (f) · ag (f) · da (f) (5)
Since the digitizer 30 has already been corrected, the acquisition signal Wgo is the same as the signal input to the digitizer 30.

Here, when the value {Wg (f) / Wm (f)} obtained by normalizing Wg (f) with Wm (f) is used as the correction coefficient, the correction device 10 represents the following equation (6). In addition, correction is performed by dividing an arbitrary output signal Wo (f) by a correction coefficient (Wg (f) / Wm (f)) in advance.
Wgo (f)
= [Wo (f) / {Wg (f) / Wm (f)}] · ag (f) · da (f) (6)

Further, the relationship between Wg (f) and Wm (f) is as shown in Expression (7).
Wg (f) = Wm (f) · ag (f) · da (f) (7)
Substituting equation (7) into equation (6) gives the following equation (8).
Wgo (f)
= [Wo (f) / {Wm (f) · ag (f) · da (f) / Wm (f)}] · ag (f) · da (f)
= Wo (f) (8)

  As shown in this equation (8), the signal generator correction unit 16 sets a value {Wg (f) / Wm (f)} obtained by normalizing Wg (f) by Wm (f) as a correction coefficient. Thus, the signal generator 20 can correctly output an arbitrary analog output signal (Wo (f)). Therefore, the correction apparatus 10 can correct the frequency characteristics of the digital analog converter 23 and the output analog circuit 24 in the signal generator 20 by using {Wd (f) / Wm (f)} as a correction coefficient. .

  As described above, according to the correction device 10, the unique analog frequency characteristics of the signal generator 20 and the digitizer 30 can be easily corrected. Further, according to the correction device 10, by storing the correction coefficient in the second correction memory 22 and the first correction memory 34, the signal generator 20 having the same frequency characteristic and the digitizer 30 having the same frequency characteristic are stored. Can be generated.

  FIG. 3 shows a processing flow of the correction apparatus 10 according to the first modification of the present embodiment. The correction device 10 according to the first modification, the signal generator 20 and the digitizer 30 to be corrected have substantially the same configuration and function as the members shown in FIG. 1, and are substantially the same as the processing shown in FIG. Therefore, the description is omitted below except for the differences.

  When the correction of the frequency characteristics of one signal generator 20 is completed in step S16, next, in step S21, the correction device 10 removes the completed signal generator 20 from the digitizer 30 in accordance with, for example, a user instruction. Then, another signal generator 20 to be corrected is connected to the digitizer 30. When the switching of the signal generator 20 is completed, the correction device 10 performs the process from step S14 on the signal generator 20 after the switching. Then, the correction device 10 repeats the processes of step S14, step S15, step S16, and step S21 to correct the frequency characteristics for the plurality of signal generators 20.

  That is, in step S14, the measured signal generator 14 causes the plurality of signal generators 20 whose frequency characteristics are to be corrected to sequentially generate measured signals having the same pattern as the reference signal. In step S15, the second characteristic acquisition unit 15 sequentially inputs each measured signal to the digitizer 30 whose frequency characteristics have been corrected by the digitizer correction unit 13 in step S13, and the digitizer 30 responds to each measured signal. The frequency characteristics of the measurement signals that are sequentially output are acquired sequentially. In step S16, the signal generator correction unit 16 sequentially compares the frequency characteristics of the respective measurement signals sequentially acquired by the second characteristic acquisition unit 15 in step S15 with the frequency characteristics of the reference signal generator 40, and the respective signal characteristics are corrected. Based on the comparison result, the frequency characteristics of the corresponding signal generator 20 are sequentially corrected.

  As described above, according to the correction apparatus 10 according to the first modified example, the frequency characteristics of the plurality of signal generators 20 are sequentially corrected, so that a plurality of signal generators 20 having the same frequency characteristics can be generated. it can.

  FIG. 4 shows the configuration of the signal generator 20 and the digitizer 30 and the reference digitizer 50 together with the configuration of the correction apparatus 10 according to the second modification of the present embodiment. The correction device 10 according to the second modification, the signal generator 20 and the digitizer 30 to be corrected have substantially the same configuration and function as the members shown in FIG. Omitted.

  The correction apparatus 10 according to this modification corrects the frequency characteristics of the signal generator 20 and the digitizer 30 using a reference digitizer 50 whose frequency characteristics are known instead of the reference signal generator 40. The reference digitizer 50 is, for example, a digitizer whose accuracy is compensated by a standard device. In addition, the digitizer 30 and the reference digitizer 50 are connected to the signal generator 20 by, for example, a user or the like in each use.

  The reference signal generation unit 11 causes the signal generator 20 to generate a predetermined reference signal. The first characteristic acquisition unit 12 inputs a reference signal to the reference digitizer 50 whose frequency characteristic is known, and acquires the frequency characteristic of the measurement signal output by the reference digitizer 50 according to the reference signal. The digitizer correction unit 13 compares the frequency characteristic of the measurement signal acquired by the second characteristic acquisition unit 15 with the frequency characteristic of the reference digitizer 50, and corrects the frequency characteristic of the digitizer 30 based on the comparison result.

  The signal under measurement generation unit 14 causes the signal generator 20 whose frequency characteristics are corrected by the signal generator correction unit 16 to generate a signal under measurement having the same pattern as the reference signal. The second characteristic acquisition unit 15 inputs the signal under measurement to the digitizer 30 whose frequency characteristics are to be corrected, and acquires the frequency characteristic of the measurement signal output by the digitizer 30 according to the signal under measurement. The signal generator correction unit 16 compares the frequency characteristic of the measurement signal with the frequency characteristic of the reference digitizer 50, and corrects the frequency characteristic of the signal generator 20 based on the comparison result.

  FIG. 5 shows a processing flow of the correction apparatus 10 according to the second modification. First, in step S31, the reference signal generation unit 11 causes the signal generator 20 to generate a predetermined reference signal. Here, the reference signal generation unit 11 may generate a reference signal having signal components at a plurality of predetermined frequencies.

  Next, in step S32, the first characteristic acquisition unit 12 inputs the reference signal to the reference digitizer 50 whose frequency characteristic is known, and acquires the frequency characteristic of the measurement signal output by the reference digitizer 50 according to the reference signal. . When the reference signal includes a plurality of frequency components, the first characteristic acquisition unit 12 may acquire signal components at a plurality of predetermined frequencies of the measurement signal.

  Next, in step S33, the signal generator correction unit 16 compares the frequency characteristic of the measurement signal with the frequency characteristic of the reference digitizer 50, and corrects the frequency characteristic of the signal generator 20 based on the comparison result. For example, the signal generator correction unit 16 may correct the frequency characteristics of the signal generator 20 by generating a correction coefficient based on the comparison result and storing the correction coefficient in the second correction memory 22. When the reference signal includes a plurality of frequency components, the signal generator correction unit 16 compares the signal component of the measurement signal with the frequency characteristic component of the reference digitizer 50 for each frequency. A correction coefficient for correcting the frequency characteristics of the signal generator 20 may be calculated for each frequency.

  Next, in step S34, the measured signal generator 14 generates a measured signal having the same pattern as the reference signal in the signal generator 20 whose frequency characteristics have been corrected by the signal generator corrector 16 in step S33. Let For example, when the reference signal includes a plurality of frequency components, the measured signal generation unit 14 may cause the signal generator 20 to generate a measured signal having signal components at a plurality of predetermined frequencies. .

  Next, in step S35, the second characteristic acquisition unit 15 inputs the signal under measurement to the digitizer 30 whose frequency characteristics are to be corrected, and acquires the frequency characteristic of the measurement signal output by the digitizer 30 according to the signal under measurement. To do. When the signal under measurement includes a plurality of frequency components, the second characteristic acquisition unit 15 may acquire signal components at a plurality of predetermined frequencies of the measurement signal.

  Next, in step S36, the digitizer correction unit 13 compares the frequency characteristic of the measurement signal acquired by the second characteristic acquisition unit 15 in step S35 with the frequency characteristic of the reference digitizer 50, and based on the comparison result, the digitizer 30. Correct the frequency characteristics. For example, the digitizer correction unit 13 may correct the frequency characteristic of the digitizer 30 by generating a correction coefficient based on the comparison result and storing it in the first correction memory 34. When the signal under measurement includes a plurality of frequency components, the digitizer correction unit 13 compares the signal component of the reference signal and the signal component of the measurement signal for each frequency, and compares the frequency components. A correction coefficient for correcting the frequency characteristic of the digitizer 30 may be calculated every time.

  As described above, according to the correction device 10 according to the second modification, even if the reference digitizer 50 is used instead of the reference signal generator 40, the inherent analog frequency characteristics of the signal generator 20 and the digitizer 30 are corrected. can do.

  FIG. 6 shows an example of a hardware configuration of a computer 1900 according to this embodiment. A computer 1900 according to this embodiment is connected to a CPU peripheral unit having a CPU 2000, a RAM 2020, a graphic controller 2075, and a display device 2080 that are connected to each other by a host controller 2082, and to the host controller 2082 by an input / output controller 2084. Input / output unit having communication interface 2030, hard disk drive 2040, and CD-ROM drive 2060, and legacy input / output unit having ROM 2010, flexible disk drive 2050, and input / output chip 2070 connected to input / output controller 2084 With.

  The host controller 2082 connects the RAM 2020 to the CPU 2000 and the graphic controller 2075 that access the RAM 2020 at a high transfer rate. The CPU 2000 operates based on programs stored in the ROM 2010 and the RAM 2020 and controls each unit. The graphic controller 2075 acquires image data generated by the CPU 2000 or the like on a frame buffer provided in the RAM 2020 and displays it on the display device 2080. Instead of this, the graphic controller 2075 may include a frame buffer for storing image data generated by the CPU 2000 or the like.

  The input / output controller 2084 connects the host controller 2082 to the communication interface 2030, the hard disk drive 2040, and the CD-ROM drive 2060, which are relatively high-speed input / output devices. The communication interface 2030 communicates with other devices via a network. The hard disk drive 2040 stores programs and data used by the CPU 2000 in the computer 1900. The CD-ROM drive 2060 reads a program or data from the CD-ROM 2095 and provides it to the hard disk drive 2040 via the RAM 2020.

  The input / output controller 2084 is connected to the ROM 2010, the flexible disk drive 2050, and the relatively low-speed input / output device of the input / output chip 2070. The ROM 2010 stores a boot program that the computer 1900 executes at startup, a program that depends on the hardware of the computer 1900, and the like. The flexible disk drive 2050 reads a program or data from the flexible disk 2090 and provides it to the hard disk drive 2040 via the RAM 2020. The input / output chip 2070 connects various input / output devices via a flexible disk drive 2050 and, for example, a parallel port, a serial port, a keyboard port, a mouse port, and the like.

  A program provided to the hard disk drive 2040 via the RAM 2020 is stored in a recording medium such as the flexible disk 2090, the CD-ROM 2095, or an IC card and provided by the user. The program is read from the recording medium, installed in the hard disk drive 2040 in the computer 1900 via the RAM 2020, and executed by the CPU 2000.

  A program installed in the computer 1900 and causing the computer 1900 to function as the correction device 10 includes a reference signal generation module, a first characteristic acquisition module, a digitizer correction module, a measured signal generation module, and a second characteristic acquisition module. A signal generator correction unit. These programs or modules work with the CPU 2000 or the like to change the computer 1900 into a reference signal generation unit 11, a first characteristic acquisition unit 12, a digitizer correction unit 13, a signal under measurement generation unit 14, a second characteristic acquisition unit 15, and a signal. It functions as the generator correction unit 16.

  The program or module shown above may be stored in an external storage medium. As the storage medium, in addition to the flexible disk 2090 and the CD-ROM 2095, an optical recording medium such as DVD or CD, a magneto-optical recording medium such as MO, a tape medium, a semiconductor memory such as an IC card, or the like can be used. Further, a storage device such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet may be used as a recording medium, and the program may be provided to the computer 1900 via the network.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

A configuration of the correction device 10 according to the present embodiment, a configuration of the signal generator 20 and the digitizer 30, and a reference signal generator 40 are shown. The processing flow of the correction apparatus 10 which concerns on this embodiment is shown. The processing flow of the correction apparatus 10 which concerns on the 1st modification of this embodiment is shown. A configuration of the signal generator 20 and the digitizer 30 and a reference digitizer 50 are shown along with the configuration of the correction apparatus 10 according to the second modification of the present embodiment. The processing flow of the correction apparatus 10 which concerns on the 2nd modification of this embodiment is shown. 2 shows an exemplary hardware configuration of a computer 1900 according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Correction apparatus 20 Signal generator 30 Digitizer 40 Reference signal generator 50 Reference digitizer 11 Reference signal generation part 12 First characteristic acquisition part 13 Digitizer correction part 14 Measured signal generation part 15 Second characteristic acquisition part 16 Signal generator correction part 21 output data memory 22 second correction memory 23 digital analog converter 24 output analog circuit 31 input analog circuit 32 analog digital converter 33 input data memory 34 first correction memory 1900 computer 2000 CPU
2010 ROM
2020 RAM
2030 Communication interface 2040 Hard disk drive 2050 Flexible disk drive 2060 CD-ROM drive 2070 Input / output chip 2075 Graphic controller 2080 Display device 2082 Host controller 2084 Input / output controller 2090 Flexible disk 2095 CD-ROM

Claims (10)

A signal generator for generating an input signal to the device under test, and a correction method for correcting frequency characteristics of a digitizer for measuring an output signal of the device under test, which is used in a test apparatus for testing the device under test,
A signal generating step for causing the signal generator to generate a predetermined reference signal;
A first characteristic acquisition step of inputting the reference signal to a reference digitizer having a known frequency characteristic, and acquiring a frequency characteristic of a measurement signal output by the reference digitizer according to the reference signal;
A signal generator correction stage that compares the frequency characteristics of the measurement signal with the frequency characteristics of the reference digitizer and corrects the frequency characteristics of the signal generator based on the comparison result;
A signal under test generating step for generating the signal under test having the same pattern as the reference signal in the signal generator whose frequency characteristics have been corrected in the signal generator correction step;
A second characteristic acquisition step of inputting the signal under measurement to the digitizer to be corrected for frequency characteristics, and acquiring a frequency characteristic of the measurement signal output by the digitizer according to the signal under measurement;
A correction method comprising: a digitizer correction step of comparing the frequency characteristic of the measurement signal acquired in the second characteristic acquisition step with the frequency characteristic of the reference digitizer and correcting the frequency characteristic of the digitizer based on the comparison result . Wherein in signal generation stage, to generate the reference signal having the signal components in a plurality of predetermined frequencies,
In the first characteristic acquisition step, signal components at the predetermined plurality of frequencies of the measurement signal are acquired,
In the signal generator correction step, for each frequency, the signal component of the measurement signal is compared with the frequency characteristic of the reference digitizer, and a correction coefficient for correcting the frequency characteristic of the signal generator is corrected for each frequency. The correction method according to claim 1. In the measured signal generation step, the signal generator generates the measured signal having signal components at the predetermined plurality of frequencies,
In the second characteristic acquisition step, signal components at the predetermined plurality of frequencies of the measurement signal are acquired,
In the digitizer correction step, the signal component of the measurement signal is compared with the frequency characteristic component of the reference digitizer for each frequency, and a correction coefficient for correcting the frequency characteristic of the digitizer is calculated for each frequency. The correction method according to claim 2. Before Symbol second characteristic acquisition step, the pre-Symbol measured signal sequentially inputted to the plurality of the digitizer to be corrected frequency characteristic of the measurement signal, each of said digitizer sequentially output in accordance with the prior SL measured signal Obtain frequency characteristics sequentially,
In the digitizer correction stage, the frequency characteristics of the measurement signals sequentially acquired in the second characteristic acquisition stage are sequentially compared with the frequency characteristics of the reference digitizer , and the corresponding digitizers are determined based on the comparison results. correction method according to any one of claims 1 to 3 for sequentially correcting the frequency characteristic of the. The digitizer is
Receiving said measured signal the signal generator output, an input analog circuitry for transmitting to the subsequent circuit,
An analog-to-digital converter that converts the signal transmitted by the input analog circuit into the digital measurement signal;
An input data memory for storing the measurement signal output by the analog-digital converter;
A first correction memory for storing a correction coefficient for correcting the measurement signal stored in the input data memory,
The second characteristic acquisition step, wherein the data memory is stored based on the measurement signal, the correction method according to claim 1, any one of 4 to calculate the frequency characteristic of the measuring signal. The correction method according to claim 5, wherein, in the digitizer correction step, the correction coefficient is generated based on the comparison result and stored in the first correction memory. The signal generator is
An output data memory for storing the waveform data of the signal to be generated;
A second correction memory for storing a correction coefficient for correcting the waveform data stored in the output data memory;
A digital-analog converter that converts the waveform data stored in the output data memory into the analog signal under measurement;
An output analog circuit that receives the signal under measurement output from the digital analog converter and outputs the signal to the digitizer;
Wherein the signal generator correction phase to produce a correction factor based on the comparison result, correction method according to any one of claims 1 6 to be stored in the second correction memory.   A reference signal generation stage for causing a reference signal generator having a known frequency characteristic to generate a predetermined reference signal;
  A third characteristic acquisition step of inputting the reference signal to the digitizer and acquiring a frequency characteristic of a measurement signal output by the digitizer according to the reference signal;
  A signal under measurement having the same pattern as the reference signal generated by the signal under test generation step is caused to be corrected by the digitizer correction step with the frequency characteristic of the reference signal generator. The frequency characteristic of the measurement signal acquired in the third characteristic acquisition step is compared, input to the digitizer whose frequency characteristic is corrected based on the comparison result, and the digitizer outputs according to the signal under measurement A fourth characteristic acquisition stage for acquiring a frequency characteristic of the measurement signal;
  Further comprising
  The signal generator correction step compares the frequency characteristic of the measurement signal acquired in the fourth characteristic acquisition step with the frequency characteristic of the reference signal generator, and based on the comparison result, the frequency characteristic of the signal generator To correct
  The correction method according to claim 1. A signal generator that generates an input signal to the device under test, and a correction device that corrects a frequency characteristic of a digitizer that measures an output signal of the device under test, which is used in a test apparatus that tests the device under test,
To the signal generator, a signal generator for generating a reference signal predetermined
A first characteristic acquisition unit that inputs the reference signal to a reference digitizer having a known frequency characteristic, and acquires a frequency characteristic of a measurement signal that the reference digitizer outputs in response to the reference signal;
A signal generator correction unit that compares the frequency characteristic of the measurement signal with the frequency characteristic of the reference digitizer and corrects the frequency characteristic of the signal generator based on the comparison result;
A signal-under-measurement generating unit that causes the signal generator whose frequency characteristics are corrected by the signal generator correction unit to generate a signal under measurement having the same pattern as the reference signal;
A second characteristic acquisition unit that inputs the signal under measurement to the digitizer to be corrected for frequency characteristics, and acquires the frequency characteristic of the measurement signal output by the digitizer according to the signal under measurement;
A correction apparatus comprising: a digitizer correction unit that compares the frequency characteristic of the measurement signal acquired by the second characteristic acquisition unit with the frequency characteristic of the reference digitizer and corrects the frequency characteristic of the digitizer based on the comparison result.   A reference signal generator having a known frequency characteristic;
  A reference signal generator that causes the reference signal generator to generate a predetermined reference signal;
  A third characteristic acquisition unit that inputs the reference signal generated by the reference signal generation unit to the digitizer and acquires a frequency characteristic of a measurement signal output by the digitizer according to the reference signal;
  A signal under test having the same pattern as the reference signal generated by the signal under test generator generated by the signal generator to be corrected for frequency characteristics is converted into a frequency characteristic of the reference signal generator by the digitizer correction unit. Is compared with the frequency characteristic of the measurement signal acquired by the third characteristic acquisition unit, and the digitizer is input to the digitizer corrected based on the comparison result, and the digitizer responds to the signal under measurement. A fourth characteristic acquisition unit for acquiring a frequency characteristic of the measurement signal to be output;
  Further comprising
  The signal generator correction unit compares the frequency characteristic of the measurement signal acquired by the fourth characteristic acquisition unit with the frequency characteristic of the reference signal generator, and based on the comparison result, the frequency characteristic of the signal generator To correct
  The correction device according to claim 9.

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