JP2011153984A - Apparatus and method for observing waveform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily relate waveform observation results in signals to be measured to S21 characteristics. <P>SOLUTION: A waveform observing apparatus 1 performs interpolation processing of the difference between line spectra of discrete digital waveform data in signals to be measured inputted via a device 70 to be tested and linear spectra for calibration stored in a storage unit 32, and displays waveforms of predicted waveform data obtained by performing inverse Fourier transform of the predicted waveform spectra obtained from spectra of S21 measurement data obtained by smoothing, spectra of S21 adjustment data obtained by varying the frequency of S21 measurement data based on operation from a setting input unit 40 and then by calculation after performing moving averaging again, and spectra for operation obtained by performing Fourier transform to the S21 adjustment data and discrete digital waveform data for calibration stored in the storage unit 32 in parallel in a display unit 60. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a waveform observation apparatus that performs waveform observation of waveform data acquired by sampling an input signal under measurement, and in particular, can measure the frequency characteristics of a signal under measurement, and can measure the measured frequency characteristics and waveform data. The present invention relates to a waveform observation apparatus and method capable of associating prediction results when arbitrarily adjusted.

  Conventionally, for example, the waveform data of the signal under measurement input via the device under test (DUT) is sampled sequentially at a predetermined cycle, and the sampled waveform data is read out appropriately and the eye pattern is reproduced and displayed on the display screen. As an apparatus for observing the waveform of a signal under measurement by doing so, for example, a device disclosed in Patent Document 1 below is known.

JP 2008-267994 A

  By the way, in a general waveform observation apparatus including the apparatus disclosed in Patent Document 1, usually only an eye waveform display of a sampled signal under measurement is displayed, and the quality of the signal is observed according to the waveform shape. . Therefore, for example, when measuring the frequency characteristics of a device under test in a high-frequency circuit network (especially, S21 transmission characteristics as a frequency characteristic with a high measurement frequency), it is necessary to perform measurement by connecting a network analyzer as a separate device.

  However, in order to measure the frequency characteristics of the device under test, a network analyzer must be prepared separately in addition to the waveform observing apparatus, and there is a problem that the measurement cost increases. In addition, each time a measurement item is changed, the system must be changed by routing a cable or the like to a new device every time, and the measurement work is complicated.

  Also, since the measurement system differs between the waveform observation apparatus and the network analyzer even when the same signal is measured, for example, the S21 characteristic measured as the frequency characteristic and the frequency characteristic measured in the eye waveform observed by the waveform observation apparatus It was difficult to grasp and relate the components of the waveform and the waveform portion.

  Therefore, the present invention has been made in view of the above problems, and in addition to a general waveform observation function, frequency characteristics can be measured, and prediction results when the measured frequency characteristics and waveform data are adjusted are easily obtained. It is an object of the present invention to provide a waveform observation apparatus and method that can be easily grasped.

In order to achieve the above-described object, the waveform observation apparatus according to claim 1 includes a pulse pattern generation unit 10 that outputs an arbitrary pattern signal that is a periodic waveform and a trigger signal synchronized with the pattern signal,
A waveform observing unit 20 that samples a signal under measurement based on a pattern signal from the pulse pattern generation unit according to a trigger signal from the pulse pattern generation unit to obtain discrete digital waveform data that is time-series data;
A waveform observation apparatus 1 comprising:
A spectrum extraction unit 31 that performs Fourier transform on the discrete digital waveform data from the waveform observation unit and extracts only its line spectral frequency;
A storage unit 32 for storing at least the calibration line spectrum extracted from the discrete digital waveform data for calibration obtained by the waveform observation unit by the spectrum extraction unit;
Obtained from the difference between the line spectrum in the discrete digital waveform data of the signal under measurement input via the device under test 70 and the harmonic line spectrum of the fundamental wave extracted from the calibration line spectrum stored in the storage unit. An S21 calculation processing unit 33 that outputs S21 measurement data obtained by performing smoothing after interpolating S21 actual measurement data;
A display control unit 50 for spectrum-displaying the S21 measurement data from the S21 calculation processing unit on the display unit 60;
It is provided with.

The waveform observation device according to claim 2 is the waveform observation device according to claim 1, further comprising a setting input unit 40 that outputs adjustment information based on operation contents when giving variation to the S21 measurement data;
An S21 adjustment processing unit 34 for outputting S21 adjustment data obtained by taking a moving average again after changing the frequency of the S21 measurement data based on the adjustment information from the setting input unit;
The calculation spectrum obtained by Fourier transforming the discrete digital waveform data for calibration stored in the storage unit 32 or arbitrarily set time-series waveform data, and the S21 adjustment data from the S21 adjustment processing unit. A waveform prediction processing unit 35 that performs inverse Fourier transform on a predicted waveform spectrum obtained by performing a filtering process using multiplication, and outputs the result as predicted waveform data;
Under the control of the display control unit 50, the spectrum of the S21 measurement data, the spectrum of the S21 adjustment data, and the waveform of the predicted waveform data are displayed in parallel on the display screen of the display unit 60.

The waveform observation device according to claim 3 is the waveform observation device according to claim 1, and further includes adjustment information based on operation contents when adjusting the waveform shape of the discrete digital waveform data sampled by the waveform observation unit 20. A setting input unit 40 to output;
A waveform adjustment processing unit 36 for outputting waveform adjustment data obtained by rewriting the discrete digital waveform data sampled by the waveform observation unit so as to be Tr / Tf based on adjustment information from the setting input unit;
FT processing for outputting a waveform adjustment spectrum obtained by Fourier transforming the waveform adjustment data from the waveform adjustment processing unit and an actually measured waveform spectrum obtained by Fourier transforming the discrete digital waveform data stored in the storage unit Part 37;
A spectrum calculation processing unit 38 for outputting S21 variation data obtained by calculating a difference between the measured waveform spectrum Fourier-transformed by the FT processing unit and the waveform adjustment spectrum;
An S21 prediction processing unit 39 that adds the S21 variation data obtained by the spectrum calculation processing unit to the S21 measurement data obtained by the S21 calculation processing unit 33 and outputs the result as S21 prediction data;
Under the control of the display control unit 40, the waveform of the measured waveform data based on the discrete digital waveform data sampled by the waveform observation unit, the spectrum of the S21 measurement data, and the spectrum of the S21 estimation result based on the S21 prediction data are displayed. The display is performed in parallel on the display screen of the unit 60.

The waveform observation method according to claim 4, wherein a pulse pattern generation step of outputting an arbitrary pattern signal that is a periodic waveform and a trigger signal synchronized with the pattern signal;
A waveform observation step of sampling the signal under measurement based on the pattern signal from the pulse pattern generation step according to the trigger signal from the pulse pattern generation step to obtain discrete digital waveform data which is time-series data;
A waveform observation method comprising:
A spectral extraction step of Fourier transforming the discrete digital waveform data from the waveform observation step to extract only its line spectral frequency;
A storage step for storing at least the calibration line spectrum extracted in the spectrum extraction step from the calibration discrete digital waveform data obtained in the waveform observation step;
S21 obtained by subtracting the harmonic line spectrum of the fundamental wave extracted from the line spectrum of the discrete digital waveform data in the signal under measurement input via the device under test 70 and the calibration line spectrum stored in the storing step. An S21 calculation processing step of outputting S21 measurement data obtained by performing smoothing after interpolating measured data;
A display control step of spectrum-displaying the S21 measurement data from the 21 calculation processing step on the display unit 60;
It is characterized by having.

The waveform observing method according to claim 5 is the waveform observing method according to claim 4, further comprising: a setting input step for outputting adjustment information based on operation contents when giving variation to the S21 measurement data;
An S21 adjustment processing step of outputting S21 adjustment data calculated by taking a moving average again after changing the frequency of the S21 measurement data based on the adjustment information from the setting input step;
The calculation spectrum obtained by Fourier transforming the discrete digital waveform data for calibration stored in the storage step or arbitrarily set time-series waveform data, and the S21 adjustment data from the S21 adjustment processing step. A waveform prediction processing step for obtaining a predicted waveform data by performing inverse Fourier transform on a predicted waveform spectrum obtained by performing a filtering process using multiplication, and
A display control step of displaying the spectrum of the S21 measurement data, the spectrum of the S21 adjustment data, and the waveform of the predicted waveform data in parallel on the display screen of the display unit 60;
It is characterized by having.

6. The waveform observation method according to claim 6, wherein the waveform observation method according to claim 4 further outputs adjustment information based on an operation content when adjusting the waveform shape of the discrete digital waveform data sampled in the waveform observation step. A setting input step to
A waveform adjustment processing step of outputting the discrete digital waveform data sampled in the waveform observation step as rewritten waveform adjustment data so as to be Tr / Tf based on adjustment information from a setting input step;
An FT that outputs a waveform adjustment spectrum obtained by Fourier transforming the waveform adjustment data from the waveform adjustment processing step and an actually measured waveform spectrum obtained by Fourier transforming the discrete digital waveform data stored in the storage unit 32. Processing steps;
A spectrum calculation processing step of outputting S21 variation data obtained by calculating a difference between the measured waveform spectrum Fourier-transformed in the FT processing step and the waveform adjustment spectrum;
An S21 prediction processing step of adding the S21 variation data obtained in the spectrum calculation processing step to the S21 measurement data obtained in the S21 calculation processing step, and outputting the result as S21 prediction data;
The waveform of the measured waveform data based on the discrete digital waveform data sampled in the waveform observation step, the spectrum of the S21 measurement data, and the spectrum of the S21 estimation result based on the S21 prediction data are displayed in parallel on the display screen of the display unit 60. Display control step to
It is characterized by having.

  According to the waveform observing apparatus of the present invention, it is not necessary to prepare a network analyzer each time when measuring the S21 characteristic which is a frequency characteristic, so that the measurement cost is reduced. In addition, since it has a function of measuring frequency characteristics, it is possible to easily perform frequency characteristic measurement processing and waveform observation processing without routing wiring such as cables associated with connection of new equipment.

  In the first mode, since the S21 characteristic before and after adjustment by the user's operation and the predicted waveform data based on the adjusted S21 characteristic are displayed in parallel on the same screen, the user can select which component of the S21 characteristic. Can be visually grasped while associating with the waveform.

Furthermore, in the second mode, the eye waveform of the discrete digital waveform data adjusted by the user's operation and the S21 characteristics based on the discrete digital waveform data before and after the waveform adjustment are displayed in parallel on the same screen. The user can visually grasp while adjusting which part of the S21 characteristic is affected by adjusting which part of the measured eye waveform of the discrete digital waveform data.
The effect to do.

It is a schematic block diagram which shows the structure of the waveform observation apparatus of the 1st form which concerns on this invention. (A)-(c) It is explanatory drawing which shows the display content in the apparatus. It is a schematic block diagram which shows the structure of the waveform observation apparatus of the 2nd form which concerns on this invention. (A)-(c) It is explanatory drawing which shows the display content in the apparatus.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment, and all other forms, examples, operation techniques, etc. that can be implemented by those skilled in the art based on this form are included in the scope of the present invention. .

[First form]
The configuration of the waveform observation apparatus according to the first embodiment of the present invention will be described with reference to FIGS.

<Device configuration>
As shown in FIG. 1, the waveform observation apparatus 1 of this example includes a pulse pattern generation unit 10, a waveform observation unit 20, a waveform data processing unit 30, a setting input unit 40, a display control unit 50, and a display unit 60. Composed. In addition to the above-described configuration requirements, the waveform observing apparatus 1 inputs a pattern signal (test signal) from the pulse pattern generation unit 10 via the device under test 70 and measures a code error rate. (Not shown) is also provided.

  The pulse pattern generation unit 10 has a function of a pulse pattern generator (PPG), and includes a clock generation unit 11, a pattern generation unit 12, and a trigger generation unit 13.

  The clock generation means 11 generates a reference clock (periodic waveform) and outputs this clock to the pattern generation means 12 and the trigger generation means 13.

  The pattern generation means 12 is synchronized with the reference clock from the clock generation means 11 and has a random “0” and “1” pattern (for example, a PRBS (Pseudorandom Binary (Bit) Sequence) pattern, “0011”). A pattern signal (test signal) of a pulse pattern arbitrarily selected from preset patterns such as “...” And “0101...” Is output to the device under test 70. Further, when the waveform data processing unit 30 acquires the discrete digital waveform data for calibration used in the S21 calculation process by the waveform data processing unit 30, the pattern generation unit 12 outputs the pattern signal as a signal under measurement in a state directly connected to the waveform observation unit 20. ing.

  The trigger generation unit 13 synchronizes the reference clock from the clock generation unit 11 for sampling the waveform data according to the subsequent process (S21 calculation process or eye waveform display process) with the pattern signal generated by the pattern generation unit 12. A synchronous clock (for example, 1/16 clock at 10 Gbit) is generated, and this synchronous clock is output to the waveform observation unit 20 as a trigger signal.

  The waveform observing unit 20 includes a sampling processing unit 21 that samples an input signal to be measured, and samples the signal to be measured based on a period (frequency division ratio) of the trigger signal from the trigger generation unit to obtain discrete data that is time-series data. Digital waveform data is acquired, and this discrete digital waveform data is output to the waveform data processing unit 30. Further, the waveform observing unit 20 outputs the acquired discrete digital waveform data to the display control unit 50 in order to display it on the display unit 60 as an eye waveform.

  The sampling processing means 21 samples the signal under measurement in accordance with the period of the trigger signal from the trigger generating means 13, so that sampling is performed when the trigger signal is 1 / n (for example, 1/16) clock, for example. The waveform is an eye waveform, and the waveform to be sampled is a time-series waveform when the trigger signal is a pattern trigger (a signal that outputs a pulse only once in one cycle of the pattern generation unit 12). Therefore, the user needs to adjust the trigger signal from the trigger generation means 13 so that the waveform to be sampled becomes an eye waveform or a time-series waveform according to the contents to be displayed on the display unit 60.

  The waveform data processing unit 30 includes a spectrum extraction unit 31, a storage unit 32, an S21 calculation processing unit 33, an S21 adjustment processing unit 34, and a waveform prediction processing unit 35.

  The spectrum extraction unit 31 has a Fourier transform (FT) function for generating a frequency domain spectrum based on time-series waveform data. The spectrum extraction unit 31 performs a Fourier transform of the discrete digital waveform data from the waveform observation unit 20, calculates the spectrum, extracts only the line spectrum frequency, and outputs the extracted line spectrum to the S21 calculation processing unit 33. Yes. Further, when the spectrum extracting unit 31 inputs discrete digital waveform data for calibration from the waveform observing unit 20, a line spectrum (hereinafter referred to as calibration line spectrum) obtained by Fourier transforming the waveform data is stored in the storage unit 32. Storing.

  The storage unit 32 stores the calibration line spectrum extracted from the discrete digital waveform data for calibration by the spectrum extraction unit 31. The storage unit 32 also stores discrete digital waveform data sampled by the waveform observation unit 20 and calibration discrete digital waveform data as necessary.

  The S21 calculation processing unit 33 includes S21 calculation means 33a, interpolation processing means 33b, and smoothing processing means 33c.

  The S21 calculating means 33a extracts the harmonic line spectrum of the fundamental wave from the line spectrum in the discrete digital waveform data of the signal under measurement input via the device under test 70 and the calibration line spectrum stored in the storage unit 32, respectively. S21 actual measurement data (non-equal intervals with respect to the frequency axis), which is the transmission characteristic of the device under test 70, is calculated from the difference between the extracted line spectra, and is output to the interpolation processing means 33b. Note that the harmonic spectrum is preferably extracted at a peak that is higher than the noise floor and that is an inflection point.

  The interpolation processing unit 33b reproduces an S21 data string at equal intervals on the frequency axis by interpolating the S21 actual measurement data calculated by the S21 calculating unit 33a (for example, linear interpolation by detecting / deleting overlapping frequencies), and S21 interpolation data Is output to the smoothing processing means 33c.

The smoothing processing means 33c performs a smoothing process by taking a moving average of the S21 interpolation data from the interpolation processing means 33b and removing abnormal points, and S21 measurement data which is a discrete array obtained by the smoothing process. Is output to the S21 adjustment processing unit 34.
When the moving average cannot be obtained during the smoothing process (eg, there are no previous and subsequent samples), the smoothing process is performed by calculating the average with the previous and subsequent samples. Further, when the spectrum display of the S21 measurement data obtained by the smoothing processing unit 33c is performed, the S21 measurement data is output to the display control unit 50.

The S21 adjustment processing unit 34 divides the frequency of the S21 measurement data from the smoothing processing unit 33c on the basis of the adjustment information from the setting input unit 40, and then takes the moving average again to calculate the S21 adjustment data. The adjusted S21 adjustment data is output to the waveform prediction processing unit 35. The adjustment information from the setting input unit 40 is a predetermined operation of the discrete input S21 measurement data from the setting input unit 40 on the GUI (Graphical User Interface) display screen displayed on the display unit 60, and the S21 measurement data This is information for giving variation to a certain frequency.
In addition, it is preferable to process in consideration of weighting when taking a moving average in the adjustment process of S21 measurement data.

  In addition, it is not necessary to set arbitrarily settable discrete digital waveform data as the waveform data for calculation. The discrete digital waveform data for calibration stored in the storage unit 32 in advance or time-series waveform data set and adjusted in advance by the user Can also be used as waveform data for computation.

  The waveform prediction processing unit 35 includes an FT processing unit 35a, a filter processing unit 35b, and an IFT processing unit 35c.

  The FT processing unit 35a calculates a spectrum by performing Fourier transform (FT) on the waveform data for calculation, which is time-series data from the setting input unit 40, and uses the calculated spectrum as a calculation spectrum to filter processing unit 35b. Is output.

  The filter processing unit 35b multiplies using the S21 adjustment data from the S21 adjustment processing unit 34 and the calculation spectrum from the FT processing unit 35a and performs a filter process to calculate a predicted waveform spectrum. It is output to the IFT processing means 35c.

  The IFT processing unit 35c obtains predicted waveform data which is a prediction result of the eye waveform by performing an inverse Fourier transform (IFT) process on the predicted waveform spectrum from the filter processing unit 35b and taking a real part thereof. Predicted waveform data is output to the display control unit 50.

  The setting input unit 40 includes a numeric keypad, various operation keys, and a pointing device such as a mouse or a touch panel that operates an image area of a display element displayed on the display screen of the display unit 60. When the user performs an operation for giving variation to the S21 measurement data displayed on the display screen, the setting input unit 40 outputs adjustment information based on the operation content to the S21 adjustment processing unit 34. Specifically, the frequency characteristics are changed by intuitively operating S21 measurement data displayed on a GUI (Graphical User Interface) display screen displayed on the display unit 60.

  In addition, various settings relating to the waveform (Tr / Tf, amplitude, jitter, transition shape, etc.) are performed on the discrete digital waveform data, which is time series data that can be arbitrarily set, by a predetermined operation of the setting input unit 40 by the user. The set time-series waveform data is output to the waveform prediction processing unit 35 as operation waveform data.

  The display control unit 50 is a waveform observation device such as display control of actually measured waveform data based on discrete digital waveform data, display control of line spectrum from the S21 calculation processing unit 33, display control of prediction result contents from the waveform prediction processing unit 35, etc. The display content necessary for driving 1 is controlled on the display screen of the display unit 60.

  Examples of display control include, for example, spectrum display control of S21 measurement data measured as shown in FIG. 2A, spectrum display control of S21 adjustment data arbitrarily adjusted by the user as shown in FIG. As shown in FIG. 2C, waveform display control (eye waveform) of the predicted waveform data predicted based on the S21 adjustment data is performed. By performing such display control, it is possible to visually grasp which component of the measured frequency characteristic has an influence on the waveform observation apparatus 1.

  The display unit 60 is composed of a liquid crystal display, for example, and is controlled by the display control unit 50 to display an actual waveform data based on discrete digital waveform data, a spectrum display of S21 measurement data, a waveform display of predicted waveform data, and the like. Display contents necessary for driving 1 are displayed on the display screen.

<Processing operation>
Next, the processing operation in the waveform observation apparatus 1 according to the first embodiment will be described.

  First, in order to acquire the discrete digital waveform data for calibration used at the time of calculating S21, the pulse pattern generation unit 10 and the waveform observation unit 20 are directly connected without using the device under test 70, and the trigger signal from the pulse pattern generation unit 10 is used. Based on this, the pattern signal generated by the pattern generation means 12 is output. Based on the trigger signal from the pulse pattern generation unit 10, the waveform observation unit 20 samples the input pattern signal and acquires discrete digital waveform data for calibration. The acquired discrete digital waveform data for calibration is stored in the storage unit 32 of the waveform data processing unit 30.

  Next, a test signal is transmitted to the device under test 70, and the signal under measurement input via the device under test 70 is sampled based on the trigger signal from the pulse pattern generator 10 to obtain discrete digital waveform data. And output to the waveform data processing unit 30.

  The waveform data processing unit 30 performs Fourier transform on the discrete digital waveform data from the waveform observation unit 20, calculates its spectrum, and extracts only the line spectrum frequency. Then, the extracted line spectrum is output to the S21 calculation processing unit 33.

  In the S21 calculation processing unit 33, S21 actual measurement data is calculated from the difference between the line spectrum of the discrete digital waveform data and the line spectrum stored in the storage unit 32. Next, the calculated S21 actual measurement data is interpolated into S21 interpolated data, and then smoothed to obtain S21 measurement data, which is output to the S21 adjustment processing unit 34.

  The S21 adjustment processing unit 34, after changing the frequency based on the adjustment information when the user operates the setting input unit 40, calculates the S21 adjustment data by taking the moving average again, and uses the calculated S21 adjustment data as the waveform. The result is output to the prediction processing unit 35.

  The waveform prediction processing unit 35 performs a Fourier transform on the calculation waveform data that is time-series data from the setting input unit 40 to calculate a calculation spectrum. Next, a predicted waveform spectrum is calculated by performing multiplication using the S21 adjustment data from the S21 adjustment processing unit 34 and performing a filter process, and taking the real part by performing an inverse Fourier transform process on the predicted waveform spectrum. Get predicted waveform data.

  Then, prediction is made based on the spectrum of S21 measurement data, which is actually measured values as shown in FIGS. 2A to 2C, the spectrum of S21 adjustment data arbitrarily adjusted by the user via the setting input unit 40, and S21 adjustment data. The waveform of the predicted waveform data is displayed in parallel on the display screen of the display unit 60. Thereby, it is possible to visually grasp which component of the measured S21 characteristic influences the waveform.

[Second form]
Next, the configuration of the waveform observation apparatus 1 according to the second embodiment of the present invention will be described with reference to FIGS. In the waveform observing apparatus 1 of the second embodiment described below, the same constituent elements as those of the waveform observing apparatus 1 of the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. Only will be described.

<Device configuration>
The waveform observation apparatus 1 of the second form is an apparatus form for predicting how the S21 characteristic changes by adjusting the discrete digital waveform data sampled by the waveform observation unit 20, and a configuration for realizing this As a requirement, as shown in FIG. 3, a waveform adjustment processing unit 36, an FT processing unit 37, a spectrum calculation processing unit 38, and an S21 prediction processing unit 39 are provided. In the second embodiment, the trigger signal necessary for waveform observation is adjusted in advance so that the discrete digital waveform data displayed on the display unit 60 becomes an eye waveform.

  The waveform adjustment processing unit 36 rewrites the time-series data so that the discrete digital waveform data stored in the storage unit 32 becomes Tr / Tf set by the user based on the adjustment information from the setting input unit 40, and the rewritten data is rewritten. The waveform adjustment data is output to the FT processing unit 37.

  The adjustment information from the setting input unit 40 is a waveform obtained by performing a predetermined operation on the eye waveform of the discrete digital waveform data actually measured on the display screen of a GUI (Graphical User Interface) displayed on the display unit 60 from the setting input unit 40. This is adjustment information for adjusting the shape to obtain a waveform shape by changing the Tr / Tf of the eye waveform. Note that, when adjusting the waveform shape, it is necessary to adjust the waveform shape to a similar shape, but a similar waveform in a certain range may be partially used.

  The FT processing unit 37 calculates a spectrum by Fourier-transforming the waveform adjustment data from the waveform adjustment processing unit 36 and outputs the calculated spectrum to the spectrum calculation processing unit 38 as a waveform adjustment spectrum. The FT processing unit 37 calculates a spectrum by performing Fourier transform on the discrete digital waveform data stored in the storage unit 32 and outputs the spectrum to the spectrum calculation processing unit 38 as the calculated actual waveform spectrum.

  The spectrum calculation processing unit 38 calculates the difference between the measured waveform spectrum converted by the FT processing unit 37 and the waveform adjustment spectrum, acquires S21 change amount data that is the change amount of S21, and sends it to the S21 prediction processing unit 39. Output.

  The S21 prediction processing unit 39 adds the S21 variation data obtained by the spectrum calculation processing unit 38 to the S21 measurement data obtained by the S21 calculation processing unit 33 to obtain S21 prediction data, and the obtained S21 prediction is obtained. Data is output to the display control unit 50.

  Then, the display control unit 50 controls the waveform display of the measured waveform data based on the discrete digital waveform data sampled by the waveform observation unit 20 as shown in FIG. 4A, for example, and calculates S21 as shown in FIG. 4B. Spectrum display control of S21 measurement data measured by the processing unit 33, and spectrum display control of S21 estimation results based on S21 prediction data obtained by the S21 prediction processing unit 39 are performed as shown in FIG.

<Processing operation>
Next, the processing operation in the waveform observation apparatus 1 of the second embodiment will be described. In the following description, description of processing contents similar to those of the first embodiment is omitted, and only processing operations relating to the present embodiment will be described.

  When the discrete digital waveform data is sampled by the waveform observing unit 20, the waveform adjustment processing unit 36 obtains the discrete digital waveform data so as to be Tr / Tf set by the user based on the adjustment information when the user operates the setting input unit 40. Is rewritten to time-series data to obtain waveform adjustment data. Next, the waveform adjustment data is Fourier transformed and then output to the spectrum calculation processing unit 38. In addition, the discrete digital waveform data before being adjusted by the waveform adjustment processing unit 36 is Fourier-transformed and then output to the spectrum calculation processing unit 38.

  The spectrum calculation processing unit 38 calculates the difference between the actually measured waveform spectrum converted by the FT processing unit 37 and the waveform adjustment spectrum, acquires S21 change amount data that is the change amount of S21, and in the S21 prediction processing unit 39 The S21 variation data is added to the S21 measurement data obtained by the S21 calculation processing unit 33 to obtain S21 prediction data.

  4A to 4C, the waveform of the measured waveform data based on the discrete digital waveform data sampled by the waveform observation unit 20, the spectrum of the S21 measurement data measured by the S21 calculation processing unit 33, and the S21 prediction The spectrum of the S21 estimation result based on the S21 prediction data obtained by the processing unit 39 is displayed in parallel on the display screen of the display unit 60. Thereby, when the eye waveform of the measured discrete digital waveform data is adjusted, it is possible to visually grasp which component of the S21 characteristic affects.

  As described above, the waveform observing apparatus 1 according to the first embodiment described above includes the discrete digital waveform data for calibration and the test device used for the S21 calculation in which the pattern signal directly input from the pulse pattern generator 10 is sampled. Discrete digital waveform data obtained by sampling the signal under measurement input via the signal is acquired and output to the waveform data processing unit 30. In the waveform data processing unit 30, the discrete digital waveform data from the waveform observation unit 20 is Fourier transformed to calculate its spectrum, and only the line spectral frequency is extracted. Then, the S21 calculation processing unit 33 obtains S21 measurement data by performing the calculation of S21, the interpolation process, and the smoothing process from the extracted line spectrum.

  This eliminates the need to prepare a network analyzer each time the S21 characteristic, which is a frequency characteristic, is measured, thereby reducing the measurement cost. In addition, since it has a function of measuring frequency characteristics, it is possible to easily perform frequency characteristic measurement processing and waveform observation processing without routing wiring such as cables associated with connection of new equipment.

  Further, the waveform prediction processing unit 35 filters the S21 measurement data acquired by the S21 calculation processing unit 33 and the calculation spectrum obtained by performing Fourier transform on the calculation waveform data from the setting input unit 40 to predict the predicted waveform. A spectrum is calculated, and the predicted waveform data is obtained by performing an inverse Fourier transform process on the predicted waveform spectrum. Then, the display unit 60 displays the spectrum of S21 measurement data, which is an actual measurement value, the spectrum of S21 adjustment data arbitrarily adjusted by the user via the setting input unit 40, and the waveform of predicted waveform data predicted based on the S21 adjustment data. They are displayed in parallel on the screen.

  As a result, the S21 characteristic before and after adjustment by the user's operation and the predicted waveform data based on the adjusted S21 characteristic are displayed in parallel on the same screen, so that the user can determine which component of the S21 characteristic corresponds to the waveform. It is possible to grasp visually while associating how they affect each other.

  In addition, when the waveform observing device 1 samples the discrete digital waveform data in the waveform observing unit 20, the waveform setting unit 36 sets the user based on the adjustment information when the user operates the setting input unit 40 in the waveform adjustment processing unit 36. Waveform adjustment data is acquired by rewriting discrete digital waveform data to time-series data so as to be Tr / Tf. The waveform adjustment data is Fourier-transformed and then output to the spectrum calculation processing unit 38, and the discrete digital waveform data before being adjusted by the waveform adjustment processing unit 36 is Fourier-transformed and then output to the spectrum calculation processing unit 38. .

  The spectrum calculation processing unit 38 acquires S21 variation data from the actually measured waveform spectrum and the waveform adjustment spectrum, and the S21 prediction processing unit 39 adds the S21 variation data to the S21 measurement data obtained by the S21 calculation processing unit 33. Then, S21 prediction data is acquired. The waveform of the actually measured waveform data based on the actually measured discrete digital waveform data, the spectrum of the S21 measurement data measured by the S21 calculation processing unit 33, and the spectrum of the S21 estimation result based on the S21 prediction data obtained by the S21 prediction processing unit 39 are obtained. They are displayed in parallel on the display screen of the display unit 60.

  As a result, the eye waveform of the discrete digital waveform data adjusted by the user's operation and the S21 characteristics based on the discrete digital waveform data before and after the waveform adjustment are displayed in parallel on the same screen. By adjusting which part of the eye waveform of the discrete digital waveform data is adjusted, which component of the S21 characteristic is affected can be visually grasped.

  By the way, in each form mentioned above, although demonstrated in the example which displays in parallel the display content, such as S21 characteristic displayed on a display screen, prediction waveform data, etc. using FIG. Therefore, the number of display data and the display format can be arbitrarily set.

DESCRIPTION OF SYMBOLS 1 ... Waveform observation apparatus 10 ... Pulse pattern generation part 11 ... Clock generation means 12 ... Pattern generation means 13 ... Trigger generation means 20 ... Waveform observation part 21 ... Sampling means 30 ... Waveform data processing part 31 ... Spectrum extraction part 32 ... Storage part 33 ... S21 calculation processing section (33a ... S21 calculation means 33, 33b ... interpolation processing means, 33c ... smoothing processing means)
34 ... S21 adjustment processing unit 35 ... Waveform prediction processing unit (35a ... FT processing means, 35b ... Filter processing means, 33c ... IFT processing means)
36 ... Waveform adjustment processing unit 37 ... FT processing unit 38 ... Spectrum calculation processing unit 39 ... S21 prediction processing unit 40 ... Setting input unit 50 ... Display control unit 60 ... Display unit 70 ... Device under test

Claims (6)

A pulse pattern generator (10) for outputting an arbitrary pattern signal having a periodic waveform and a trigger signal synchronized with the pattern signal;
A waveform observing section (20) for sampling a signal under measurement based on a pattern signal from the pulse pattern generating section according to a trigger signal from the pulse pattern generating section to obtain discrete digital waveform data as time series data;
A waveform observation apparatus (1) comprising:
A spectrum extraction unit (31) for performing Fourier transform on the discrete digital waveform data from the waveform observation unit and extracting only its line spectral frequency;
A storage unit (32) for storing at least the calibration line spectrum extracted from the calibration discrete digital waveform data obtained by the waveform observation unit by the spectrum extraction unit;
From the difference between the line spectrum in the discrete digital waveform data of the signal under measurement input via the device under test (70) and the harmonic line spectrum of the fundamental wave extracted from the calibration line spectrum stored in the storage unit. An S21 calculation processing unit (33) for outputting S21 measurement data obtained by performing smoothing after interpolating the obtained S21 actual measurement data;
A display control unit (50) for spectrum-displaying the S21 measurement data from the S21 calculation processing unit on a display unit (60);
A waveform observation apparatus characterized by comprising: Furthermore, a setting input unit (40) for outputting adjustment information based on the operation content when giving variation to the S21 measurement data;
An S21 adjustment processing unit (34) that outputs the S21 adjustment data obtained by calculating the moving average again after changing the frequency of the S21 measurement data based on the adjustment information from the setting input unit;
The calculation spectrum obtained by performing Fourier transform on the discrete digital waveform data for calibration stored in the storage unit (32) or arbitrarily set time-series waveform data, and the S21 adjustment data from the S21 adjustment processing unit A waveform prediction processing unit (35) that performs inverse Fourier transform on the predicted waveform spectrum obtained by performing the filter processing by multiplication using
Under the control of the display control unit (50), the spectrum of the S21 measurement data, the spectrum of the S21 adjustment data, and the waveform of the predicted waveform data are displayed in parallel on the display screen of the display unit (60). The waveform observation apparatus according to claim 1. Furthermore, a setting input unit (40) for outputting adjustment information based on the operation content when adjusting the waveform shape of the discrete digital waveform data sampled by the waveform observation unit (20);
A waveform adjustment processing unit (36) for outputting waveform adjustment data obtained by rewriting the discrete digital waveform data sampled by the waveform observation unit so as to be Tr / Tf based on adjustment information from the setting input unit;
FT processing for outputting a waveform adjustment spectrum obtained by Fourier transforming the waveform adjustment data from the waveform adjustment processing unit and an actually measured waveform spectrum obtained by Fourier transforming the discrete digital waveform data stored in the storage unit Part (37);
A spectrum calculation processing unit (38) for outputting S21 variation data obtained by calculating a difference between the measured waveform spectrum Fourier-transformed by the FT processing unit and the waveform adjustment spectrum;
An S21 prediction processing unit (39) for adding the S21 variation data obtained by the spectrum calculation processing unit to the S21 measurement data obtained by the S21 calculation processing unit (33), and outputting the result as S21 prediction data;
Under the control of the display control unit (40), the waveform of the measured waveform data based on the discrete digital waveform data sampled by the waveform observation unit, the spectrum of the S21 measurement data, and the spectrum of the S21 estimation result based on the S21 prediction data are obtained. The waveform observation apparatus according to claim 1, wherein the waveform observation apparatus performs parallel display on a display screen of the display unit (60). A pulse pattern generation step for outputting an arbitrary pattern signal which is a periodic waveform and a trigger signal synchronized with the pattern signal;
A waveform observation step of sampling the signal under measurement based on the pattern signal from the pulse pattern generation step according to the trigger signal from the pulse pattern generation step to obtain discrete digital waveform data which is time-series data;
A waveform observation method comprising:
A spectral extraction step of Fourier transforming the discrete digital waveform data from the waveform observation step to extract only its line spectral frequency;
A storage step for storing at least the calibration line spectrum extracted in the spectrum extraction step from the calibration discrete digital waveform data obtained in the waveform observation step;
Obtained by subtracting the harmonic line spectrum of the fundamental wave extracted from the line spectrum of the discrete digital waveform data in the signal under measurement input via the device under test (70) and the calibration line spectrum stored in the storing step. S21 calculation processing step for outputting S21 measurement data obtained by performing smoothing processing after interpolating S21 actual measurement data;
A display control step of displaying the S21 measurement data from the 21 calculation processing step on the display unit (60) as a spectrum;
The waveform observation method characterized by having. Furthermore, a setting input step for outputting adjustment information based on the operation content when giving variation to the S21 measurement data;
An S21 adjustment processing step of outputting S21 adjustment data calculated by taking a moving average again after changing the frequency of the S21 measurement data based on the adjustment information from the setting input step;
Using the calibration discrete digital waveform data stored in the storing step or arbitrarily set time-series waveform data by Fourier transform and the S21 adjustment data from the S21 adjustment processing step. A waveform prediction processing step for performing inverse Fourier transform on the predicted waveform spectrum obtained by performing the filter processing by multiplication, and outputting the result as predicted waveform data;
A display control step of displaying the spectrum of the S21 measurement data, the spectrum of the S21 adjustment data, and the waveform of the predicted waveform data in parallel on the display screen of the display unit (60);
The waveform observation method according to claim 4, further comprising: Furthermore, a setting input step for outputting adjustment information based on the operation content when adjusting the waveform shape of the discrete digital waveform data sampled in the waveform observation step;
A waveform adjustment processing step of rewriting the discrete digital waveform data sampled in the waveform observation step so as to be Tr / Tf based on the adjustment information from the setting input step and outputting as waveform adjustment data;
A waveform adjustment spectrum obtained by Fourier transforming the waveform adjustment data from the waveform adjustment processing step and an actual measurement waveform spectrum obtained by Fourier transforming the discrete digital waveform data stored in the storage unit (32) are output. FT processing steps to
A spectrum calculation processing step of outputting S21 variation data obtained by calculating a difference between the measured waveform spectrum Fourier-transformed in the FT processing step and the waveform adjustment spectrum;
An S21 prediction processing step of adding the S21 variation data obtained in the spectrum calculation processing step to the S21 measurement data obtained in the S21 calculation processing step, and outputting the result as S21 prediction data;
The waveform of the measured waveform data based on the discrete digital waveform data sampled in the waveform observation step, the spectrum of the S21 measurement data, and the spectrum of the S21 estimation result based on the S21 prediction data are displayed on the display screen of the display unit (60). A display control step for displaying in parallel;
The waveform observation method according to claim 4, further comprising:

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