JP5177796B2 - Waveform display device - Google Patents

Description

  The present invention relates to a waveform display device that reads out a plurality of waveform data obtained by capturing an input signal at a predetermined trigger cycle and stores it, and displays each history in a comparative manner.

  A waveform display device typified by a digital oscilloscope measures the waveform of an input signal for each trigger and captures and stores the measured waveform data in a memory. A record number of 0 to n-1 is assigned to those that have been performed n times. When referring to the history of specific waveform data, a record number is designated or specific data is called up and displayed using a search with a designated condition.

  FIG. 11 is an example of a display screen of a conventional waveform display device that reads a plurality of waveform data and displays each history in a comparative manner, and shows a case where a plurality of records are superimposed and displayed in the same area of the screen. .

JP 2007-0573303 A JP 2000-147017 A

The conventional history display method has the following problems.
(1) As the amount of history increases, visual monitoring on the waveform display screen and confirmation of abnormal records become difficult. There is a high possibility that the amount of history will continue to increase due to technological trends.

(2) There are various searches for history (see Patent Document 1), but it is difficult to perform an appropriate search because an unknown waveform is desired in the first place. That is, if the symptom cannot be specified, an appropriate search cannot be performed.

  The present invention has been made to solve the above-described problems, and an object thereof is to realize a waveform display device with improved history searchability and visibility.

In order to achieve such a subject, the present invention has the following configuration.
(1) In a waveform display device that reads a plurality of waveform data obtained by capturing an input signal at a predetermined trigger cycle and displays each history in comparison,
The plurality of waveform data with respect to the time axis are displayed in two-dimensional coordinates, and the maximum value and the minimum value of the physical values of the plurality of waveform data are equally allocated to be divided into a plurality of sections. And a waveform display device that displays in correspondence with color or monochrome gradients that are independent and visually continuous .

(2) The waveform display device according to (1), wherein the waveform of the input signal and the physical quantities of the plurality of waveform data are displayed on the same screen on the same time axis.

( 3 ) When there are n measurement values corresponding to one point on the display, the value A (maximum value−median value) is obtained from the median value, maximum value, and minimum value obtained from these n measurement values. And the value B (median value−minimum value). When A> B, the maximum value is the representative value of the one point, and when A <B, the minimum value is the representative value of the one point. In the case of = B, the waveform display device according to (1) or (2), wherein the maximum value or the minimum value is set as the representative value of the one point.

( 4 ) When there are n measurement values corresponding to one point on the display, the time axis resolution is halved and one point on the display is displayed at two points, and the center is greater than the 2n measurement values. The waveform display device according to (1) or (2) , wherein a value and a representative value are obtained and displayed as a set of a median value and a representative value at two points on the display.

( 5 ) The waveform display device according to any one of (1) to ( 4) , wherein the waveform data obtained by differentiating a physical value of the waveform data is displayed.

According to the configuration of the present invention, the following effects can be expected.
(1) A history of several hundred records can be displayed as a list in a form of data display by plane.

(2) Compared to the conventional search function, a complicated search operation is unnecessary, and there is an advantage that an unknown phenomenon (= difficult search) can be intuitively searched.

(3) By developing three dimensions (time on the X-axis, physical value (voltage) on the color, and record on the Y-axis), it is difficult to recognize in the conventional display form, and the generation tendency of the noise Drift tendency can be easily recognized.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram showing an embodiment of a waveform display device to which the present invention is applied. The waveform capture unit 1 measures the waveform of the input signal for each trigger, passes it to the waveform data storage unit (memory), and stores it with a record number.

  The display management unit 3 reads a plurality of waveform data records stored in the waveform data storage unit 2, assigns colors to physical values of the data by the color conversion means 100, and records each record to the history display unit 4 in a two-dimensional manner. Display them side by side. In addition, there is a technical disclosure in Patent Document 2 regarding a technique for assigning colors to physical values and displaying them.

  FIG. 2 shows an example of a display screen of a waveform display device to which the present invention is applied, which reads a plurality of waveform data and displays their respective histories in comparison. FIG. 2A is a waveform diagram of an input signal exemplified by a sawtooth wave. In FIG. 2B, the time axis is taken as the X axis, the record number is taken as the Y axis, and the physical values of the data are displayed two-dimensionally in correspondence with the colors.

A color between the maximum value V _H and the minimum value V _L of the physical value of the waveform data is evenly allocated and divided into a plurality of sections, and the colors are independent and visually continuous for each section (red → blue). Or, display in correspondence with monochrome gradient (white → black).

  FIG. 3 shows another display screen example of the waveform display device to which the present invention is applied. In this screen, a rectangular wave input signal waveform is displayed on the upper screen (A), and the history is displayed on the lower screen (B). Note that the display of the input signal waveform in the upper part of the screen is selective, and it is not always necessary to display it simultaneously.

  FIG. 4 is a flowchart showing the color determination and drawing procedure. In step S1, the maximum value and the minimum value of the voltage are obtained from all records of the display target channel.

  In step S2, the maximum value and the minimum value are equally allocated to be divided into a plurality of sections, and color or monochrome gradients that are independent and visually continuous with respect to each section are made to correspond.

  In step S3, the magnitude of the value is converted into a color or gradient and rendered with one record and one line. The drawing end of all records is checked in step S4. If not finished, the drawing position is lowered by one line in step S5 and step S3 is executed. If drawing of all records is completed, the drawing process is ended in step S5.

  FIG. 5 is a flowchart showing a procedure for determining a representative value when a plurality of measurement values (samples) are included in one point (1 dot) on the display. FIG. 5A shows a waveform example having n measurement values corresponding to one point on the display, and shows a maximum value, a minimum value, a median value, an average value, and a mode value.

  The flowchart in FIG. 5B shows a procedure for determining a representative value using the maximum value, the minimum value, and the median value. In the case where n is relatively small, when there are n measurement values corresponding to one point on the display in step S1, the median, maximum value, and minimum value are obtained from these n measurement values in step S2. .

  In step S3, the value A is obtained from (maximum value−median value), and the value B is obtained from (median value−minimum value). In step S4, the value A and the value B are compared.

  If A> B, the maximum value is set as the representative value of the one point in step S5. If A <B, the minimum value is set as the representative value of the one point in step S6. In the case of A = B, the maximum value or the minimum value is set as the representative value of the one point in step S7 according to the design policy.

  When n is extremely large, the time axis display resolution is halved and one point on the display is displayed as two points. In step S8, the median value and the representative value are obtained from 2n measured values, and displayed in step S9. A pair of median and representative value is displayed at the upper two points.

  FIG. 6 is an image diagram for explaining one-record, one-line conversion drawn in the processing procedure of FIGS. 6A to 6D show one-line history displays corresponding to the respective signal waveforms of record numbers No. 0 to No.-3.

  Pulse number noise P is superimposed on the waveform of record number No.-2, but this noise is displayed as a red dot with contrast in blue in the history display, so it is easy to see. It is.

  FIG. 7 is an example of a screen showing a history display of waveforms including noise according to color. In a record including noise, a dot having a color having a contrast is displayed at the noise generation points P, Q, and R, so that the history of all data and the state of noise generation can be grasped at a glance.

  FIG. 8 is an example of a screen showing the frequency drift of the input signal. By visually recognizing that the continuous period of the color display pattern changes, it is possible to intuitively understand whether the frequency of the input signal is drifting in the high direction or the low direction.

  FIG. 9 is a screen example illustrating a method for extracting a record including noise. On the history display screen, a record containing noise and its surrounding records are selected by surrounding them with box-shaped cursors (A) and (B), and the waveform of the selected record is displayed in another window to observe the noise waveform and Cause analysis can be performed. The cursor can be moved in conjunction with the conventional record number operation.

  FIG. 10 shows an example of a history display screen in which the physical value of each record is differentiated and displayed. FIG. 10A shows a case where positive direction noise P and negative direction noise Q are superimposed on the signal waveform.

  When the ratio of the noise level to the signal waveform level is low, in the display in which the signal waveform level corresponds to the color as shown in FIG. Visibility may be reduced.

  FIG. 10C shows a history display of the waveform data obtained by differentiating the physical value of the waveform data. When the signal waveform is a sawtooth waveform, the history has the same color in a section where the rate of change of the waveform is constant, so that it is possible to improve the visibility by increasing the contrast of the noise occurrence location. The differential operation has a relatively light calculation load and can be realized without difficulty even in an embedded device.

  As described above, in the present invention characterized by a plane history display, there are cases where it is not possible to display on one screen when the number of records to be displayed increases, but this can be easily dealt with by scrolling the screen Y axis.

  FIG. 5 shows a general procedure for determining a representative value. However, depending on the calculation of the representative value, various characteristics of the waveform can be selectively expressed as a history.

It is a functional block diagram which shows one Embodiment of the waveform display apparatus to which this invention is applied. It is an example of a display screen of the waveform display device to which the present invention is applied. It is another example of a display screen of the waveform display device to which the present invention is applied. It is a flowchart which shows the determination of a color, and a drawing procedure. It is a flowchart which shows the determination procedure of the representative value in case a some point on a display contains a some sample. It is an image figure explaining 1 record 1 line conversion. It is an example of a screen which shows the display according to the color of the history of the waveform containing noise. It is an example of a screen which shows the frequency drift of an input signal. It is an example of a screen explaining the extraction method of the record containing noise. It is the example of a display screen of the history which displayed the physical value of each record by differentiation. It is an example of the display screen of the conventional waveform display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Waveform acquisition part 2 Waveform data storage part 3 Display management part 4 History display part 100 Color conversion means

Claims (5)

In a waveform display device that reads a plurality of waveform data that is acquired by storing an input signal at a predetermined trigger cycle and displays each history in comparison,
The plurality of waveform data with respect to the time axis are displayed in two-dimensional coordinates, and the maximum value and the minimum value of the physical values of the plurality of waveform data are equally allocated to be divided into a plurality of sections. And a waveform display device that displays in correspondence with color or monochrome gradients that are independent and visually continuous . The waveform display apparatus according to claim 1, wherein the waveform of the input signal and the physical quantities of the plurality of waveform data are displayed on the same screen on the same time axis. When there are n measurement values corresponding to one point on the display, a value A (maximum value−median value) and a value B are obtained from the median value, maximum value, and minimum value obtained from these n measurement values. (Median value−minimum value) is obtained. When A> B, the maximum value is the representative value of the one point, and when A <B, the minimum value is the representative value of the one point, and A = B. case, the waveform display apparatus according to the maximum or minimum value to claim 1 or 2, characterized in that a representative value of said one point. When there are n measured values corresponding to one point on the display, the time axis resolution is halved and one point on the display is displayed as two points, and the median and representative are represented by 2n measured values. 3. The waveform display device according to claim 1, wherein a value is obtained and displayed as a set of a median value and a representative value at two points on the display. Waveform display device according to any one of claims 1 to 4, characterized in that displaying the waveform data obtained by differential operation of the physical value of the waveform data.