JP3669312B2 - Waveform display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waveform display device such as a digital oscilloscope, and more particularly to a waveform display device that selects and displays desired waveform data from a large number of waveform data.
[0002]
[Prior art]
Recent digital oscilloscopes have been devised so that an observer can easily grasp the characteristics of an input analog signal by synthesizing a large number of waveform display data while having a high waveform capturing speed.
For example, there is a persistence display method for performing display similar to the afterglow characteristics of an analog oscilloscope. In this method, the latest signal waveform is displayed with the highest luminance in time order, and the older signal waveform is displayed with a lower luminance. As a result, temporal conversion of the input analog signal can be easily understood.
[0003]
As another example, there is a frequency display method subjected to statistical processing. In this frequency display method, a large number of waveform display data is accumulated in units of display pixels, and brightness or color is assigned and displayed according to frequency information in units of pixels. This makes it easier to obtain a more statistical understanding of the input analog signal.
[0004]
[Problems to be solved by the invention]
In such an oscilloscope, for example, when it is desired to observe a rare waveform such as an abnormal waveform in order to analyze a malfunction of a circuit, the following problem occurs.
Normally, the observer cannot identify in advance what the abnormal waveform is like, and initially waits for the appearance of the abnormal waveform while capturing under a simple trigger condition. If an abnormal waveform is detected during waveform observation, the observer immediately presses down the STOP key to freeze the display screen.
[0005]
However, most of the rare abnormal waveforms are already buried in the normal waveform. This makes subsequent analysis difficult. Therefore, the observer again sets special trigger conditions again and gradually approaches the details of the abnormal waveform.
Such a method is time consuming and laborious and is not an efficient observation method.
[0006]
Some conventional digital oscilloscopes can display past waveform data one waveform at a time. However, such an apparatus requires a lot of time and operation to retrieve desired waveform data from a large number of waveform display data. For example, when searching for desired waveform data from the past 1,000 times of waveform data, if the observer performs a search while displaying one waveform data at a time per second in order, the search time will be as short as 16 minutes or more. .
[0007]
In order to solve the above problems, a new means for efficiently searching for a single waveform from a large number of display waveforms is required.
An object of the present invention is to provide a waveform display device and a waveform display method that can easily and quickly search and display single waveform data desired by an observer.
[0008]
[Means for Solving the Problems]
In the waveform display device of the present invention, an input analog signal is converted into time-series data quantized by an analog-digital (AD) converter, and the time-series data is temporarily stored as waveform data in a capture memory. A predetermined number of waveform data stored in the capture memory is converted into a bitmap format by a waveform processor to create image data, which is stored in the image memory. Display data is created from a plurality of stored image data by a display processor and displayed on a display device.
[0009]
In the display device, the waveform processor identifies a part of the image data selected from the plurality of image data in response to an operation of the input means, and sets time series data constituting the image data as new Redistributing into a plurality of image data, the display processor creates display data from the redistributed image data.
[0010]
When using the waveform display device, the observer waits for a desired waveform to appear on the display device. When the display data including the desired waveform is found, the STOP key is pressed to stop updating the waveform data. Then, by operating the input means, a plurality of image data stored in the image memory are sequentially scroll-displayed, and image data including a desired waveform is selected. Then, since the waveform data constituting the selected image data is redistributed into a plurality of image data, the observer scrolls the waveform data by operating the input means, and finally displays a desired single waveform. Can be displayed.
[0011]
In this way, image data including desired waveform data is selected from a plurality of image data created by dividing a large number of waveform data into a predetermined number, and the selected image data is selected. Desired single waveform data can be obtained. Accordingly, it is not necessary to sequentially scroll all waveform data as in the prior art, and by simply scrolling a predetermined number of image data, a desired waveform can be selected and displayed from a large number of input waveforms in a short time. it can.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a circuit configuration of the waveform display device. However, portions of the waveform display device that are not directly related to the present invention are omitted. FIG. 2 is a diagram showing waveforms processed by the circuit of FIG.
[0013]
The analog input signal is converted into quantized time series data by the AD converter 1. The time-series data from the AD converter 1 is once stored in the capture memory 2 as waveform data via the capture control circuit 12 when a trigger condition is established (not shown). The capture memory 2 is divided into a plurality of segments so as to store a plurality of waveform data groups W1 to Wn, Wn + 1 to Wm (FIG. 2).
When the AD converter 1 has a resolution of 8 bits, the memory length of one waveform data is 1 k words, and a 16 Mbit memory is used for the capture memory 2, 2 k pieces of waveform data can be stored.
[0014]
The waveform processor 3 sequentially reads out the waveform data from the capture memory 2, rasterizes it, creates image data P0, P1,... P15 in a bitmap format and stores them in the image memory 4.
The image memory 4 is divided into a plurality of segments so as to store a plurality of image data P0, P1,... P15. The image data P0 is generated by combining a plurality of waveform data W1 to Wn, and P1 is generated by combining Wn + 1 to Wm. However, the image data P0 may be generated using only single waveform data.
[0015]
The display processor 5 reads a plurality of image data P0, P1,... P15 from the image memory 4, weights them, and creates display data D. The display data D is displayed on the display device 6. The display processor 5 has a weighting circuit 9 and a color data conversion circuit 10.
The waveform processor 3 and the display processor 5 can be realized by hardware or software (processing by a microprocessor).
For the display device 6, a general color TFT-LCD is used.
[0016]
The input means 8 can also be used as a brightness adjustment knob arranged on the front panel. As this input means 8, a rotary encoder with a push switch is used. Control information input by the observer's operation of the input means 8 is transmitted to the control means 7 constituted by a microprocessor or the like, and controls the waveform processor 3 and the display processor 5.
[0017]
Next, the components of the circuit shown in FIG. 1 will be described.
First, the operation of the waveform processor 3 will be described.
When new waveform data W1 to Wn are written in the capture memory 2, the waveform processor 3 sequentially reads the waveform data W1 to Wn and converts them into a bitmap format to be a display image by rasterization processing. During a predetermined time, the waveform data W1 to Wn are accumulated to create one image data P0. When a predetermined time elapses, the image data P0 is written into a divided area (hereinafter referred to as a segment) of the image memory 4, and accumulation of the next image data P1 is started from the next waveform data Wn + 1 to Wm.
[0018]
Strictly speaking, when accumulating a plurality of waveform data W1 to Wn in one image data P0, it is desirable to accumulatively count the pixels of each waveform data. However, in consideration of the data processing amount or cost, the pixels of the image data Can be expressed by a predetermined number of bits. In addition, it is possible to simplify and express to the minimum 1 bit (OR writing of pixels).
In the persistence display (or frequency display) of a general digital oscilloscope, the observer sets the persistence time and the like by operating a knob (not shown) provided on the front surface of the panel.
[0019]
When the display processor 5 reads out 16 pieces of image data and synthesizes one display data, the waveform processor 3 creates image data P0 to P15 for each time obtained by dividing the persistence time by 16. For example, if the persistence time is set to 8 seconds, the waveform data for 500 milliseconds is stored in one image data P. When the persistence time has passed, the latest image data P is overwritten in the area of the image data P written first.
[0020]
Next, the operation of the display processor 5 will be described. The display processor 5 reads the image data P0 to P15 stored in each segment from the image memory 4 respectively. Next, the weighting circuit 9 creates composite data for each pixel, and the color data conversion circuit 10 creates display data D.
[0021]
The observer can control the brightness of the entire waveform display on the display device 6 by rotating the knob of the input means 8 to increase or decrease the weighting coefficient.
The weighting coefficient will be described with reference to FIG.
FIG. 3 shows an example of time-ordered weighting factors as used in the persistence display. In this example, the largest weighting coefficient is assigned to the latest image data P15 in time order, and the smallest weighting coefficient is assigned to the oldest image data P0. By setting the luminance according to each weighting factor, the latest waveform is bright and the old waveform is displayed dark, and the persistence display in which the old waveform gradually becomes dark can be realized.
[0022]
Next, means for emphasizing and displaying a specific segment of the image data D will be described.
When the observer pushes the knob of the input means 8 once, the mode is switched to a mode in which a specific segment of the image data is highlighted (hereinafter referred to as “inspection mode”).
[0023]
FIG. 4 shows an example of the weighting coefficient when the image data P2 is highlighted in the inspection mode. Here, a predetermined weighting coefficient is assigned to the image data P2, and the other weighting coefficients of the image data P0, P1, P3 to P15 are set to zero. Thereby, only the image data P2 is displayed, and other image data is not displayed.
[0024]
In this state, the image data to which the weighting coefficient is given is changed by turning the knob of the input unit 8. Thereby, the image data stored in the segments of the image memory 4 can be sequentially switched, and the displayed image data can be scrolled in the range of P0 to P15.
At this time, an indicator as shown in FIG. 5 is displayed on a part of the screen. With this indicator, the observer can visually confirm the position of the segment of the image data P0 to P15 currently displayed.
[0025]
FIG. 4 shows an example in which only the single image data P2 is displayed, but modifications such as adding weighting coefficients to the image data P1 and P3 before and after that are possible. In this way, when the observer scrolls the image data, the brightness of the desired waveform gradually increases as it approaches the segment containing the desired waveform data, and the brightness gradually decreases as it moves away from this segment. become. For this reason, the effect that a search becomes easy visually can be expected.
[0026]
The procedure for searching for desired waveform data from the synthesized image data will be described with reference to FIG.
When the observer pushes the knob of the input means 8 once, the inspection mode is entered, and the process of FIG. 6 is started.
[0027]
First, an inspection mode is set (step S1).
Here, the correlation between the segment number of the image memory 4 and the segment number of the capture memory 2 shown in FIG. In the capture memory 2 and the image memory 4, segment numbers are assigned to the respective divided areas, and waveform data and image data are stored in that order. The waveform processor 3 holds the first segment number of the capture memory 2 corresponding to each segment of the image memory 4.
[0028]
The observer rotates the knob of the input means 8 to scroll the image data P0 to P15 (step S2). Thereby, the observer can visually exclude unnecessary image data and display image data including desired waveform data.
[0029]
Next, a segment of image data is selected by pushing the knob of the input means 8 again while displaying image data including desired waveform data (step S3).
In accordance with the contents shown in FIG. 7, the waveform processor 3 reads the original waveform data (waveform data constituting the selected segment) W from the capture memory 2 corresponding to the selected segment, and re-rasterizes it to generate an image. Each segment of the memory 4 is divided and stored (redistributed) (step S4).
The image data P stored in the image memory 4 is displayed on the display device 6 by the display processor 5.
[0030]
When the area of the image memory 4 is divided into 16 segments, if the image data per segment is initially composed of 64 waveform data, 64 waveform data W are obtained by redistribution. It is divided into 16 segments and stored. Therefore, the number of waveform data of one segment after redistribution is reduced to 4 of 1/16 of 64.
[0031]
In step S5, it is determined whether the waveform data stored in one segment of the image memory 4 is single data or composite data. In the above example, since synthesis of four waveform data is stored in one segment, the process returns to step S2.
The observer again scrolls the image data in step S2, and selects a segment in step S3.
[0032]
In step S4, the original waveform data W corresponding to the selected segment is read from the capture memory 2, and the re-rasterized image data P is divided into segments of the image memory 4 and stored. In the above example, single image data P is stored in each of the four segments. In this case, next, the process proceeds from step S5 to step S6.
[0033]
When the observer rotates the knob of the input means 8, the image data P is scrolled (step S6), and desired single waveform data is selected (step S7). The observer performs analysis by looking at the waveform (single waveform) displayed on the display device 6.
When the analysis is finished and the observer pushes the knob of the input means 8, the inspection mode is canceled (step S8). Thus, even when returning from the inspection mode to the normal waveform display state, it can be easily recovered by controlling the input means 8.
[0034]
The processing of FIG. 6 will be described using waveforms.
When the display waveform is stopped in a state in which the input analog signal or the like shown in FIGS. 8A to 8E is taken in, the display screen is usually as shown in FIG. 9A or 9B. Waveform is displayed. Here, (a) is a waveform in the case of frequency display, pixels that appear with high frequency are expressed with high luminance, and pixels with low frequency are expressed with low luminance. Alternatively, the color may be represented by a different color instead of the brightness level. (B) is a waveform in the case of persistence display. A waveform that newly appears in time is displayed with high luminance, and an old waveform is displayed with low luminance.
[0035]
When the desired waveform is a waveform in which the two pulses of FIG. 8C are continuous, unnecessary image data is eliminated by sequentially displaying the image data in the above-described steps S2 to S4. A display including a desired waveform as shown in FIG.
Furthermore, the desired single waveform shown in FIG. 8C can be finally reached by the procedure of steps S6 and S7.
[0036]
As described above, in this embodiment, the observer can search for desired waveform data by sequentially selecting the segment to which the desired waveform data belongs by only operating the single input means 8. it can. As a result, it is possible to search for a desired single waveform data in a sufficiently short time compared with the conventional case of scrolling for each waveform data.
[0037]
The embodiments of the present invention have been described above. The present invention is not limited to the embodiment described above, and can be modified as follows, for example.
In the above embodiment, the image memory 4 is divided into a plurality of segments so that the image data can be scrolled at a high speed in accordance with the rotation of the knob of the input means 8, and the image data is stored in advance in each segment. did. On the other hand, without dividing the image memory 4, image data is sequentially recreated by the operation of the waveform processor 3 in accordance with the operation of the input means 8, and as a result, scrolling of the image data can be realized. Is possible.
[0038]
In the above embodiment, the existing brightness adjustment knob is used as the input means 8. On the other hand, other existing knobs arranged on the front panel of the apparatus may be used. Further, a selection knob may be newly provided.
[0039]
【The invention's effect】
According to the present invention, when an observer operates only a single input means, a desired single waveform data can be searched and displayed from a large number of display waveforms at high speed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a circuit configuration of a waveform display device to which the present invention is applied.
FIG. 2 is a diagram showing waveforms in FIG.
FIG. 3 is a diagram illustrating a weighting coefficient.
4 is a diagram showing an example of assigning weighting coefficients in the waveform display circuit of FIG. 1; FIG.
FIG. 5 is a diagram showing an indicator displayed in the inspection mode in the waveform display circuit of FIG. 1;
6 is a diagram showing a search flow of waveform data in the waveform display circuit of FIG. 1; FIG.
7 is a diagram illustrating a correspondence relationship between an image memory and a capture memory in the waveform display circuit of FIG. 1;
FIG. 8 is an example of waveform data in the waveform display circuit of FIG. 1;
FIG. 9 is an example of waveform display in the waveform display circuit of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... AD converter 2 ... Capture memory 3 ... Waveform processor 4 ... Image memory 5 ... Display processor 6 ... Display apparatus 7 ... Control means 8 ... Input means 9 ... Weighting circuit 10 ... Color data conversion circuit 11 ... Indicator 12 ... Capture control circuit

Claims (4)

An analog-digital converter that converts the input analog signal into quantized time-series data;
Capture memory that stores time-series data as waveform data;
A waveform processor that sequentially converts the waveform data stored in the capture memory into a bitmap format to create image data;
An image memory for storing a plurality of the image data;
A display processor that creates display data by combining a plurality of image data in the image memory;
A display device for displaying display data;
In the waveform display device having
Comprising input means;
The waveform processor identifies a part of the image data selected from the plurality of image data in accordance with the operation of the input means, and reconfigures the waveform data constituting the image data into a plurality of new image data. Distribute and store in the image memory ,
The display processor creates display data from the plurality of redistributed image data;
A waveform display device characterized by the above.   The waveform display device according to claim 1, wherein the image memory is divided into a plurality of segments, and the display processor sequentially displays display data for each of the plurality of segments in accordance with an operation of the input unit. The input analog signal is quantized and converted to time series data,
Time series data is stored in the capture memory as waveform data,
Image data is created by sequentially converting the waveform data stored in the capture memory into bitmap format,
Store multiple image data in the image memory,
Display data is created by combining multiple image data in this image memory,
In the waveform display method for displaying the display data on a display device,
In response to the operation of the input means, a part of the image data selected from the plurality of image data is identified, and the waveform data constituting the image data is redistributed to a plurality of new image data, and the image memory Remember
Creating display data from the plurality of redistributed image data;
Waveform display method characterized by the above.   The waveform display method according to claim 3, wherein the image memory is divided into a plurality of segments, and display data for each of the plurality of segments is sequentially displayed according to an operation of the input unit.

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