JP2011038982A - Waveform-measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waveform-measuring device, capable of measuring at a time a logic level of overall serial data, by solving the problems wherein, in a waveform measuring device for displaying a waveform and a cursor on a screen, moving the cursor to a measuring point, and measuring a logic level at the position, in order to measure the logic level of serial data, the cursor is required to be moved many times, and when the same logic level continues, the measuring point becomes unclear and makes alignment of the cursor difficult. <P>SOLUTION: In the waveform-measuring device, a plurality of cursors having equal intervals, and having the number corresponding to the number of bits of serial data to be measured are displayed, and each interval between the cursors is adjusted corresponding to a bit rate of the serial data, and the cursors are moved, while keeping each interval, and a head cursor is aligned to a start bit of the serial data, and the logic level at each cursor position is measured. Logic levels of all the bits of the serial data can be measured in one sitting, by aligning the head cursor to the start bit and by adjusting the interval. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a waveform measuring apparatus that displays a waveform and measures its level, and more particularly to a waveform measuring apparatus that is suitable for use in serial data measurement.

  By displaying a signal waveform and specifying a part of the waveform with a cursor, the amplitude, period, or signal logic level is measured. Patent Document 1 describes an invention of a waveform display device used for such measurement. The outline of the present invention will be described below with reference to FIGS.

  FIG. 3 is a block diagram of the waveform display device. In FIG. 3, waveform data is stored in the memory 10. Further, the threshold value setting means 11 sets a threshold value for determining the logic level.

  The data processing unit 12 includes an amplitude value calculation unit 13 and a comparison unit 14. The amplitude value calculation means 13 reads the waveform data from the memory 10 and calculates the amplitude of the waveform at the position specified by the cursor. The comparison means 14 compares this amplitude with the threshold value set by the threshold value setting means 11, binarizes the amplitude, and converts it to a logic level.

  The display processing unit 15 includes a result display unit 16 and displays the amplitude value calculated by the amplitude calculation unit 13 and the binarized data by the comparison unit 14 on the display unit 17.

  A cursor for designating a measurement point is displayed on the display unit 17 by the display processing unit 15. The cursor can move the screen of the display unit left and right by a moving means (not shown).

  Next, the procedure of logic level measurement will be described with reference to FIG. In FIG. 4, 20 is a displayed waveform, 21 is a threshold set by the threshold setting means 11, and 22 and 23 are cursors. When the cursors 22 and 23 are moved to a point where the logic level is to be measured, the logic level at that point is displayed.

  The lower left of FIG. 4 shows the measured values, the threshold value (Vth) is 1.65 V, and the voltages at the positions of the cursors 22 and 23 are 1.6 V and 3.0 V, respectively. Since the threshold value is 1.65 V, it is determined that the logic level at the point designated by the cursor 22 (Y1) is “L” and the logic level at the point designated by the cursor point 23 (Y2) is “H”.

JP 2006-177893 A

  However, such a waveform display device has a problem that the operation becomes complicated when measuring the logic level of serial data. This will be described with reference to FIG.

  In FIG. 5, 24 is the displayed serial data, and 25 and 26 are cursors for designating measurement points. The serial data is a signal that continues from the data bit of bit 13 (b13) to bit 0 (b0) with the start bit (Stb) at the high level at the head and ends with the stop bit (Spb) at the low level.

  In order to measure the logic level of such serial data, the cursor 25 is first positioned at the start bit position, the logic level is measured, and the cursor 25 is sequentially shifted by a time corresponding to the bit rate of the serial data. Measure the level.

  However, since the cursor must be moved many times, the operation becomes complicated, and when the same level continues from bit 7 (b7) to bit 3 (b3), the bit position is specified and the cursor is positioned. There was a problem that it was difficult.

  A measuring instrument having a function of analyzing a UART (Universal Asynchronous Receiver Transmitter) signal is commercially available. When this measuring instrument is used, it is possible to easily measure, but there is a problem that it is expensive and a signal other than the UART standard cannot be analyzed.

  An object of the present invention is to realize a waveform measuring apparatus that can easily measure serial data on a waveform display screen.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In the waveform measuring apparatus for displaying the waveform to be measured and the cursor on the display unit, positioning the cursor at the measurement point of the displayed waveform, and measuring the waveform,
Cursor setting means for inputting the number of bits of serial data to be measured, having a number corresponding to this number of bits, and setting a cursor with an equal interval between them,
The number of cursors and the interval set by the cursor setting means are input, these cursors are moved while maintaining the interval, the cursor moving means for outputting the cursor position, and a threshold value are set, and this setting is made. Threshold setting means for outputting a threshold value;
A memory for storing waveform data displayed on the display unit;
The outputs of the cursor moving means and the threshold setting means are input, the waveform data is read from the memory based on the output of the cursor moving means, the value is calculated from the read waveform data, and the calculated value And a data processing unit for comparing the output of the threshold value setting means and outputting the result,
A display processing unit that receives an output of the data processing unit, displays a waveform to be measured, the cursor, and an output of the data processing unit on the display unit;
Is provided. The logic level of serial data can be measured at a time simply by adjusting the cursor position and interval.

The invention according to claim 2 is the invention according to claim 1,
A bit rate of serial data to be measured is input to the cursor setting means, and the cursor setting means determines a cursor interval from the input bit rate. Since there is no need to adjust the cursor interval, measurement can be performed more easily.

The invention according to claim 3 is the invention according to claim 1 or 2,
The display processing unit converts the output of the data processing unit into a binary number and a hexadecimal number and displays them on the display unit. You can easily grasp serial data.

The present invention has the following effects.
According to the first, second, and third aspects of the invention, the number of equally spaced cursors corresponding to the number of bits of serial data is generated, and the interval between these cursors is adjusted according to the bit rate of serial data, and The logic level of the entire serial data was measured at a time by comparing the value of each cursor point with a threshold value so that it could move with the interval kept.

  The logic level of the entire serial data can be measured at once by adjusting the cursor interval according to the bit rate and aligning the first cursor with the start bit of the serial data. There is no need to match each one. Therefore, there is an effect that serial data can be measured with a simple operation and in a short time.

  In addition, since the cursor is visually aligned with the serial data, non-standard serial data that cannot be measured with a dedicated measuring instrument, or signals that cannot be used with a dedicated measuring instrument due to noise superposition and quality degradation can be measured. There is also an effect that can be done.

  Further, if the cursor interval is automatically set according to the bit rate of the serial data, the measurement can be performed simply by moving the cursor to the top of the serial data, and thus the measurement can be simplified.

It is the block diagram which showed one Example of this invention. It is a figure for demonstrating operation | movement of this invention. It is a block diagram of the conventional waveform display apparatus. It is a figure for demonstrating operation | movement of the conventional waveform display apparatus. It is a figure for demonstrating the conventional subject.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention generates a plurality of cursors having a number corresponding to the number of bits of serial data to be measured and having the same interval, and allows the cursors to be moved while maintaining the interval so that these cursors are displayed. The logic level of all the bits of serial data can be measured at one time.

  FIG. 1 is a block diagram showing an embodiment of a waveform measuring apparatus according to the present invention. In addition, the same code | symbol is attached | subjected to the same element as FIG. 3, and description is abbreviate | omitted.

  In FIG. 1, reference numeral 30 denotes a cursor setting means for inputting the number of bits of serial data to be measured and the cursor interval. The cursor setting unit 30 generates a cursor having a number corresponding to the input bit number, and outputs the information. By changing the value of the input cursor interval, the generated cursor interval can be varied.

  Reference numeral 31 denotes a cursor moving means, which receives the cursor information set by the cursor setting means 30 and moves them together without changing the interval between the cursors, and outputs the position information of each cursor. The cursor moving means 31 has a rotary knob, for example, and the cursor can be moved by rotating the rotary knob.

  The memory 10 stores waveform data of a waveform to be measured. The threshold value setting means 11 sets a threshold value for determining the logic level and outputs this threshold value.

  A data processing unit 32 includes a voltage value calculation unit 33 and a comparison unit 34. The cursor position output by the cursor moving unit 31 is input to the voltage value calculating unit 33. The voltage value calculation means 33 reads the waveform data corresponding to the cursor position from the memory 10, calculates the voltage at that position, and outputs it to the comparison means 34. The voltage value calculation means 33 performs this operation for all cursor positions and outputs a voltage value corresponding to the cursor position.

  The cursor moving unit 31 outputs the cursor position on the screen in the display unit 17. The data processing unit 32 calculates the address of the waveform data stored in the memory 10 from this cursor position, and reads the waveform data at this address. The address can be calculated from the time at the left end of the screen and the scale (Time / div) on the horizontal axis of the screen.

  The comparison means 34 compares the value (voltage) output from the voltage value calculation means 33 with the threshold value output from the threshold value setting means 11, determines the logic level at the cursor position, and outputs it to the display processing unit 34. To do. The comparison means 34 performs this operation for all cursor positions and determines the logic level of each cursor position.

  The display processing unit 35 displays the waveform to be measured, the cursor, and the threshold value on the display unit 17. The display processing unit 35 also has a result display means 36 built therein. The display processing unit 35 edits the logic level determined by the comparison unit 34 into an easy-to-see format, and the result display unit 36 displays the result edited by the display processing unit 35 on the display unit 17.

  Next, the operation of this embodiment will be described in detail with reference to FIG. FIG. 2 shows an example of measuring serial data consisting of one start bit (Stb), 14 data bits (b13 to b0), and one stop bit (Spb). A solid line 40 represents the waveform of the serial data. A two-dot chain line 41 is a threshold value, and 44 is an edited measurement value.

  Both the alternate long and short dash line 42 and the dotted line 43 are cursors. The cursor 42 is a reference cursor, and the cursor 43 is a cursor positioned at a position corresponding to all data bits (b13 to b0) and stop bits (Spb).

  When measuring serial data, the reference cursor 42 is set to the position of the start bit (Stb) using a rotary knob or the like. The start bit is the bit that goes high first so it can be easily identified.

  Then, while looking at the displayed waveform, the cursor interval is adjusted so that each cursor is positioned at each bit position of the serial data. Since the cursors change so that the intervals are the same, the intervals between the cursors can be easily adjusted.

  In this way, all the cursors can be positioned at each bit position simply by aligning the first cursor with the position of the first bit and adjusting the cursor interval.

  The voltage value calculation means 33 reads the positions of the reference cursor 42 and other cursors 43 on the screen, and the address of the memory 10 where the cursor position waveform data is stored from the time at the left end of the screen and the time scale of the horizontal axis of the screen , Read the waveform data at this address, calculate its voltage value, and output it to the comparison means 34. The comparison means 35 determines the logic level.

  As shown at 44, the determined logic level is displayed in an easily understandable format. The first line of 44 is the position of the reference cursor 42, that is, the voltage value of the start bit. In FIG. 2, the voltage is 4.9V.

  The second line represents the data bits b13 to b0 in this order as binary values (1, 0), and the third line represents the hexadecimal number. Thus, data can be easily understood by displaying in various formats.

  As described above, the cursor is automatically arranged at each bit position only by adjusting the reference cursor to the start bit and adjusting the cursor interval, and the logic level at that point is measured and displayed. Therefore, serial data can be analyzed with a simple operation.

  Further, serial data can be analyzed without using an expensive measuring instrument having a UART analysis function. Even when noise is superimposed and a dedicated measuring instrument cannot be used, analysis can be performed.

  Furthermore, since any number of bits and bit rates can be supported, non-standard serial data and serial data with superposed noise and degraded quality can be easily analyzed.

  In this embodiment, the interval of the cursor 43 is input to the cursor setting means 30. However, the bit rate of the serial data is input, and the cursor setting means 30 determines the interval of the cursor from this bit rate. Also good. In this way, the trouble of adjusting the cursor interval can be saved.

  The cursor interval can be calculated from the bit rate and the horizontal scale of the screen. For example, when the bit rate is 1 Mbps and the horizontal scale is 2 μS / div, the cursor interval is 0.5 div.

  In this embodiment, the logic level of the data bit is displayed, but the voltage value may also be displayed.

DESCRIPTION OF SYMBOLS 10 Memory 11 Threshold value setting means 17 Display part 30 Cursor setting means 31 Cursor movement means 32 Data processing part 33 Voltage value calculation means 34 Comparison means 35 Display processing part 36 Result display means 40 Measurement waveform 41 Threshold value 42, 43 Cursor 44 Edited measurements

Claims (3)

In the waveform measuring apparatus for displaying the waveform to be measured and the cursor on the display unit, positioning the cursor at the measurement point of the displayed waveform, and measuring the waveform,
Cursor setting means for inputting the number of bits of serial data to be measured, having a number corresponding to this number of bits, and setting a cursor with an equal interval between them,
The number of cursors and the interval set by the cursor setting means are input, these cursors are moved while maintaining the interval, and the cursor moving means for outputting the cursor positions;
Threshold setting means for setting a threshold and outputting the set threshold;
A memory for storing waveform data displayed on the display unit;
The outputs of the cursor moving means and the threshold setting means are input, the waveform data is read from the memory based on the output of the cursor moving means, the value is calculated from the read waveform data, and the calculated value And a data processing unit for comparing the output of the threshold value setting means and outputting the result,
A display processing unit that receives an output of the data processing unit, displays a waveform to be measured, the cursor, and an output of the data processing unit on the display unit;
A waveform measuring apparatus comprising:   2. The waveform measurement according to claim 1, wherein a bit rate of serial data to be measured is input to the cursor setting means, and the cursor setting means determines a cursor interval from the input bit rate. apparatus.   3. The waveform measuring apparatus according to claim 1, wherein the display processing unit converts the output of the data processing unit into a binary number and a hexadecimal number and displays the converted number on the display unit.

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