JP4109140B2 - Waveform display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waveform display device for displaying a waveform based on a measurement value obtained by measuring an electrical parameter of an input signal at a predetermined period on a display unit.
[0002]
[Prior art]
For example, when analyzing the characteristics of an input signal, generally, a waveform display device that displays the signal waveform of the input signal (as an example, a waveform display device disclosed in JP-A-5-133980) is used. . This type of waveform display device measures an electrical parameter (in this case, a voltage) of an input signal (for example, an AC signal) at a predetermined period and outputs a measurement value, and a measurement value output by the measurement unit. A storage unit that stores data, a display control unit that reads measurement values stored in the storage unit and outputs display data, and a display unit that inputs display data and displays a signal waveform of an input signal are configured. ing. In this waveform display device, the signal waveform of the input signal is displayed on the display unit together with the time scale in the horizontal axis direction and the voltage scale in the vertical axis direction. Therefore, the operator can analyze the characteristics of the input signal by reading the voltage at each time.
[0003]
[Patent Document 1]
JP-A-5-133980 (page 2-3)
[0004]
[Problems to be solved by the invention]
However, the conventional waveform display device has the following problems. In other words, this waveform display device simply displays the signal waveform of the input signal based on the measured value. In this case, the voltage read from the displayed waveform does not always indicate the true value of the voltage of the input signal, but tolerances caused by internal elements constituting the waveform display device (predetermined maximum error) In addition, an error within a tolerance range caused by an external element such as a measurement cable connecting the measurement object and the measurement unit is included. For this reason, in order to accurately analyze the characteristics of the input signal, it is necessary to consider the range in which the true value exists. However, since this waveform display device displays only the signal waveform based on the measured value, in order to confirm the range where the true value exists, the tolerance described in the waveform display device, the specifications of the external element, etc. It is necessary to perform complicated calculation based on the voltage read from the signal waveform. Therefore, this waveform display device has a problem that it is difficult to accurately analyze the input signal characteristics due to the complicated work of confirming the range where the true value of the input signal exists. .
[0005]
The present invention has been made in view of such problems, and a main object of the present invention is to provide a waveform display device that can easily perform an accurate characteristic analysis on an input signal.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a waveform display device according to claim 1, wherein a measurement unit that measures an electrical parameter of an input signal at a predetermined period and outputs a measurement value, and a waveform based on the measurement value is displayed on the display unit. a waveform display apparatus and a display control unit for, among the external tolerances on the measurement value due to external factors other than the internal tolerances and the inner element relative to the measurement value caused by the internal components of the waveform display device A calculation unit that calculates a lower limit value by adding a plus tolerance in at least one tolerance of the difference to the measured value and calculating an upper limit value and subtracting a minus tolerance in the one tolerance from the measured value , display control unit displays the lower limit waveform based on the upper limit waveform and the lower limit value based on the upper limit value before Symbol display unit.
[0007]
The waveform display device according to claim 2 is the waveform display device according to claim 1, wherein the calculation unit is configured to determine the upper limit value and the lower limit value based on both the internal tolerance and the external tolerance and the measured value. Is calculated.
[0008]
The waveform display device according to claim 3 is the waveform display device according to claim 1 or 2, wherein the display control unit displays a display area on the display unit sandwiched between the upper limit waveform and the lower limit waveform with a predetermined display color. To display.
[0009]
The waveform display device according to claim 4 is the waveform display device according to claim 3, wherein the display control unit displays the signal waveform of the input signal based on the measurement value in a display color different from the display color of the display region. It is displayed superimposed on the display area. In the present invention, the “display color different from the display color of the display area” means that the display color of the display area and the display color of the signal waveform are three attributes of color (hue (color distinction), brightness (color) The degree of brightness and darkness) and saturation (degree of color vividness)) are different from each other.
[0010]
The waveform display device according to claim 5 is the waveform display device according to claim 1 or 2, wherein the display control unit has a predetermined filling pattern in a display area on the display unit sandwiched between the upper limit waveform and the lower limit waveform. Fill and display with.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a waveform display device according to the invention will be described with reference to the accompanying drawings.
[0012]
First, the configuration of the waveform display device 1 will be described with reference to the drawings.
[0013]
As shown in FIG. 1, the waveform display device 1 includes a measurement unit 2, an operation unit 3, a control unit 4, a display unit 5, a VRAM 6, a ROM 7, a storage memory 8, and a RAM 9. A signal waveform WS (see FIG. 2) of the input signal S1 based on a measured value VS obtained by measuring an electrical parameter (a voltage as an example) of a wavy AC signal at a predetermined cycle is displayed on the display unit 5. Moreover, the waveform display apparatus 1 displays the upper limit waveform WU and the lower limit waveform WL on the display unit 5 as shown in FIG. In this case, the upper limit waveform WU represents the upper limit of the range in which the true value of the voltage of the input signal S1 exists, and the lower limit waveform WL represents the lower limit of the range. In addition, as shown in the figure, the waveform display device 1 displays a band-like region (display region) F sandwiched between the upper limit waveform WU and the lower limit waveform WL on the display unit 5 in a predetermined display color (for example, light blue). . In this case, the band-like region F represents a range where the true value of the voltage of the input signal S1 exists.
[0014]
The measuring unit 2 includes an A / D converter, measures (samples) the voltage of the input signal S1 at a predetermined period, and outputs a measured value VS of binary data. The operation unit 3 includes a numeric key for inputting an external tolerance MO with respect to a measured value VS caused by an external element other than each component (internal element) of the waveform display device 1, a display key for displaying various waveforms, and A range setting key for setting the measurement range is provided, and an operation signal S2 corresponding to the key operation is output.
[0015]
The control unit 4 corresponds to the display control unit and the calculation unit in the present invention, and executes various processes according to the operation signal S2 output from the operation unit 3. Further, the control unit 4 records the measurement value VS output from the measurement unit 2 in the storage memory 8. Further, the control unit 4 stores the external tolerance MO input via the operation unit 3 in the RAM 9. The control unit 4 also includes an internal tolerance MI for the measurement value VS such as a range error and a reading error caused by each component of the waveform display device 1, an external tolerance MO input via the operation unit 3, and the measurement value VS. Based on the above, the upper limit value VU and the lower limit value VL of the range where the true value of the voltage of the input signal S1 exists are calculated and stored in the RAM 9. Further, the control unit 4 determines the signal waveform WS of the input signal S1 based on the measurement value VS, the upper limit waveform WU based on the upper limit value VU, the lower limit waveform WL based on the lower limit value VL, the band-like region F, the voltage scale V, and the time scale T. By virtually drawing on the virtual plane of the VRAM 6, display data D for displaying them on the display unit 5 is generated in the VRAM 6. In this case, the control unit 4 makes it possible to distinguish between the waveforms WS, WU, WL and the belt-like region F, so that the three attributes of color (hue (color distinction)), lightness (the degree of lightness of the color) and color degrees included in the display data D color data order to display them in any one was different from each other or more of the (color degree of vividness of)).
[0016]
The display unit 5 is configured to include, for example, a liquid crystal panel capable of displaying an image in color. As illustrated in FIG. 2, the signal waveform WS, the upper limit waveform WU, the lower limit waveform WL, the strip region F, A voltage scale V and a time scale T are displayed on the liquid crystal panel. The VRAM 6 stores display data D generated by the control unit 4. The ROM 7 stores a plurality of internal tolerances MI defined for each measurement range and an operation program of the control unit 4. The storage memory 8 stores the measurement value VS output from the measurement unit 2 and transferred by the control unit 4. The RAM 9 stores the external tolerance MO input by the operation unit 3 and transferred by the control unit 4, and the upper limit value VU and the lower limit value VL calculated by the control unit 4.
[0017]
Next, the overall operation of the waveform display device 1 will be described with reference to the drawings.
[0018]
First, the range setting key of the operation unit 3 is operated to set the measurement range corresponding to the input signal S1, and then the input signal S1 (measurement target signal) is input to the measurement unit 2. At this time, the measurement unit 2 samples the input signal S1 at a predetermined cycle, and sequentially outputs the measurement value VS. Next, the control unit 4 sequentially stores the measurement values VS output from the measurement unit 2 in the storage memory 8. Next, by operating the numeric keys of the operation unit 3, for example, an external tolerance MO caused by an external element of the waveform display device 1 such as a measurement cable connecting the measurement object and the measurement unit 2 is input. At this time, the operation unit 3 outputs an operation signal S2 corresponding to the key operation. Subsequently, the control unit 4 causes the RAM 9 to store the external tolerance MO specified based on the operation signal S2.
[0019]
Next, the display key of the operation unit 3 is operated. At this time, the operation unit 3 outputs an operation signal S2, and the control unit 4 executes waveform display processing according to the operation signal S2. In this waveform display process, the control unit 4 first reads the internal tolerance MI corresponding to the set measurement range from the ROM 7 and also reads the external tolerance MO input via the operation unit 3 from the RAM 9. Next, the control unit 4 reads the measurement value VS from the storage memory 8. Next, the control unit 4 calculates the above upper limit value VU and lower limit value VL according to a predetermined calculation formula based on the internal tolerance MI, the external tolerance MO, and the measured value VS, and stores them in the RAM 9. In this case, as an example, the control unit 4 adds each positive tolerance in the internal tolerance MI and the external tolerance MO to each measured value VS, calculates each upper limit value VU corresponding to each measured value VS, The absolute value of each negative tolerance in the tolerance MI and the external tolerance MO is subtracted from each measured value VS to calculate each lower limit value VL corresponding to each measured value VS.
[0020]
Subsequently, the control unit 4 displays the signal waveform WS, the upper limit waveform WU, the lower limit waveform WL, the band-like region F, the voltage scale V, and the time scale T by virtually drawing them on the virtual plane of the VRAM 6. Display data D for this purpose is generated in the VRAM 6. At this time, for example, the control unit 4 sets the signal waveform WS to blue (blue hue), the upper limit waveform WU and the lower limit waveform WL to red (red hue), and the strip region F to light blue (light blue hue). ), The display data D includes color data for display. Next, the control unit 4 causes the display unit 5 to output display data D to the VRAM 6. As a result, as shown in FIG. 2, the blue signal waveform WS, the red upper limit waveform WU, the red lower limit waveform WL, the light blue strip region F, the time scale T, and the voltage scale V are displayed on the display unit 5. . In this case, since the upper limit waveform WU and the lower limit waveform WL are displayed in red and the strip-like region F is displayed in light blue, the existence range of the true value of the voltage in the input signal S1 is reliably and easily recognized.
[0021]
Thus, according to the waveform display device 1, the upper limit value VU and the lower limit value VL of the range where the true value of the voltage in the input signal S1 exists are calculated based on the internal tolerance MI, the external tolerance MO, and the measured value VS. By displaying the upper limit waveform WU based on the upper limit value VU and the lower limit waveform WL based on the lower limit value VL on the display unit 5, it is possible to reliably and easily recognize the range in which the true value exists without performing complicated calculations. it can. Therefore, the operator can easily perform an accurate characteristic analysis of the input signal S1, for example.
[0022]
In addition, since the band-like region F sandwiched between the upper limit waveform WU and the lower limit waveform WL is displayed in a light blue display color, the width of the band-like region F can be clearly recognized, so that the range in which the true value exists exists. Furthermore, it can be recognized reliably and easily. Furthermore, since the blue signal waveform WS is superimposed on the band-like region F and displayed, the position of the measurement value VS within the range where the true value exists can be easily recognized. It is possible to easily grasp the magnitude and ratio of the plus and minus tolerances in the tolerance MO.
[0023]
The present invention is not limited to the above-described embodiments. For example, the input signal S1 is not limited to the above sinusoidal AC signal, and an arbitrary electric signal can be input. Also in this case, by displaying the upper limit waveform WU and the lower limit waveform WL, it is possible to reliably and easily recognize the range where the true value of the electrical parameter in the input signal exists. In the above-described embodiment, the example in which the upper limit value VU and the lower limit value VL are calculated based on both the tolerances of the internal tolerance MI and the external tolerance MO and the measured value VS has been described. When the external tolerance MO is sufficiently small, it is possible to adopt a configuration in which the upper limit value VU and the lower limit value VL are calculated based only on the internal tolerance MI and the measured value VS. Further, when the internal tolerance MI is sufficiently small as compared with the external tolerance MO, a configuration in which the upper limit value VU and the lower limit value VL are calculated based only on the external tolerance MO and the measured value VS may be employed.
[0024]
Further, the internal tolerance MI is not necessarily stored in the ROM 7 and can be input from the operation unit 3. Furthermore, a configuration in which the external tolerance MO is stored in the ROM 7 or RAM 9 in advance can be employed. Further, the display colors of the signal waveform WS, the upper limit waveform WU, the lower limit waveform WL, and the band-like region F are not limited to the display colors described above, and can be displayed in other display colors. Furthermore, the band-like region F can be filled and displayed with an arbitrary filling pattern such as diagonal lines, shaded lines, broken lines, and spots. In this case, since the other area on the display unit 5 and the band-like area F can be clearly distinguished, the width of the band-like area F can be clearly recognized. Further, the band-like region F can be displayed in a display color different from the display colors of the signal waveform WS, the upper limit waveform WU, and the lower limit waveform WL, and can be displayed with an arbitrary fill pattern. Further, the signal waveform WS and the band-like region F are not necessarily displayed, and only the upper limit waveform WU and the lower limit waveform WL can be displayed.
[0025]
【The invention's effect】
As described above, according to the waveform display device of claim 1, the upper limit value is calculated by adding the plus tolerance in at least one of the internal tolerance and the external tolerance to the measured value, and the tolerance of one of the tolerances is calculated. By subtracting the negative tolerance in the measured value from the measured value, the lower limit value is calculated, and the upper limit waveform based on the upper limit value and the lower limit waveform based on the lower limit value are displayed on the display unit . Since the range where the true value exists can be recognized reliably and easily, the operator can easily perform an accurate characteristic analysis of the input signal, for example.
[0026]
Further, according to the waveform display device of claim 2, by calculating the upper limit value and the lower limit value based on both the internal tolerance and the external tolerance and the measured value, one of the internal tolerance and the external tolerance and the measured value are calculated. Compared with the calculation of the upper limit value and the lower limit value based on the above, the operator can, for example, more accurately analyze the characteristics of the input signal.
[0027]
According to the waveform display device of the third aspect, the display area on the display unit sandwiched between the upper limit waveform and the lower limit waveform is displayed in a predetermined display color so that the width of the display area is clearly visible. Therefore, the range in which the true value exists can be recognized more reliably and easily.
[0028]
According to the waveform display device of the fourth aspect, the signal waveform of the input signal is displayed in a display color different from the display color of the display area sandwiched between the upper limit waveform and the lower limit waveform. Therefore, it is possible to easily recognize the position of the measurement value within the range where the true value exists, for example, to easily grasp the magnitudes and ratios of the plus and minus tolerances in the internal tolerance and the external tolerance. be able to.
[0029]
According to the waveform display device of claim 5, by displaying the display area sandwiched between the upper limit waveform and the lower limit waveform with a predetermined fill pattern, the other areas on the display unit and the display area are displayed. Can be clearly distinguished, and the width of the display area can be clearly recognized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a waveform display device 1 according to an embodiment of the present invention.
FIG. 2 is a display screen diagram of the display unit 5 displaying a signal waveform WS, an upper limit waveform WU, a lower limit waveform WL, and a band-like region F.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Waveform display apparatus 2 Measuring part 4 Control part 5 Display part F Strip | belt area MI Internal tolerance MO External tolerance VL Lower limit value VS Measurement value VU Upper limit value WL Lower limit waveform WS Signal waveform WU Upper limit waveform

Claims (5)

A waveform display device comprising: a measurement unit that measures an electrical parameter of an input signal at a predetermined period and outputs a measurement value; and a display control unit that displays a waveform based on the measurement value on a display unit,
The plus tolerance in at least one of the internal tolerance for the measurement value caused by the internal element of the waveform display device and the external tolerance for the measurement value caused by an external element other than the internal element is added to the measurement value. And calculating an upper limit and subtracting a negative tolerance in the one tolerance from the measured value to calculate a lower limit,
The display controller, a waveform display device for displaying the lower limit waveform based on the upper limit waveform and the lower limit value based on the upper limit value before Symbol display unit.   The waveform display device according to claim 1, wherein the calculation unit calculates the upper limit value and the lower limit value based on both the internal tolerance and the external tolerance and the measured value.   The waveform display device according to claim 1, wherein the display control unit displays a display region on the display unit sandwiched between the upper limit waveform and the lower limit waveform in a predetermined display color.   The waveform display apparatus according to claim 3, wherein the display control unit displays the signal waveform of the input signal based on the measurement value so as to be superimposed on the display area with a display color different from the display color of the display area. The waveform display device according to claim 1 , wherein the display control unit fills and displays a display area on the display unit sandwiched between the upper limit waveform and the lower limit waveform with a predetermined fill pattern.

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