JP3095520B2 - Waveform display method of waveform recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform display method for a waveform recording apparatus, and more particularly, to a waveform display method in which an input signal is subjected to arithmetic processing such as differentiation and integration and the arithmetic waveform is displayed. Things.

[0002]

2. Description of the Related Art In a waveform recording apparatus of this type, various arithmetic processing functions (for example, a central processing unit (CPU)) (for example,
Log, square root, moving average, differentiation, integration, absolute value calculation, etc.), and the calculated waveform data can be appropriately displayed on a display screen such as a CRT.

[0003]

By the way, as shown in FIG. 7, for example, PP (Peak to Pe
ak), a sine wave of 10 V and 200 Hz is input, and the input waveform W has an upper limit value = + 10.000E + 0,
In a state where the lower limit value is displayed on the screen of −10.000E + 0, when the same waveform is differentiated and displayed on the screen of the same upper limit value and lower limit value, as shown in FIG. A part of the differentiated waveform Wd may not be displayed on the screen.

On the other hand, when an integral operation is performed to display the integrated waveform Wi, as shown in FIG. 9, the waveforms are gathered around 0 V, making signal analysis difficult.

[0005] For this reason, conventionally, there has been a problem that the upper limit value and the lower limit value have to be manually reset each time while watching the display state of the screen, and the operation is troublesome.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and has a structural feature that an analog input signal is converted into a digital signal by an A / D converter. A central processing unit (CPU) performs predetermined arithmetic processing on the digital signal, and displays the arithmetically processed waveform data on a display unit such as a CRT. The maximum value MAX and the minimum value M from the processed waveform data
IN, and a PP width W and an intermediate value C thereof are obtained.
The same width W is compared with a numerical value represented by a series of m × 10 ⁿ (m and n are arbitrary integers), and the immediately higher value is set as a correction width CW. CW / 1
Compared with a numerical value represented by a series of 0 ^p ） × q (p and q are arbitrary integers), the nearest upper or lowermost value is set as a corrected intermediate value CC, and the corrected intermediate value CC ± corrected above The width CW / 2 is set to the upper limit value U when the calculated waveform is displayed.
The waveform data is displayed on the screen as L and the lower limit value LL.

If one of the maximum value MAX and the minimum value MIN is out of the range of the corrected intermediate value CC ± the corrected width CW / 2, the corrected width CW is changed to a numerical value of a higher order system. Good.

[0008]

According to the above arrangement, the scale value is automatically set according to the width, and the calculated waveform is developed centering on the intermediate value of the scale without being shifted to the upper or lower side of the display screen. You.

The upper limit value UL and the lower limit value LL are simple numerical values, for example, 1 × 10 ⁿ , 2 × 10 ⁿ , 5 × 10 ⁿ (where n is an integer), and the step size is also corrected. legible to be displayed in decimal as width CW / 10 ^p.

[0010]

FIG. 1 is a schematic block diagram of a waveform recording apparatus used in the embodiment of the present invention. First, the apparatus will be described.

This waveform recording apparatus has an input unit 1 including an A / D converter for converting an analog input signal into a digital signal.
0 is provided. The digital signal converted by the input unit 10 is written to the RAM 12a according to a write address output from the central processing unit (CPU) 11.

The CPU 11 reads out waveform data from the RAM 12a in accordance with a control program stored in the ROM 12b, performs predetermined arithmetic processing on the waveform data, and stores the calculated waveform data in a video RAM (V-RAM) 1.
Write to 3.

In this manner, the display screen 1 such as a CRT
4 shows the calculated waveform. Reference numeral 15 denotes an operation unit for setting measurement conditions and the like. When the upper and lower limits of the display screen 14 are manually set, the operation unit 1 is used.
The setting is performed in 5.

Next, the operation of the present invention will be described with reference to FIGS.
This will be described with reference to the flowchart shown in FIG.

First, an analog input signal is input to the input unit 10 in advance.
Is converted into a digital signal, and the waveform data is
If it is assumed that M12a has been loaded, step S
At T1, waveform data is read from the RAM 12a, and CP
In U11, waveform calculations, for example, calculations such as Log, square root, moving average, absolute value, differentiation, and integration are performed.

Next, it is determined in step ST2 whether the upper limit value and the lower limit value are automatically set. If the setting is automatic, the maximum value MAX and the minimum value MIN are detected from the calculated waveform data in step ST3.

Then, an auto-scale subroutine is executed in step ST4. That is, as shown in FIG. 3, first, in sub-step SUB1, the maximum value MAX is set to the temporary upper limit value HI, and the minimum value MIN is set to the temporary lower limit value LO.

Thereafter, in a sub-step SUB2, the upper limit value HI and the lower limit value LO are used to calculate the PP (Pea)
(k to Peak) width W and intermediate value C are obtained.

Then, in the next sub-step SUB3, the width W and the intermediate value C are corrected to values that are easy to read on the display. That is, the width W is compared with a numerical value represented by a series of m × 10 ⁿ (m and n are integers), and the immediately higher value is set as the correction width CW.

Here, if the numerical sequence is 1 × 10 ⁿ ,
2 × 10 ⁿ and 5 × 10 ⁿ are set, for example, the width W
Is 1.25 V, the correction width CW is set to 2 × 10 ⁰ V.

Further, regarding the intermediate value C, the correction width CW
The value is compared with a numerical value represented by a series of / 10 ^p ｝ × n, and the nearest upper or lowermost value is set as the corrected intermediate value CC.

For example, as described above, the correction width CW is 2 × 1
If it is set to ⁰ V and the step size (one scale on the display screen) is set to 1/10 in advance, the numerical value is {2.0 × 10 ^-1 } × n [V]. ... -0.2, 0, 0.2, 0.4, 0.6
[V]...

Here, when the intermediate value C of the calculated waveform data is 0.
If it is 246 V, the nearest lower 0.2 V is set as the corrected intermediate value CC. The intermediate value C of 0.24
When 6V is divided by the step size of 0.2V, one less than 0.1V is obtained. 0
Since it is 46, the corrected intermediate value CC may be obtained by setting 0.2 × 1 = 0.2.

When the correction width CW and the correction intermediate value CC are set in this way, the next substep SUB4
, The upper limit value UL and the lower limit value LL of the scale on the display screen are obtained from these values.

That is, upper limit value UL = modified intermediate value CC +
Correction width CW / 2, lower limit value LL = correction intermediate value CC−correction width CW / 2. Specifically, when the above numerical values are applied, the upper limit value UL = 0.2V + 2.0 / 2V = 1.
2V, lower limit = 0.2V−2.0 / 2V = −0.8V.

Thereafter, in substep SUB5, the maximum value MAX and the minimum value MIN in the calculated waveform data are set to the upper limit value U.
It is determined whether it is within the range between L and the lower limit LL, and if it is within the range and YES, the process returns to the main routine of FIG. 2 and in step ST5, scaling is executed based on the upper limit UL and the lower limit LL. You. For example, assuming that the individual waveform data is X and the Y axis of the display screen 14 has a resolution of 0 to 100 dots, Y = ｛(X−lower limit LL) /
The calculated waveform is developed on the display screen 14 as (upper limit value UL-lower limit value LL)｝ × 100, and the waveform is displayed in step ST6.

In sub-step SUB5, NO
In the case of are substeps SUB6 run, after the correction range CW is re-corrected to the nearest higher value of the series numerical upper represented by m × 10 ^n, the flow returns to sub-step SUB5.

As described above, the scale value on the display screen is automatically set according to the width of the calculated waveform.
The calculated waveform is developed centering on the intermediate value. If manual setting is selected in the previous step ST2, the process proceeds to step ST7 and the operation unit 1
The manual setting of the upper limit value and the lower limit value is performed via 5.

Next, a specific display example will be described. FIG. 4 shows an example in which a sine waveform having a width of 2.4 V and 200 Hz is used as an original waveform, an absolute value is calculated, and the calculated waveform Wa is displayed.

In this case, the maximum value MAX = 1.185V,
When the minimum value MIN = 0.001V, the PP width W = 1.
184V. The step width is set to 1/10 in advance.

Therefore, first, the correction width CW is set to 2.0 V, and the step width is 2.0 × 10 ⁻¹ =
0.2V.

The intermediate value C is (1.185 + 0.001) /
Since 2 = 0.593V, when this is chopped by 0.2V, 0.593V ÷ 0.2V = 2, which is 0.193, which is much smaller. Thereby, the corrected intermediate value CC = 0.2 × 2 = 0.4
V is set.

Therefore, the upper limit value UL = 0.4 + 2.0 / 2
= 1.4V, lower limit value LL = 0.4-2.0 / 2 = -0.
6V.

Upper limit value UL (1.4 V)> maximum value MAX
(1.185V) and the lower limit value LL (-0.6V) <minimum value MIN (0.001V), the scale value was adopted.

FIG. 5 shows a differential waveform Wd of the original waveform. With the maximum value MAX = 1.584 × 10 ³ V and the minimum value MIN = −1.562 × 10 ³ V, the PP width W
= 3.146 x 10 ³ V. Note that the step width is set to 1/10 in advance similarly to the above.

Therefore, first, the correction width CW is 5.0 × 1
0 ³ together is set to V, the step size is 5.0 × 1
0 ² V.

The intermediate value C is (1.584 × 10 ³ −1.5
62 × 10 ³ ) / 2 = 22 V.
When chopping at × 10 ² V, 0.593V ÷ 5.0 × 10 ² V
= 0, which is 22. Thereby, the corrected intermediate value CC =
5.0 × 10 ² × 0 = 0 V is set.

Therefore, the upper limit value UL = 0 + 5.0 × 10 ³
/2=2.5×10 ³ V, lower limit value LL = 0−5.0 × 1
0 ³ /2=−2.5×10 ³ V

Upper limit UL (2.5 × 10 ³ V)> maximum MAX (1.584 × 10 ³ V) and lower limit LL (−
2.5 × 10 ³ V) <minimum value MIN (−1.562 × 1)
Because it meets the 0 3 ^V) conditions, the scale value has been adopted.

FIG. 6 shows an integral waveform Wi of the original waveform.
It is shown. Maximum value MAX = 1.941 × 10 ⁻³
V, the minimum value MIN was 1.164 × 10 ⁻¹⁰ V, and the PP width W was 1.941 × 10 ⁻³ V. In addition,
The step width is set to 1/10 in advance as described above.

Therefore, first, the correction width CW is 2.0 × 1
0 ^-3 together is set to V, the step size is 2.0 ×
10 ⁻⁴ V.

The intermediate value C is (1.941 × 10 ⁻³ +1.
164 × 10 ⁻¹⁰ ) /2=9.705×10 ⁻⁴ V, and when this is cut at 2.0 × 10 ⁻⁴ V, 9.7 is obtained.
05 × 10 ⁻⁴ V ÷ 2.0 × 10 ⁻⁴ V = 4
705 × 10 ⁻⁴ . Thereby, the corrected intermediate value CC
= 2.0 × 10 ⁻⁴ × 4 = 8 × 10 ⁻⁴ V

Therefore, the upper limit value UL = 8 × 10 ⁻⁴ +2.
^{0 × 10 -3 /2=1.8×10 - 3 V} , the lower limit LL =
8 × 10 ⁻⁴ −2.0 × 10 ⁻³ /2=−0.2×10
^-3V .

However, the upper limit value UL (1.8 × 10
⁻³ V) <maximum value MAX (1.941 × 10 ⁻³ V) and lower limit value LL (−0.2 × 10 ⁻³ V) <minimum value MI
N (1.164 × 10 ⁻¹⁰ V) and the maximum value MAX is larger than the upper limit value UL, so the correction width CW is corrected again to 5.0 × 10 ⁻³ V, and the upper limit value UL = 8 × 10 ⁻⁴ + 5.0 × 10 ⁻³ / 2 =
3.3 × 10 ⁻³ V Lower limit value LL = 8 × 10 ⁻⁴ −5.0 × 10 ⁻³ / 2 = −
1.7 × 10 ⁻³ V was set.

In the above embodiment, the upper limit value UL and the lower limit value LL are represented as 1 × 10 ⁿ , 2 × 10 ⁿ , 5 × 1
0 ⁿ is used, but the present invention is not limited to this, and in some cases, for example, 1 × 10 ⁿ , 3 × 10
ⁿ , a sequence numerical value of 6 × 10 ⁿ may be used. Similarly, the step width is not limited to 1/10 of the above embodiment. Further, the grid (ruled lines) on the display screen 14 may be fixed display or may be divided according to the display width.

Further, as the display means, a printer or the like can be used in addition to the display screen such as the CRT of the above embodiment.

[0047]

As described above, according to the present invention, the upper limit value UL and the lower limit value LL of the scale value on the display screen are automatically set according to the amplitude of the calculated waveform.
This is convenient for observing the waveform. Also, the upper limit U
L and the lower limit LL are, for example, 1 × 10 ⁿ , 2 × 10 ⁿ ,
Since it is set to a simple numerical value such as 5 × 10 ⁿ (where n is an integer), it is easy to read when observing the waveform.

Further, one scale (1 DI)
V) is set, for example, in 1/10 units, so that the intermediate value, the upper limit value, and the lower limit value can be represented by two significant figures, and when the display screen is divided into ten equal parts, the center of the waveform is always 4
Since it is set at the position of / 10 to 6/10, effects such as that the calculation waveform is developed almost at the center of the screen are obtained.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a waveform recording apparatus used in carrying out the present invention.

FIG. 2 is a flowchart for explaining an example of the operation of the present invention.

FIG. 3 is a flowchart showing a subroutine of auto scaling.

FIG. 4 is an explanatory diagram showing a display example of an absolute value calculation waveform.

FIG. 5 is an explanatory diagram showing a display example of a differential operation waveform.

FIG. 6 is an explanatory diagram showing a display example of an integral calculation waveform.

FIG. 7 is an explanatory diagram showing a display example of an input waveform.

FIG. 8 is an explanatory diagram showing a conventional display example of a calculation waveform obtained by differentiating the input waveform of FIG. 7;

FIG. 9 is an explanatory diagram showing a conventional display example of a calculation waveform obtained by integrating the input waveform of FIG. 7;

[Explanation of symbols]

 Reference Signs List 10 A / D converter 11 CPU 12 Memory 13 V-RAM 14 Display unit 15 Operation unit W Original input waveform Wa Absolute value calculation waveform Wd Differentiation calculation waveform Wi Integration calculation waveform

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 13/00-13/42 G09G 5/36

Claims (2)

(57) [Claims] An analog input signal is converted into a digital signal by an A / D converter and a central processing unit (C).
PU) performs predetermined arithmetic processing on the digital signal, and displays the arithmetically processed data as a waveform on a display unit such as a CRT. , The maximum value MAX and the minimum value MIN are detected, the width W and the intermediate value C are obtained, and the width W is represented by a series of m × 10 ⁿ (m and n are arbitrary integers). , And the intermediate value C is defined as {correction width CW / 10 ^p } × q (p and q are arbitrary integers).
Is compared with the numerical value represented by the series, and the nearest upper or lowermost value is set as the corrected intermediate value CC, and the corrected intermediate value C
C. A method for displaying a waveform of a waveform recording apparatus, wherein the waveform data is displayed on a screen with the correction width CW / 2 as an upper limit value UL and a lower limit value LL when a calculated waveform is displayed, respectively. 2. If one of the maximum value MAX and the minimum value MIN is out of the range of the corrected intermediate value CC ± the corrected width CW / 2, the corrected width CW is changed to a numerical value of a higher order series. The waveform display method for a waveform recording apparatus according to claim 1, wherein: