JP3142347B2 - 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, derivative, integral, absolute value, etc.)
, So that the calculated waveform data can be appropriately displayed on a display screen such as a CRT.

[0003]

By the way, as illustrated in FIG. 7, a PP (Peak to Pea) is used.
k), a sine wave of 10 V and 200 Hz is input, and the input waveform W has an upper limit value of + 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 the maximum value MAX and the minimum value MIN.
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 larger than the maximum value MAX is displayed as the upper limit value UL when displaying the calculated waveform
And the lowermost value smaller than the minimum value MIN is set as the lower limit value LL in displaying the calculated waveform, and the waveform data is displayed on the screen.

[0007]

According to the above arrangement, the calculated waveform is displayed large enough to fit on the screen without setting a scale value in advance.

Further, since the upper limit value UL and the lower limit value LL are simple numerical values such as 1 × 10 ⁿ , 2 × 10 ⁿ , and 5 × 10 ⁿ (n is an integer), it is easy to read.

[0009]

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 arithmetic 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 the sub-step SUB1, the maximum value MAX becomes the temporary upper limit value IMAX and the minimum value MIN
Are respectively set to the temporary lower limit value IMIN.

Thereafter, in the sub-step SUB2 and the next sub-step SUB3, the temporary upper limit value IMAX is corrected upward and the temporary lower limit value IMIN is corrected downward. That is, the upper limit value UL and the lower limit value LL on the display screen 14 are set to m × 10
Correction is performed so as to obtain a numerical value represented by a series of ⁿ (both m and n are integers).

Here, if the numerical sequence is 1 × 10 ⁿ ,
When it is assumed that 2 × 10 ⁿ and 5 × 10 ⁿ are set, the upper limit value UL is the provisional upper limit IM
The nearest higher value larger than AX is selected. For example,
When the provisional upper limit IMAX is assumed to be ^{1.1 = 1.1 × 10 0, 2.0} × 10 0 of the next-higher upper limit UL
Is set as the value of

Similarly, as the lower limit value LL, the nearest lower value smaller than the temporary lower limit value IMIN is selected. For example, the provisional lower limit value IMIN is 0.3 = 3.0 × 10 ⁻¹
, The nearest lower 2.0 × 10 ⁻¹ is set as the lower limit value LL.

When this correction is completed, the process returns to the main routine of FIG. 2 and in step ST5, the upper limit value UL,
Scaling is performed based on the lower limit value LL. For example, each waveform data is X, and the Y axis of the display screen 14 is 0 to 0.
Assuming that the resolution is 100 dots, Y = ｛(X−
Lower limit LL) / (Upper limit UL-Lower limit LL) Ｌ × 100
The calculated waveform is developed on the display screen 14 as
The waveform is displayed at T6.

In this way, the calculated waveform is displayed in such a size as to automatically fit on the display screen 14. If manual setting is selected in the previous step ST2, the process proceeds to step ST7. Then, the upper limit value and the lower limit value are manually set via the operation unit 15.

Here, the input waveform W of FIG.
(P-P10V, sine wave of 200 Hz) will be described in which the absolute value is calculated and the calculated waveform is displayed. In this case, the maximum value MAX is 5V and the minimum value MIN is 0V.
Therefore, “5 × 10 ⁰ ” is selected as the upper limit value UL, and the lower limit value LL is set to “0”, and the absolute value waveform Wa is displayed on the display screen 14 as shown in FIG.
Is displayed in a state of being stretched about twice.

Next, the case where the input waveform W is differentiated and its calculated waveform is displayed will be described. In this case, the maximum value MAX is 1.67 × 10 ⁴ and the minimum value MIN is −0.66 × 10 ^4.
Is selected as the value “2 × 10 ⁴ ”, and the value “−1 × 10 ⁴ ” is selected as the lower limit value LL on the display. As a result, as shown in FIG. Is displayed.

The case where the same input waveform is integrated and displayed will be described. In this case, the maximum value is 0.73 × 1
0 ^-2, since the minimum value was 0, the upper limit U in the display
L is set to “1 × 10 ⁻² ”. On the other hand, “0” is selected as the lower limit LL on the display, and the integrated waveform Wi is balanced on the display screen 14 as shown in FIG. It is displayed to fit well.

In the above embodiment, the sequence values of the upper limit value UL and the lower limit value LL are 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.

The grid (ruled lines) on the display screen 14 may be fixedly displayed or divided according to the display width.

[0027]

As described above, according to the present invention, the upper limit value UL and the lower limit value LL on the display screen are automatically set according to the amplitude of the operation waveform, which is extremely convenient in use.

Since the upper limit value UL and the lower limit value LL are set to simple numerical values such as 1 × 10 ⁿ , 2 × 10 ⁿ , and 5 × 10 ⁿ (where n is an integer), the waveform is observed. This has the effect of making it easier to read.

[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 as an original waveform.

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

FIG. 9 is an explanatory diagram showing a conventional display example of a calculation waveform obtained by integrating the input waveform of FIG. 8;

[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 (1)

(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. Are detected from among the maximum value MAX and the minimum value MIN.
And the minimum value MIN are compared with numerical values represented by a series of m × 10 ⁿ (m and n are arbitrary integers), and the immediately higher value larger than the maximum value MAX is displayed as the upper limit value UL when displaying the calculated waveform. And the minimum value M
A waveform display method for a waveform recording apparatus, wherein the waveform data is displayed on a screen, with the nearest lower value smaller than IN as a lower limit value LL at the time of displaying the calculated waveform.