JP2928867B2 - measuring device - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a measuring device, and more particularly to a technique for displaying measured values at regular intervals in the order of measurement.

[Prior Art and Problems] Most of measurement devices perform measurement in one of two major fields called time domain measurement and frequency domain measurement.

An oscilloscope is a typical measuring device for performing time domain measurement, and many digital oscilloscopes are commercially available due to advances in digital technology. Digital oscilloscopes sample the input signal,
Convert to digital value and store. At the same time, the stored waveform data is fast Fourier transformed using an electronic calculator and displayed in the frequency domain, and differentiation, integration, average,
Some perform various mathematical operations such as the product of two signals. Japanese Patent Publication No. 1-24269 discloses an invention of such a signal processing and display device of a digital oscilloscope.

In the above invention, the input signal and the time axis sawtooth wave are sampled, digitally converted and stored, and the stored data is operated. Then, the real-time waveform as a function of time and the processed data are selectively displayed on the display screen.

In addition, the logic analyzer VP-3666A commercially available from Matsushita Communication Industrial Co., Ltd. can display real-time waveforms and also can perform enlarged display of two different data areas that keep a part thereof.

A representative measurement device for performing frequency domain measurement is a spectrum analyzer, a network analyzer, or the like.

Even in a digitized frequency domain measuring instrument, the measurement frequency is swept from a low frequency to a high frequency or from a high frequency to a low frequency. It is also possible to perform an arithmetic process such as storing the measured once in a storage device and displaying a part of them.

That is, it is a partial enlargement based on the stored data, or a calculation display of a time domain display and a distance domain display by the inverse Fourier transform.

In any of the above-described frequency-domain or time-domain measurement devices, display is generally performed on the frequency or time as a sweep parameter.

However, in recent years, as the frequency range to be measured has been widened, it has been desired that the measurement accuracy and the measurement order can be arbitrarily set.

Although there are various causes, for example, it is necessary to precisely monitor several points representing the overall characteristics in order to perform the design in more detail. In addition, there is a demand for a sweep that is not always a one-way sweep depending on a requirement in an actual manufacturing process. That is, one or a plurality of narrow frequency ranges are observed in detail, and adjustment is performed, and the entire characteristics are also observed to check whether an abnormality occurs.

As a first example, taking the measurement of the bandpass filter is the bandwidth dF at the center frequency f _0. FIG. 4 shows the transfer characteristic W of the bandpass filter. The measurement range is from f _L to f _H , and the measurements are performed on three overlapping frequency intervals (f _L , f ₂ ),
It is often desired to measure (f ₁ , f ₄ ) and (f ₃ , f _H ) continuously at different resolutions in each section and obtain the results. In this case, measurement from changing from f ₂ to f _1, can not be swept in one sweep. In addition, the prior art does not have a function of simultaneously displaying them.

A second example will be described with reference to FIG. FIG. 5 (a) is for observing the resonance characteristics of the crystal unit from its impedance characteristics. Frequency f ₁ is the fundamental resonance frequency, f ₂ is the second-order resonance frequency. Resonance frequencies f ₁ , f
_In order to observe the vicinity of ₂ in detail, as shown in FIG. 5 (b), only a part is cut out and a high-resolution sweep is performed.
There must be only as many measurement points as can be displayed on the display surface. Because such swept instrument with the display function is not conventionally After performing the display of f ₁ near had performed the display of f ₂ vicinity. It is clear that the section near f ₁ is about 1 / 10,000 of f ₂ −f ₁ and can hardly be visually recognized in the display of FIG.

Furthermore, the frequency resolution of f ₁ near the resolution of f ₂ near 1 /
Since 2 is appropriate, the display width of both sections will not be the same,
In order to make the display widths of both sections the same as shown in FIG. The display as shown in FIG. 5B is possible by implementing the present invention.

[Object of the Invention] Accordingly, an object of the present invention is to solve the above-mentioned problem by a measuring device that enables sweeping in an arbitrary frequency order and displays the order in the sweeping order.

SUMMARY OF THE INVENTION In order to achieve the above object, a recently developed high-speed switching signal source is used at low cost. In recent years, high-speed frequency synthesizers require several μs to several
Since it can be performed in 00 μs and is inexpensive,
Switching of 000 points can be realized within about several hundred millimeters.

Therefore, the measurement frequency is input in a desired order, and the measurement is performed in that order. Further measured values are displayed for the order. Since the horizontal axis of the display is not the frequency but the order, the display can also be performed so that the density of the measurement points is constant regardless of the size of the measurement frequency interval.

If necessary, it is possible to perform designation using a marker as in the related art, and to read other parameters such as the frequency at the designated point.

FIG. 1 is a schematic block diagram of a measuring apparatus 100 according to one embodiment of the present invention.

The user of the measuring device 100 issues a desired command to the central processing unit (CPU) 3 via the keyboard control unit 2 by using input means such as the keyboard 1. The CPU 3 communicates with each component of the measuring device 100 via the data bus 5 and the address bus 4 based on the command. ROM6 contains C
The program and constants for PU3 are stored in RAM7
Stores input programs, measurement data, and the like. The display device (CRT) 10 of the measuring device 100 is controlled by the CRT control unit 8, and the video memory device (V
-RAM) 9 data is displayed. A CRT is a display device such as a cathode ray tube or a liquid crystal.

The CRT control unit 8 receives the command list from the RAM 7, interprets the command list, and forms a display image on the V-RAM 9. The V-RAM 9 is different from the address bus 4 and the data bus 5 in the address bus 11 of the CRT control unit 8.
And the data bus 12.

On the other hand, the CPU 3 further controls the signal source 2 under the control of the storage program in the ROM 6 in accordance with the program stored in the RAM 7.
1. Operate the receiver 23 and the analog-to-digital (A / D) converter 24 to measure the characteristics of various parameters of the device under test (DUT) 22 connected between the signal source 21 and the receiver 23. Do.

In FIG. 1, the DUT 22 has a structure requiring an input, but when the DUT 22 is a signal source to be measured, the signal source 2
1 may be unnecessary.

In the following, the DUT 22 is a filter and the measuring device 100
Perform a network analyzer operation to measure the transfer characteristic.

The user selects an appropriate input format from the keyboard 1. An input screen according to the selected input format is displayed on the CRT 10. In the description of the present embodiment, a conventionally known segment table system and a target table format input format are used. FIG. 3A shows the result of inputting in this format.
This shows a case where it is displayed on CRT10.

Each row is called a segment and has a series of segment numbers. Each segment is determined by the start point which is the lowest frequency, the end point which is the highest frequency, and the number (points) of the measurement points among the measurement frequencies (measurement points) included therein.

For example, segment 2 is composed of 101 points having a lowest frequency of 40 kHz and a highest frequency of 100 kHz. The intervals between the measurement points are equal. If necessary, the intervals can be unequal. It is possible to add additional amplitude and other factors to the segment.

Editing of the input segment table can be performed from the keyboard 1.

When the editing of the segment table is completed, the display format of the measurement result is specified, and a measurement start command is input from the keyboard 1, the CPU 3 reads a segment different from the segment 1 as desired, Set 23 and other necessary parts. First, set the frequency to 1.5 kHz, measure the DUT 22 with the desired amplitude, and store the measured data in RAM7.
To be stored. Further, if necessary, further calculation is performed to obtain a measurement result.

The measurement result is sent to the CRT control unit 8 and plotted on a screen in a display format specified in advance by a command. Next, the same measurement is performed with the measurement frequency set to 1.99 kHz. Thereafter, at about 0.49 kHz intervals, 101 points are measured up to 50 kHz, and the measurement of segment 1 is completed.

Next, in segment 2, 0.6kHz (= (100kHz-40kHz)
z) / (101-1)) and 101 points at the frequency interval of 0.49 kHz (= (500 kHz-90 kHz) / (201-
Measure 201 points sequentially at the frequency interval of 1)) and plot the measurement results.

Assuming that the display format of the present invention is all three segments in the segment table of the present invention, 100 + 101
+ 201 = 402 points will be displayed.

The total length of the horizontal axis of the display or a part thereof is equally divided by 402, and the measurement points are displayed in the order of measurement. In particular, for the purpose of discriminating between segments, display such as inserting a vertical line between segments, adding an identification mark, and making the interval between segments larger than the interval between points in the segment can be appropriately selected.

Conventionally, with measuring instruments such as HP8573A / B marketed by Yokogawa Hewlett-Packard Co., Ltd., the measurement points included in the segment input in the segment table method are sorted in ascending or descending order of the measurement frequency over all segments, and the final Sweeping table has been gained. The actual measurement is performed according to the sorted measurement order of the sweep table. In addition, the display is performed with the horizontal axis representing the frequency. The horizontal axis is generally a linear or logarithmic frequency.

In the embodiment of the present invention, since the segments are measured sequentially without overlapping, the segment table functions as the sweep table itself, and the three segments in FIG. 4 are sequentially measured and displayed, and FIG. The display of b) can be easily performed.

1kHz, 2kHz, 1kHz, 2kHz with 2 points for each segment
Segs that perform a zigzag sweep like ……, 1kHz, 2kHz, 3kHz,… 9kHz, 10kHz
It is easy to perform a triangular sweep like z, 9kHz, 8kHz, ... 2kHz, 1kHz.

The zigzag sweep can be realized by repeatedly sweeping two segments. The display may be selected so that only the required points can be displayed. Therefore, a program for inputting two segments and repeating the desired number N times may be input to the RAM 7 and executed.

FIG. 3 (b) shows 1kHz, 2kHz, 3kHz, 10kHz11kHz,
It is a display screen that measures and displays 12 kHz by the conventional method,
When this is displayed on the segment table according to the present invention, the segment number is as follows: segment number start point end point number 1 1 kHz 3 kHz 3 2 10 kHz 12 kHz 3 In FIG.
Only the 6 points, which is the total number of measurements, are displayed. At this time, the intervals on the horizontal axis are shown at regular intervals.

It should be noted that the horizontal axis in FIG. 3B is frequency and the horizontal axis in FIG. 3C is order.

 FIG. 2 is a flowchart of a typical measurement.

In a first step 200, the type of measurement is selected and set, the measurement frequency _{(f 1, f 2 ,, f} n) set of parameters required such as is carried out. Measured parameters of the DUT (V ₁ ,
Selection of V _2, ..., V _n ) and setting of limit values such as prevention of DUT destruction need to be performed at this stage.

In the second step 202, a configuration is adopted in which a DUT is mounted and measurement is possible.

In a third step 204, the measurement result _(1, y ₂ ,,,
performing display format designated y _n). The horizontal axis is specified in order, and the vertical axis is linear or logarithmic.

In the fourth step 206, other (parameter) inputs such as the output amplitude of the signal source 21 and the input of the segment table are performed.

In the fifth step 208, a signal is applied to the DUT with the pointer set to 1 based on the measurement execution start command, and measurement is started, and the measurement result (V ₁ , V _2, ..., V _n ) is R
Stored in AM7. If necessary, a further operation is performed in a sixth step 210, and the display addresses (x ₁ , y ₁ ), (x ₂ ,
y ₂₎ ,, (x _n, to calculate the y _n). The display address is C
The coordinates of where to plot on the RT screen, and the measurement results (y ₁ ,
y _2, ..., y _n ) are displayed on the ordinate, and the abscissas (x ₁ ,
x ₂ , x _n ) are values equally divided by the number of measurement points. Alternatively, a value equally divided by (the number of measurement points-1) may be used as the value of the abscissa.

In a seventh step 212, a display instruction is given to the CRT control unit based on the result of the sixth step,
The measurement result is displayed on RT. It is measured in an eighth step 214 whether or not the value of the pointer has reached the maximum value (the number of measurement points) N. If affirmative, the process is terminated in a ninth step 215; The next measurement point is measured. Upon completion of the ninth step 215, the pointer is cleared, and the process returns to the step determined in the initial setting. However, the set parameters and display are left as they are.

When the display with the order on the horizontal axis is realized in a conventional measuring instrument, a suitable display range is specified (for example,
The increment is calculated from the number of measurement points (for example, 10) (1 kHz to 10 kHz) (1 kHz in this example), and the starting point is set to 1 kHz. As the measurement proceeds, the horizontal axis of the display point may be designated as 1 kHz + (order) kHz.

Further, it is easy to perform input from an external computer or the like using an interface such as GPIB instead of a keyboard.

[Effects of the Invention] As described in detail above, various effects can be obtained by implementing the present invention.

When measuring the frequency characteristics of the device under test, some of the overlapping measurement ranges can be observed simultaneously. It is convenient when the characteristics of the device to be measured are considered as a pattern for each measurement range or as a total thereof, and the easiness and efficiency of research and development, inspection, and testing are improved.

Since only the measurement points can be displayed on the screen, the use efficiency of the screen is increased, and the amount of information per screen is maximized.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of one embodiment of the present invention. FIG. 2 is a flowchart showing a measurement flow according to one embodiment of the present invention. FIG. 3 is a diagram for comparing a display (b) according to a conventional example of measurement including the same measurement points as the segment table (a) with a display (b) according to an embodiment of the present invention. FIG. 4 is a diagram for explaining overlapping measurement ranges when performing bandpass filter measurement. FIG. 5 shows examples of a conventional display (a) and a display (b) that can be implemented in one embodiment of the present invention when only the fundamental resonance frequency and the vicinity of the secondary resonance frequency of the crystal unit are taken out for detailed measurement. FIG. 1: Keyboard 2: Keyboard control unit 3: CPU (central processing unit) 4, 11: Address bus 5, 12: Data bus 6: ROM (read only memory) 7: RAM (random access memory) 8: CRT control unit 9: V-RAM (video RAM) 10: Display device (CRT) 21: Signal source 22: Device under test (DUT) 23: Receiver 24: Analog to digital converter (A / D converter) 100: measuring device

Claims (3)

(57) [Claims] 1. At least three different frequencies f ₁ ,
measuring frequency setting means for setting f ₂ , f _{3 so} that f ₁ ｆf ₂ ≠ f ₂ ｆf ₃ , an input signal is received, and the frequencies f ₁ , f 2 of at least one parameter of the input signal are received. Measuring means for sequentially measuring the components V ₁ , V ₂ , and V ₃ respectively corresponding to ₂ and f ₃ in this order; and measuring results regarding the measurements of the components V ₁ , V ₂ , and V ₃ with y ₁ respectively. , Y ₂ and y _3, and x ₁ , x ₂ and x ₃ corresponding to the measurement frequencies f ₁ , f ₂ and f ₃ and representing the abscissa are x ₂ −x ₁ = x ₃ −x ₂ > 0. By definition, the graphs (x ₁ , y ₁ ), (x ₂ , y ₂ ) and (x ₃ ,
y ₃ ) display means for displaying the measured value. 2. The measuring device according to claim 1, wherein said display is an orthogonal display. 3. The frequency f ₁ , f ₂ and f ₃ are set to (f ₂ −f
_3. The measuring device according to claim 1, wherein the measuring device is selected so that ₁ ) × (f ₃ −f ₂ ) <0.