JPH0356821A - Measuring instrument - Google Patents

Abstract

PURPOSE:To observe some of overlapping frequency characteristic measurement ranges at the same time and to maximize the amount of information per screen by sweeping and measuring a measurement point by a CPU according to a segment table. CONSTITUTION:When an input format is selected through a keyboard 1, a corresponding input image plane is displayed on a CRT 10 and when a measurement start is commanded after the editing of the segment table and the display format of a measurement result are specified, a CPU 3 reads a start point, a measurement point, and an end point among measurement frequencies of one line of the segment table to set a signal source 21, a reception part 23, etc., measure an element DUT 22 to be measured as to the corresponding points, and stores data on a RAM 7. In this case, the segment table is made to function as a sweep table. The measurement result is sent to the CRT 10 through a CRT control unit 8 and plotted and displayed according to the specified display format.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a measuring device, and more particularly to a technique for displaying measured values at equal intervals in the order of measurement.

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

An oscilloscope is a typical measurement device that performs time domain measurements, and with advances in digital technology, many models called digital oscilloscopes are now commercially available. Digital oscilloscopes sample input signals, convert them to digital values, and store them. At the same time, an electronic computer is used to perform fast Fourier transform on this stored waveform data and display it in the frequency domain.
Some perform various mathematical operations such as signal multiplication. Japanese Patent Publication No. 1-24269 discloses an invention regarding such a signal processing display device for 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 subjected to calculations. The real-time waveform as a function of time and the processed data are selectively displayed on the screen.

Furthermore, the logic analyzer VP-3666A commercially available from Matsushita Tsushin Kogyo Co., Ltd. is capable of displaying a real-time waveform as well as enlarging two different data areas that retain a portion of the waveform.

Typical measurement devices that perform frequency domain measurements include spectrum analyzers and network analyzers.

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

That is, partial enlargement based on stored data, time domain display by inverse Fourier transform, and calculation display such as distance domain display are examples.

In both the frequency domain and time domain measurement devices described above, it has been common practice to use frequency or time as a sweep parameter, and to display these parameters as well.

However, in recent years, as the frequency range to be measured has become wider, it has become desirable to be able to arbitrarily set measurement accuracy and measurement order.

There are various reasons for this, but for example, in order to design more precisely, it is necessary to precisely monitor several locations 4 that represent the overall characteristics. Further, depending on the requirements of the actual manufacturing process, there may be a requirement for a sweep that is not necessarily a unidirectional sweep. That is, one or more narrow frequency ranges are observed in detail to make adjustments, and the overall characteristics are also observed to confirm whether any abnormalities occur.

As a first example, the center frequency r. Let us consider the measurement of a bandpass filter whose bandwidth is dF. FIG. 4 shows the transfer characteristic W of the bandpass filter. The measurement range is from fL force to fl. I, and measurements are taken over three mutually overlapping frequency intervals (fL,
In many cases, it is desired to continuously measure each section of f2), (f+, f4), and (f1, flI) at different resolutions and obtain the results. In such a case, the measurement is from r, to f
Since it changes to 1, it cannot be swept in one sweep. Furthermore, the prior art does not have a function to display these simultaneously.

A second example will be explained with reference to FIG. (”) in Figure 5
This method observes the resonance characteristics of a crystal resonator from its impedance characteristics. Frequency f1 is the fundamental resonant frequency,
f, is the secondary resonance frequency.

Resonant frequency f. , f. In order to observe the area around the area in detail, it is necessary to cut out only a part of it and perform a high-resolution sweep to obtain only the number of measurement points that can be displayed on the display screen, as shown in Figure 5 (b). . Since there is no measuring instrument with such a sweep and display function, conventionally it has been necessary to display the vicinity of f1 and then display the vicinity of f2. The section near f1 is f. -r, and it is clear that it becomes almost invisible in the display of (a).

Also, the frequency resolution in the vicinity of r is 1 of the resolution in the vicinity of f,
Since /2 is appropriate, the display widths of both sections are not the same, and it was necessary to perform further calculations in order to make the display widths of both sections the same as shown in FIG. 5(b). Figure 5)
A display like this is possible by implementing the present invention.

[Object of the Invention] Therefore, it is an object of the present invention to solve the above-mentioned problems by providing a measuring device that allows sweeping in arbitrary frequency order and displays the results in the order of strokes.

SUMMARY OF THE INVENTION To achieve the above objectives, a recently developed fast switching signal source is used at low cost. Recent high-speed frequency matching devices can switch frequencies on the order of 14H2 within a few μs.
1. It can be done in several 100 μS and is inexpensive. ,000 point switching is involved. This can be accomplished within 1 second.

Therefore, the measurement frequencies are selected in a desired order, and measurements are performed in that order. Further measured values are displayed against the order.

Since the horizontal axis of the display is not the frequency but the order, the density of the measurement points can be displayed to be constant regardless of the size of the measurement frequency interval.

If necessary, it is possible to specify using a marker as in the past, and to read other parameters such as the frequency of the specified point.

[Embodiment of the Invention] FIG. 1 shows a measuring device 1 according to an embodiment of the present invention. FIG. 2 is a schematic block diagram of O.O.O.

A user of the measuring device 100 uses manual means such as the keyboard 1 to issue desired commands to the central processing unit (CPU) 2 via the keyboard control unit 2. Based on the command, the CPU 2 communicates with each component of the measuring device 100 via the data bus 5 and address bus 4. R
The OMB stores programs and constants for cpv2, and the RAM 7 stores input programs, measurement data, and the like. Display device of measuring device 1.00 (C R T) 10ha C R Tl! lJal
7 person Akiyu = -/ } 8! : It is under control and displays the data in the video memory device (VRAM) 9. A CRT is a display device such as a cathode ray tube or liquid crystal.

- A display image is configured in RAM9. VR A
M9 is a CR different from address bus 4 and data bus 5.
Address bus 11 and data bus l2 of T control unit 8
controlled by

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

In FIG. J, the DUT 22 has a structure that requires an input, but if the DUT 22 is a signal source to be measured, the signal source 21 may be unnecessary.

In the following description, it will be assumed that the DUT 22 is a filter and the measurement device 100 performs a network analyzer operation to measure the transfer characteristics thereof.

The user selects an appropriate manual format using the keyboard 1.

A manual screen according to the selected input format is displayed on the CRT 1.0. In the explanation of this embodiment, the conventionally known segment table method and the giant tabular manual format are used. FIG. 3(a) shows the case where the results of manual operation in this format are displayed on the CRTIO.

Each row is called a segment and is assigned a series of segment numbers. Each segment is determined by a starting point having the lowest frequency, an end point having the highest frequency, and the number of measurement points (scores) among the measurement frequencies (measurement points) included in the segment.

For example, segment 2 is composed of 101 points with a minimum frequency of 40 kHz and a maximum frequency of 10 kL.

The intervals between each measurement point are equal. They can also be spaced unevenly if necessary. It is also possible to add amplitude and other elements to the segment.

The input segment table can be edited using the keyboard 1.

When the editing of the segment table is completed, the display format of the measurement results is specified, and a command to start measurement is input from the keyboard l, the CPU 2 reads segment 1 and a different segment if desired, and sends the signal source 21 and the receiver. 23 and other necessary settings. First frequency is 1
．． 5k[IZ] and measure the D U T 22 with a desired amplitude, and store the measured data in the RAM 7. Furthermore, if necessary, further calculations are performed to obtain the measurement value.

The measurement results are sent to the RT control unit 8 and plotted on a screen in a display format specified by a command in advance. Next, the measurement frequency is changed to 2 kHz, and the measurement is performed for the first time, and the measurement is performed at 50 kHz, and the measurement of segment 1 is completed.

Next, segment 2 and segment 3 are sequentially measured and the measurement results are plotted.

The display format of the present invention is 100 + assuming that there are 3 segments in the segment table of the present invention.
101. +201 = 402 points will be displayed.

The entire length of the horizontal axis of the display or a portion thereof is divided into 402 equal parts, and the measurement points are displayed in the order of measurement. In particular, for the purpose of distinguishing between segments, it is possible to select an appropriate display such as inserting a vertical line between segments, attaching an identification mark, or making the interval between segments larger than the interval between points within a segment.

Conventionally, with measuring instruments such as the HP 8573A/B sold by Yokogawa Hewlett-Packard Corporation, measurement points included in segments input using the segment table method are sorted in ascending or descending order of measurement frequency across all segments. , you are getting the final sweep table. Actual measurements are performed in accordance with the sorted measurement order of the sweep table. Also, the display is performed with frequency on the horizontal axis. The horizontal axis is generally linear or logarithmic frequency.

In the embodiment of the present invention, since each segment is measured sequentially without overlapping, the segment table functions as if it were a sweepbow table itself, and the three segments shown in FIG. ) can be easily displayed.

1 kHz, 2 kHz with 2 points for each segment
z1 kHz! , 2 kHz, etc., or by setting each point to 1 and
kHz, 2 kflz, 3 kHz,...9 ktlz
, 10kll! , 9 kllz , 8 kllz
, . . . It is also easy to perform a triangular sweep such as 2 kHz, 1 kHz.

Furthermore, the zigzag sweep can be realized by repeatedly sweeping two segments. It is only necessary to select the display so that the required number of points can be displayed. Therefore, 2 segments were manually created,
A program that repeats this process a desired integer number N times may be input into the RAM 7 and executed.

(b) in Figure 3 shows 1 k}Iz, 2 kHz, 3
This is a display screen that measures and displays kL 110kHz, 11kHz, and 12kHz using the conventional method.
) is a display screen of a similar measurement according to the present invention.

It should be noted that the horizontal axis in FIG. 3('b) is frequency, and the horizontal axis in FIG. 3(C) is order.

Note that FIG. 2 is a flowchart of a typical measurement.

In a first step 200, the type of measurement is selected and the necessary parameters are set.

At this stage, it is necessary to select parameters to be measured for the DUT and set limit values to prevent damage to the DUT.

In a second step 202, the DOT is installed and configured to be measurable.

In the third step 204, the display format of the measurement results is specified. The horizontal axis is specified in order, and the vertical axis is chosen to be linear or logarithmic.

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

In a fifth step 208, based on a command to start measurement execution, a signal is applied to the DUT with the pointer set to 1 to start measurement, and the result is stored in RAM7. If necessary, perform further calculations in the sixth step 2!0 (for example, perform calculations such as error correction) to calculate the display address.1.The display address is the coordinates of where to plot on the CRT screen, and the third According to the display format determined in step, the ordinate is the measurement result, and the abscissa is a value proportional to the value of the pointer. Alternatively, the value of the pointer -1 may be a value proportional to the abscissa.

In a seventh step 212, based on the result of the sixth step, a display instruction is given to the CRT control unit, and the measurement result is displayed on the CRT.

It is measured in the eighth step 214 whether the value of the pointer has reached the maximum value (number of measurement points) N, and if affirmative, the process ends in the ninth step 215, and if negative, the process returns to the fifth step 208 and the pointer is increased by 1. Next measurement? Perform measurements. When the process ends at the ninth step 216, the pointer is cleared and the process returns to the step defined in the initial settings. However, the set parameters and display will remain as they are.

When implementing a display with the order on the horizontal axis in a conventional commercially available measuring instrument, specify an appropriate display range (for example, 1
kHz to 10k}I. ) Number of measurement points (e.g. 11)
(1k}lz in this example) and set the starting point to 1 kHz. As the measurement progresses, the horizontal axis of the display point is changed to 1 kllz + (ordinal) kH. You can specify .

Furthermore, it is easy to perform manual input from an external computer using an interface such as GPIB instead of using a keyboard.

[Effects of the Invention] As detailed above, by implementing the present invention, the second effect can be obtained.

■ When measuring the frequency characteristics of a
Several measurement ranges can be observed simultaneously. It is convenient to understand the characteristics of the device under test as a pattern for each measurement range or as a composite of them, and facilitates and improves the efficiency of research and development, inspection, and testing.

Since only the measurement points can be displayed on the screen, the efficiency of screen usage increases and the amount of information per screen is minimized.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of one embodiment of the present invention. FIG. 2 is a flow diagram showing a measurement flow in an embodiment of the present invention. FIG. 3 is a diagram for comparison between a conventional display of measurements including the same measurement points as the segment table (a) and a display according to an embodiment of the present invention (b). FIG. 4 is a diagram for explaining overlapping measurement ranges when measuring bandpass filters. FIG. 5 is an example of a conventional display (a) and a display that can be implemented using an embodiment of the present invention (b) when detailed measurement is performed by extracting only the fundamental resonance frequency and the vicinity of the secondary resonance frequency of a crystal resonator. 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 (DOT) 23: Receiving section 24; Analog-to-digital conversion fi (A/D converter) 100: Measurement Device

Claims (1)

[Claims] 1. At least three different frequencies f_1, f_2f
measuring frequency setting means for setting f_3 such that f_1 to f_2≠f_2 to f_3;
Components V_1, V_2 and V_ corresponding to _3, respectively
a measuring means for sequentially measuring the components V_1, V_2 and V_3;
3-Determine X_2>0, graph (x_1, y_1),
A measuring device comprising display means for displaying (x_2, y_2) and (x_3, y_3). 2. The measuring device according to claim 1, wherein the display is an orthogonal display. 3. The frequencies f_1, f_2 and f_3 are (f_2
-f_1)×(f_3-f_2)<0.