JPH05273243A - Waveform measuring device - Google Patents

Abstract

PURPOSE:To increase utilization efficiency of an external memory by compressing measurement data in a waveform measuring device. CONSTITUTION:This measuring device is provided with an A/D conversion part 1 for converting measurement waveform to a digital signal, an acquisition RAM 2 for storing the output data of the A/D conversion part 1 as a measurement data a display processing part 3 for processing the measurement data which is stored in the acquisition RAM 2 to a waveform data status which can be displayed, a display 4 for displaying the waveform data which is processed by the display processing part, and a first histogram processing part 7 for obtaining the level frequency distribution of the output data of the A/D conversion part 1. Furthermore, it is also provided with a second histogram processing part 8 for sorting the level frequency distribution of the first histogram processing part 7 in the order of frequency, a re-coding part 9 for creating a conversion map by re-coding the processing result of the second histogram processing part 8 and then converting the measurement data which is stored in the acquisition RAM 2 to an optimum bit length code data based on a conversion map, and an external memory 6 for storing the optimum bit length code data which is converted by the re-coding part 9 and the conversion map.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform measuring apparatus, and more particularly to compression of measured data when the measured data is stored in an external memory in the waveform measuring apparatus using an A / D converter.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of an example of a conventional waveform measuring apparatus. In the figure, reference numeral 1 is an A / D converter for converting a measured waveform into a digital signal.
Output data of the acquisition RAM as measurement data
Stored in 2. The measurement data stored in the acquisition RAM 2 is processed by the display processing unit 3 into a form of waveform data that can be displayed on the display unit 4 such as a CRT. The CPU 5 has a function of transferring and outputting the measurement data stored in the acquisition RAM 2 to an external memory 6 such as an IC card.

By the way, in the conventional transfer of the measurement data to the external memory 6 having such a configuration, the measurement data stored in the acquisition RAM 2 is transferred and output as it is.

[0004]

For this reason, a large capacity is required as the data storage capacity of the external memory in proportion to the increase in the measured data length. When the data storage capacity is constant, there is a problem that the number of measurement waveforms that can be stored decreases as the data length increases.

The present invention has been made in view of such problems, and an object thereof is to improve the utilization efficiency of an external memory by compressing measurement data.

[0006]

A waveform measuring apparatus of the present invention which solves such a problem measures an A / D conversion section for converting a measured waveform into a digital signal and output data of the A / D conversion section. Acquisition RAM to store as data
And a display processing unit for processing the measurement data stored in the acquisition RAM into a form of displayable waveform data,
A display unit that displays the waveform data processed by the display processing unit, a first histogram processing unit that obtains a level frequency distribution of output data of the A / D conversion unit, and a level frequency of the first histogram processing unit Second sort distribution by frequency
Of the histogram processing unit and the second histogram processing unit to recode the conversion map to create a conversion map, and the measured data stored in the acquisition RAM is used as the optimum bit length code data based on the conversion map. The re-encoding unit for converting into the following, and an external memory for storing the optimum bit length code data converted by the re-encoding unit and the conversion map are characterized by being configured.

[0007]

The waveform data converted by the A / D converter is efficiently compressed at high speed based on the level histogram data and stored in the external memory.

As a result, the external memory can be effectively used and a large amount of measured waveform data can be stored.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention, in which parts common to those in FIG. In the figure, the output data of the A / D conversion unit 1 is also added to the first histogram processing unit 7. The first histogram processing section 7 obtains a level frequency distribution of output data over a certain data length of the A / D conversion section 1, and the result is added to the CPU 5 and the second histogram processing section 8. The first histogram processing unit 7 is provided with a number of counters corresponding to the conversion bit number of the A / D conversion unit 1. For example, the A / D converter 1
When an 8-bit configuration is used, 256 counters are provided, and each counter has a 4-byte configuration to support a data length of 100 Kbytes or more. The second histogram processing unit 8 sorts the level frequency distribution of the first histogram processing unit 7 in frequency order, and the result is sorted by the CPU 5
Output to. Reference numeral 9 is a re-encoding unit, which is connected between the CPU 5 and the external memory 6 and also has an acquisition R.
The output terminal of AM2 is also connected. The recoding unit 9
Recodes the processing result of the second histogram processing unit 8 and stores it as a conversion map, and also converts the measurement data stored in the acquisition RAM 2 into optimum bit length code data based on the conversion map. The optimum bit length code data and the conversion map converted by the re-encoding unit 9 are stored in the external memory 6. CPU5 has
A ROM 10 that stores a program required to execute a series of processes of the CPU 5 and a RAM 11 that temporarily stores various data are also connected.

The operation in such a configuration will be described.
The writing of the measurement data from the A / D conversion unit 1 to the acquisition RAM 2 is started by using some signal as a trigger, and the measurement data is acquired as shown in FIG.
Stored in.

The first histogram processing section 7 also starts processing in synchronization with the start of writing of the measurement data, and every time a corresponding level is output, the count of the counter corresponding to that level is sequentially incremented by one. These processes are repeated a predetermined number of times. As a result, the count data of the first histogram processing unit 7 becomes as shown in FIG.

When outputting the measurement data stored in the acquisition RAM 2 to the external memory 6, the second histogram processing unit 8 is activated, and the processing results of the first histogram processing unit 7 are arranged in descending order of the level frequency. The process is executed. FIG. 4 shows an example of the result.
With respect to the result, a minimum bit code is newly added to a level having a high appearance frequency, and thereafter, a new bit code is given to all levels while increasing the bit length as the frequency becomes lower. The code conversion map thus obtained as shown in FIG. 5 is input to the recoding unit 9.

The measurement data stored in the acquisition RAM 2 is converted into an optimum bit length code by the recoding unit 9 based on the code conversion map and subjected to data compression processing, and then stored in the external memory 6. The conversion map is also stored in the external memory 6 at the end, and is used when the compressed data stored in the external memory 6 is restored to the original data form and stored again in the acquisition RAM 2.

When restoring the compressed data stored in the external memory 6 and re-storing it in the acquisition RAM 2, the conversion map stored in the external memory 6 is reloaded into the re-coding unit 9 and the external memory 6 is loaded. The compressed data stored in is input to the re-encoding unit 9 to execute the data format decompression process.

Although the external memory is an IC card in the above embodiment, it may be a floppy disk or hard disk, or may be a networked one.

[0016]

As described in detail above, according to the present invention, the following effects can be obtained. That is, A / D
Since the waveform data converted by the converter is data-compressed based on the level histogram data, the data can be compressed efficiently at high speed, the external memory can be effectively used, and a large amount of measured waveform data can be stored.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is an example diagram of writing measurement data to an acquisition RAM 2 in FIG.

FIG. 3 is an exemplary diagram of count data of a first histogram processing unit 7 in FIG.

FIG. 4 is a diagram showing an example of sorting processing by a second histogram processing unit 8 in FIG.

5 is an example diagram of a code conversion map of FIG.

FIG. 6 is a block diagram of an example of a conventional waveform measuring device.

[Explanation of symbols]

 1 A / D conversion unit 2 Acquisition RAM 3 Display processing unit 4 CRT (display unit) 5 CPU 6 External memory 7 First histogram processing unit 8 Second histogram processing unit 9 Recoding unit 10 ROM 11 RAM

Claims (1)

[Claims] 1. A for converting a measured waveform into a digital signal
An A / D conversion unit, an acquisition RAM that stores output data of the A / D conversion unit as measurement data, a display processing unit that processes the measurement data stored in the acquisition RAM into a form of waveform data that can be displayed, A display unit that displays the waveform data processed by the display processing unit, a first histogram processing unit that obtains a level frequency distribution of output data of the A / D conversion unit, and a level frequency of the first histogram processing unit A second histogram processing unit that sorts the distribution in order of frequency, and a conversion map is created by recoding the processing result of the second histogram processing unit, and the measurement data stored in the acquisition RAM is converted into the conversion map. A re-encoding unit for converting into optimum bit length code data based on the above, and an optimum bit length code data converted by the re-encoding unit And an external memory for storing a conversion map, and a waveform measuring device.