KR100291079B1 - Method for storing maximum and minimum value of digital storage oscilloscope in peak detecting mode - Google Patents

Abstract

PURPOSE: A method for storing maximum and minimum value of a digital storage oscilloscope in peak detecting mode is provided to accurately output maximum value and minimum value of an input wave while reducing required amount of acquisition memory in half amount by selecting maximum and minimum value of input data in all equivalent sample region. CONSTITUTION: A method for storing maximum and minimum value of a digital storage oscilloscope in peak detecting mode is implemented on the assumption that waveform of input data is periodic and start and end of data collection cycle is determined on the basis of same position in input waveform. In a first data collection cycle, only maximum value of input data is selected in all equivalent sample range and stored in an acquisition memory in a first step(10). After the first cycle, the maximum value data stored in the memory is stored in CPU memory in a second step(20). In a second data collection cycle, only minimum value of input data is selected in all equivalent sample range and stored in the acquisition memory in a third step(30). After the second cycle, the minimum value data stored in the memory is stored in CPU memory in a fourth step(40). The maximum and minimum value data are outputted at the same time so as to overlap maximum and minimum value waveform each other in a fifth step(50).

Description

How to Store Maximum and Minimum Values for Peak Detect Modes in Digital Storage Oscilloscopes

The present invention relates to a method for storing maximum and minimum values in peak detection mode of a digital storage oscilloscope.

When the digital storage oscilloscope operates in the peak detection mode, data in the equivalent sample interval is collected, the maximum and minimum values in the equivalent sample interval are detected, stored in the acquisition memory, and then output to the screen.

Equivalent sample intervals in a digital storage oscilloscope are described. The digital storage oscilloscope screen consists of 10 divisions horizontally, with a total of 500 points of 50 points in each partition and a total of 501 points of 1 vertical. Since the horizontal resolution of the screen is 500 points, no matter how fast the sampling rate of the input data is, only 500 points are output through the screen. That is, regardless of the sampling rate of the input data, the screen seems to be sampled once every time between points on the screen. The section between the points on the screen is an equivalent sampling section, and the time between the points on the screen is called the equivalent time, and the inverse of the equivalent time is the equivalent sampling rate.

Even if the sampling rate of the data increases, if the time per section on the screen of the digital oscilloscope is fixed, all the data cannot be output on the screen. That is, the sampled data is lost due to the limitation of the horizontal resolution of the screen. In such a case, the peak detection mode is a data acquisition mode for outputting data on the screen of the digital oscilloscope without losing information about data sampled at a high sample rate.

In the peak detection mode, the maximum and minimum values for the data in the equivalent sampling interval are respectively detected, stored in the acquisition memory, and output on the screen.

1 is related with the prior art, and is a block diagram of the maximum and minimum value detection apparatus in the peak detection mode of a digital storage oscilloscope. The maximum and minimum value detection apparatus shown in FIG. 1 has a dual input stage of A bank data and B bank data, and can be used in connection with an A / D converter of a dual output stage.

The maximum and minimum value detection apparatus shown in FIG. 1 detects the maximum and minimum values for each equivalent sample interval, but performs both the maximum value detection and the minimum value detection during a single data collection period. To this end, as shown in FIG. 1, both a maximum value detection device and a minimum value detection device are included.

The default behavior is as follows: Among the data of the A and B banks, a larger value is sent to the uppermost maximum value detection device, and a smaller value is sent to the lowermost minimum value detection device. The upper maximum detection device outputs the maximum value among the data in the equivalent sample interval, and the lower minimum detection device outputs the minimum value among the data in the equivalent sample interval. That is, according to the apparatus shown in FIG. 1, it is possible to obtain the maximum and minimum values in the equivalent sample interval, and to obtain both the maximum and minimum values in a single data collection interval.

However, a large number of elements are needed to construct the apparatus shown in FIG. In addition, since the maximum and minimum values acquired for each equivalent sample interval must be stored in the acquisition memory, the capacity of the acquisition memory must be large.

To solve this problem, LeCroy detects the maximum value in one equivalent sample interval and the minimum value in the next equivalent sample interval, detects the maximum value and the minimum value for the equivalent sample interval, and stores it in the acquisition memory. Thus, a method of reducing the required acquisition memory capacity in half has been proposed.

However, the LeCroy method described above reduces the required capacity of the acquisition memory by half, but has the maximum peak of the input waveform in the equivalent sample interval detecting the minimum value, or the minimum peak of the input waveform in the equivalent sample interval detecting the maximum value. If there is, the maximum or minimum value of the input waveform cannot be accurately captured, and if this problem is repeated, information on the peak value of the input waveform may be lost.

SUMMARY OF THE INVENTION The present invention is directed to solving the problems of the prior art as described above, and an object of the present invention is to provide a digital storage oscilloscope capable of accurately outputting the maximum and minimum values of an input waveform while reducing the amount of required memory in half. It is to provide a method for storing the maximum value and the minimum value in the peak detection mode.

1 is a maximum and minimum value detection apparatus according to the prior art.

2 is a flow chart of the maximum and minimum value storage method according to the present invention.

3 is a block diagram of an apparatus for applying the maximum and minimum value storage method according to the present invention.

4 is a diagram for explaining a waveform output by the method according to the present invention.

In the peak detection mode of the digital storage oscilloscope according to the present invention for achieving the above object, the method of storing the maximum value and the minimum value of the digital storage oscilloscope is characterized in that the waveform of the input data is periodic and the start and end of the data acquisition cycle Assuming that it is determined based on the same position in the input waveform, and storing only the maximum value for all equivalent sample intervals of the input data in the first data collection period in the acquisition memory, after the first data collection period is over, Storing the maximum value data stored in the acquisition memory in the central operation memory, obtaining only the minimum value for all equivalent sample intervals of the input data in the second data acquisition cycle, and storing the minimum value data in the acquisition memory, after the second data acquisition cycle is over, The minimum value data stored in the acquisition memory And transmitting the maximum value waveform and the minimum value waveform by using the maximum value data and the minimum value data stored in the central operation memory.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a flowchart of a method for storing maximum and minimum values according to the present invention, and FIG. 3 is a configuration diagram of an apparatus for applying the method for storing maximum and minimum values according to the present invention shown in FIG.

In the method according to the present invention, it is assumed that the waveform of the input data is periodic, and that the start and end of the data acquisition interval are always determined based on the same position of the input waveform by the trigger function of the digital storage oscilloscope.

As shown in FIG. 2, the first step of the method according to the present invention is the step 10 of capturing only the maximum value for all equivalent sample intervals of the input data in the first data collection period and storing it in the acquisition memory.

After the first data collection period ends, the maximum value data for each equivalent sample interval stored in the acquisition memory in the first data collection period is stored in the central operation memory (step: 20).

In the second data collection period, only the minimum value is obtained for all equivalent sample intervals of the same input data as the maximum value obtained in the first data collection period and stored in the acquisition memory (step: 30).

After the second data collection period ends, the minimum value data for each equivalent sample interval stored in the acquisition memory in the second data collection period is stored in the central operation memory (step 40).

As a result, after the first and second data collection periods, the maximum value data and the minimum value data for each equivalent sample interval of the input data are stored in the central operation memory.

Therefore, the maximum value data and the minimum value data stored in the central operation memory can be output at the same time. That is, the maximum value waveform and the minimum value waveform are output so that they overlap (step 50).

The apparatus shown in FIG. 3 is a modification of the maximum value detection device having two input stages, and adds four XOR gates so that the maximum value detection mode or the minimum value detection mode can be selected. The input signal of the four additional XOR gates is commonly input the 'SEL' signal to select the maximum value detection mode or the minimum value detection mode. The other input of each XOR gate comes from the outputs of four comparators. If the 'SEL' signal is 'LOW', the input value of the XOR gate is output as it is. If the 'SEL' signal is 'HIGH', The input value is inverted to invert the output value of the comparator. That is, the output value of the comparator is inverted when the minimum value detection mode is selected, and the output value of the comparator is not inverted when the maximum value detection mode is selected. Therefore, the maximum value detection mode and the minimum value detection mode can be selected by the 'SEL' signal.

In the method according to the present invention, the maximum value detection mode is selected in the first data collection period to detect the maximum value for all equivalent sample intervals of the input data, and the minimum value detection mode is selected in the second data collection period to select all the input data. Since the minimum value is detected for the equivalent sample interval, there is no fear that information about the peak value of the input waveform is lost.

Further, in the first data collection period, first, the maximum value data for all equivalent sample intervals are stored in the acquisition memory, and when the first data collection period is finished, the data is sent to the central operation memory, and then, in the second data collection period, Since the minimum value data for the equivalent sample interval is stored in the acquisition memory, the capacity of the required acquisition memory can be reduced by half.

4 illustrates a waveform output by the method according to the present invention.

4 (a) is a waveform measured at 250M / s when the 1MHz square wave input. In FIG. 4 (a), it can be seen that overshoot and undershoot occur at the up / down edges of the square wave.

4 (b) is a waveform measured at 25 M / s at the same 1 MHz square wave input. It can be seen that in the waveform shown in FIG. 4 (b), the overshoot and undershoot information of the square wave may be lost and not appear.

4 (c) shows a case where the peak detection mode is used for a waveform measured at 25 M / s when a 1 MHz square wave is input under the same condition as that of FIG. 4 (b). In the waveform shown in FIG. 4 (c), unlike the waveform shown in FIG. 4 (b), all overshoots and undershoots of the square wave are shown.

As described above, according to the method of storing the maximum value and the minimum value in the peak detection mode of the digital storage oscilloscope according to the present invention, it is possible to output the information of the input waveform without losing the amount of the required acquisition memory in half. .

Claims (1)

A method of storing the maximum and minimum values in the peak storage mode of a digital storage oscilloscope, wherein the waveform of the input data is periodic and the start and end of the data acquisition cycle are based on the same position in the input waveform by the trigger function of the digital storage oscilloscope. Assuming that it is determined, taking only a maximum value for all equivalent sample intervals of the input data in the first data collection period and storing it in the acquisition memory; Storing, after the first data collection period, the maximum value data stored in the acquisition memory in the central operation memory; Storing only the minimum value for all equivalent sample intervals of the input data in the second data collection period and storing in the acquisition memory; Storing the minimum value data stored in the acquisition memory to the central operation memory after the second data collection period is finished; And outputting the maximum value data and the minimum value data at the same time by overlapping the maximum value waveform and the minimum value waveform by using the maximum value data and the minimum value data stored in the central operation memory. How to store the maximum and minimum values in mode.