CN101726644B - Digital storage oscilloscope with functions of waveform fast location and zooming - Google Patents

Abstract

The invention discloses a digital storage oscilloscope with waveform rapid positioning and zooming functions, which also includes: a characteristic value detection module and a characteristic value storage FIFO; a large-capacity detailed waveform memory is used to cache all sampling data, and the characteristic value detection module is used for The sampling data is screened, and the eigenvalue data is screened out from the continuous N sampling data. When observing the waveform, the eigenvalue data is first read and displayed. Since the eigenvalue data is 1/N of all collected data, the response speed is very fast and the waveform capture rate is high. When there is an abnormality in a certain segment of eigenvalue data, through the corresponding storage relationship between the sampling data of the detailed waveform memory and the corresponding storage relationship of the eigenvalue data, the corresponding acquisition data of the large-capacity detailed waveform memory is read in for processing and display, and the corresponding eigenvalue data of the segment is observed in detail. The waveform can be quickly positioned and zoomed, which solves the problems of slow response speed, low waveform capture rate, and difficult detection of harmful signals such as glitches under deep storage.

Description

A Digital Storage Oscilloscope with Waveform Rapid Locating and Scaling Functions

technical field

The present invention relates to a digital storage oscilloscope, in particular to a digital storage oscilloscope with the functions of fast positioning and scaling of waveforms under deep storage

Background technique

Since the digital storage oscilloscope was born in the 1970s, its application has become more and more extensive, and it has become one of the necessary tools for test engineers.

Sampling rate, memory depth (memory depth) and waveform capture rate are the three main performance indicators of digital storage oscilloscope (DSO). Sampling rate refers to the number of samples extracted from continuous signals and composed of discrete signals per second; storage depth indicates the ability to continuously collect and store sampling points at the highest real-time sampling rate, usually expressed in sampling points (pts); waveform capture rate Indicates the number of waveforms that the oscilloscope can capture and display per unit time, usually expressed in waveforms/second (wfms/s). The sampling rate is directly related to the memory depth, because the digital storage oscilloscope must manage the memory according to the user's instructions about the length of the capture time. If the user sets the time base control of the digital storage oscilloscope to 100us/div, if the waveform display area has 10×8 divisions, which means that the entire screen represents a time of 1ms, then the digital storage oscilloscope must be sure not to exhaust its memory The highest sampling rate that can be used to capture signals up to 1 ms without resource constraints. If the maximum sampling rate of the digital storage oscilloscope is 5GSPS and the storage space is 10k, then the actual sampling rate cannot be higher than 10MSPS. This sampling rate is significantly lower than the highest sampling rate, and the user's measurements will be susceptible to the adverse effects of undersampling—aliasing, loss of signal detail, and erroneous measurement results. These are serious problems for shallow memory oscilloscopes.

Manufacturers of digital storage oscilloscopes at home and abroad have made breakthroughs in improving storage depth. TDS6000 series digital storage oscilloscope from Tektronix, when two channels are used, the storage depth of each channel is 64Mpts, and when four channels are used at the same time, the storage depth of each channel is 32Mpts; 4000 series digital phosphor oscilloscope (DPO) Standard memory depth of 10Mpts per channel enables capture of long signal windows while maintaining fine timing resolution. The memory depth of Agilent's 54642A DSO and 54642D MSO series is 8Mpts; the memory depth standard of Agilent's DSO/DSA90000A series oscilloscope is 10Mpts, and the maximum is 1Gpts. The storage depth of the LT342L series of American LeCroy (LeCroy) is 1Mpts. In China, taking Puyuan's DS1000E series as an example, the maximum storage depth reaches 1Mpts for a single channel and 512Kpts for a dual channel. It can be seen that the improvement of the storage depth is one of the development directions of the digital storage oscilloscope in the future.

Applying large-capacity memory, such as DDR, DDR2, DDR3, LPDDR, etc., to digital storage oscilloscopes can greatly increase the storage depth of digital storage oscilloscopes, and at the same time, the sampling rate of AD will require a corresponding increase. The higher the memory depth of the DSO, the more detailed waveforms can be recorded.

In the deep storage working mode, data collection and storage are completed by trigger control. Based on the trigger signal, a large amount of waveform data before and after the arrival of the trigger signal is recorded in the entire storage space. The large storage depth ensures the acquisition time of waveform data at a high sampling rate, provides sufficient data information for waveform analysis, and can ensure the acquisition and recording of detailed signals. However, compared with the analog oscilloscope, DSO itself has the defect of poor response. As the storage depth increases, due to the processing time of digital waveform recording, it will inevitably bring about slow response. Some digital storage oscilloscopes with extremely deep memory can refresh the screen waveform for as long as 8 to 10 seconds each time. Applying such a large memory to DSO will definitely bring about the problem of slow response speed while increasing the memory depth. For example, with a sampling rate of 1GSPS and a storage depth of 128Mpts, the time to store a sample data is 1ns, then it takes 128ms to fully store, the microprocessor needs 100ns to read a sample data, and it takes 128Mpts×100ns to read the stored data. =12.8s, the response speed will inevitably be very slow. The higher the memory depth, the longer the continuous waveform capture time, the longer the data processing time of the system, the slower the response speed, the larger the dead time, the lower the waveform capture rate, and the harder it is for harmful signals such as glitches to be found.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a digital storage oscilloscope with fast waveform positioning and zooming functions. While realizing deep storage, it also solves the problem of slow response speed, low waveform capture rate, and difficult detection of harmful signals such as glitches. The problem.

To achieve the above object, the present invention has a digital storage oscilloscope with waveform fast positioning and zooming functions, including a signal conditioning channel, an analog-to-digital converter, a detailed waveform storage control module, a large-capacity detailed waveform storage, a microprocessor, and a display. It also includes:

A characteristic value detection module, connected with the analog-to-digital converter, used to detect the sampling data stream output by the analog-to-digital converter, and filter out the characteristic value data from the continuous N sampling data;

A eigenvalue storage FIFO is connected with the eigenvalue detection module for storing the eigenvalue data screened out by the eigenvalue detection module;

The conditioned analog signal output by the signal conditioning channel is sent to the analog-to-digital converter for sampling, and the obtained sampling data stream of discrete signal flows into the detailed waveform memory control module and the characteristic value detection module at the same time; the detailed waveform memory control module controls the sampling All the sampling data of the data stream are stored in the large-capacity detailed waveform memory for deep buffering, and the characteristic value detection module detects the sampling data stream, and selects the characteristic value data from the continuous N sampling data and stores them in the characteristic value storage FIFO; The sampling data of the detailed waveform memory of the capacity and the characteristic value data of the characteristic value storage FIFO are correspondingly stored;

When observing the waveform, the microprocessor first reads the eigenvalue data in the eigenvalue storage FIFO for processing, and sends it to the display for display. Store the corresponding storage relationship of the eigenvalue data of the FIFO, quickly find the address corresponding to the eigenvalue data in the large-capacity detailed waveform memory, and the microprocessor reads the sampling data corresponding to the large-capacity detailed waveform memory for processing, and sends it to It is displayed on the monitor, and the waveform corresponding to the eigenvalue data of this segment is observed in detail, which realizes the rapid positioning and zooming of the waveform.

The purpose of the invention of the present invention is achieved like this:

Firstly, use the large-capacity detailed waveform memory to buffer all the sampled data, and at the same time, the feature value detection module screens the sampled data, filters out the feature value data from the continuous N sampled data, and sends them to the feature value storage FIFO for storage . The detected eigenvalue data can include maximum value, minimum value, inflection point, average value, number of eigenvalues, etc. Then, when observing the waveform, first read the eigenvalue data in the eigenvalue storage FIFO for processing, and send it to the display for display. Since the eigenvalue data in the eigenvalue storage FIFO is 1/N of all sampled data, the display , the response speed is very fast and the waveform capture rate is high. When it is found that a certain segment of eigenvalue data is abnormal, for example, when the detected eigenvalue is the maximum value, harmful signals such as glitches can suddenly increase or decrease the eigenvalue data. At this time, the sampling data and eigenvalue of the detailed waveform memory Store the corresponding storage relationship of the eigenvalue data of the FIFO, quickly find the address corresponding to the eigenvalue data in the large-capacity detailed waveform memory, and the microprocessor reads the sampling data corresponding to the large-capacity detailed waveform memory for processing, and sends it to Display on the monitor, observe the waveform corresponding to the eigenvalue data in detail, such as a section of waveform with glitches, so as to complete the rapid positioning and zooming of the waveform, and solve the problem of slow response speed, low waveform capture rate and glitches under deep storage. problem dicovered.

Description of drawings

Fig. 1 is a schematic diagram of a specific embodiment of a digital storage oscilloscope with waveform rapid positioning and zooming functions in the present invention;

Fig. 2 is the address correspondence diagram when the data bit width is equal among the present invention;

Fig. 3 is the address correspondence when the data bit width is unequal among the present invention;

Fig. 4 is the rapid positioning and zooming of detailed waveform data between eigenvalues T _i and T _i+m ;

Figure 5 is an effect diagram of the positioning and zooming of the waveform.

Detailed ways

Specific embodiments of the present invention will be described below in conjunction with the accompanying drawings, so as to better understand the present invention. It should be noted that in the following description, when detailed descriptions of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

Example

Fig. 1 is a schematic diagram of a specific embodiment of a digital storage oscilloscope with waveform rapid positioning and zooming functions according to the present invention.

As shown in Figure 1, in this embodiment, the digital storage oscilloscope with waveform fast positioning and zooming functions includes a signal conditioning channel 1, an analog-to-digital converter 2, a detailed waveform memory control module 3, a large-capacity detailed waveform memory 4, Microprocessor 5 and display 6. In order to realize fast positioning and zooming functions, on the basis of the existing deep storage digital storage oscilloscope, an eigenvalue detection module 7 and a eigenvalue storage FIFO 8 are added, the eigenvalue detection module 7 is connected with the analog-to-digital converter 2, and the detection mode The sampling data stream output by the digital converter 2 filters out the eigenvalue data from the continuous N sampling data, and stores it in the eigenvalue storage FIFO 8.

The signal conditioning channel 1 conditions the input analog signal, and outputs an analog signal within the input range of the analog-to-digital converter 2 , and the analog signal is sampled in the analog-to-digital converter 2 to obtain a sampled data stream as a discrete signal. The sampling data flow is divided into two paths, one of which flows into the detailed waveform memory control module 3, and all the sampling data of the control sampling data flow are stored in the large-capacity detailed waveform memory 4 for deep buffering; one path flows into the characteristic value detection module for detection, from the continuous The eigenvalue data filtered out from the N sampling data are stored in the eigenvalue storage FIFO.

The sampling data of the large-capacity detailed waveform memory and the characteristic value data of the characteristic value storage FIFO are correspondingly stored. In this embodiment, this corresponding relationship is placed in the address mapping module 9 . There is a certain correspondence between the address of the eigenvalue data stored in the eigenvalue storage FIFO 8 and the address of the sampling data stored in the large-capacity detailed waveform memory 4.

的比例筛选特征值数据(即特征值存储FIFO 8中第i～i+k的存储空间对应着详细波形存储器中

段存储空间。As shown in Figure 2, under the condition that the data bit width is equal, if the capacity used for storing the detailed waveform memory 4 of large capacity is D, and the capacity of the characteristic value storage FIFO 8 is d, then the characteristic value detection module 7 according to

The proportion of screening eigenvalue data (ie The i-i+k storage space in the eigenvalue storage FIFO 8 corresponds to the detailed waveform storage

segment memory.

大容量的详细波形存储器4的存储地址数为

则特征值存储FIFO 8按照

的比例筛选特征值数据即

特征值存储FIFO 8中第i～i+k的存储空间对应着大容量的详细波形存储器4中第

段存储空间。As shown in Figure 3, under the condition that the data bit width is not equal, if the capacity used in the large-capacity detailed waveform memory 4 storage is D, the data bit width is M, the capacity of the characteristic value storage FIFO 8 is d, the data bit The width is m, then the number of storage addresses of the eigenvalue storage FIFO 8 is

The number of storage addresses of the large-capacity detailed waveform memory 4 is

Then the characteristic value storage FIFO 8 according to

The proportion of screening eigenvalue data is

The i-i+k storage space in the eigenvalue storage FIFO 8 corresponds to the large-capacity detailed waveform memory 4.

segment memory.

When the waveform corresponding to a certain section of characteristic value data needs to be observed in detail, the microprocessor 5 outputs the address of this section of characteristic value data to find the corresponding address in the address mapping module 9, that is, the corresponding sampling data address in the large-capacity detailed waveform memory 4 , then according to the sampling data address, the microprocessor 5 reads the corresponding sampling data in the large-capacity detailed waveform memory 4 through the detailed waveform memory control module 3 into the microprocessor 5 for processing, and sends it to the display 6 for processing. show.

In this embodiment, on the basis of the existing deep storage digital storage oscilloscope, a data flow switching module 10 is also added, and under the control of the microprocessor 5, the characteristic value storage FIFO 8 or large-capacity detailed waveform storage is switched. The data flow of 4 enters the microprocessor 5, and the microprocessor 5 realizes control and data processing functions, and the data processed by the microprocessor 5 is sent to the display for display.

When observing the waveform, first select the eigenvalue data in the eigenvalue storage FIFO 8 to observe, that is, the data flow switching module 10 switches to the eigenvalue storage FIFO 8, and the eigenvalue data stream of the eigenvalue storage FIFO 8 enters the microprocessor 5 process, and send it to the display 6 for display; when a certain section of characteristic value data needs to be observed in detail, the address of the microprocessor 5 outputting this section of characteristic value data finds the corresponding address in the address mapping module 9, that is, a large-capacity Corresponding sampling data address in the detailed waveform memory 4; under the control of the microprocessor 5, the data stream switching module 10 switches to the large-capacity detailed waveform memory 4 data streams, and the sampling data stream of the large-capacity detailed waveform memory 4 enters Processed in the microprocessor 5, and sent to the display 6 for display, which realizes rapid positioning and zooming of the waveform.

As shown in Figure 1, in this implementation, the detailed waveform memory control module 3, the characteristic value detection module 7, the characteristic value storage FIFO 8, the address mapping module 9 and the data stream switching module 10 are designed with a field programmable logic gate array .

In the specific implementation process, the analog-to-digital converter generally uses parallel time-alternating sampling analog-to-digital converters to increase the sampling rate, and the number of ADs used is a, so it is necessary to perform H: 1 feature on each AD sampling data After value detection and screening, perform secondary eigenvalue detection on the selected a eigenvalue data to filter a eigenvalue data, and the final screening ratio is (a×H):1 (N=a×H), then the eigenvalue The sampling data in the detailed waveform memory 4 corresponding to the i-th eigenvalue data in the storage FIFO8 can be represented by formula (1):

$\left(\begin{array}{c}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; i</span>}}\\ <span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span>\\ {\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; ai</span>}}\end{array}\right)<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

A _ni (n=1, 2, . flow. When storing W eigenvalue data in the eigenvalue storage FIFO 8, the detailed waveform storage 4 of large capacity is stored full, and the data and the amount of data stored in the detailed waveform storage 4 of large capacity can be represented by formula (2):

Then the sampling data storage of the storage space of the detailed waveform memory 4 of large capacity can be represented by formula (3):

The eigenvalue data storage of eigenvalue storage FIFO 8 is represented by formula (4):

(T ₁ , T ₂ , ..., T _i , ..., T _w ) (4)

The storage of the large-capacity detailed waveform memory 4 is to store according to the row of formula (3). The address count is stored from the first position of the first row. When one row is full, the next row is stored, and the address corresponding to the stored data is counted. The value represents where the data is stored. The number of elements in the formula (3) is the storage capacity of the large-capacity detailed waveform memory 4, and the formula (4) represents the characteristic value data stored in the characteristic value storage FIFO 8 and the storage location of the characteristic value data. Represents the storage data and its storage location in the large-capacity detailed waveform memory 4 corresponding to the i-th eigenvalue _Ti of the eigenvalue storage FIFO, and the elements in the formula represent the corresponding storage data in the large-capacity detailed waveform memory 4, and the elements The position of represents the storage position of the corresponding data in the large-capacity detailed waveform memory 4, and the storage position of the corresponding data is N×(i-1)+1 to Ni, where 1≤i≤W. When it is necessary to observe detailed waveform data between eigenvalues T _i and T _i+m , as shown in Figure 4, when using fast positioning and zooming, the microprocessor 5 stores the initial storage position of the waveform to be observed N× (i-1)+1 is sent to the addressing counter as the starting address of the addressing counter to start counting, and the m×N data required for fast reading is processed and sent to the display for display, so that there is no need to read irrelevant data, Greatly saves data reading and processing time; if fast positioning and zooming are not used, then the microprocessor 5 reads data and reads all the data in the detailed waveform memory from the initial address of the memory, and then processes and displays , it is obvious that the amount of data read at this time is much greater than the amount of data read when using the fast positioning and zooming technology, and the time required is much longer than the time required for data reading when using the fast positioning and zooming technology. The detailed waveform data between eigenvalue data T _i and T _i+m and the storage position of the detailed waveform data in the large-capacity detailed waveform memory 4 can be represented by formula (5).

In this embodiment, the characteristic value detection module 7 is configured by a field programmable logic gate array. The eigenvalue data can be screened and stored in the eigenvalue storage FIFO8 through the field programmable logic gate array. There are two methods for eigenvalue configuration: one method is to directly use the hardware language to perform eigenvalue screening and configuration on the field programmable logic gate array, and the software does not participate in the selection of eigenvalues; the other method is to pass all the eigenvalues through the hardware language Perform eigenvalue screening configuration on the field programmable logic gate array, and then realize the selection of eigenvalue data detection through software control according to user needs.

In this embodiment, the storage and addressing of the detailed waveform data of the large-capacity detailed waveform memory 4 is realized by a field programmable logic gate array, and a storage data addressing counter is configured inside the field programmable logic gate array to realize detailed waveform data. Correct storage of waveform memory data. The detailed waveform data reading and addressing of the large-capacity detailed waveform memory 4 is realized by the microprocessor control counter. The address signal and the number of read data are used to quickly read out the desired detailed waveform data from the large-capacity detailed waveform memory 4, and then send the detailed waveform data to the display 5 for display.

Using waveform rapid positioning and zooming technology, we can easily find harmful signals such as glitches, as shown in Figure 5. As shown in the lower figure of Figure 5, the displayed waveform is the waveform data in the eigenvalue storage FIFO. There are glitches in the waveform, and the detailed waveform at the glitch needs to be observed. Switch the data stream, quickly locate and zoom in on the waveform, and observe the detailed waveform at the burr. The upper figure in Figure 5 shows the detailed waveform within the marking range around the burr in the figure below.

Although the illustrative specific embodiments of the present invention have been described above, so that those skilled in the art can understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, As long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

Claims (4)

1. a kind of digital storage oscilloscope with waveform rapid positioning and scaling function, comprises signal conditioning channel, analog-to-digital converter, detailed waveform memory control module, large-capacity detailed waveform memory, microprocessor and display, it is characterized in that, also include: A characteristic value detection module, connected with the analog-to-digital converter, used to detect the sampling data stream output by the analog-to-digital converter, and filter out the characteristic value data from the continuous N sampling data; A eigenvalue storage FIFO is connected with the eigenvalue detection module for storing the eigenvalue data screened out by the eigenvalue detection module; The conditioned analog signal output by the signal conditioning channel is sent to the analog-to-digital converter for sampling, and the obtained sampling data stream of discrete signal flows into the detailed waveform memory control module and the characteristic value detection module at the same time; the detailed waveform memory control module controls the sampling All the sampling data of the data stream are stored in the large-capacity detailed waveform memory for deep buffering, and the characteristic value detection module detects the sampling data stream, and selects the characteristic value data from the continuous N sampling data and stores them in the characteristic value storage FIFO; The sampling data of the detailed waveform memory of the capacity and the characteristic value data of the characteristic value storage FIFO are correspondingly stored; When observing the waveform, the microprocessor first reads the eigenvalue data in the eigenvalue storage FIFO for processing, and sends it to the display for display. Store the corresponding storage relationship of the eigenvalue data of the FIFO, quickly find the address corresponding to the eigenvalue data in the large-capacity detailed waveform memory, and the microprocessor reads the sampling data corresponding to the large-capacity detailed waveform memory for processing, and sends it to It is displayed on the monitor, and the detailed waveform corresponding to the eigenvalue data of this segment is observed in detail, which realizes the rapid positioning and zooming of the waveform. 2. The digital storage oscilloscope with waveform fast positioning and zooming function according to claim 1, is characterized in that, also comprises an address mapping module, is used to store the sampling data of the large-capacity detailed waveform memory and the eigenvalue storage FIFO Eigenvalue data corresponds to the storage relationship; When it is necessary to observe in detail the detailed waveform corresponding to a certain section of eigenvalue data, the microprocessor outputs the address of this section of eigenvalue data to find the corresponding address in the address mapping module, that is, the corresponding sampling data address in the large-capacity detailed waveform memory, and then According to the sampling data address, the microprocessor reads the corresponding sampling data in the large-capacity detailed waveform memory into the microprocessor through the detailed waveform memory control module for processing, and sends it to the display for display. 3. The digital storage oscilloscope with waveform fast positioning and zooming function according to claim 2, further comprising a data flow switching module, under the control of the microprocessor, switching characteristic value storage FIFO or large-capacity The data flow of the detailed waveform memory enters the microprocessor, and the data processed by the microprocessor is sent to the display for display. When observing the waveform, first select the eigenvalue data in the eigenvalue storage FIFO to observe, that is, the data flow switching module switches to the eigenvalue storage FIFO, and the eigenvalue data stream of the eigenvalue storage FIFO enters the microprocessor for processing and sends display on the display; when a certain section of characteristic value data needs to be observed in detail, the microprocessor outputs the address of the characteristic value data to find the corresponding address in the address mapping module; under the control of the microprocessor, the data flow switching module Switch to the data flow of the large-capacity detailed waveform memory, and the sampling data flow of the large-capacity detailed waveform memory enters the microprocessor for processing and is sent to the display for display. 4. the digital storage oscilloscope with waveform rapid positioning and zooming function according to claim 1, is characterized in that, described analog-to-digital converter is parallel time alternate sampling analog-to-digital converter, and the AD number wherein is a, The large-capacity detailed waveform memory is stored as follows:

in,

is the transposition matrix of A _ni , and A _ni represents the sampling data stream composed of the H data of the nth AD sample stored in the detailed waveform memory corresponding to the i-th eigenvalue data T _i in the eigenvalue storage FIFO, n=1 , 2, ..., a, i=1, 2, ..., W, W is the number of feature value data stored in the feature value storage FIFO; The eigenvalue data of the eigenvalue storage FIFO is stored as: (T ₁ , T ₂ , ..., T _i , ..., T _w ) Among them, T _i is the eigenvalue data of the i-th eigenvalue detection.

Images