JP4953000B2 - Waveform parameter measuring device - Google Patents

Description

  The present invention relates to a waveform parameter measuring apparatus that automatically measures waveform parameters, and more particularly to a waveform parameter measuring apparatus that measures a delay between channels when the number of edges of a waveform is indefinite.

  In general, the waveform parameter measuring apparatus can measure changes in delay time, frequency, and the like. For example, in the automatic measurement of delay (delay time) in the waveform parameter measuring apparatus, first, a measurement range is set with a cursor, a predetermined channel (CH1, CH2,..., CHn) is selected, and delay measurement between channels is performed. Is performed by selecting the edge count, reference Ch, level setting, and predetermined measurement conditions (DISTAL, PROXIMAL, and MESIAL). As a prior art document of such a waveform parameter measuring apparatus, there is one such as Patent Document 1.

Japanese Patent Laid-Open No. 2001-165961

  FIG. 3 shows a configuration example of a conventional waveform parameter measuring apparatus. The A / D converter 1 performs A / D conversion (analog / digital conversion) on measurement data. Then, the measurement data is processed into waveform data representing a time-series signal change by the primary data processing circuit 2 and stored in the primary memory 3.

The data written in the primary memory 3 is subjected to data processing such as averaging in the secondary data processing circuit 4 and written into the acquisition memory 5 (storage unit). The data written in the acquisition memory 5 is transferred to the display processing circuit 6 and stored in the display memory 7, and also used for parameter measurement by the secondary data processing circuit 4 as will be described later. Data stored in the display memory 7 is displayed on the display means 8.

Hereinafter, problems of the waveform parameter measuring apparatus of FIG. 3 will be described with reference to FIGS. FIG. 4 shows a case where a trigger is applied at the rising edge 121 (trigger point) of the CH2 waveform 120. However, since the measurement can be performed only in the direction from the cursor 130 on the left side to the cursor 131 on the right side, when the number of rising and falling edges of the CH1 waveform 110 changes for each measurement, or indefinite, The edge count number of the CH1 waveform 110 cannot be specified, and the delay at the measurement location (A) cannot be automatically measured.

For this reason, conventionally, as shown in FIG. 5, the manual measurement cursors 140 and 141 have to be manually adjusted to perform measurement. That is, it is necessary to align the manual measurement cursor 140 with the falling edge of the CH1 waveform 110 while viewing the display means 8 and align the manual measurement cursor 141 with the rising edge 121 of the CH2 waveform 120 to obtain the difference between the two. It was said.

Specific problems will be described by taking USB (Universal Serial Bus) timing evaluation as an example. In FIG. 6, CH1 represents a D-waveform 150, and CH2 represents a D + waveform 160. The purpose is to measure the time from the last packet issued until the D + waveform 160 becomes H level. Here, the D + waveform 160 and the D− waveform 150 of the USB signal are pseudo differential signals. The packet signal is issued every 125 us, and it takes several ms from the last packet until the D + waveform 160 becomes H level.

Further, FIG. 6 is classified into an upper stage and a lower stage, the lower stage is an enlarged view of the upper stage, and is further classified as follows on the left and right of FIG. That is, the lower left side is an enlarged waveform of the waveform 170 including the last packet, and the lower right side is an enlarged waveform of the waveform 171 including the trigger point. The measurement location (B) is the time from the last fall of the enlarged waveform 151 of the D− waveform to the rise of the enlarged waveform 161 of the D + waveform. Even in this waveform, the delay cannot be measured because the number of packets and the number of edges are uncertain.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a waveform parameter measuring apparatus that measures a delay between channels when the number of edges of a waveform is indefinite.

In order to achieve such a problem, the invention described in claim 1
Equipped with a storage unit that stores measurement data for multiple channels, sets the measurement range with the cursor, and measures the waveform parameters in the measurement range set with the cursor based on the measurement data for the multiple channels stored in the storage unit In the waveform parameter measuring device to
A second channel rising or falling falling or rising edge of the first channel set to edge count is undefined edges as the first point among the measurement data of a plurality of channels stored in the storage unit A point setting register for setting which of the cursor for setting the measurement range as a measurement start point is set as a second point;
An arithmetic processing processor that searches the measurement data stored in the storage unit from the measurement start point set in the point setting register toward the measurement end point, and calculates waveform parameters according to the set conditions .

The invention described in claim 2 is the waveform parameter measuring apparatus according to claim 1,
The arithmetic processor, by searching among the first point and the second point, and measuring the delay between the first point of the second point.

The present invention has the following effects.
The first point is selected from the data stored in the storage unit, the point setting register for selecting the second point consisting of an indefinite value, the second point from the first point is searched, and the waveform parameter Since an arithmetic processing processor that performs arithmetic operations is provided, it is possible to measure the delay between channels when the number of waveform edges is indefinite.

  Hereinafter, a configuration example of the waveform parameter measuring apparatus of the present invention will be described with reference to FIG. 1, but the same components as those in FIG.

The secondary data processing circuit 40 includes an arithmetic processor 41, a point setting register 42, and an arithmetic result storage register 43. The arithmetic processor 41 searches the acquisition memory 5 for data, and performs parameter arithmetic processing according to the set conditions. The point setting register 42 sets the measurement range, measurement start and end points of the waveform data stored in the acquisition memory 5. The calculation result storage register 43 stores the parameter value calculated by the calculation processor 41.

Next, the operation of FIG. 1 will be described with reference to the flowchart of FIG. However, the operation after the measurement data is input to the secondary data processing circuit 40 via the primary data processing circuit 2 and after the result of the arithmetic processing is output from the secondary data processing circuit 40 to the display processing circuit 6 Since this is the same as that in FIG.

User First, prior to automatic measurement of waveform parameters, measurement items (Vpp, Max, Min, Rise, Fall, Freq, ...), target channels (CH1, CH2, ...) and other measurement conditions of the waveform parameter measurement device (Distal, Proxymal, Mesial ...) is set (Step 1). In addition, when performing delay measurement between channels, the edge count number, reference Ch, and level are also set.

For example, when measuring the measurement location (A) in FIG. 4, the user uses the point setting register 42 to set the waveform data measurement range, measurement start and end points, and start measurement on the left cursor. Select whether to search toward the right cursor as a point (condition A) or whether to search toward the left cursor with the right cursor as the measurement start point (condition B) (step 2). Here, for example, in the case of the measurement location (A) in FIG. 4, when the edge count number is unknown and not known, the above condition B is selected, and the first edge is measured for the edge count number, so “1”. And

The arithmetic processor 41 searches the waveform data stored in the acquisition memory 5 from the measurement start point set in step 2 to the measurement end point (step 3), and performs parameter calculation processing according to the set conditions. (Step 4). The parameter values calculated by the calculation processor 41 are stored in the calculation result storage register 43 and output to the display processing circuit 6.

Thus, searching with a point setting register 42 for selecting a second point, between the first point of the second point to select the first point of the data stored in the acquisition memory 5 Therefore, the delay between channels when the number of edges of the waveform is indefinite can be measured.

The waveform parameter measuring apparatus is provided with a data search function, for example, the following two types of functions. The first function is to search whether the automatically measured waveform parameter value is within a specified range or not. In this case, the measurement item (upper limit / lower limit setting) is set, and whether or not the value is within the set range is searched.

The second function is to search whether the automatically measured waveform parameter value is within the range of the polygon figure. In this case, it is searched whether or not the target waveform is in the search zone.

Regardless of whether the waveform parameter measuring device performs data measurement using either the first function or the second function, the left cursor should be used as the measurement start point and the search should be performed toward the right cursor, or the right cursor should be measured. It is possible to select whether to search toward the cursor on the left side as a start point, and data can be searched.

It is a structural example of the waveform parameter measuring apparatus by this invention. It is a flowchart of FIG. It is an example of composition of a conventional waveform parameter measuring device. FIG. 6 is a waveform diagram in which a trigger is applied at the rising edge (trigger point) of the CH2 waveform. It is drawing which measures a measurement location (A) using the cursors for manual measurement 140,141. It is explanatory drawing of timing evaluation of USB.

Explanation of symbols

5 Acquisition Memory 40 Secondary Data Processing Circuit 41 Arithmetic Processing Processor 42 Point Setting Register 43 Operation Result Storage Register

Claims (2)

Equipped with a storage unit that stores measurement data for multiple channels, sets the measurement range with the cursor, and measures the waveform parameters in the measurement range set with the cursor based on the measurement data for the multiple channels stored in the storage unit In the waveform parameter measuring device to
A second channel rising or falling falling or rising edge of the first channel set to edge count is undefined edges as the first point among the measurement data of a plurality of channels stored in the storage unit A point setting register for setting which of the cursor for setting the measurement range as a measurement start point is set as a second point;
An arithmetic processing processor that searches the measurement data stored in the storage unit from the measurement start point set in the point setting register toward the measurement end point, and calculates waveform parameters according to the set conditions . A waveform parameter measuring apparatus characterized by the above. 2. The arithmetic processor measures a delay between the first point and the second point by searching between the first point and the second point. Waveform parameter measuring device.

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