JPH04116785U - jitter measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] To measure measurement signals output from non-measured objects in short cycles. [Structure] Edges of the measurement signal S output from the object to be measured are detected by the edge detection section 3. While this edge is being detected, the counter 6 sequentially stores the count value CNT obtained by counting the clock CLK of the clock 4 in the RAMs 7a and 7b. As a result, after the measurement is completed, RAM7
The object to be measured can be measured for each edge of the measurement signal S from the stored contents of a and 7b.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a jitter measuring instrument that performs basic measurements of pulse width and pulse duty. do.

0002

[Conventional technology]

Motor rotation speed measurement, frequency measurement, rise characteristics, etc., or card reader Measurement of recording density, etc. of magnetic cards is performed by any of the following methods: was. The rotation speed of the motor is measured using a power generator installed in the motor 40 as shown in FIG. 4(a). Based on the analog output of the machine 41a or the digital output from the rotary pulse generator. Therefore, the generator output S1 shown in the same figure (b) or the pulse generation shown in the same figure (c) Measures fluctuations in the motor rotation speed, etc. by changes in the cycles T1 and T2 of the output S2 of the motor. can be done. In this measurement, part 1: Waveform observation is performed using a frequency counter. Part 2…Memo Analyze the stored waveform using Rescope. Part 3…Wah flat meter Use. This was done using one of the following methods.

0003

[Problem that the idea aims to solve]

However, the above frequency counter captures several pulses of several seconds and calculates the frequency. Because it is displayed, it is impossible to measure the fluctuation of T1 and T2 (for each pulse). Met. In addition, the memory scope is configured to store all waveforms, and the waveform can be stored in one pulse. It took time for the operator to read and process each page. Also , the equipment is expensive. The wow/flat meter measures large fluctuations and is similar to the above. It was not possible to measure each waveform. In this way, all conventional measuring instruments are suitable for measuring fixed characteristics and can be easily It was not possible to measure the waveform of each pulse. For this reason, short-period pulses instantaneous motor rotation speed measurement, especially starting characteristics etc. I couldn't do it.

0004 This invention was made in view of the above problems, and the output from the object to be measured is The waveform of each pulse can be measured for each pulse, allowing for highly accurate measurement. The purpose is to provide data measuring instruments.

[0005]

[Means to solve the problem]

In order to achieve the above purpose, the jitter measuring instrument of the present invention is designed to Outputs an edge detection signal (E) every time an edge of the measurement pulse (S) is detected. an edge detection section (3); The clock (CLK) is counted for a certain period until the edge detection signal is input. a counter (6) that counts and outputs a count value (CNT); RAMs (7a, 7b) that sequentially store the count values of the counter; It is characterized by having the following.

[0006]

[Effect]

The edge detection unit 3 detects an edge in the measurement signal S output from the non-measurement target. , the period between edges, the count value CNT of the corresponding clock 4 is the counter It is counted as 6. This count value CNT is sequentially stored in RAMs 7a and 7b. . As a result, various characteristics of non-measurable objects can be read from RAM7a, 7b after measuring the characteristics. At the shortest, each edge (for example, half period).

[0007]

【Example】

FIG. 1 is a block diagram showing an embodiment of a jitter measuring instrument 1 according to the present invention. In the start/stop control unit 2, a start/stop trigger is input to 2 channels A and B. For example, Ach is used as the measurement start trigger STA. It can be set for input, and Bch can be set for input of the measurement end trigger STP. still , this start/stop control section 2 can use a general-purpose input capture. . The edge detection unit 3 detects the edge of the measurement pulse S of the non-measurement target, and detects the edge of the measurement pulse S each time. The edge detection signal E is output to the counter 6. Clock 4 clocks a clock signal CLK with a sufficiently short period compared to the measurement pulse S. Supplied to counter 6. The counter 6 measures the measurement pattern from the start of measurement to the end of measurement by the start/stop control unit 2. A counting operation that counts the pulse S by a predetermined count from "0" for each edge. Repeat the work.

[0008] The CPU 5 controls the operation of each component, and sends the measurement pulse S to each component. The counted value is transferred from the counter 6 to the RAM 7a at the timing of the change. . In addition, an external RAM 7b can be freely added to this RAM 7a, and the measurement pulse It is possible to cope with an increase in the columns S1, S2, . . . . Further, the CPU 5 stores these measurement pulse trains S1, S2,..., in the RAM 7a, 7b and an external personal computer via the interface 8. Output to 10. The personal computer 10 displays a graphic for each measurement pulse S. , perform waveform printing, and perform various waveform analyses.

[0009] Next, we will explain the operation of the above configuration based on the motor rotation speed characteristics (motor startup rotation rise characteristics). An example in which this method is applied to the measurement of Furthermore, Figure 2 shows the output from each component. Figure 3 is a timing chart showing the signals that occur. be. When starting the motor (not shown), simultaneously press the measurement start trigger STA shown in Figure 2(a). This measurement start trigger STA is input to the start/stop control section 2. At the same time, the measurement pulse S shown in (d) is output from the pulse generator of this motor. is input to the edge detection section 3 (SP1).

0010 The edge detection unit 3 detects the rising edge of the measurement pulse S and detects the edge in (e). Outputs signal E and clears counter 6 to "0" at each rise timing. Ru. Then, the counter 6 receives the next edge detection signal E as shown in (f). In other words, the period of one cycle T1 until the rise of the measurement pulse S, The count value of the clock signal CLK of clock 4 shown in (c) is counted and held. (SP2). Note that edge detection by the edge detection section 3 starts from the rising edge of the measurement pulse S. Until the fall, or from the fall to the rise, or from the fall to the rise You can select either from to rising or from falling to falling. It can be selected at will and is set in advance.

[0011] In addition, the CPU 5 uses the startup output of the startup/stop control section 2 to The count value CNT is read from the counter 6 and sequentially stored in the RAM 7a (S P3). In addition, when the count value CNT becomes multiple cycles Tn, the CPU 5 is This count value CNT can be stored using the RAM 7b. and, This counting and memory operation is performed when a measurement end trigger STP is sent to the start/stop control unit 2. This is continued until the input is made (determiner SP4).

0012 Due to the above operation, the period from the start of measurement to the end of measurement is stored in RAM7a, 7b. Count values CNT for a plurality of cycles Tn are stored. Therefore, after measuring one period T1 for the CPU 5, read it out. Thus, each measurement pulse S can be obtained as a count value. This results in From this count value, the period, frequency, and rise of each period of the measurement pulse S are calculated. It is possible to measure the time between rise and fall, and the time between fall and rise. Ru.

[0013] The count value CNT for multiple cycles Tn stored in the RAMs 7a and 7b is the I/F 8 to an external computer 10 for graph display, printing, and external storage media. It is possible to re-storage, etc.

[0014] According to the above jitter measuring instrument, the measurement pulse is divided into one period T in the past. Since it is possible to measure can be measured. We also measure the transport speed of card readers that use magnetic cards as media, and measure magnetic information clocks. It can also be applied to bulk measurements. Card readers transport magnetic cards at a constant speed; When performing processing such as writing to a magnetic card that causes a load on transportation under the following conditions: , it is possible to measure whether or not an accurate pulse train is stored on this magnetic card. this In this case, the measurement start trigger STA is set to the insertion detection sensor installed in the card insertion hole. The measurement end trigger STP can be obtained using the ejection detection sensor of the card ejection hole. can. In addition, there is no measurement end trigger STP, and there is no intermediate position setting in the magnetic head. The trigger timing may be configured such that a sensor is provided to obtain this timing. The configuration and arrangement can be set arbitrarily for measurement purposes. Furthermore, according to the jitter measuring instrument, by measuring the count value CNT, It is possible to easily detect gaps in periodic pulses.

[0015]

[Effect of the idea]

According to the jitter measuring instrument of the present invention, the edge of the measurement signal output from the non-measurement target The configuration stores count values at predetermined intervals upon detection, so it is possible to After the measurement is completed, the waveform can be measured for each cycle, and at the shortest time, the waveform can be measured for each cycle. This has the effect of making it possible to perform highly accurate measurements for each edge. Furthermore, this effect , can be obtained with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a jitter measuring instrument according to the present invention.

FIG. 2 is a timing chart showing signals output from each component.

FIG. 3 is a processing flowchart of the above operation.

FIG. 4(a) is a diagram showing a state in which rotational characteristics of a motor are measured. (b) is a waveform diagram showing the generator output. (c)
is a waveform diagram showing the pulse generator output.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Jitter measuring instrument, 2...Start/stop control section, 3...Edge detection section, 4...Clock, 5...CPU, 6...Counter, 7
a...RAM, 7b...External RAM, 8...Interface, 10...Personal computer, STA...Measurement start trigger, STP...Measurement end trigger, CLK...Clock,
S...Measurement signal, E...Edge detection signal, CNT...Count value.

Claims (1)

[Scope of utility model registration request] [Claim 1] An edge detection signal (E) is generated every time an edge of a measurement pulse (S) output from the object to be measured is detected.
an edge detection section (3) that outputs an edge detection signal; a counter (6) that counts a clock (CLK) and outputs a count value (CNT) during a fixed period until the edge detection signal is input; and a counter (6) that outputs a count value (CNT); Sequentially stores the count values of R
A jitter measuring instrument comprising: AM (7a, 7b).