JP4476709B2 - Sampling device and waveform observation system - Google Patents

Description

  The present invention relates to a technique for performing sampling on a signal in which the same waveform repeatedly appears at a predetermined period and acquiring and observing waveform information with a high time resolution, in which the waveform repetition period is wider than the sampling period. The present invention also relates to a technique for enabling waveform information to be acquired accurately with high time resolution.

  For example, in order to acquire and observe waveform data of a signal in which the same waveform repeatedly appears in a short cycle, such as an optical signal intensity-modulated with a high-speed clock signal of several tens GHz, sampling shown in FIG. A waveform observation apparatus 10 of the type is used.

  This waveform observing apparatus 10 repeats longer by a predetermined value (offset delay time) ΔT than N times the repetition period Tx of the waveform of the input optical signal P (N is an arbitrary integer greater than or equal to 1 such as 100, 1000, etc.). The optical sampling pulse generator 11 generates an optical sampling pulse Ps having a cycle Ts (= N · Tx + ΔT) and a narrow pulse width.

  Then, the generated optical sampling pulse Ps is input to the optical sampling unit 12, the optical signal P is sampled by the optical sampling pulse Ps, and the pulse light obtained by the sampling is photoelectrically converted into an electrical pulse signal Eo. The amplitude intensity of the pulse signal Eo is converted into digital data by the A / D converter 13 and stored in the waveform data memory 14, and the series of waveform data stored in the waveform data memory 14 is displayed on the display control means. 15 reads out and displays the waveform on the display 16.

  In the sampling type waveform observation apparatus 10 as shown in FIG. 10A, the sampling timing by the optical sampling pulse Ps is shown every time the repetitive waveform of the optical signal P is input N times continuously. As shown in (b) of FIG. 10, since it is shifted by ΔT time, the waveform information of the optical signal P can be acquired with high resolution by sampling much slower than the repetition period Tx. It can be observed on the screen.

  A technique for acquiring a signal waveform by sampling as described above is disclosed in Patent Document 1 below.

JP 2002-071725 A

  By the way, the pulse used for sampling is a very narrow signal such as 0.1 ps as described above, and the cycle of such a signal, that is, the sampling cycle, can be varied with high accuracy over a wide range. Is extremely difficult.

  That is, when realizing a width of 0.1 ps with pulsed light, the pulsed light is generally input to a dispersion reducing fiber and emitted with a narrowed pulse width due to its nonlinear effect. In order to generate a stable pulse having a shape, the instantaneous intensity of the input light must be large to some extent and within a predetermined range.

  For this reason, normally, in the optical sampling pulse generating means 11, as shown in FIG. 11, an automatic gain control type fiber amplifier 11b for stabilizing the average power of the pulsed light Pb 'incident on the dispersion reducing fiber 11a is provided. Used.

  However, since the automatic gain type fiber amplifier 11b is controlled so as to stabilize the average power of the emitted light, when the sampling period, that is, the interval of the input pulsed light Pb changes significantly, the automatic gain type fiber amplifier 11b responds accordingly. The gain changes significantly, and it becomes impossible to enter pulse light having an appropriate instantaneous intensity into the dispersion reducing fiber 11a.

  For this reason, the variable range is generally limited to about 1% of the sampling period.

  This narrowness of the variable sampling period limits the waveform observation of a signal with a long repetition period, and the waveform observation of a signal with a long repetition period of the same waveform such as a signal modulated with a pseudo random pattern cannot be performed well. .

In other words, if the maximum value of the sampling period is Tmax and the minimum value is Tmin, the range that the integer N can take is
(Tmin−ΔT) / Tx ≦ N ≦ (Tmax−ΔT) / Tx
It becomes.

Here, if ΔT can be ignored with respect to Tmax and Tmin, the above equation is
Tmin / Tx ≦ N ≦ Tmax / Tx
Can be approximated.

The above formula is
Tmin = 1 / Fmax,
Tmax = 1 / Fmin,
Tx = 1 / Fx
As a frequency,
Fx / Fmax ≦ N ≦ Fx / Fmin
It becomes.

  In the above inequality, when Fx is smaller than Fmin, an integer N of 1 or more cannot be obtained, and even when Fx is Fmin or more, an integer N of 1 or more may not be obtained when Fx is small. .

For example, in terms of frequency, if the sampling frequency range is 9.9 to 10.1 MHz, the repetition frequency of the same waveform of the input signal is 455 MHz, and ΔT = 0.1 ps,
44.06 ≦ N ≦ 44.95
Thus, the integer N cannot be obtained, and the above-mentioned conventional apparatus cannot correctly observe this signal.

  In addition, this type of waveform observation apparatus requires an optical mixer that generates an optical sampling pulse with a narrow width or mixes light with each other. If the display unit is included, the entire apparatus becomes complicated and expensive. There is a problem.

  The present invention solves these problems by providing a sampling device and a waveform observation system that can accurately acquire waveform information not only for a signal having a short repetition period of the same waveform but also for a signal having a long repetition period. It is intended to provide.

In order to achieve the above object, a sampling apparatus according to claim 1 of the present invention comprises:
An input terminal (20a) for inputting a signal in which the same waveform repeatedly appears in a predetermined cycle (Tx);
Parameter designation means (21) for designating information corresponding to the repetition period (Tx) of the waveform and the offset delay time (ΔT) of sampling;
Based on the information specified by the parameter specifying means and the variable range of the sampling period (Ts),
Q · Ts = N · Tx + ΔT
An arithmetic means (22) for calculating one or more integers Q and N satisfying the above and a sampling period;
Signal generating means (23) for outputting a first clock signal (C1) having a sampling period calculated by the calculating means;
Sampling pulse generating means (24) for generating a sampling pulse synchronized with the first clock signal at a sampling period calculated by the calculating means;
A sampling unit (25) for sampling the input signal by the sampling pulse;
A second clock signal generating means (26) for outputting a second clock signal (C2) having a period which is synchronized with the first clock signal and having the integer Q times the sampling period;
A clock output terminal (50a) for outputting the second clock signal to the outside;
A pulse output terminal (50b) for outputting a pulse signal output from the sampling unit to the outside;

The waveform observation system according to claim 2 of the present invention is:
An input terminal (20a) for inputting a signal in which the same waveform repeatedly appears in a predetermined cycle (Tx);
Parameter designation means (21) for designating information corresponding to the repetition period (Tx) of the waveform and the offset delay time (ΔT) of sampling;
Based on the information specified by the parameter specifying means and the variable range of the sampling period (Ts),
Q · Ts = N · Tx + ΔT
An arithmetic means (22) for calculating one or more integers Q and N satisfying the above and a sampling period;
Signal generating means (23) for outputting a first clock signal (C1) having a sampling period calculated by the calculating means;
Sampling pulse generating means (24) for generating a sampling pulse synchronized with the first clock signal at a sampling period calculated by the calculating means;
A sampling unit (25) for sampling the input signal by the sampling pulse;
A second clock signal generating means (26) for outputting a second clock signal (C2) having a period which is synchronized with the first clock signal and having the integer Q times the sampling period;
An A / D converter (33) for converting the pulse signal output from the sampling unit into digital data and outputting the digital data;
A waveform data memory (35) for storing waveform data;
Data acquisition control means (34) for writing data output from the A / D converter to the waveform data memory in synchronization with the second clock signal;
Waveform display means (36, 37) for reading a series of waveform data stored in the waveform data memory and displaying the waveform on the time axis of the offset delay time interval;

  As described above, the waveform observation system of the present invention obtains the integers Q and N at which the difference between the integer N times the waveform repetition period Tx of the input signal and the integer Q times the sampling period Ts becomes the offset delay time ΔT. Since the waveform information synchronized with the second clock signal having a period Q times the sampling period Ts is acquired from the signal obtained by sampling at the sampling period Ts corresponding to the integer, the limited variable range Even with this sampling period, it is possible to acquire waveform information for a signal having a long waveform repetition period with high accuracy.

  In the sampling device of the present invention, the second clock signal is input to the external clock input terminal of the digital oscilloscope, and the signal obtained by the sampling is input to the channel input terminal of the digital oscilloscope, so that a limited variable range is obtained. Waveform information can be acquired with high accuracy for signals with a long waveform repetition period, and the waveform can be displayed correctly, using existing digital oscilloscopes. The system can be configured easily.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of a waveform observation system 20 to which the present invention is applied.

  This waveform observation system 20 is for receiving and sampling the optical signal P having the same waveform repeated at the input terminal 20a, obtaining the waveform data, and displaying the waveform. The parameter specifying means 21 is an operation not shown. This is for designating information corresponding to the repetition period Tx of the same waveform of the optical signal P and the sampling offset delay time ΔT by the operation of the unit.

  Note that this information only needs to be information that can identify the repetition period Tx and the offset delay time ΔT. For example, information corresponding to the repetition period Tx is not only the value of the repetition period Tx itself, but also the repetition frequency fx (= 1). / Tx), or information such as a number for designating one of a plurality of preset ones.

  In addition, when one of the signal period and frequency is determined, the other is uniquely specified. Therefore, in the present specification, “period” and its relationship are replaced with “frequency” and its relationship, and vice versa. What replaced "frequency" and its relationship with "period" and its relationship shall also be included in this invention.

The calculating means 22 is based on the information specified by the parameter specifying means 21 and the variable range of the cycle Ts of the first clock signal C1 output by the signal generating means 23 described later.
Q.Ts = N.Tx + .DELTA.T (1)
One or more integers Q and N satisfying the above and the sampling period Ts are calculated.

If this expression (1) is expressed in frequency,
Fs = Q · Fx / (N + Fx · ΔT) (1 ′)
It becomes.

Also, the above formula (1) is
N = (Q · Ts−ΔT) / Tx
The calculation means 22 sets the maximum value of the sampling period Ts (= 1 / Fs) to Tmax (= 1 / Fmin), the minimum value to Tmin (= 1 / Fmax), and the offset delay time ΔT is the sampling period Ts. As small as
Q · Tmin / Tx ≦ N ≦ Q · Tmax / Tx (2)
One or more integers N and Q that satisfy the above are selected, and a sampling period Ts that meets the condition is calculated.

If expression (2) is expressed in frequency,
Q · Fx / Fmax ≦ N ≦ Q · Fx / Fmin (2 ′)
It becomes.

  As shown in an actual numerical example, as described above, when Fmax = 10.1 MHz, Fmin = 9.9 MHz, Fx = 455 MHz, and ΔT = 0.1 ps, when Q = 1, as described above, 44. 06 ≦ N ≦ 44.95, and the integer N does not exist.

  Next, assuming that Q = 2, 88.12 ≦ N ≦ 89.90, and the integer 89 exists as N.

Then, by substituting the integers Q = 2 and N = 89 into the equation (1 ′),
Fs = 9.9999995 (MHz)
Is obtained.

  Although the integers N and Q satisfying the above inequality exist infinitely, the smaller the integers N and Q, the shorter the time required for data income for one waveform, so unless there are special circumstances, the integers N, The minimum value is selected as Q.

  The signal generator 23 generates a first pulse signal C1 having a sampling period Ts (= 1 / Fs) calculated by the calculator 22 and a narrow pulse light by the optical sampling pulse generator 24 described later. The necessary high frequency signal U is generated and output.

  The signal generator 23 generates a signal U by multiplying a stable high frequency signal (for example, 1 GHz ± 1 MHz), and divides the signal U to generate the first clock signal C1. It is configured.

  In addition, as indicated by a dotted line in FIG. 1, a system that outputs an optical signal P to be observed generates a reference signal R necessary for generating the optical signal P by the signal generating means 23 to the system. In some cases, it may be synchronized.

  The optical sampling pulse generator 24 generates an optical sampling pulse Ps having a period Ts synchronized with the first clock signal C1 output from the signal generator 23.

  The pulse width of the optical sampling pulse Ps generated by the optical sampling pulse generating means 24 determines the upper limit of the sampling time resolution. As the pulse width is narrower, the sampling can be performed with higher time resolution.

  In order to obtain this narrow optical sampling pulse, the optical sampling pulse generating means 24 enters the continuous light CW emitted from the light source 24a into the modulator 24b and modulates it with the signal U as shown in FIG. Then, as shown in FIG. 3A, the pulse light Pa having a relatively narrow width is generated with the period Tu of the signal U, and the pulse light Pa is input to the thinning means 24c.

  The thinning means 24c has an optical switch that is turned on for a short time in the cycle of the first clock signal C1, and outputs the pulsed light Pb having the cycle Ts of the first clock signal C1 as shown in FIG. To do. This pulsed light Pb is incident on an automatic gain control type fiber amplifier 24d, amplified to pulsed light Pb ′ having an appropriate intensity and incident on the dispersion reducing fiber 24e. From the dispersion reducing fiber 24e, (c) in FIG. The optical sampling pulse Ps having a narrow width (for example, 0.1 ps or less) as shown in FIG.

  The optical sampling pulse Ps emitted from the optical sampling pulse generator 24 is set so as to be synchronized with the first clock signal C1.

The optical sampling pulse Ps is incident on the optical sampling unit 25.
For example, as shown in FIG. 4, the optical sampling unit 25 includes an optical mixer 25a and a photoelectric converter 25b, and the optical signal P and the optical sampling pulse Ps input from the input terminal 20a are supplied to the optical mixer 25a. The optical signal P is sampled with the optical sampling pulse Ps, and the pulsed light Po obtained by the sampling is converted into an electrical pulse signal Eo by the photoelectric converter 25b and output.

  The second clock signal generating means 26 is constituted by, for example, a frequency divider capable of varying the frequency division ratio, and is synchronized with the first clock signal C1 and has a cycle Q · Ts that is an integer Q times the sampling cycle Ts. 2 clock signal C2 is output.

  The trigger signal generating unit 27 generates a trigger signal W indicating the start of data acquisition, and outputs it to the data acquisition control unit 34.

  In the case of single measurement in which waveform drawing is performed only once, this trigger signal W is, for example, a step-like signal having one rising edge.

  In the case of repeat measurement in which waveform drawing is repeated, a cycle (Q · Ts) obtained by dividing the product (Q · Ts · Tx) of the repetition cycle Tx, the sampling cycle Ts and the integer Q by the offset delay time ΔT. A rectangular wave signal having a period Tw equal to Tx / ΔT) or an integral multiple thereof.

  Here, of the periods Q.Ts.Tx / .DELTA.T, Q.Ts indicates the period of the second clock signal C2, and Tx / .DELTA.T samples one waveform of the repetition period Tx with the offset delay time .DELTA.T. It shows the number of samplings required for this.

  That is, the period Q · Ts · Tx / ΔT represents the time required to sample one waveform of the repetition period Tx with the offset delay time ΔT by the second clock signal C2. In a numerical example, if Q = 2, Ts = 0.1 μs, Tx = 2 ns, and ΔT = 0.1 ps, the period Q · Ts · Tx / ΔT is 4 ms (frequency 250 Hz).

  On the other hand, the pulse signal Eo output from the optical sampling unit 25 is input to the A / D converter 33.

  Each time the A / D converter 33 receives the second clock signal C2 (which may be the first clock signal C1 as indicated by the dotted line), the A / D conversion process for the pulse signal Eo output from the optical sampling unit 25 is received. And the peak value data Dp of the pulse signal Eo obtained by the A / D conversion processing is output to the data acquisition control means 34 described later.

  Based on the trigger signal W, the data acquisition control means 34 writes the data Dp output from the A / D converter 33 in the waveform data memory 35 in synchronization with the second clock signal C2.

  That is, the second clock from the timing when the trigger signal W rises from “0” to “1” (conversely, the timing may fall from “1” to “0” or both may be selected). Writing of data Dp to the waveform data memory 35 is started in synchronization with the signal C2, and a predetermined number of data is written. In the case of the single measurement, the measurement is completed by this operation. However, in the repeat measurement mode, the above operation is repeated every time the trigger signal W rises. Note that the number of data written in the waveform data memory 35 corresponds to the number of display points on the time axis displayed on the display 37 described later.

  The display control unit 36 forms a waveform display unit together with the display unit 37, displays a coordinate screen composed of a time axis and a voltage axis on the display unit 37, and a series of data Dp stored in the waveform data memory 35. Are plotted and displayed on the coordinate screen, and a waveform corresponding to the read series of data Dp is displayed.

  The display control means 36 performs processing and display processing on the data Dp stored in the waveform data memory 35 in accordance with the observation mode designated by the observation mode designation means 38.

That is, when the persistence mode is designated, a series of data Dp stored in the waveform data memory 35 is displayed by leaving its afterimage, and when the averaging mode is designated, the waveform data memory A predetermined set of data Dp stored in 35 is obtained, the averaging process is performed, and the series of data obtained by the averaging process is displayed as a waveform.
A single sweep mode is also possible in which the trigger signal generating means 27 outputs a trigger signal W in synchronization with a manual operation on an operation unit (not shown).

Next, the operation of the waveform observation system 20 will be described.
First, as shown in FIG. 5A, for example, an optical signal P that is intensity-modulated with a pseudo-random signal (1100101... 0) and appears in the same waveform with a repetition period Tx equal to the code length is input to the input terminal 20a. The parameter designation means 21 designates information corresponding to the repetition period Tx of the waveform and the offset delay time ΔT of sampling.

  Based on the specified information, the minimum integers N and Q satisfying the above equation (2) are obtained, and the sampling period Ts is calculated on the basis of the integers. It is output to the clock signal generating means 26 (here, integer N = 89, Q = 2).

  Therefore, the first clock signal C1 having the sampling period Ts and the optical sampling pulse Ps synchronized with the first clock signal C1 are generated as shown in (b) and (c) of FIG.

  Then, the optical sampling pulse Ps is input to the optical sampling unit 25, the optical signal P is sampled at the cycle Ts by the optical sampling unit 25, and the electrical pulse signal Eo obtained by the sampling is input to the A / D converter 33. Output sequentially.

  Here, when Q is 2, as described above, an unnecessary signal is also input to the A / D converter 33 between the pulse signals Eo having the period Q · Ts having the waveform information shifted by the offset delay time ΔT. Is done.

  On the other hand, the second clock signal generator 26 outputs a second clock signal C2 having a period of Q · Ts as shown in FIG. For this reason, the A / D converter 33 performs sampling for each desired Q number of pulse signals Eo among the pulse signals Eo input at the cycle Ts as shown in FIG. Convert to digital data Dp.

  Further, as shown in FIG. 6B, the trigger signal generating means 27 samples one waveform of the repetition period Tx with the offset delay time ΔT by the second clock signal C2 having the period Q · Ts. A trigger signal W having a period Tw of time Q · Ts · Tx / ΔT (or an integer multiple thereof) required for the data is generated and output to the data acquisition control means 34. FIG. 6A shows the time axis of the waveform shown in FIG.

  The data output from the A / D converter 33 by the data acquisition control means 34 that detects the rising (or falling) of the trigger signal W until the predetermined time elapses from the timing t0. Dp is written into the waveform data memory 35 in synchronization with the second clock signal C2.

  Here, if the persistence mode is designated, a series of waveform data written to the waveform data memory 35 is read out, and the optical signal P of the optical signal P is read on the screen of the display 37 as shown in FIG. The waveform is displayed as an afterimage at the point of the offset delay time ΔT.

  If the number of display points on the time axis displayed on the display 37 is, for example, 1001 points, the number of data Dp acquired in one data acquisition period and written in the waveform data memory 35 is also 1001. After the 1001st data Dp is written in the waveform data memory 35, it waits until the next rising timing of the trigger signal W. Similarly to the above, A The waveform data output from the / D converter 33 is acquired.

  Then, a series of newly acquired waveform data is read in place of the previously acquired waveform data, plotted on the time axis at intervals of the offset delay time ΔT, and the waveform is displayed as an afterimage. .

  Similarly, the acquisition of waveform data synchronized with the second clock signal C2 starts immediately after the rising timing of the trigger signal W, and the afterimage waveform corresponding to the acquired series of waveform data becomes the previous afterimage waveform. Displayed instead.

  If the averaging mode is designated by the observation mode designating means 38, the display control means 36 performs averaging processing of a plurality of sets of waveform data acquired during a plurality of data acquisition periods, and the averaging is performed. The processed waveform is displayed on the display 37. In any mode, the trigger signal W triggers and acquisition of each data is started.

  Therefore, the start timing of each data acquisition can be synchronized with the trigger signal W, and a display waveform shift and waveform reproducibility do not occur.

  Further, as shown in the equation (1), integers Q and N are calculated such that the difference between the integer N times the waveform repetition period Tx of the input signal and the integer Q times the sampling period Ts becomes the offset delay time ΔT. Since the sampling period Ts corresponding to the integer is set and the acquisition of the signal obtained by sampling is performed for every Q pieces, the waveform can be obtained even in a limited variable range sampling period. It is possible to acquire waveform information for a signal having a long repetition period.

  In the waveform observation system 20 described above, an A / D conversion processing function for the input signal of the A / D converter 33, a function of comparing the input signal voltage and the threshold value V, and starting acquisition of data based on the comparison result The multi-channel type digital oscilloscope can be substituted for the persistence display function for displaying the waveform of the acquired data while sequentially leaving afterimages, and the averaging display function for displaying after averaging.

  In this case, as shown in FIG. 8, the waveform observation system 20 ′ can be configured by the sampling device 50 and the digital oscilloscope 60.

  The sampling device 50 has a housing (not shown) independent from the digital oscilloscope 60, and also includes the input terminal 20a, the parameter specifying means 21, the calculating means 22, the signal generating means 23, the waveform observation system 20, and the like. In addition to the sampling pulse generator 24, the sampling unit 25, the second clock signal generator 26, and the trigger signal generator 27, a clock output terminal 50a for outputting the second clock signal C2 to the outside, and the sampling unit 25 Are provided with a pulse output terminal 50b for outputting the pulse signal Eo output from the outside to the outside and a trigger output terminal 50c for outputting the trigger signal W to the outside.

  The clock output terminal 50a, the pulse output terminal 50b, and the trigger output terminal 50c of the sampling device 50 are cable-connected to the external clock input terminal 60a, the first channel input terminal 60b, and the second channel input terminal 60c of the digital oscilloscope 60, respectively. Yes.

  The digital oscilloscope 60 arbitrarily designates an external clock synchronization function for performing A / D conversion processing on signals input from the channel input terminals 60b and 60c in synchronization with a clock signal input to the external clock input terminal 60a. A certain period of time (depending on the display width of the time axis and the number of display points described later) elapses from the timing at which the voltage of the input signal at the channel input terminal or trigger input terminal exceeds the arbitrarily set threshold value in the predetermined direction. It has an external trigger function for storing data obtained by A / D conversion processing as waveform data for each channel, and a waveform display function for displaying the stored waveform data on the time axis. As the display mode, any one of the persistence display mode and the averaged display mode can be arbitrarily selected. It is configured.

  The operation of each part of the sampling device 50 is the same as that described in the waveform observation system 20, and the digital signal that has received the second clock signal C2, the pulse signal Eo, and the trigger signal W from the sampling device 50 is received. The oscilloscope 60 performs A / D conversion processing on the pulse signal Eo input to the first channel input terminal 60b in synchronization with the second clock signal C2 input to the external clock input terminal 60a. To a data value Dp corresponding to the peak value of each pulse.

  Then, when the trigger signal W input to the second channel input terminal 60c rises at a certain time and exceeds the threshold value V from the lower side to the higher side, the first channel is output for a certain time from that timing. The data obtained by the A / D conversion process is sequentially stored in the internal memory as waveform data, and the stored series of waveform data is read out and plotted on the time axis of the display unit in the same manner as described above to generate the waveform of the optical signal P. Display according to the specified mode.

  In this waveform observation system 20 ′, the functions of data acquisition and waveform display are realized by the digital oscilloscope 60. Therefore, the second clock signal C 2, the pulse signal Eo and the trigger signal W are supplied to each terminal of the oscilloscope 60. By providing from each of the output terminals 50a to 50c, the same operation as that of the waveform observation system 20 described above can be performed, and if the digital oscilloscope 60 is owned, the sampling device 50 can be simply prepared. Signals can be observed, and the entire system can be configured at low cost.

  In the waveform observation system 20 'described above, data acquisition and waveform display processing are performed by the digital oscilloscope 60. Instead of the digital oscilloscope 60, an A / D for converting an input signal into digital data. A personal computer having a conversion function and performing the same functions as the data acquisition control means 34, the waveform data memory 35, and the display control means 36 by program processing may be used.

  In the above description, the waveform information of the optical signal is acquired and observed. However, the present invention can be similarly applied to an apparatus that samples an electrical signal with an optical pulse or an electrical pulse.

The figure which shows the structure of embodiment of this invention Configuration diagram of the main part of the embodiment Signal diagram for explaining the main part operation of the main part Configuration diagram of the main part of the embodiment Signal diagram for explaining the operation of the embodiment Signal diagram for explaining the operation of the embodiment The figure which shows one Example of the waveform displayed Waveform observation system composed of sampling device and digital oscilloscope Diagram showing the configuration of a conventional device Operation explanatory diagram of conventional equipment The figure which shows the structural example of an optical sampling pulse generation means

Explanation of symbols

  20, 20 '... waveform observation system, 21 ... parameter designation means, 22 ... calculation means, 23 ... signal generation means, 24 ... optical sampling pulse generation means, 25 ... sampling section, 26 ... second Clock signal generating means, 27... Trigger signal generating means, 33... A / D converter, 34... Data acquisition control means, 35. 38 ... Observation mode designating means 50 ... Sampling device 50a ... Clock output terminal 50b ... Pulse output terminal 50c ... Trigger output terminal 60 ... Digital oscilloscope 60a ... External clock input terminal , 60b... First channel input terminal, 60c... Second channel input terminal

Claims (2)

An input terminal (20a) for inputting a signal in which the same waveform repeatedly appears in a predetermined cycle (Tx);
Parameter designation means (21) for designating information corresponding to the repetition period (Tx) of the waveform and the offset delay time (ΔT) of sampling;
Based on the information specified by the parameter specifying means and the variable range of the sampling period (Ts),
Q · Ts = N · Tx + ΔT
An arithmetic means (22) for calculating one or more integers Q and N satisfying the above and a sampling period;
Signal generating means (23) for outputting a first clock signal (C1) having a sampling period calculated by the calculating means;
Sampling pulse generating means (24) for generating a sampling pulse synchronized with the first clock signal at a sampling period calculated by the calculating means;
A sampling unit (25) for sampling the input signal by the sampling pulse;
A second clock signal generating means (26) for outputting a second clock signal (C2) having a period which is synchronized with the first clock signal and having the integer Q times the sampling period;
A clock output terminal (50a) for outputting the second clock signal to the outside;
A sampling apparatus comprising: a pulse output terminal (50b) for outputting a pulse signal output from the sampling unit to the outside. An input terminal (20a) for inputting a signal in which the same waveform repeatedly appears in a predetermined cycle (Tx);
Parameter designation means (21) for designating information corresponding to the repetition period (Tx) of the waveform and the offset delay time (ΔT) of sampling;
Based on the information specified by the parameter specifying means and the variable range of the sampling period (Ts),
Q · Ts = N · Tx + ΔT
An arithmetic means (22) for calculating one or more integers Q and N satisfying the above and a sampling period;
Signal generating means (23) for outputting a first clock signal (C1) having a sampling period calculated by the calculating means;
Sampling pulse generating means (24) for generating a sampling pulse synchronized with the first clock signal at a sampling period calculated by the calculating means;
A sampling unit (25) for sampling the input signal by the sampling pulse;
A second clock signal generating means (26) for outputting a second clock signal (C2) having a period which is synchronized with the first clock signal and having the integer Q times the sampling period;
An A / D converter (33) for converting the pulse signal output from the sampling unit into digital data and outputting the digital data;
A waveform data memory (35) for storing waveform data;
Data acquisition control means (34) for writing data output from the A / D converter to the waveform data memory in synchronization with the second clock signal;
A waveform observation system comprising waveform display means (36, 37) for reading a series of waveform data stored in the waveform data memory and displaying the waveform on the time axis of the offset delay time interval.

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