JPH06201728A - Automatic observation waveform display setting device - Google Patents

Abstract

PURPOSE:To judge the optimal input sensitivity and a time axis range at high speed when a display waveform is set automatically only by adding comparatively simple constitution to a common waveform taking-in circuit. CONSTITUTION:An analog input signal Sa of a waveform observing object is stored in a memory 5 through an attenuating 1, a preamplifier 2, an A/D converter 3 and a peak detecting circuit 4. The analog input signal Sa is also inputted to trigger circuits 6 and 7. A peak value of the analog input signal Sa is detected at automatic setup processing time by the peak detecting circuit 4, and a period is detected by a delay counter 9 and the trigger circuits 6 and 7. Operational switching of waveform taking-in and automatic setup processing is carried out by a selector 8 and gate circuits 11 and 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a waveform observing device such as a digital oscilloscope, and sets the optimum input sensitivity and time axis range for determining the amplitude and period of an input signal and displaying the waveform. The present invention relates to a waveform automatic display setting device.

[0002]

2. Description of the Related Art Recent digital oscilloscopes and the like judge the amplitude and cycle of an input signal and automatically display the waveform of the input signal with the optimum input sensitivity and time axis range. So-called display waveform automatic setting processing (auto setup processing) is performed.

FIG. 2 shows a configuration for setting the optimum input sensitivity and time axis range by judging the amplitude and cycle of the input signal in the case of automatically setting the display waveform in the conventional digital oscilloscope. In FIG. 2, this example shows an attenuator 21 that sets an analog input signal to a predetermined level.
And a preamplifier 22 and an A / D converter 2 for converting an analog input signal from the preamplifier 22 into a digital signal
3 and a memory 24 for storing this digital signal, that is, storing the waveform. Further, it has a trigger circuit 25 for detecting a trigger signal when the polarity of a preset waveform, for example, a positive polarity, is detected from the analog input signal output from the preamplifier 22, and a time axis control circuit 26. The trigger signal detected by the trigger circuit 25 is input to the controller 27 that controls the entire digital oscilloscope, and the controller 27 controls the time axis control circuit 26 to trigger the digital signal converted by the A / D converter 23. Call. In addition, the controller 27 controls the attenuation amount of the attenuator 21 and the amplification degree of the preamplifier 22 by A) to set the optimum input sensitivity. Further, the time axis control circuit 26 is controlled to switch the time axis range.

Next, the operation of this conventional configuration will be described. Controller 2 to which the auto setup processing instruction signal was input at the start of the auto setup processing
Reference numeral 7 controls to set the attenuator 21 and the preamplifier 22 to the lowest input sensitivity. The analog input signal from the preamplifier 22 is converted into a digital signal by the A / D converter 23 and stored in the memory 24. Controller 27
Searches the maximum amplitude value and the minimum amplitude value of the digital signal stored in the memory 24. Then, it is determined whether or not the difference between the maximum amplitude value and the minimum amplitude value can be displayed at, for example, about 3 div to 4 div. When this display is not possible, the analog input signal is converted into a digital signal again while switching the input sensitivity of the attenuator 21 and stored in the memory 24, and the difference between the maximum amplitude value and the minimum amplitude value is 3 div to 4 d.
These processes are repeated until it can be displayed at about iv.
Further, the same processing is performed on the time axis. First, the controller 27 detects the waveform cycle of the digital signal stored in the memory 25, and determines whether or not a waveform of about 2 to 3 cycles can be displayed on one screen such as a CRT. If it cannot be displayed, the time axis control circuit 26 is controlled to switch the time axis range, and the processing is repeated so that the waveform of the analog input signal can be displayed for about 2 to 3 cycles on the display surface such as a CRT.

As described above, even in the automatic setup process of the conventional digital oscilloscope described above, the amplitude and period of the input waveform can be detected to display the waveform with the optimum input sensitivity and the optimum time base range.

[0006]

However, in the detection processing in the above-mentioned conventional digital oscilloscope, it is necessary to detect the amplitude and cycle of the analog input signal every time the controller 27 takes in the digital signal waveform. Therefore, there is a problem that it takes a long time to perform the process of detecting the optimum input sensitivity and the time axis range when displaying the waveform.

The present invention solves such a conventional problem, and the optimum input sensitivity and time axis at the time of automatic setting of the display waveform are obtained only by adding a relatively simple configuration to the conventional waveform capturing circuit. It is an object of the present invention to provide an excellent observation waveform automatic display setting device capable of determining a range and a high speed.

[0008]

In order to achieve the above object, an observation waveform automatic display setting apparatus of the present invention is an input for detecting an amplitude value of an input waveform from a digital signal obtained by converting an analog input signal of a waveform observation target. Waveform amplitude value detection means, input sensitivity set value calculation means for calculating a set value for setting a predetermined input sensitivity at the time of waveform display based on the detected amplitude value, and first and first analog input signal input terminals. A delay time measuring means having two trigger means and a counter for measuring the delay time of two triggers, and the second trigger means is enabled after the trigger is generated by the first trigger means. The input signal cycle calculating means for calculating the delay of the two trigger generation times in the second trigger means by the delay time measuring means to calculate the cycle of the analog input signal.

[0009]

With such a configuration, the observed waveform automatic display setting device of the present invention detects the amplitude value of the waveform from the digital signal obtained by converting the analog input signal of the waveform observation target, and based on this amplitude value, at the time of displaying the waveform. A set value for setting a predetermined input sensitivity is calculated. Furthermore, since the delay of the two trigger generation times is measured to calculate the cycle of the analog input signal, the optimum input sensitivity and time axis range at the time of automatically setting the display waveform can be determined at high speed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an observation waveform automatic display setting device of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of an observation waveform automatic display setting device of the present invention. In FIG. 1, in this example, an attenuator 1 that attenuates an analog input signal Sa that is a waveform observation target, a preamplifier 2 that amplifies the analog input signal Sa from the attenuator 1, and an analog input signal Sa from the preamplifier 2 are digitally output. It has an A / D converter 3 for converting into a signal and a peak detection circuit 4 for detecting a peak value of amplitude from the digital signal converted by the A / D converter 3.

A memory 5 for storing a digital signal, that is, a waveform, and a trigger circuit 6 for outputting a trigger signal when the waveform of the analog input signal Sa from the preamplifier 2 has a preset polarity, for example, a positive polarity. 7 and 7. Further, a selector 8 for switching the operation between the waveform acquisition and the auto setup process, a delay counter 9 for measuring the delay time of the trigger signal, and a gate circuit 11 for switching the operation between the waveform acquisition and the auto setup process. , 12, a time axis control circuit 13, and a controller 14 for controlling each of these units. Next, the operation of the configuration of this embodiment will be described.

The analog input signal Sa is attenuator 1,
It is stored in the memory 5 through the preamplifier 2, the A / D converter 3, and the peak detection circuit 4. Also, the analog input signal Sa
Is input to the trigger circuits 6 and 7 from the preamplifier 2. In the trigger circuit 6, a trigger signal Sta generated with a preset polarity in the waveform of the analog input signal Sa, for example, a positive polarity, is supplied to one input end of the selector 8 and further input to the gate circuit 11. The output signal from the selector 8 becomes the enable signal Sna of the trigger circuit 7. The trigger signal Stb generated in the trigger circuit 7 is output to the waveform acquisition control circuit (not shown) as well as the processing in the trigger circuit 6 and the gate circuit 1 through the gate circuit 12.
Input to 1. The output signal of the gate circuit 11 becomes the enable signal Snb of the delay counter 9. The output signal Sc of the delay counter 9 is input to the other input terminal of the selector 8. The controller 14 controls the attenuator 1, the preamplifier 2, the peak detection circuit 4, the trigger circuit 6, the time axis control circuit 13, the selector 8, and the delay counter 9. The output signal of the time axis control circuit 13 is input to the A / D converter 3 as a clock signal. During the auto setup process, the controller 14 first sets the attenuator 1 and the preamplifier 2 to the lowest sensitivity. Further, the analog input signal Sa is converted into a digital signal by the A / D converter 3, and the peak value detected by the peak detection circuit 4 is fetched from this digital signal. In addition, the time axis control circuit 13 is set to 0 s, for example, when starting the auto setup process for the analog input signal Sa having a frequency of 50 Hz or more.
/ Div, and the selector 8 selects the output signal of the trigger circuit 6.

Then, the controller 14 controls the writing of "0" to the counter and starts the data acquisition by the waveform acquisition control circuit (not shown). That is, 50 Hz has a period of 20 ms and 1000 samples / d.
In the case of iv, acquisition of 20 ms / sample is set, the trigger circuit 6 is enabled, and waveform acquisition is started. Then, the trigger circuit 6 outputs the trigger signal Sta when the trigger is applied, and this trigger signal Sta becomes the enable signal Sna of the trigger circuit 7 through the selector 8 and causes the delay counter 9 to start counting.

When a trigger is applied thereafter, the count of the delay counter 9 is stopped by the trigger signal Stb from the trigger circuit 7. At this time, the trigger signal S from the trigger circuit 6
When ta and the trigger signal Stb from the trigger circuit 7 have the same level and the same polarity, the time difference between the trigger signal Sta and the trigger signal Stb is obtained as the cycle of the analog input signal Sa.

In this processing, if the resolution of at least one of the sensitivity and the time axis is insufficient for the analog input signal Sa, the controller 14 repeats the reset processing so that the sensitivity or the resolution of the time axis becomes high. return.

In this way, based on the amplitude detected by the peak detection circuit 4 from the analog input signal Sa and the cycle detected by the trigger circuits 6 and 7 and the delay counter 9,
The controller 14 controls the attenuation amount of the attenuator 1 and the amplification degree of the preamplifier 2 to set the optimum input sensitivity. Further, the time axis control circuit 13 is controlled to switch the time axis range. That is, a display waveform automatic setting process (auto setup process) is performed.

In this case, since the controller 14 can surely detect the waveform by taking in the waveform once or twice, the auto setup process can be speeded up. Further, it can be realized only by adding the trigger circuits 6 and 7, the delay counter 9, the selector 8 for switching the operation between the waveform acquisition and the auto setup processing, and the gate circuits 11 and 12 to the conventional waveform acquisition circuit.

[0019]

As is apparent from the above description, the observation waveform automatic display setting device of the present invention detects the amplitude value of the waveform from the digital signal obtained by converting the analog input signal of the waveform observation target, and determines this amplitude value. Based on this, the set value for setting the specified input sensitivity during waveform display is calculated, and the delay of the two trigger occurrence times is measured to calculate the analog input signal cycle. It has an effect that the optimum input sensitivity and the time axis range can be determined at high speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an observation waveform automatic display setting device of the present invention.

FIG. 2 is a block diagram showing a configuration of an observation waveform automatic display setting device in a conventional digital oscilloscope.

[Explanation of symbols]

 1 Attenuator 2 Preamplifier 3 A / D converter 4 Peak detection circuit 5 Memory 6,7 Trigger circuit 8 Selector 9 Delay counter 11,12 Gate circuit 13 Time axis control circuit 14 Controller

Claims (1)

[Claims] 1. An input waveform amplitude value detection means for detecting an amplitude value of an input waveform from a digital signal obtained by converting an analog input signal of a waveform observation target, and a predetermined input sensitivity at the time of waveform display based on the detected amplitude value. A delay that includes input sensitivity set value calculation means for calculating a set value for setting, first and second trigger means to which the analog input signal is input, and a counter, and measures delay time of two triggers. After the trigger is generated by the time measuring means and the first trigger means, the second trigger means is enabled and the delay of the two trigger generation times in the first and second trigger means is measured by the delay time. An observation waveform automatic display setting device, comprising: an input signal period calculation unit that measures the period of the analog input signal by measuring by means.