JPH0283455A - Digital oscilloscope - Google Patents

Abstract

PURPOSE:To share the title oscilloscope for both uses of analogue and digital signals by changing over the signal of an analogue input part and that of a digital input part to make it possible to input either one of them. CONSTITUTION:A digital terminal 2 to which an n-bit digital signal is inputted and an analogue terminal 1 are provided to a digital oscilloscope and the input from the analogue terminal 1 is subjected to digital conversion in an A/D conversion processing system part 3 to be inputted to a switching part 5. The input from the digital terminal 2 is converted to a predetermined code by a code conversion part 4 to enter a switching part 5. The signal selected by the switching part 5 is subjected to predetermined processing in a digital processing system part 7 and converted to an analogue signal in a D/A conversion processing system 8 to be displayed on a CRT 9.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a digital oscilloscope that A/D converts an input signal and stores and displays it, and more specifically, it is capable of directly inputting a digital signal as an input signal, Furthermore, the present invention relates to a digital oscilloscope that displays the signal more stably.

[Conventional Example] In recent years, the performance of digital oscilloscopes that store and display input signals has improved due to advances in high-speed A/D converters and equivalent sampling technology. Additionally, digital oscilloscopes have
Something that stores the input analog signal and then converts it to A/D.
It can be divided into two types: one that converts the input analog signal into A/D and then stores it. In any case, in order to display the input signal, the input analog signal is converted into digital data and then waveform processed by a digital processing circuit.

The signal is converted back to an analog signal and displayed on a CRT.

On the other hand, CDs (compact discs), digital televisions, high-definition televisions, and the like are equipped with digital signal processing circuits that digitally process analog signals. As a result, signal processing can be performed with higher precision, improving the performance and operability of the above devices.

[Problems to be Solved by the Invention] By the way, when prototyping and manufacturing a device implemented using a digital signal processing circuit, there are cases where it is desired to directly observe the circuit operation using analog values. In such a case, one method is to convert the signal at the point you want to observe, that is, a digitally processed signal (hereinafter referred to as a digital signal), to analog, and input this analog signal to the digital oscilloscope. There is.

Therefore, a D/A conversion circuit or the like must be manufactured each time according to the target device, which often lacks versatility and stability.

This invention was made in view of the above points.

Its purpose is to directly input a signal (digital signal) that has been digitally processed by the device under test into the digital signal processing circuit of a digital oscilloscope. Our goal is to provide a digital oscilloscope with a high level of functionality.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides an input signal that is
/D converter converts it into a digital signal.

In a digital oscilloscope, this digital signal is processed by a digital processing section, this processed signal is converted into an analog signal by a D/A conversion section, and a waveform corresponding to this analog signal is displayed.

an n-bit digital terminal, a code conversion means for converting a digital signal input to the digital terminal into a predetermined code, and a digital signal converted by the A/D converter and a code converted by the code conversion means. A switching means is provided for switching between a code signal and a code signal, and the signal switched by the switching means is input to the digital processing section.

[Function] With the above configuration, when the input signal is digital, that signal is input to the n-bit digital terminal. Then, the switching means is switched to the digital signal input side, and the digital signal input to the digital terminal is converted by the code conversion means into a predetermined code, that is, a processing code in the digital processing section,
The signal is input to the digital processing section. That is, the digital signal is directly input to the digital oscilloscope, and is digitally processed in the same manner as the input analog signal and displayed.

[Example] Embodiments of the present invention will be described below based on the drawings.

In the figure, the digital oscilloscope has analog terminal 1, which receives analog signals for observing waveforms, etc.
Digital terminal 2 into which an n-bit digital signal (digitally processed signal) is input, and its analog terminal 1
A/D conversion processing system unit 3゜ samples the signal input through the digital terminal 2 at a predetermined sampling frequency and converts it into digital data; converts the signal input through the digital terminal 2 into a code necessary for internal digital processing. a code conversion unit 4; a switching unit (for example, a switch) 5 for switching between the signal processed by the A/D conversion processing system unit 3 and the signal of a predetermined code converted by the code conversion unit 4;
A switching drive section 6 drives the switching of the switching section 5, a digital processing system section 7 performs processing such as digital signal processing on the switched signal, and a D/D converter converts the processed signal into analog for CR7 display. A conversion processing system unit 8, a CRT device 9 that displays waveforms etc. based on this analog converted signal, and this CRT device 9.
A deflection circuit 10 for deflecting the electron beam is provided. In addition, the digital oscilloscope has the above A/D
Conversion processing system section 3, code conversion section 4, switching drive section 6
．． A timing circuit 11 that outputs operation timing signals for the digital processing system section 7, the D/A conversion processing system section 8, and the deflection circuit 10 is provided. Note that, except for the code conversion section 4, switching section 5, and switching drive section 6,
The configuration of the digital oscilloscope is almost the same as one already commercially available, and is not shown in the figure.

A memory section for storing signals is also provided. Further, the n bits of the digital terminal 2, that is, the number of quantization bits, may be adjusted to the measurement range of the digital oscilloscope.

Next, the operation of the digital oscilloscope with the above configuration will be explained.

First, it is assumed that a digital signal is inputted to the digital terminal 2 from a predetermined circuit of the device through a lead wire or the like, and that an operation is performed to observe the signal as an analog value.

Then, the switching unit 5 is driven by the switching drive unit 6 according to the timing signal generated by the timing circuit 11.
The digital signal is switched to the terminal 5a side, and the digital signal converted into a predetermined code by the code conversion section 4 is input to the digital processing system section 7.

At this time, since the digital processing system section 7 and the D/A conversion processing system section 8 operate in the same manner as in the conventional case, the code-converted digital signal is subjected to digital signal processing (for example, waveform processing).

D/A! The digital signal is converted into a CR7 display signal by the conversion processing system section 8. That is, on the screen of the CRT device 9, the waveform of the input digital signal is displayed as an analog value.

In this way, the digital signal in the predetermined circuit of the device realized by the digital signal processing circuit is directly input to the digital oscilloscope without being converted to analog, so that it is displayed in a stable waveform on the CR7 screen.

Further, as the code converter 4, several commonly used types such as binary, offset binary, etc. are provided, and can be switched using a switch or the like.

On the other hand, when an operation for detecting a normal input analog signal w4 is performed, the switching section 5 is switched to the terminal 5b side. The analog signal input to analog terminal 1 is
Processing is performed in exactly the same way as in conventional digital oscilloscopes. That is, the screen of the CRT device 9 displays signal waveforms and the like as in the conventional case, and normal analog signal waveforms can be observed.

[Effects of the Invention] As explained above, according to the digital oscilloscope of the present invention, there is an n-bit digital terminal into which a digital signal (a signal digitally processed in a predetermined circuit of the device to be measured) is input, and a A code conversion means converts an input signal through a terminal into a predetermined code, and a switching means switches between the code-converted signal and a normally digitally converted input signal, and the switching means converts the switched signal into a digital signal. Since the digital signal can be input directly to the processing section, there is no need to create a D/A converter section, etc. for various target devices, and the signal can be more stable as an analog value. w4
It has the effect of being able to be easily understood and also has excellent versatility.

[Brief explanation of the drawing]

The drawing is a schematic block diagram of a digital oscilloscope showing an embodiment of the present invention. In the figure, 1 is an analog terminal, 2 is a digital terminal, and 3 is an A
/D conversion processing system unit, 4 is a code conversion unit, 5 is a switching unit (switch), 6 is a switching drive unit, 7 is a digital processing system unit, 8 is a D/A conversion processing system unit, 9 is CR
In the T device, 10 is a deflection circuit, and 11 is a timing circuit.

Claims (1)

[Claims] (1) Convert the input signal into a digital signal in the A/D converter, process this digital signal in the digital processor, convert this processed signal into an analog signal in the D/A converter, and A digital oscilloscope that displays a waveform corresponding to an analog signal includes an n-bit digital terminal, a code conversion means for converting the digital signal input to the digital terminal into a predetermined code, and a conversion unit that converts the digital signal input to the digital terminal into a predetermined code. and a switching means for switching between the converted digital signal and the code signal converted by the code conversion means, and the signal switched by the switching means is input to the digital processing section. Digital oscilloscope.