CN101131403A - Waveform display method of digital oscilloscope and digital oscilloscope - Google Patents

Abstract

The invention relates to a waveform display method of a digital oscilloscope and a digital oscilloscope. The invention collects external analog signals and converts the collected analog signals into digital signals; receives the digital signals and stores them as digital signal data; receives external responses to generate second A window parameter and a second window parameter, and obtain the first window scaling ratio and the second window scaling ratio according to the first window parameter and the second window parameter; read the stored digital signal data, and according to The first window scaling ratio and the second window scaling ratio scale the read digital signal data to generate the first display data and the second display data; the waveform and/or data corresponding to the first display data are displayed in the second A window display; displaying the waveform and/or data corresponding to the second display data in the second window. Waveforms can be displayed on two windows with different time bases, making the digital storage oscilloscope more intuitive and convenient when displaying special signals.

Description

Waveform display method of digital oscilloscope and digital oscilloscope

technical field

The invention relates to digital oscilloscope technology, in particular to waveform processing and display of the digital oscilloscope, in particular to a digital oscilloscope waveform display method and the digital oscilloscope.

Background technique

In the prior art, the main composition of a digital oscilloscope is shown in Figure 1, which includes: a control processing unit, an external analog signal input unit (analog front end), an LCD display unit, a keyboard input unit, and a power supply, wherein: the control processing unit consists of It is composed of CPU, memory and logic circuit; the analog front end is composed of probe 102, VGA amplifier 101 and analog-to-digital converter (A/D).

Digital oscilloscopes in the prior art generally display waveforms in the traditional display mode of a single window, that is to say, signals of channels CH1, CH2, CH3, CH4, MATH, etc. are all displayed in the same window. Since the oscilloscope has only one time base, that is, channels CH1, CH2, CH3, and CH4 can only use one trigger source to trigger synchronization. Therefore, although this display method can meet the needs of most measurements, its weakness is clearly reflected when measuring some complex signals. For example, when measuring an AM signal, since the oscilloscope has only one time base, only the AM signal or the carrier signal can be observed when the waveform is displayed, and the carrier and modulating waves cannot be observed at the same time, which makes analyzing the waveform more complicated.

As shown in Figure 7, in the prior art, when the signal is observed on the window of the oscilloscope display, only the outline or details of the waveform can be observed, and it is impossible to observe both the overall outline of the waveform and the details of the waveform at the same time . However, when the two channels observe signals of different frequencies at the same time, especially when the frequency difference is relatively large, it is often impossible to observe the overall contours of the two signals at the same time under one time base.

Contents of the invention

The object of the present invention is to provide a waveform display method of a digital oscilloscope and a digital oscilloscope, so that the digital oscilloscope can display two windows (main window and delay window) at the same time, and can use different forms on the two windows. The unique time base displays waveforms, making the digital storage oscilloscope more intuitive and convenient when displaying special signals.

In order to achieve the above-mentioned purpose of the invention, the present invention provides: a waveform display method of a digital oscilloscope, which includes the following steps: collecting an external analog signal and converting the collected analog signal into a digital signal; receiving the digital signal and storing it as Digital signal data; receive external response to generate the first window parameter and the second window parameter, and obtain the first window scaling ratio and the second window scaling ratio according to the first window parameter and the second window parameter; read Take the stored digital signal data, and perform scaling processing on the read digital signal data according to the first window scaling ratio and the second window scaling ratio to generate first display data and second display data; The corresponding waveform and/or data is displayed in the first window; the waveform and/or data corresponding to the second display data is displayed in the second window.

The first window is the main window, and the second window is the delay window; according to the scaling ratio of the main window, the read digital signal data is scaled to generate the main display data; according to the delay window Scale the read digital signal data to generate delayed display data; display the waveform and/or data corresponding to the main display data in the main window; display the waveform and/or data corresponding to the delayed display data and/or data is displayed in the delayed form.

The first window and the second window display waveforms with different time bases.

The first window is used to display the data of one channel, and the second window is used to display the data of another channel.

In order to achieve the above-mentioned purpose of the invention, the present invention also provides a digital oscilloscope, which includes: an analog signal acquisition device, an analog-to-digital conversion device, a control processing device, a storage device, an external response device and a display device; The signal acquisition device is connected to the control processing device through the analog-to-digital conversion device, and the storage device, the external response device and the display device are respectively connected to the control processing device; the digital oscilloscope also includes: a waveform processing device, which is connected to the waveform processing device respectively The control processing device, the storage device and the analog-to-digital conversion device are connected; wherein: the control processing device receives the instruction of the external response device to generate the first window parameter and the second window parameter, and according to the first window parameter and the second window parameter to obtain the first window scaling ratio and the second window scaling ratio; the waveform processing device further includes: a digital signal receiving unit, which is used to receive the analog signal acquisition device and is converted by analog to digital The digital signal converted by the device, and the received digital signal is stored in the storage device; the scaling ratio receiving unit is used to receive the first window scaling ratio and the second window scaling ratio transmitted from the control processing device; the digital signal a scaling unit, configured to read the stored digital signal data from the storage device, and perform scaling processing on the read digital signal data according to the first window scaling ratio and the second window scaling ratio to generate first display data and the second display data; the waveform processing device transmits the generated first display data and second display data to the control processing device, and the control processing device controls the display device to convert the first display data The corresponding waveform and/or data are displayed in the first window, and the waveform and/or data corresponding to the second display data are displayed in the second window.

The display device is a display screen.

The display device can also be composed of two display screens, the waveform and/or data corresponding to the main display data are displayed on one display screen; the waveform and/or data corresponding to the delayed display data are displayed on the other display screen show.

The external response device includes a keyboard, a mouse, a touch screen, and a communication interface.

The beneficial effect of the present invention is that, by providing a digital oscilloscope waveform display method and the digital oscilloscope, detailed observation of complex signals can be realized, and clear outlines of amplitude modulation signals and carrier signals can be observed simultaneously.

When the two channels observe signals of different frequencies at the same time, especially when the frequency difference is relatively large, the signal of one channel can be displayed in the main window, and the data of two channels can be displayed in the delay window, so that the data of two channels can be observed clearly and simultaneously.

Description of drawings

Fig. 1 is a structural block diagram of a digital oscilloscope in the prior art;

Fig. 2 is the structural block diagram of the digital oscilloscope with waveform processing device of the present invention;

Fig. 3 is the structural block diagram of embodiment 2 of the present invention;

Fig. 4 is the structural block diagram of waveform processing device of the present invention;

Fig. 5 is a flow chart of scaling processing in the present invention;

Fig. 6 is a structural block diagram of Embodiment 3 of the present invention;

Fig. 7 is a schematic diagram showing a single window in the prior art;

Fig. 8 is a schematic view showing two windows of the present invention.

Detailed ways

The specific embodiments of the present invention will be described below in conjunction with the accompanying drawings.

Example 1

As shown in Figure 3, the present invention is a waveform display method of a digital oscilloscope, the method collects external analog signals through the analog front end of the digital oscilloscope, and the analog front end consists of a channel 1 front end (CH1), a channel 2 front end (CH2) and other front-end composition. The analog front end transmits the collected analog signal to an analog-to-digital converter (ADC) to convert the collected analog signal into a digital signal. The digital signals are sequentially stored to the storage depth of the digital oscilloscope. Then the control processing device generates the main frame (first frame) parameter and the delay frame (second frame) parameter after receiving the configuration instruction of the external corresponding device, and according to the main frame parameter, the delay frame parameter and the time base, The sampling rate generates a main-frame scale and a delay-window scale, and transmits the generated main-frame scale and delay-window scale to the waveform processing device. The waveform processing device executes the following zoom processing steps (as shown in Figure 5) when performing the zoom processing: if the zoom ratio of the main form is greater than or equal to 1, then the data read from the storage device is reduced; If the scaling ratio is less than 1, the data read from the storage device is enlarged. If the delay window scaling ratio is greater than or equal to 1, the data read from the storage device is reduced; if the delay window scaling ratio is less than 1, the data read from the storage device is enlarged. Main display data and delayed display data are generated after scaling processing.

The waveform processing device transmits the scaled and processed main display data and delayed display data to the control processing device. The control processing device controls the display device to display the waveform and/or data corresponding to the main display data in the main window, and display the waveform and/or data corresponding to the delay display data in the delay window , both forms appear on the same display.

When realizing detailed observation of complex signals, the clear contours of the AM signal and the carrier signal can be observed at the same time. When two channels observe signals of different frequencies at the same time, especially when the frequency difference is relatively large, the signal of one channel can be displayed in the main window, and the data of two channels can be displayed in the delay window, so that the data of two channels can be observed clearly and simultaneously.

Example 2

As shown in Figure 2, it is the digital oscilloscope that realizes the inventive method, and this digital oscilloscope comprises: analog signal acquisition device, analog-to-digital conversion device, CPU as control processing device, memory, the keyboard (also can adopt touch screen, Mouse, communication interface etc.), LCD as display device; Described analog signal acquisition device is connected with CPU through analog-to-digital conversion device, and LCD is connected with CPU; This digital oscilloscope also includes: waveform processing device, and this waveform processing device is connected with respectively The CPU, the memory and the analog-to-digital conversion device are connected.

The CPU receives the keyboard instruction to generate the first window parameter and the second window parameter, and obtains the first window zoom ratio and the second window zoom ratio according to the first window parameter and the second window parameter.

As shown in Figure 4, the described waveform processing device further includes: a digital signal receiving unit, which is used to receive the digital signal collected by the analog signal acquisition device and converted by the analog-to-digital conversion device, and store the received digital signal into the storage device; the scaling ratio receiving unit is used to receive the first window scaling ratio and the second window scaling ratio transmitted by the CPU; the digital signal scaling unit is used to read the stored digital signal data from the storage device , and perform scaling processing on the read digital signal data according to the first window scaling ratio and the second window scaling ratio to generate the first display data and the second display data; the waveform processing device will generate the first display The data and the second display data are sent to the CPU, and the CPU controls the display device to display the waveform and/or data corresponding to the first display data in the first window, and the waveform and/or data corresponding to the second display data /or data is displayed in the second form. Both forms are displayed on the same LCD display.

Example 3

The basic principle of digital oscilloscope of the present invention, with reference to Fig. 6: this digital oscilloscope mainly comprises analog front end, analog-to-digital conversion (ADC) signal conversion, field programmable gate array (FPGA) unit data processing, control, digital signal processing (DSP) System control, high-speed memory (SRAM), keyboard, LCD.

The main function of the analog front end is to realize the gain, offset, and bandwidth control of the signal. The control signal comes from the FPGA, and the control information is transmitted from the DSP to the FPGA.

The main function of ADC signal conversion is to convert the analog signal conditioned by the front end into a digital signal and send it to FPGA for processing.

The DSP receives the instruction of the external response device to generate the main window parameter and the delayed window parameter, and obtains the main window scaling ratio and the delayed window scaling ratio according to the main window parameter and the delayed window parameter.

The main functions of FPGA include data processing, logic control, triggering, time base control, etc. It is the core of the entire digital oscilloscope. There is a waveform processing device in the FPGA, and the waveform processing device further includes: a digital signal receiving unit for receiving the ADC signal and storing the received ADC signal data into the SRAM; a scaling receiving unit for receiving the main window from the DSP Volume scaling and delay window scaling; the digital signal scaling unit is used to read the stored digital signal data from the SRAM, and scale the read digital signal data according to the main window scaling and delay window scaling , to generate main display data and delayed display data. FPGA transmits the generated main display data and delayed display data to DSP.

Refer to accompanying drawing 5 for the technical realization principle process of zooming (Ultrazoom), wherein the waveform processing device performs the following zooming processing steps when performing zooming processing: if the main window zooming ratio is greater than or equal to 1, then the data read from the storage device Perform zoom-out processing; if the scaling ratio of the main window is less than 1, zoom-in processing is performed on the data read from the storage device. If the delay window scaling ratio is greater than or equal to 1, the data read from the storage device is reduced; if the delay window scaling ratio is less than 1, the data read from the storage device is enlarged. Main display data and delayed display data are generated after scaling processing.

When the ADC collects signals to the FPGA Field Programmable Gate Array (Field Programmable Gate Array), the FPGA itself is a standard cell array and does not have the functions of a general IC. However, users can use special layout and routing tools according to their own needs. Internal programming, design their own ASIC. Since the FPGA performs parallel processing in a pure hardware manner and does not occupy CPU resources, the system can achieve high performance.

The DSP receives the main display data and the delayed display data from the FPGA, and controls the LCD to display the waveform and/or data corresponding to the main display data on the main window, and to display the waveform and/or data corresponding to the delayed display data Displayed in the delayed form. After that, DSP reads all the data of high-speed SRAM.

The DSP system includes various functions such as data processing, display, interface, and message processing. It has powerful functions and a wide range of applications, which is the soul of the entire digital oscilloscope.

FIG. 8 is a schematic diagram of displaying waveforms in two windows, which is obviously different from the display in the prior art (as shown in FIG. 7 ). Adopting the above technical scheme can achieve the following technical effects:

1) Realize detailed observation of complex signals. Generally, when the signal is only observed in the main window, only the outline or details of the waveform can be observed, but the overall outline of the waveform and the details of the waveform cannot be observed at the same time. As shown in Figure 8: When observing an AM signal, using Ultrazoom technology, you can observe the clear outline of the AM signal and the carrier signal at the same time.

2) When the two channels observe signals of different frequencies at the same time, especially when the frequency difference is relatively large, it is often impossible to observe the overall outline of the two signals at the same time under one time base. In this case, the Ultrazoom technology can be used to display the 1-channel signal in the main window, and the 2-channel data in the delay window, so that the two-channel data can be observed clearly and simultaneously.

There is an optional scheme in embodiment 3, namely: adopt two LCD monitors, connect with DSP respectively, one is used for displaying the main form and its waveform data, another display delay form and its waveform number, two LCDs The displays can be of equal size or of different sizes.

The above specific embodiments are only used to illustrate the present invention, but not to limit the present invention.

Claims (10)

1. a waveform display method of digital oscilloscope, it is characterized in that comprising the following steps: Collect external analog signals and convert the collected analog signals into digital signals; receiving said digital signal and storing it as digital signal data; Receive the external response to generate the first window parameter and the second window parameter, and obtain the first window scaling ratio and the second window scaling ratio according to the first window parameter and the second window parameter; reading the stored digital signal data, and performing scaling processing on the read digital signal data according to the first window scaling ratio and the second window scaling ratio to generate first display data and second display data; displaying the waveform and/or data corresponding to the first display data in the first window; Displaying the waveform and/or data corresponding to the second display data in the second window. 2. the waveform display method of digital oscilloscope according to claim 1, is characterized in that, described first form is main form, and described second form is delay form; Scale the read digital signal data according to the scaling ratio of the main window to generate main display data; scale the read digital signal data according to the scaling ratio of the delay window to generate delayed display data; convert the main display data The corresponding waveform and/or data are displayed in the main window; the waveform and/or data corresponding to the delay display data are displayed in the delay window. 3. The waveform display method of a digital oscilloscope according to claim 1, wherein the first window and the second window display waveforms at different time bases. 4. The waveform display method of a digital oscilloscope according to claim 1, wherein the first window is used to display the data of one channel, and the second window is used to display the data of another channel . 5. A digital oscilloscope, comprising: an analog signal acquisition device, an analog-to-digital conversion device, a control processing device, a storage device, an external response device and a display device; the analog signal acquisition device is connected with the control processing device by an analog-to-digital conversion device , the storage device, the external response device and the display device are respectively connected with the control processing device; it is characterized in that it also includes: a waveform processing device, and the waveform processing device is respectively connected with the control processing device, the storage device and the analog-to-digital conversion device connection; where: The control processing device receives an instruction from the external response device to generate the first window parameter and the second window parameter, and obtains the first window scaling ratio and the second window parameter according to the first window parameter and the second window parameter. window scaling; The described waveform processing device further includes: The digital signal receiving unit is used to receive the digital signal collected by the analog signal acquisition device and converted by the analog-to-digital conversion device, and store the received digital signal into the storage device; a scaling ratio receiving unit, configured to receive the scaling ratio of the first window and the scaling ratio of the second window transmitted from the control processing device; The digital signal scaling unit is used to read the stored digital signal data from the storage device, and perform scaling processing on the read digital signal data according to the first window scaling ratio and the second window scaling ratio to generate the first display data and second display data; The waveform processing device transmits the generated first display data and second display data to the control processing device, and the control processing device controls the display device to display the waveform and/or the waveform corresponding to the first display data or the data is displayed in the first window, and the waveform and/or data corresponding to the second display data is displayed in the second window. 6. The digital oscilloscope according to claim 5, wherein said display device is a display screen, said first window is a main window, and said second window is a delay window; Scale the read digital signal data according to the scaling ratio of the main window to generate main display data; scale the read digital signal data according to the scaling ratio of the delay window to generate delayed display data; convert the main display data The corresponding waveform and/or data are displayed in the main window; the waveform and/or data corresponding to the delay display data are displayed in the delay window. 7. The digital oscilloscope according to claim 5, wherein the first window and the second window display waveforms at different time bases. 8. The digital oscilloscope according to claim 5, wherein the first window is used to display the data of one channel, and the second window is used to display the data of another channel. 9. The digital oscilloscope according to claim 6, wherein the display device is composed of two display screens, and the waveform and/or data corresponding to the main display data are displayed on one display screen; The waveform and/or data corresponding to the data is displayed on another display. 10. The digital oscilloscope according to claim 6, wherein said external response device comprises a keyboard, a mouse, a touch screen, and a communication interface.

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