How to measure DC voltage?
A: First, set the coupling mode to DC, adjust the vertical scale to a suitable value according to the approximate range, and then compare the displacement of the offset line with the channel mark.
2. When measuring 220V power, the amplitude exceeds the screen range? How to measure the phase difference of three-phase power supply?
Answer: The maximum input peak-to-peak voltage of the DS5000 series is 400V. According to the effective value, the peak-to-peak formula is 220V, and the commercial power exceeds 400V peak-to-peak. The amplitude exceeds the normal range of the screen. When using an oscilloscope to measure the phase shift of the three-phase power supply, you can set the trigger source to mains, and use a channel to measure the AB waveform first, then store it as a reference waveform, and then use the probe to connect BC. Then you can measure the phase shift.
3, what is the inhibition of confusion?
A: Confusion refers to a situation where the frequency collected by the oscilloscope is less than 2 times the maximum frequency of the actual signal. Confusion suppression is specifically designed to prevent the generation of confusion. Confusion suppression can discriminate the maximum frequency of the signal and acquire the signal at twice the maximum frequency.
How to capture non-periodic signals?
Answer: 1. Set the trigger level to the desired value. 2. Click the master button SINGLE. The machine starts waiting. If a certain signal reaches the set trigger level, it will be sampled once and displayed on the screen. This function can easily capture incidents that happen by chance, such as large bursts of glitches: set the trigger level just above the normal signal level, click the SINGLE button, then when the glitches occur, the machine will automatically trigger and Record the waveforms before and after the trigger. Drag the trigger position marker line to obtain negative delay triggers of different lengths, which is convenient for observing the waveform before the glitch occurs.
5. How to observe the noise of low voltage DC power supply?
Answer: 1. Connect the oscilloscope probe between channel A1 (or A2) and the measured point. 2. Set the Trigger Source to A1 or A2 (must be the same as the actual signal input channel). 3. Click the A1 or A2 button and select the coupling mode as AC (AC) coupling. 4. Adjust the sampling rate and vertical sensitivity until a satisfactory display is obtained.
6, DS5000 oscilloscope acquisition methods can be applied in what occasions?
A: Please use the real-time sampling method to observe the single-shot signal, and observe the high-frequency periodic signal by using the equivalent sampling method. Want to observe the envelope of the signal to avoid confusion, please use the peak detection method. To reduce the random noise in the displayed signal, select the average sampling method. The average number of times can be selected. Observe the low frequency signal and select the scroll mode. You want to display the waveform close to an analog oscilloscope. Use the analog acquisition method.
7. What is the relationship between trigger and waveform acquisition?
A: For different types of oscilloscopes, the oscilloscope has different capture modes, and the relationship between trigger and waveform acquisition is different. If it is an equivalent time sampling mode of a sampling oscilloscope or a real-time oscilloscope, the acquisition of one waveform needs to be triggered multiple times. For real-time oscilloscope real-time sampling mode, once triggered, the waveform will certainly be collected once, not triggered, the waveform may also be collected, this is the triggering AUTO mode. (There are three trigger modes, one is AUTO, no trigger, the waveform will be refreshed, but the waveform will be unstable on the screen, the other is NORMAL, only the trigger is refreshed, the last is SINGLE, the first trigger capture The waveform will not be captured later.)
8, RIGOL products save the waveform data can automatically generate EXCEL table?
Answer: Yes. Ultrascope software can automatically save the downloaded waveform data to the file format of the Excel spreadsheet. The RVO virtual instrument does not have the function of automatically generating the Excel table in the software, but we provide a conversion tool (a free download is available on the RIGOL official homepage, software name: DatKit for RVO3000&4000 Series). Use this tool to save RVO as a "*.dat" file format converted to "*.txt" text file format, modify txt to xls to save the data on the Excel table.
9, after the acquisition of the signal, the signal waveform does not appear in the picture, how to deal with?
Answer: You can check the following steps: 1. Check whether the probe is properly connected to the signal cable; 2. Check whether the signal cable is properly connected to the BNC (channel connector); 3. Check whether the probe is connected to the test object. Normal connection; 4. Check whether there is a signal generated by the object to be tested (the channel with the signal generated can be connected with the problematic channel to determine the problem). 5. Recollect the signal again.
10. What are the applications of glitch/pulse width trigger?
Answer: There are two typical applications for glitch/pulse width trigger. One is synchronous circuit behavior, such as using it to synchronize serial signals, or for applications with very severe interference, the correct synchronization signal cannot be triggered by edges. Pulse width trigger is One choice; the other is to find anomalies in the signal, such as narrow glitches caused by interference or competition, because the anomaly is sporadic, it must be captured with glitches (another method is peak detection, but the peak The detection method may be limited by its maximum sampling rate. At the same time, it can generally be seen and cannot be measured). If the pulse width of the measured object is 50 ns, and the signal has no problem, that is, there is no signal distortion due to interference or competition, or is narrower, the signal can be synchronized by using edge trigger without glitch triggering. .
11. When selecting an oscilloscope, the bandwidth is usually considered the most. Under what circumstances should the sampling rate be considered?
A: Depending on the object to be measured, it is expected that the minimum sampling interval (reciprocal of the sampling rate) can capture the signal details you need, provided that the bandwidth is satisfied. There are some empirical formulas for sampling rate in the industry, but they are basically based on the bandwidth of the oscilloscope. In practical applications, it is better not to use the oscilloscope to measure signals of the same frequency. If you are in the selection, for the sine wave, select the oscilloscope bandwidth is 3 times the measured sinusoidal frequency, above, the sampling rate is 4 to 5 times the bandwidth, in fact, the signal is 12 to 15 times, if other waveforms, to Ensure that the sampling rate is sufficient to capture signal details. If you are using an oscilloscope, verify that the sample rate is sufficient by stopping the waveform and amplifying the waveform. If you notice a change in the waveform (such as some amplitude), the sampling rate is not enough, otherwise it will not be a problem. Can also be used to analyze the point, sampling rate is sufficient.
12. How to eliminate glitches when using an oscilloscope?
Answer: If the glitch is inherent in the signal and you want to use edge trigger to synchronize the signal (such as sinusoidal signal), you can use high-frequency suppression trigger mode, usually the signal can be synchronized. If the signal itself is a glitch, but you want the oscilloscope to consider the glitch, without displaying glitches, it is usually difficult to do. You can try to use the method of limiting the bandwidth, but carelessness may also take the signal itself out of part of the information. If you use logic analysis instruments, in general, using the state acquisition method, some of the glitches collected in the timing mode will not be visible.
13, DS5000 oscilloscope edge trigger, pulse width trigger and video trigger suitable for the kind of signal?
A: Edge trigger, can set the trigger level, rising or falling edge. Edge triggering is also called basic triggering. Pulse width trigger, according to the pulse width to determine the trigger moment. You can capture abnormal pulses by setting pulse width conditions. Video triggering can be triggered on the field or line of an NTSC, PAL or SECAM standard video signal.
14, using the DS5000 series of oscilloscopes, how to completely capture and save a one-time random signal, and then re-display analysis?
A: If the so-called random signal measured is a single signal, then just set the vertical and horizontal scales that match the signal, adjust the trigger level, use a single trigger to wait for the signal to appear, and then use STORAGE storage type The waveform save function can store the captured waveforms, and the saved waveforms need to be re-displayed. Simply recalling the waveforms will re-display the analysis.
15. Why is the waveform memory already stored and what is the storage setting?
A: First of all, the main difference between the two is that the storage space occupied by waveform storage is much larger than the storage space. Therefore, considering the space and cost of storage, it is necessary to save the two separately. Second, there are also differences in the recall of the two. Waveform recalls that the oscilloscope is in the STOP state. Setting the recalled state does not change the saved operating state. It is convenient to observe the waveform directly.
16, each oscilloscope has a frequency range, such as 10M, 60M, 100M. . The oscilloscope I use at hand is nominally 60 MHz. Can it be understood that it can measure up to 60 MHz? I can not measure it with 4.1943MHz square wave, what is the reason?
A: A 60MHz bandwidth oscilloscope does not mean that it can measure 60MHz signals well. According to the oscilloscope's bandwidth definition, if you enter a 60MHz sine wave with a peak-to-peak value of 1V to a 60MHz bandwidth oscilloscope, you will see a 0.707V signal (30% amplitude measurement error) on the oscilloscope. If you test the square wave, select the oscilloscope reference standard should be the signal rise time, oscilloscope bandwidth = 0.35 / signal rise time & TImes; 3, then your rise time measurement error is about 5.4%.
The bandwidth of the oscilloscope's probe is also very important. If the oscilloscope probe used, including its front-end accessories, constitutes a system with a very low bandwidth, the bandwidth of the oscilloscope will be greatly reduced. If you use a 20MHz bandwidth probe, the maximum bandwidth that can be achieved is 20MHz. If you use a connecting wire at the probe tip, it will further reduce the probe performance, but it should not have much impact on the square wave around 4MHz because the speed is not very fast.
Also look at the oscilloscope user manual, some 60MHz oscilloscope in 1:1 settings, the actual bandwidth will be sharply reduced to 6MHz or less, for 4MHz square wave, the third harmonic is 12MHz, 5th harmonic is 20MHz If the bandwidth is reduced to 6MHz, the amplitude of the signal is greatly attenuated. Even if the signal can be seen, it is definitely not a square wave, but a sine wave whose amplitude is attenuated.
Of course, there are many possible causes for undetectable signals, such as poor probe contact (the phenomenon is easily eliminated). It is recommended to use a BNC cable to connect a function generator to check if the oscilloscope itself has any problems and if the probe has any problems, such as There is a problem and you can contact the factory directly.
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