- How to understand the bandwidth in oscilloscope index?

Bandwidth is the basic index of oscilloscope, and the definition of amplifier bandwidth is the so-called -3db point, that is, in the input of oscilloscope plus sine wave, amplitude attenuation of 70.7% of the actual amplitude of the frequency point called bandwidth. That is to say, using the oscilloscope with 100MHz bandwidth to measure 1V and the sinusoidal wave with 100MHz, the amplitude obtained is only 0.707v.And that's just the sine wave case.Therefore, when we choose oscilloscope, in order to achieve a certain measurement accuracy, we should choose the bandwidth of the signal's highest frequency five times.Siglent's ADS1000CE oscilloscope provides 300MHz bandwidth and 2GSa/a real-time sampling rate, leading the domestic counterparts.

- Does too large a sampling frequency make little sense given a given bandwidth?

Bandwidth is the basic condition to limit the capture of high frequency components of the measured signal.Due to the advanced waveform reconstruction algorithm and interpolation algorithm display provided by Siglent oscilloscope, the real-time sampling rate of the minimum 500MS/s is provided to ensure the perfect capture and real quantization of the trigger signal, and the accurate reproduction of the collected signal is finally achieved.

- What factors affect the working speed of oscilloscope?

Simply speaking, the principle of oscilloscope is the same, the front end is the data acquisition system, the back end is the computer processing.The speed of oscilloscope is mainly affected by two aspects, one is the data transmission from the front-end data acquisition to the back-end processing, which is generally transmitted by bus, the other is the back-end processing mode.

- How to eliminate burrs when using oscilloscope?

If the burr is intrinsic to the signal and you want to use the edge trigger to synchronize the signal (such as a sinusoidal signal), you can suppress the trigger with high frequency and usually synchronize the signal.If the signal itself has a burr, but want to get the oscilloscope to remove the burr, do not show the burr, it is often difficult to do.You can try to use bandwidth-limiting methods, but if you don't take care, you may also lose some information from the signal itself.

- In the selection of oscilloscope, the general consideration is more bandwidth.So, under what circumstances should we consider the sampling rate?

Depending on the object under test, the minimum sampling interval (the inverse of the sampling rate) is expected to capture the signal details you need, provided that the bandwidth is satisfied.The industry also has some empirical formulas about sampling rate, but basically it is based on the oscilloscope bandwidth, in practical application, it is best not to use oscilloscope to measure the bandwidth frequency signal. If you are selecting sinusoidal waves, choose an oscilloscope with a bandwidth of more than 3 times the frequency of the sinusoidal signal under test, a sampling rate of 4 to 5 times the bandwidth, actually 12 to 15 times the signal, and for other waveforms, ensure that the sampling rate is sufficient to capture the signal details.If you are using an oscilloscope, you can verify that the sampling rate is sufficient by stopping the waveform and amplifying the waveform. If the waveform changes (such as certain amplitude values), the sampling rate will not be sufficient. Otherwise, the sampling rate will meet the measurement accuracy.Point display can also be used to analyze whether the sampling rate is sufficient.Professional siglenet oscilloscopes have solved the problems of bandwidth and sampling rate.

- What is the fixed relationship between bandwidth and sampling frequency?

In theory, the sampling rate should meet the sampling law of agropyron, that is, at least 2 points should be taken for each period of the highest frequency signal of the measured signal, otherwise it will cause aliasing.