Analog oscilloscopes are outdated and they have been successfully replaced by digital storage oscilloscopes. This information has been confirmed by statistics and become a standard. However, it should be noted that these statistics also include so-called combination oscilloscopes. Combination oscilloscope is a combination of analog and digital oscilloscope. Because DSOs have some serious defects, some applications must also rely on analog-to-digital oscilloscopes.
Traditionally, in addition to research and development departments, universities and training centers will also purchase oscilloscopes. These users care about the quality of the oscilloscope, the operation is simple, and they are particularly dependent on the measurement results. This is why some well-known manufacturers provide analog / digital oscilloscopes (analog-to-digital oscilloscopes).
Analog and digital For basic physical reasons, analog oscilloscopes have been unable to surpass in terms of signal reproduction and highest capture rate. DSOs can not only display signals but also reconstruct signals through sampling, analog-to-digital conversion and further processing of stored information. Most of them use 8bit A / D converter, which can distinguish 256 levels. The effective sampling rate of DSOs is not fixed, it depends on the time base setting used. When the scanning speed is reduced, any DSO will inevitably reduce its maximum sampling rate. GS / s may be reduced to KS / s. To correctly reconstruct the signal, the sampling rate is at least twice the highest frequency component of the signal. Strictly speaking, the DSO should include a low-pass filter whose cut-off frequency must automatically decrease as the sampling rate decreases. This is obviously not feasible. Or the user must adjust the frequency component of the signal according to the effective sampling rate. Therefore, if the effective sampling rate is too low, signal distortion and artifacts will occur. In this case, the DSO measurement results may produce huge errors. There is only one remedy: expensive storage depth. The manufacturer provides, for example, 1 MPts storage to reduce the maximum sampling rate to a scanning speed of 100 μs / cm. If the DSO storage depth is 10kPts, the sampling rate drops from 1GS / s to 10MS / s at a scanning speed of 100μs / cm.
In contrast, the analog oscilloscope signal itself and bandwidth are independent of the time base speed. Analog oscilloscopes produce neither distortion nor artifacts. If the signal changes very quickly during the oscilloscope rise time, the corner becomes smooth.
Analog-to-digital combination oscilloscope DSOs can only replace analog oscilloscopes in certain applications. They have some advantages: the signal is easy to archive in digital format; it is easy to further mathematically process. DSOs are easier to handle signals with low repetition frequency or capture a single event. An analog oscilloscope can also present this signal on the screen, but it is invisible to the human eye.
The analog-to-digital combination oscilloscope integrates the advantages of analog and digital oscilloscopes, and the analog-to-digital conversion is performed with one key. If you suspect the signal presented in DSO mode, you can quickly switch to analog mode to view and find the problem. Therefore, for oscilloscope applications, analog combination oscilloscope is the best choice.
Analog and digital work do not contradict each other, but complement each other, each with different characteristics. Huimei Oscilloscope is designed for cost-sensitive applications such as schools, factories, research institutes and development laboratories. Although some important parameters such as simulation work, sampling rate, memory depth and logic channel are optimized, the price remains unchanged. Not only has high performance, but also easy to operate, like a typical analog oscilloscope.
Quick response to operator commands is by no means inevitable, especially when deep storage is provided. A RISC 32-bit processor (166MHz clock) and a 32-bit RISC vector graphics engine provide graphics and character display without interference in analog mode. Develop special operating systems to ensure quick response and compressed code. The interface module is a plug-in type.
Sampling rate, storage, storage amplification Sampling rate storage determines the time interval, this time interval can still be measured with the highest sampling rate. When the scan rate is 100μs / cm, the sampling rate can reach 1GS / s at a time interval of 1ms. This is equivalent to 100,000 sampling points per cm for generating a signal display. The signal display is a preview of the entire stored content. In order to get the signal details, you can use the storage amplification function. When the frequency component of the signal is higher than the bandwidth limit, a study may be necessary. When the signal frequency is greater than 500MHz and much greater than the 150MHz bandwidth, false frequencies are unpredictable. The following table compares the performance of DSOs with different storage depths. Assume that the oscilloscope has a maximum sampling rate of 1GS / s, a time interval of 1ms, and a storage depth of 10KPts. The storage reduces the sampling rate to 10MS / s. The storage depth is only 2KPts. The sampling rate even drops to 2MS / s. Therefore, when the alias frequency is much lower than the oscilloscope bandwidth, the alias frequency and erroneous measurement can be pre-programmed.
to sum up
If you choose an analog-to-digital oscilloscope, you do not need to make a decision between analog and digital oscilloscopes. The analog-digital combination oscilloscope consists of a single instrument. Other special measurement tasks can be carried out.
The analog mode is unique, it does not produce erroneous measurements, and also shows the highest signal quality. Therefore, only this model can guarantee the correct result. The capture rate can be higher than one million times per second. The highest sampling rate of DSO in analog-digital combination oscilloscope is 1GS / s and 1MPts. Storage depth.
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