A Brief Discussion on the Differences Between Analog and Digital Oscilloscopes
An oscilloscope is a window to observe waveforms, allowing designers or maintenance personnel to see electronic waveforms in detail, achieving a real-time visual effect. Because the human eye is the most sensitive visual organ, it can perceive minute details and quickly reflect objects to the brain for comparison and judgment. According to the different classifications of signals, oscilloscopes can be divided into analog oscilloscopes and digital oscilloscopes.Analog oscilloscopes use analog circuits (oscilloscope tubes, which are based on electron guns). The electron gun emits electrons towards the screen, and the emitted electrons are focused to form an electron beam that strikes the screen. The inner surface of the screen is coated with a fluorescent material, so the points hit by the electron beam will emit light. Digital oscilloscopes are high-performance oscilloscopes made using a series of technologies such as data acquisition, A/D conversion, and software programming. Their operating method is to convert the measured voltage into digital information through an analog-to-digital converter (ADC). It captures a series of sample values of the waveform and stores them. The storage limit is determined by whether the accumulated sample values can depict the waveform, and subsequently, the digital oscilloscope reconstructs the waveform.
The Differences Between Analog and Digital Oscilloscopes:
Bandwidth Difference: Due to the influence of electron deflection speed, the bandwidth of analog oscilloscopes can only reach a few hundred MHz at most, while the bandwidth of digital oscilloscopes has now exceeded 100 GHz;Functional Differences: In addition to being able to stably observe some continuous periodic signals, digital oscilloscopes can realize various functions such as automatic measurement of waveforms, waveform storage, waveform analysis, multiple waveform triggering, and remote control because the waveforms have been digitized;Stability Differences: Analog oscilloscopes, being composed entirely of analog components, are more severely affected by discrete indicators and thermal drift;Other differences include that analog oscilloscopes are relatively larger; analog oscilloscopes can achieve real-time waveform capture, while digital oscilloscopes may lose some waveforms due to processing, but with the improvement of ADC speed and processing algorithms, the waveform capture rate of digital oscilloscopes can now meet usage needs.Operating Method Differences: The operating method of analog oscilloscopes is to directly measure signal voltage and depict the voltage in the vertical direction through the electron beam passing from left to right across the oscilloscope screen; the operating method of digital oscilloscopes is to convert the measured voltage into digital information using an ADC, capturing a series of sample values of the waveform and storing them, with the storage limit being determined by whether the accumulated sample values can depict the waveform, after which the digital oscilloscope reconstructs the waveform.Principle Differences: Analog oscilloscopes use analog circuits, where the electron gun emits electrons to the screen, and the emitted electrons are focused to form an electron beam that strikes the screen, which is coated with a fluorescent material, causing the points hit by the electron beam to emit light; digital oscilloscopes generally support multi-level menus, providing users with various options, multiple analysis functions, and some oscilloscopes can offer storage capabilities to save and process waveforms.Size and Weight Differences: Analog oscilloscopes are generally larger and bulkier than digital oscilloscopes, making them less portable, while digital oscilloscopes are lightweight and very convenient to carry.Display Differences: The waveform displayed by analog oscilloscopes is continuous, representing the true waveform of the signal, and has a very fast response speed; the waveform displayed by digital oscilloscopes is composed of points obtained through digital circuit sampling, resulting in a discontinuous waveform. The higher the sampling rate of the oscilloscope, the closer it is to the true waveform, but the display speed is not as fast as that of analog oscilloscopes.Response Speed Differences: This is one of the greatest advantages of analog oscilloscopes, which is difficult for digital oscilloscopes to replace. For example, when testing a certain signal, analog oscilloscopes can display the waveform instantaneously with almost no delay, while digital oscilloscopes need to process the tested signal through digital circuits before displaying the simulated waveform, resulting in a delay compared to analog oscilloscopes.
