What is an oscilloscope?USB-powered PC oscilloscopes?
Oscilloscope is a widely used electronic measuring instrument. It can transform invisible electrical signals into visible images, which is convenient for people to study the change process of various electrical phenomena. The oscilloscope can be used to observe the waveform curves of various signal amplitudes varying with time, and can also be used to test various electric quantities, such as voltage, current, frequency, phase difference, modulation amplitude and so on.Digital Oscilloscopes, analog oscilloscope
Classification of oscilloscopes
Classification according to different signals
The analog oscilloscope adopts the analog circuit (oscilloscope tube, which is based on the electron gun). The electron gun emits electrons to the screen. The emitted electrons are focused to form an electron beam and hit the screen. The inner surface of the screen is coated with fluorescent material, so that the spot hit by the electron beam will emit light.
Digital oscilloscope is a high-performance oscilloscope manufactured by a series of technologies such as data acquisition, a / D conversion, software programming and so on. The working mode of digital oscilloscope is to convert the measured voltage into digital information through analog converter (ADC). The digital oscilloscope captures a series of sample values of the waveform and stores the sample values. The storage limit is to judge whether the accumulated sample values can depict the waveform. Then, the digital oscilloscope reconstructs the waveform. Digital oscilloscope can be divided into digital storage oscilloscope (DSO), digital fluorescence oscilloscope (DPO) and sampling oscilloscope.
In order to improve the bandwidth of analog oscilloscope, oscilloscope tube, vertical amplification and horizontal scanning need to be promoted in an all-round way. In order to improve the bandwidth of digital oscilloscope, only the performance of front-end A / D converter needs to be improved, and there are no special requirements for oscilloscope and scanning circuit. In addition, the digital oscilloscope tube can make full use of memory, storage and processing, as well as a variety of trigger and lead trigger capabilities. In the 1980s, digital oscilloscopes have sprung up with numerous achievements, and there is a great potential to completely replace analog oscilloscopes. Analog oscilloscopes have indeed retreated from the front desk to the back desk.
Classification according to structure and performance
① Ordinary oscilloscope. The circuit has simple structure, narrow frequency band and poor scanning linearity. It is only used to observe the waveform.
② Multipurpose oscilloscope. With wide frequency band and good scanning linearity, it can quantitatively test DC, low frequency, high frequency, UHF signals and pulse signals. With the help of amplitude calibrator and time calibrator, the measurement accuracy can reach ± 5%.
③ Multi line oscilloscope. Multi beam oscilloscope tube is adopted, which can simultaneously display the waveforms of more than two signals with the same frequency on the fluorescent screen without time difference and accurate timing relationship.
④ Multi trace oscilloscope. With the structure of electronic switch and gating circuit, the waveforms of more than two signals with the same frequency can be displayed simultaneously on the fluorescent screen of a single beam oscilloscope. However, there is time difference and the timing relationship is not accurate.
⑤ Sampling oscilloscope. The sampling technology is used to convert the high-frequency signal into analog low-frequency signal for display, and the effective frequency band can reach GHz level.
⑥ Memory oscilloscope. Using storage oscilloscope tube or digital storage technology, the transient process of single electrical signal, aperiodic phenomenon and ultra-low frequency signal are retained on the fluorescent screen of oscilloscope tube or stored in the circuit for repeated test.
⑦ Digital oscilloscope. There is a microprocessor inside and a digital display outside. Some products can display both waveforms and characters on the fluorescent screen of the oscilloscope tube. The measured signal is sent to the data memory through the analog-to-digital converter (A / D converter). Through keyboard operation, the data of the captured waveform parameters can be added, subtracted, multiplied, divided, averaged, square root and root mean square, and the answer number is displayed.
