Working Principle of Digital Storage Oscilloscope

Digital storage oscilloscope is a common type of electronic measuring instrument. I believe that everyone has come into contact with it in daily life to a greater or lesser extent. Here I will introduce to you the working principle and other related knowledge of the digital storage oscilloscope.

A digital storage oscilloscope is different from a general analog oscilloscope. It converts the collected analog voltage signals into digital signals, which are analyzed, processed, stored, displayed or printed by an internal microcomputer.

Digital storage oscilloscopes usually have program control and remote control capabilities, and can also transmit data to external devices such as computers for analysis and processing through the GPIB interface.

The working process of a digital storage oscilloscope is generally divided into two stages: storage and display. In the storage stage, the analog signal to be measured is first sampled and quantized, converted into a digital signal by an A/D converter, and then stored in RAM in sequence. When the sampling frequency is high enough, the signal can be stored without distortion.

When it is necessary to observe this information, just take it out from the memory RAM in the original order at a suitable frequency, and send it to the oscilloscope after D/A conversion and LPE filtering to observe the restored waveform.

The P31  phosphor  on  a common analog oscilloscope  CRT  has an afterglow time of less than 1 ms. In some cases,  a CRT  using a P7  phosphor  can give an afterglow time of about  300 ms  .

As long as there is a signal irradiating the fluorescent material, the CRT  will continue to display the signal waveform. When the signal is removed,  the scanning trace on  the CRT  using P31  material  quickly darkens, while the scanning trace on the CRT  using P7  material  stays a little longer.

Digital storage is the storage of signals in the form of digital codes in an oscilloscope. When a signal enters a digital storage oscilloscope, or  DSO  , the oscilloscope will sample the signal voltage at certain time intervals before the signal reaches  the deflection circuit of the CRT.

These samples are then converted using an analog-to-digital converter (ADC) to create a binary word representing each sampled voltage. This process is called digitization.

The binary values ​​obtained are stored in memory. The rate at which the input signal is sampled is called the sampling rate. The sampling rate is controlled by the sampling clock. For general use, the sampling rate ranges from  20  megasamples per second (20MS/s) to  200MS/s.

The above is a brief introduction to the working principle of the digital storage oscilloscope . You can combine your existing knowledge to gain a deeper understanding.