Microprocessor-based pcm pulse code modulation principle analysis experiment method and system

Abstract

The present invention disclosed an analysis method and system of PCM pulse encoding modulation based on microprocessor -based PCM pulse coding, including limited, sampling, quantitativeness, and encoding processing of input analog signals;The time, quantitative value, and binary coding code group are simultaneously displayed on a LCD display.The present invention realizes the simulation signal, sampling time, quantitative value, binary encoding group on a screen, solving the problem of traditional PCM pulse encoding modulation experimental oscilloscope.The intuitive observation of the corresponding relationship between the phase and the value of the four -in and binary code set of analog signal waveform, sampling time, quantitative value, and binary code group can help students understand the principles and processes of PCM pulse encoding modulation. At the same timeChannel oscilloscope spends time spent tedious complex operations and debugging processes.

Description

technical field [0001] The present invention relates to the communication field, in particular to a microprocessor-based PCM pulse code modulation principle analysis experiment method and system, which is an STM32 microprocessor-based PCM pulse code modulation principle analysis experiment method and system. Background technique [0002] Modern communication is mainly digital communication. The process of digitizing analog signals is source coding. PCM pulse code modulation is a commonly used source coding method. The principle of PCM pulse code modulation is an important knowledge in the course "Digital Communication Principles" in colleges and universities. It is also a difficult point in teaching. How to intuitively reveal the principle and process of PCM pulse code modulation by means of experiments and help students understand the profound and abstract theoretical knowledge has always been an urgent problem in teaching. [0003] The complete PCM pulse code modulation pr...

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Problems solved by technology

If you want to better analyze the principle of PCM pulse code modulation, you need a 4-channel oscilloscope to observe the above four signals at the same time. Only in this way can you observe the correspondence between the sampling time corresponding to the position on the analog signal, the encoding rate and the encoding waveform. Since the sampling pulse and the analog signal in the experimental system are controlled by different clock sources, the sampling position of the sampling pulse on the analog signal cannot be guaranteed to be relatively fixed, resulting in the binary code group obtained after the analog signal is sampled, quantized and encoded. The lowest bit symbol cannot be determined. According to the signal displayed by the oscilloscope, students cannot obtain a definite binary code group. At the same time, because the oscilloscope can only display waveforms and cannot directly display numerical values, such as quantized values ​​and binary codes, students also need to use A-law or U Law code table to analyze the relationship between quantized value and binary code group, to achieve the purpose of understanding and mastering the principle of PCM pulse code modulation, so the quantization value and binary code group cannot be observed intuitively through traditional PCM pulse code modulation experiments, and cannot be reflected intuitively Therefore, the traditional PCM pulse code modulation experimental method cannot show the coding process, and it is not obvious for students to understand and master the principle of PCM pulse code modulation.

[0005] Even so, the oscilloscope used to complete the above experiments must be a 4-channel oscilloscope, because it is impossible to observe the corresponding relationship between the phase and time of the 4 signals when viewing 4 signal waveforms with two dual-channel oscilloscopes, but the oscilloscopes currently equipped in university laboratories Generally, it is a dual-channel oscilloscope or a single-channel oscilloscope, because the operation of a 4-channel oscilloscope is relatively complicated, and the debugging process takes time

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