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| Pulse Code Modulation |
Pulse code modulation (PCM) is a method of converting analog signals into digital signals. Quantizing is of fundamental importance in this process.
Pulse Code Modulation
- This includes three main steps
- Sampling
- Quantizing
- And coding.
- Steps
- Sampling
Sampling means to value different points of analog signal. Analog signal is measured at intervals. The frequency of taking it is called a sampling rate.
Sampling is a process in which the constant analog signal is measured at different periods of time to convert it into a digital signal.
The following points included in the detail of the sampling process.
Sampling of appreciation
Sampling is a process in which the amplitude is taken at various points of analog signal. These points are called samples. There is a number in which samples are taken per second. Its unit is HZ (HZ). For example, 44.1 KHZ’s sampling rate means going to 44,100 samples every second
Sample and Hold Circuit
The sampling process usually uses a sampling and hold circuit that maintains the value of analog signal for a short time so that it can be easily quiet.
Nyquist Theorem (Nyquist Theorem)
Nyquist According to theorem, the sampling rate should be minimal of the highest frequency doubled so that the original analog signal can be properly reproduced.
If the sampling rate is lower than the nyquist rate, the problem of “aliasing” may arise, in which data from different frequency is found and the original signal is damaged.
Digitization
After sampling, samples are quiet and then converted to binary numbers to make digital signals. This process is part of the full phase of PCM.
Use
Audio processing
In audio recording and play back, the sampling process is necessary to convert the sound into a digital format.
Video processing
video capture and processing also uses sampling process so that video signals can be converted into digital data.
Data Communication
Sampling is used to convert analog signals into digital signals in various communication systems.
Sampling is a basic and necessary process for converting analog signals into digital form. Understanding the importance of its accuracy and sampling rate is important for success in digital signal processing.
Plus Code Modulation (Pulse Code Modulation or PCM) is a digital scheme in which analog signals are converted into digital data.
Quantizing
Sample -made values are divided into a fixed range. These values are converted into a nearby potential digital value. Some information may be lost at this stage. To whom quantization is called.
Pulse code modulation (PCM) is a method of converting analog signals into digital signals. Quantizing is of fundamental importance in this process.
what is quantizing?
how is it works?
What is its purpose.
Definition of quantizing
Quantizing is the process of converting the continuous values of a sampled analog signal to discrete levels. The purpose of this process is to convert an analog signal into a digital signal. It can be processed by computers and digital devices.
Quantizing Process Sampling
In the first step the analog signal is sampled, which means the values of the signal are measured at specific time intervals. These intervals are called sampling rates.
Quantizing
which is mapped to the specified levels closest to the sampled values. These levels are called quantizing levels.
For example, if we use 8 bits, we will have 256 (2^8) quantizing levels.
Quantization Error
During the quantizing process there may be some difference between the sampled value and the quantized value. This is called quantization error. This error occurs when the original analog value is mapped to its nearest quantizing level. Due to this error, the quality of the signal may also decrease to some extent. But such error is minor and can be easily controlled.
Advantages of quantizing are as follows
Digital Processing
With the help of quantizing, analog signals can be easily converted into digital signals that can be easily processed by computers and digital devices.
Compression
Due to quantizing, signal data can also be reduced, thereby improving storage and transmission efficiency. Fault Resistance: Digital signals are more immune to noise and errors than analog signals.
Benefits of Quantization
High quality
PCM eliminates all other noise except quantization error. The high quality of the signal retains Digital Storage: PCM data is easy to save on digital mediums.
Immediate processing
Digital signal processing is easier and faster than analog signal.
Telecommunications
Telephone networks uses PCM for sound transfer.
Video Forms
In some video formats, audio is stored in PCM format. PCM is a basic technique that modern digital communication And provides the basis for storage systems.
