Pulse code modulation
Abstract
In digital communication systems, we basically show represent the discrete time signals in the form of symbols and processsend the signals with the help of digital signal processors. Pulse cCode mModulation (PCM) is a methodscheme for representing analog data in their digital form and transmitting them. We can digitize all forms of analog data, including full motion video, music, and virtual reality (VR) by using PCM. The PCM- encoded signals are in the binary form;, that is, there can only be only two possible states, represented by logic 1 (high) and logic 0 (low). A sine wave is sampled and quantizsed in PCM. The amplitude of the analog signal amplitude is sampled at regular intervals of time. Firstly, we have to convert the continuous signals to their discrete form, for examplee.g., converting of sound waves were converted to a series of some samples. This conversion is done performed by a process called sampling. At the source of a communication system, the amplitude of the analog signal is sampled at regular intervals of time. The nNext step is the quantization. The amplitude of the analog signal at each sampling is rounded off taken to the nearestclosest pre-determined levels. This process is called quantization. The number of levels is always a power of 2two. The output of PCM pulse code modulation is a series of binary numbers, each represented by some a certain power of 2two bits. At the receiver end, a pulse code demodulator reconverts the binary numbers into pulses. These pulses are processed to restoreget back the original analog waveform. The circumstances under way by which we can completely reconstruct the originalactual signal completely from the sampleding signal is are given by the Nnyquist criterion, according to which says a perfect reconstruction fromof the sampled version is possiblebecause only if the sampling rate is more than two times2 times