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A Brief Overview of Pulse Code Modulation (PCM)

“Pulse Code Modulation” is one of the most used forms of digital audio that successively makes use of digital representation for analogue signal samples.

In the study, the main focus is being catered to the methods associated with transmitting signals digitally over several channels that are of analogy communication. Primarily “Pulse Code Modulation” has been discussed in the study that originally dates back to 1939. Catering to the discussion it is acknowledged that the usage of “Pulse Code Modulation” has been standardised due to its over usage within the communication industries. Moreover, evidence is there that has proved that the technique used in this system caters to prove to be quite an effective method in the notions of sampling and as well as quantizing audio. 

Understanding All About Pulse Code Modulation

It is to be noted that in delving into the study it is noticed that the much usage of “Pulse Code Modulation” has made it a standardised format. It is known to our basic knowledge that computers, telephones and several other digital applications of audio are extensively used by people. Therefore, it can be easily acknowledged the importance of PCM is highly significant, due to its effective usage in these devices. Moreover, the method is quite effective in actively transforming the analogy signals into digital ones. This Device seems to be beneficial in several transmission channels. This method is generally used in encoding in a format of digitisation. “Pulse Code Modulation” seems to have several subtypes that include “LPCM”, “A-LAW”, “ADPCM”, “DPCM” and many more.

What Is Pulse Code Modulation?

Catering to the definition of the “Pulse Code Modulation”, it is noticed that it is primarily a technique where conversion occurs for the analogue signals into a digital format. This Is consequently done in order to conduct signal transmission through the network of digitisation.

As this method transmits single coders onto several devices, in a binary format, it is also termed the “waveform coders”.

Types of Pulse Code Modulation

It is evidenced that there are majorly two types of “Pulse Code Modulation” that are as follows.

  • “Modulation for Differential pulse code” and
  • “ Modulation for adaptive differential pulse code”

“Differential pulse code modulation” refers to an encoder of signals that actively makes use of the baseline of PCM. Moreover, it is a technique that effectively codes the differences among the sample points in order to compress the digital data. On the other hand, the method of “Adaptive differential pulse code modulation” is majorly used in order to convert binary signals from analogue signals. In addition to these, analogue signals are converted by frequent sound sampling that represents that value in binary format.

Three Steps in Pulse Code Modulation

Three steps that are essential in determining the basic steps followed in “Pulse Code Modulation” are as follows.

  • “Sampling”, is majorly a process of measuring the amplitude of signals at discrete instants into discrete signals,
  • “Quantization”, caters to conversion of analogue samples into digital samples and lastly,
  • Coding, is a sample of quantized notion, is encoded with A-Law into “codeword of 8 bit”. 

Advantages of Pulse Code Modulation

Several advantages are noticed in the usage of “Pulse Code Modulation”, the first one is that it has immunity to higher noise and also has transmitter efficiency that is higher. Moreover, this PCM can be easily multiplexed and as well acknowledges uniform quality of transmission. It has a relatively low cost for manufacturing and has an integrated circuit that is digital in nature and is more secure. This method is quite secure and has readily available efficient codes.

Disadvantages of Pulse Code Modulation  

Certain major disadvantages are noticed in the use of PCM systems, that is, it requires a larger bandwidth with respect to the methods associated with analogue. PCM is quite complex due to quantizing circuits.


In concluding the study, it is acknowledged that the major focus is given to the method of “Pulse Code Modulation” that was first developed in the year 1939, by Alec H. Reeves and is known to be an inventor of English origin. Moreover, in diving into the topic, it is noted that this method is widely used in several machines including computers, discs that are compact in nature, telephony of digitisation and several other applications associated with digital audio. These methods seem to represent the analogue signal samples in a digital format and therefore are known to waveform coders. Furthermore, in the study, certain basics are there in the technique of “Pulse Code Modulation”, that constitutes three steps such as, “encoding”, “sampling” and lastly, “quantizing”.


Frequently asked questions

Get answers to the most common queries related to the UPSC Examination Preparation.

Why is “PCM” referred to as a complex technique?

Ans. “Pulse Code Modulation” can be referred to as one of the more complex methods as its techniques are more in...Read full

Name the different ways that are present in making effective conversion of analogue to digital.

Ans. The different ways present in conducting conversion of analogue to digital is known as “delta modulations...Read full

What is the type of modulation that is followed in the methods of PCM?

Ans. In the system of “Pulse Code Modulation”, the signals of intelligence effectively convert carriers into a s...Read full

What is the limitation that is acknowledged in the system of PCM?

Ans. As we all know every system has its benefits and as well as limitations, it is no exception for PCM. This is be...Read full