Difference between PCM and DPCM

Last Updated : 11 Sep, 2024

When it comes to digital communication, two important techniques often come into play: In analog compression, we have Pulse Code Modulation (PCM) while Differential Pulse Code Modulation (DPCM is another kind of analog compression. These method are widely used for sampling the analog signals in to digital form, which can then be easily processed, transmitted and stored. But it is extremely important to comprehend the difference between the two for deciding the applicability of the method according to requirements in need of processing sound, in telecommunication, or data compression. Now let’s take a closer look at what defines the difference between these two directions.

Pulse Code Modulation (PCM):

PCM is the technique used for remodeling analog signal into digital signal. Pulse Code Modulation has good signal to noise ratio. For transmission channel, Pulse Code Modulation needs high bandwidth than DPCM.
The PCM method is split into 3 components, initial is that the transmission at the supply finish, second regeneration at the transmission path and also the receiving finish.

These steps are given below through figure:

How PCM Works

PCM can be understood in that it starts with an ordinary critical analog signal and samples it at a regular interval also known as the sampling rate. Thus, each sample is rounded down to a value within the quantize scale of discrete values/levels. Last, these quantized values are converted from analog format to binary format for transmission or storage in digital form. PCM is applied to audio recording, telephony and any other communication system where it is essential to have accurate model of the analog signal in digital form.

Differential Pulse Code Modulation (DPCM)

DPCM is same as the PCM technique used for remodeling analog signal into digital signal. DPCM has moderate signal to noise ratio.
DPCM differs from PCM as a result of it quantizes the distinction of the particular sample and expected price. that's the explanation it's referred to as differential PCM.
The operations at DPCM transmitter and DPCM receiver are given below through figure:

How DPCM Works

DPCM begins with estimation of the current sample from the previous sample of the series. It then determines the differential, or error between the actual sample and the predicted value. It is this difference that gets transmitted and encoded. The decoding process entails the reconstruction of the original signal through a technique of adding the transmitted difference on the last sample attained. That is why DPCM is particularly useful when the amount of bandwidth available is limited – in conference communications and streaming.