What is the Differential Pulse Code Modulation?

[aslamzohaib]

Hi,
I am new to telecom
I want to ask what is Differential Pulse Code Modulation....and how it is different from simple PCM...It would be great for me if someone explains through graphs....
Thanks....

 

[abhayinhyd]

Re: DPCM

Hi
DPCM stands for Differential pulse coding modulation it is a data modulation scheme where you use a predictor at the transmitter and reciever and send only the sampled and quantized difference between the original signal and the predicted signal . NOTE : This scheme only works for signals which are correlated i.e. u can design a linear predictor . The scheme is significantly better than PCM in which u directly sample the signal , quantize it and send it u get SNR gains of as high as 25DB in some cases for the same bit rate or advantage of 3 to 4 bits for the same SNR .