26-06-2013, 12:48 PM
Implementation of delta modulation and demodulation using matlab
Learning Objectives
To be familiar with concept of delta modulation and demodulation with the use of MATLAB.
THEORY
Delta Modulation:
Delta modulation (DM or -modulation) is an analog-to- digital and digital-to- analog signal conversion technique used for transmission of voice information where quality is not of primary importance. DM is the simplest form of differential pulse-code modulation (DPCM) where the difference between successive samples is encoded into n-bit data streams. In delta modulation, the transmitted data is reduced to a 1-bit data stream.
This scheme sends only the difference between pulses, if the pulse at time tn+1 is higher in amplitude value than the pulse at time tn, then a single bit, say a ―1 , is used to indicate the positive value.
If the pulse is lower in value, resulting in a negative value, a ―0 is used.
This scheme works well for small changes in signal values between samples. If changes in amplitude are large, this will result in large errors.