digital pulse modulation
TRANSCRIPT
-
7/29/2019 Digital Pulse Modulation
1/18
Digital Pulse Modulation
-
7/29/2019 Digital Pulse Modulation
2/18
Advantages of DPM
The advantages offered by digital pulse modulation Performance
Digital pulse modulation permits the use of regenerative repeaters, when placed alongthe transmission path at short enough distances, can practically eliminate the degradingeffects of channel noise and signal distortion.
Ruggedness A digital communication system can be designed to withstand the effects of channel
noise and signal distortion Reliability
Can be made highly reliable by exploiting powerful error-control coding techniques.
Security Can be made highly secure by exploiting powerful encryption algorithms
Efficiency Inherently more efficient than analog communication system in the tradeoff between
transmission bandwidth and signal-to-noise ratio System integration
To integrate digitized analog signals with digital computer data
-
7/29/2019 Digital Pulse Modulation
3/18
-
7/29/2019 Digital Pulse Modulation
4/18
PCM (Pulse-Code Modulation)
A message signal is represented by a
sequence of coded pulses, which is
accomplished by representing the signal indiscrete form in both time and amplitude
The basic operation
Transmitter : sampling, quantization, encoding Receiver : regeneration, decoding, reconstruction
-
7/29/2019 Digital Pulse Modulation
5/18
Operation in the Transmitter Sampling
The incoming message signal is sampled with a train ofrectangular pulses
The reduction of the continuously varying message signal to alimited number of discrete values per second
Non uniform Quantization The step size increases as the separation from the origin of
the input-output amplitude characteristic is increased, the
large end-step of the quantizer can take care of possibleexcursions of the voice signal into the large amplitude rangesthat occur relatively infrequently.
-
7/29/2019 Digital Pulse Modulation
6/18
Quantization
-
7/29/2019 Digital Pulse Modulation
7/18
Quantization
-
7/29/2019 Digital Pulse Modulation
8/18
-
7/29/2019 Digital Pulse Modulation
9/18
Requantization
-
7/29/2019 Digital Pulse Modulation
10/18
-
7/29/2019 Digital Pulse Modulation
11/18
Companding
-
7/29/2019 Digital Pulse Modulation
12/18
DPCM
-
7/29/2019 Digital Pulse Modulation
13/18
DM
-
7/29/2019 Digital Pulse Modulation
14/18
DM-O/P
-
7/29/2019 Digital Pulse Modulation
15/18
-
7/29/2019 Digital Pulse Modulation
16/18
Problems in LDM
-
7/29/2019 Digital Pulse Modulation
17/18
ADM
-
7/29/2019 Digital Pulse Modulation
18/18
O/P