DocumentCode :
746308
Title :
A Multidigit Adaptive Delta Modulation (ADM) System
Author :
Chakravarthy, C.V. ; Faruqui, M.N.
Author_Institution :
Indian Institute of Tech., Kharagpur, West Bengal, India
Volume :
24
Issue :
8
fYear :
1976
fDate :
8/1/1976 12:00:00 AM
Firstpage :
931
Lastpage :
935
Abstract :
A multidigit adaptive delta modulation (ADM) system has been proposed where the error signal, between the input and the approximated signal produced by ADM coder, is coded in an auxiliary encoder. The error in the auxiliary coder is processed by another ADM and so on. The bit rate of each of these coders is 
where fr is the overall transmission rate and 
is the number of coders used. The bit streams are interleaved for transmission and at the receiver they are separated and decoded, and these signals are added and filtered. It is shown that for a given transmission rate, each coder operates at a basic sampling rate of frB such that 
gives the optimum number of coders to be used for maximum signal-to-noise ratio (SNR). A bound is derived for the maximum SNR of such a system and is compared with the bounds derived for other predictive coders. The experimental results of a two-digit ADM are presented. An average SNR of 30 dB is obtained with a dynamic range of 32 dB at fr = 32 kbits/s for band-limited noise signals. The SNR increases with the sampling rate at 15 dB/octave, as against 9 dB for a single-digit ADM. The frequency response is good and the variation of SNR with the message frequency of the delta coding system has been improved. The effect of channel errors has also been studied and the performance of the system is found satisfactory.
where f is the number of coders used. The bit streams are interleaved for transmission and at the receiver they are separated and decoded, and these signals are added and filtered. It is shown that for a given transmission rate, each coder operates at a basic sampling rate of f gives the optimum number of coders to be used for maximum signal-to-noise ratio (SNR). A bound is derived for the maximum SNR of such a system and is compared with the bounds derived for other predictive coders. The experimental results of a two-digit ADM are presented. An average SNR of 30 dB is obtained with a dynamic range of 32 dB at fKeywords :
Adaptive coding; Delta modulation communication; Bit rate; Decoding; Delta modulation; Dynamic range; Frequency response; Phase change materials; Pulse modulation; Sampling methods; Signal to noise ratio; TV;
fLanguage :
English
Journal_Title :
Communications, IEEE Transactions on
Publisher :
ieee
ISSN :
0090-6778
Type :
jour
DOI :
10.1109/TCOM.1976.1093385
Filename :
1093385
Link To Document :
