A performance study of delta modulation systems for voiceband data signals
Abstract
In the paper, the performances of delta modulation systems have been studied by computer simulation when the input signal to the DM coder is a voiceband data signal. The parameter values of three DM systems, linear delta modulation (LDM), constant factor DM (CFDM), and continuously variable slope DM (CVSD) have been optimized for 4800 bits/sec differential phase shift keying (DPSK) signal. The performances of the three DM systems have been studied in ideal and noisy channels. It has been found that the peak SQNR is nearly the same regardless of coding scheme used, but CFDM yields the widest dynamic range. In a noisy channel, however, CFDM is very sensitive to channel bit errors. Considering the overall performance, CVSD appears to be the best among the three DM systems studied. Also, the performances of DMs have been compared with those of PCM and DPCM systems. In addition, the effect of DM quantization noise on modem bit error rate by the Monte Carlo simulation method has been studied. It is possible to transmit a 4800 bits/sec DPSK signal at a bit error rate below 1/100,000 by DM with the rate of 32 kbits/sec.
- Publication:
-
NTC 1980; National Telecommunications Conference, Volume 3
- Pub Date:
- 1980
- Bibcode:
- 1980ntc.....3...50L
- Keywords:
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- Computerized Simulation;
- Data Transmission;
- Delta Modulation;
- Performance Prediction;
- Phase Shift Keying;
- Voice Communication;
- Channel Noise;
- Error Analysis;
- Modems;
- Monte Carlo Method;
- Optimization;
- Signal Encoding;
- Systems Simulation;
- Transmission Efficiency;
- Communications and Radar