Investigation of Data Transmission over an Adaptive Delta Modulated Voice Channel211 by Simulations Using a Spreadsheet Program

摘要

This paper presents voice and data transmission simulations of the tactical211u001etelecommunication network. The network uses adaptive delta modulation (ADM) as 211u001ethe encoding method of analog signals. Recommendations are for digital data 211u001etransmission and the use of analog standard modems is not recommended. Our 211u001emeasurements have demonstrated the present performance of the analog data 211u001etransmission over ADM-channel. We have hardly acceptable bit error rates (BER) 211u001eand the other effects of the ADM-channel parameters. Thus a special simulator was 211u001ebuilt using a worksheet program. We wanted to investigate delta modulation 211u001eparameters and find out useful waveforms for the ADM-channel. Thus we modeled the 211u001echannel and simulated its performance. In this report, we find out the effect of 211u001edifferent ADM-parameters (step size, adaptation memory, and sample rate) on the 211u001equality of service(QOS) of the channel, the effect of some waveforms on BER vs 211u001eS/N, and the selection of digital modulation method to give acceptable BER values 211u001efor the available bandwidth of the ADM-channel. We consider some combinations of 211u001eamplitude, frequency, and phase modulation, symbol time, symbol(modulation) 211u001erates, bit rates, and sample rates. We develop complex waveforms by simulations 211u001eand use BER-values as QOS. In this report, we find that new non-standard 211u001ewaverforms have much better BER values in the ADM-channel than standard ITU-211u001emodems. According to our simulation results and some tests last year, we have 211u001edemonstrated with our prototype modem using some new waveforms seamless data 211u001etransmission through different analog and digital telecommunication networks with 211u001emuch higher bit rates than with standard ITU-T modems.