Analysis and measurements of information transmission over an adaptive delta modulated voice channel

This paper presents voice and data transmission measurements of the present tactical telecommunication network in Finland. EUROCOM recommendations show that adaptive delta modulation (ADM) is suitable only to low frequencies 0...2600 Hz if the sample frequency is 16 kHz. Digital data transmission is the recommended method there. On the other hand a lot of analogue modems are in important use in the tactical networks and they do not have seamless communication through the integrated networks. Problems arise if analogue data has to be transmitted with data modems over the ADM-channel. Still in 1997 a large number of message transmission systems use frequency shift keying (FSK) modems on voice grade circuits over digital voice channels. Also other analogue modems are in use. These message or data transmissions are the basis of the proper operation of weapons and other military systems. Thus it was important to investigate data transmission over tactical networks with analogue modems. Measurements demonstrate the performance of information transmission over the ADM-channel. The quality measure of the ADM-channel itself is the phase and amplitude response characteristics. The quantitative measures are distortion of voice transmission. The quality of the data transmission is measured by the bit error rate (BER). We provide records of these measurements.