Error Performance of Voice Band Data Signals with an Overloaded delta Modulator

摘要

Error measurements for digital transmission of voice band data signals in 2400 bit/sec four-phase shift keying signals in combination with an overloaded 16 kbs digitally controlled delta modulator are discussed. Overloading a delta codec (+2 dBm input level) results in an error improvement factor (measured channel bit error rate (BER) 16 kbs compare with injected trunk BER, 265 kbs) of 10 in the BER range of 0.0001 to 0.1. An input level of -24 dBm (point of highest signal to noise ratio and lowest BER within the normal range of input levels) results in a measured channel BER which almost equals the injected BER in the range of 0.0001 to 0.1.