In this thesis work, we study on an implementation of the 2400 bits/s V.26ter modem using a TMS320C50 fixed point DSP for telephone voiceband channels which modified the ITU-T V.26ter specification. Trellis-coded Modulation of constraint length 3 is included to this modem algorithm, and decoding method employs Viterbi decoding algorithm.
The building receiver blocks of the modem algorithm include Band Edge Component Maximization(BECM) timing recovery, the T-spaced equalizer, and Viterbi decoding. The equalizer adopts the Least Mean Square(LMS) algorithm to compensate coefficient of equalizer. All algorithm in this thesis is implemented by TMS320C50 DSP assembly coding.
The Bit Error Rate(BER) performance of the Viterbi algorithm is compared with that of the uncoded 4-PSK. The performance of the Viterbi algorithm is 3 to 4 dB superior to that of the uncoded 4-PSK.
