The V.34 Transmitter And Receiver In The Dsp System

The work of this thesis is one part of the project, V34 Modem. Its main task is to accomplish modulation, encoding, demodulation and decoding of V 34 modem.V34 data transfer protocol is an international standard drafted by ITU-T in June 1994, which increases the data transfer rate of telephony modem to 28.8 kbps. The standard was modified in October 1996 and increases the data rate up to 33.6kbps, which was ever considered as a breakthrough of telephony data transfer. In the standard, seven key techniques are used to efficiently increase the data rate, including adaptive bandwidth, adaptive data transfer rate, multi-dimensional trellis encoding, shaping and shell mapping, super-constellation, equalization and pre-encoding, nonlinear encoding.The thesis firstly introduces V34 protocol in detail, and then discusses the implementation schemes of V34 modem, including the design of hardware and software. The DSP+CPLD architecture is employed to construct the hardware platform for running the supporting software. DSPs are used to implement signal-processing algorithms, while CPLDs are used as logic controllers. Software is consisted of signal processing procedures in transmitter and receiver: in the transmitter, data are scrambled, mapped, pre-encoded and modulated; in the receiver, the incoming sequences are filtered, equalized, demodulated, viterbi decoded, inverse-mapped and decoded to recover the original data. The software also includes the hardware interfacial routines, such as routines interfacing to DA/AD converters, UART etc.In the end, the thesis discusses the project progress and analyzes the real-time performance of current code and the whole signal processing system.