Dmt Modulation Method And Design

This paper presents the framework and principle of Discrete Multi-tone Modulation algorithm used in ADSL modem, and then analyses the system structure in detail. Finally, we focus on some key technologies in DMT system, such as Encoder/Decoder, Equalization and Echo Cancellation. In addition, we present a computationally efficient, integer-bit power allocation algorithm for DMT which optimally maximizes performance margin, and simulate the performance of this allocation algorithm by MATLAB.Although we have made great progress in the filed of communication, there still exists a technical gap between our country and some developed country. Most of manufacturers in our country refer to the foreign schemes directly. In order to accumulate the key technology for us, it is very important to design a real DMT system.In modern computer system, USB interface becomes the most important interface between host computer and peripherals for its simple and high data rate. In this project, we design the hardware with one Cypress USB chip, two FIFO, ADC, DAC and PLD.This DMT system consists of two parts: hardware and software algorithm. The software algorithms are realized in host CPU, including channel parameters estimation, bit allocation, equalization, echo cancellation, FFT, IFFT, encoding, decoding, etc. A peripheral receives the data from host CPU and delivers it via hybrid wire, or receives the data from hybrid wire and deliver it to host CPU.