Design and performance of a variable-rate QAM modem for digital cable television

The paper presents the design and performance of a quadrature amplitude modulation (QAM) modem for digital cable TV broadcasting. The modem fully complies with the European DVB standard and includes a number of additional features. The most distinctive feature is that this fully-digital modem offers a variable symbol rate and handles all modulation schemes from 16-QAM up to 256-QAM. It also includes a powerful blind equalizer and a carrier synchronization technique with extended frequency acquisition capability that allows one to use low-cost tuners and analog front-ends. The authors present the architecture of the modem and discuss its performance.<
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