This white paper describes Altera's Versatile Digital QAM Modulator, and introduces the features and application scenarios of the module.
The document explains that the logic structure of Altera's Stratix and Arria series FPGAs, combined with enhanced DSP blocks and memory, offers a flexible way to implement Quadrature Amplitude Modulation (QAM) signal-processing paths. These features are ideal for cable head-end system designers requiring flexibility and speed in time-to-market.
The paper details the implementation of various digital cable standards, including ITU-T/J.83B Annex B used in North America and DVB-C used in Europe and China. It covers key components such as data interleaving to combat burst errors, Reed-Solomon encoding, and Trellis Coded Modulation (TCM) for error correction within the modulation process.
The data input format for a DTV modulator is either a parallel or a serial MPEG2 transport interface.
The interleaver depth can be 8, 12, 16, 32, 64, or 128 for DOCSIS.
The default value is 8 for DOCSIS.