| 摘要 |
PURPOSE: A demapper of an ADSL DMT modem is provided to improve time delay generated in a mapper of the receiver of the DMT modem and to satisfy expansion to multiport. CONSTITUTION: A demapper of an ADSL DMT modem includes a constellation decoder(220) for decoding data by tones generated by a demodulator, and a bit de-allocation unit(210) for demapping the decoded data to each channel. The constellation decoder includes a plurality of decoding engines for decoding input data, a DSP interface for performing interface for digital signal processing, and a gain table unit for receiving a control signal that has been digital-signal-processed by the DSP interface and storing a gain table according to channel identification. The decoder further has a RAM for storing data processed by a control register, and a controller for controlling the demapping of the data decoded by the decoding engines according to the gain table.
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