| 摘要 |
PURPOSE: A demodulation device of a cable modem is provided to perform a high-speed data transmission by utilizing efficiently a bandwidth of data using an OFDM method. CONSTITUTION: A demodulation device of a cable modem comprises a symbol mapping portion(400), Nyquist filters(410,440), interpolation filters(420,450), serial/parallel converters(430,460), an IDFT portion(470), a multiplexer(480), and a D/A converter(490). The symbol mapping portion maps input data to I and Q signals. The Nyquist filters limits bands of the I and Q signals. The interpolation filters vary transmission rates by interpolating data. The serial/parallel converters serial I and Q signals to parallel I and Q signals. The IDFT portion performs an IDFT for the parallel I and Q signals. The multiplexer converts the output from the IDFT portion to a serial signal. The D/A converter converts the digital signal of the multiplexer to an analog signal.
|
