| 摘要 |
PURPOSE: An upstream transmitter of a cable modem for preventing noise is provided to have an amplifier and an amplification controller built-in a cable modem chip, so as to prevent spurious noise from being generated and optimize communication through the cable modem. CONSTITUTION: A cable modem chip(24) converts data signals corresponding to an Internet search command and an information use command of a subscriber PC(Personal Computer)(30) into IF(Intermediate Frequency) signals. An amplifier(23) amplifies the IF signals of the cable modem chip(24). An RF(Radio Frequency) circuit(22) converts the IF signals amplified in the amplifier(23) into RF signals. A tuner(21) filters and amplifies the RF signals of the RF circuit(22), and outputs desired RF signals to a cable modem terminal system(10). The amplifier(23) is built in and integrated in the cable modem chip(24). And an amplification controller built-in the cable modem chip(24) receives signals provided from the cable modem terminal system(10), to output signals controlling the amplification of the amplifier(23).
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