Patent ID: 7289566
Filing Date: 2007-10-30
Classification: H04L

Abstract:
1. A cable modem tuner, comprising: a tuner portion taking and amplifying a signal corresponding to a reception channel from input signals, and converting to an intermediate frequency signal; a surface acoustic wave filter connected to an output of said tuner portion and limiting said intermediate frequency signal to a frequency band for transmission; a gain control unit connected to an output of said surface acoustic wave filter, including at least one dual gate type MOSFET and performing control based on an externally provided control voltage such that gain of said intermediate frequency signal is constant; an intermediate frequency amplifying unit connected to an output of said gain control unit and amplifying said intermediate frequency signal; a lowpass filter connected to an output of said intermediate frequency amplifying unit and limiting the output of said intermediate frequency amplifying unit by filtering out a signal out of a transmission band; and an unbalance/balance converting circuit connected to an output of said lowpass filter and converting an unbalanced signal into a balanced signal to output the balanced signal to a QAM demodulating circuit.