BIDIRECTIONAL AMPLIFIER FOR CABLE AND HFC NETWORK USING UPSTREAM PILOT SIGNAL AND CABLE MODEM OF HFC NETWORK

摘要

PURPOSE: A bidirectional amplifier for cable and HFC(Hybrid Fiber and Coax) network using an upstream pilot signal and a cable modem of an HFC network are provided to perform an automatic gain control for an upstream signal and a downstream signal by using a bidirectional signal. CONSTITUTION: A tuner is connected with a coaxial cable. A saw filter is connected with the tuner. A mixer/AGC(Automatic Gain Control) portion is connected with the saw filter. A downstream demodulator(601) is connected with the mixer/AGC portion. A gain controller controls a gain of a signal of the downstream decoder. A MAC(Medium Access Control) portion(602) receives or transmits signals from or to the downstream demodulator(601). A CPU(604) controls the MAC portion(602) and a terminal. An upstream modulator is connected with the MAC portion(602). A programmable attenuator is connected between the upstream modulator and the tuner. A pilot generator(605) generates a pilot signal. A switch(606) is used for turning on/off the pilot generator.