Patent ID: 6615407
Filing Date: 2003-09-02
Classification: H04H,H04N

Abstract:
An in-building CATV transmission system for communicating a downward signal input from a CATV system to an in-building terminal and for transmitting an upward signal from the terminal to the CATV transmission system, comprising:an in-building transmission line, a down-converter, and an up-converter, the down-converter connected with the CATV system for receiving the downward signal in a first frequency range and transmitting a corresponding in-building downward signal through the in-building transmission line to the up-converter, the up-converter being connected with the terminal and providing a corresponding downward signal to the terminal, the up-converter being connected to the terminal for receiving the upward signal from the terminal and transmitting a corresponding in-building upward signal to the down-converter through the in-building transmission line, and the down-converter receiving the in-building upward signal and providing the corresponding upward signal to the CATV system, the down-converter including a frequency generator for generating a first converting reference signal and a reference signal generator for generating a transmitting reference signal wherein the transmitting reference signal frequency is lower than a lowest frequency of the downward signal, a down-mixer for generating the in-building downward signal by adding the transmitting reference signal to the downward signal, so that the downward signal in the in-building downward signal is in the first frequency range, and an up-signal receiving mixer connected from the first converting reference signal for extracting the upward signal from an in-building upward signal in a second frequency range and providing the upward signal to the CATV system, the up-converter including a receiving filter for extracting the downward signal from the in-building downward signal and providing the downward signal to the terminal and a phase-locked loop circuit for extracting the transmitting reference signal from the in-building downward signal and generating a second converting reference signal having the same frequency as the first converting reference signal, and an up-signal sending mixer connected from the second converting reference signal for frequency converting the upward signal into the in-building upward signal in the second frequency range and transmitting the in-building upward signal to the up-signal receiving mixer of the down-converter.