VIDEO MODEM

摘要

An apparatus and method is provided for modulating and transmitting full- motion, television quality color video signals along with digital data signa ls over a pair of ordinary unshielded twisted pair telephone wires (UTP) withou t interfering with normal telephone data on the wires. The invention is characterized by a transmission method involving frequency modulation (VCO1) of a baseband video signal and subsequent filtering (BPF1) to suppress an upper sideband corresponding to a color component of the original signal. Th e filtered signal is received from the telephone wires at a different location , filtered, demodulated and provided to a display device. Full-duplex modulati on over the same pair of wires is possible, such that two video signals may be simultaneously transmitted, each signal having an approximate bandwidth of 6 MHz and shifted to a desirable non-interfering frequency location within the approximately 20 MHz of useable bandwidth on the telephone wires. No pre- emphasis or de-emphasis is required to achieve good quality video transmissi on.