发明名称 |
Video modem for transmitting video data over ordinary telephone wires |
摘要 |
An apparatus and method is provided for modulating and transmitting full-motion, television-quality color video signals along with digital data signals over a pair of ordinary unshielded twisted pair telephone wires without interfering with normal telephone data on the wires. The invention is characterized by a transmission method involving frequency modulation of a baseband video signal and subsequent filtering to suppress an upper sideband corresponding to a color component of the original video signal. The filtered signal is received from the telephone wires at a different location, filtered, demodulated and provided to a display device. Full-duplex operation 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 usable bandwidth on the telephone wires. No pre-emphasis or de-emphasis is required to achieve good quality video transmission. The system has many applications including video distribution, conferencing, and communications.
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申请公布号 |
US5621455(A) |
申请公布日期 |
1997.04.15 |
申请号 |
US19940352112 |
申请日期 |
1994.12.01 |
申请人 |
OBJECTIVE COMMUNICATIONS, INC. |
发明人 |
ROGERS, STEVEN;GERIG, JOHN |
分类号 |
H04N7/00;H04N7/08;H04N7/10;H04N7/14;H04N11/00;H04N11/02;(IPC1-7):H04N7/10 |
主分类号 |
H04N7/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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