发明名称 |
Method of and apparatus for extracting or inserting a signal in a time division multiplex communication system |
摘要 |
This invention relates to methods and apparatus for extracting data of a channel from and for inserting low speed input data into a channel of time division bit multiplex. An optical data transmission system is used for distribution of video signals or information services. A variable frequency divider generates a timing signal by frequency dividing a clock signal by N. The resulting timing signal is phase shifted by M clock periods by inserting one cycle of 1/(N+M) frequency dividing in accordance with a synchronous command signal. With the timing signal, data of a channel is extracted from the time division multiplexed data of N channels by an extracting circuit, such as a D-type flip-flop. With a synchronous signal generated from the timing signal having the same pulse width of the multiplexed data, a low speed input data is inserted into a channel of the multiplexed data of N channels by a selector.
|
申请公布号 |
US5757807(A) |
申请公布日期 |
1998.05.26 |
申请号 |
US19950523223 |
申请日期 |
1995.09.05 |
申请人 |
NEC CORPORATION |
发明人 |
TEZUKA, HIROSHI;SUZAKI, TETSUYUKI |
分类号 |
H03M9/00;H04J3/04;H04J3/08;(IPC1-7):H04J3/04 |
主分类号 |
H03M9/00 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|