发明名称 |
Subscriber line interface circuit having an impedance synthesizer. |
摘要 |
A subscriber line interface circuit described wherein a pair of line terminals are connected to a subscriber loop and a pair of output terminals are connected to a telecommunication exchange. A first amplifier is provided having a first pair of input terminals coupled to the line terminals and a second pair of input terminals. The first amplifier has a unity gain over a path from the input terminals of the first pair to said output terminals and a gain K over a path from the terminals of the second pair to said output terminals. A pair of reference resistors are cross-coupled from said output terminals to the line terminals, each of the reference resistors having a resistance Ro. A second amplifier is connected from the line terminals to the terminals of the second pair, the second amplifier having a transfer function -Ro/KxZt, where Zt is an impedance to be synthesized across the line terminals. |
申请公布号 |
EP0147230(A2) |
申请公布日期 |
1985.07.03 |
申请号 |
EP19840309078 |
申请日期 |
1984.12.27 |
申请人 |
NEC CORPORATION |
发明人 |
HIRATA, HIDEYUKI C/O NEC CORP. |
分类号 |
H03H11/40;H03F1/48;H03H11/46;H04M19/00;H04Q3/42 |
主分类号 |
H03H11/40 |
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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