发明名称 |
Method for current supply to a subscriber telephone from a telephone exchange |
摘要 |
PCT No. PCT/SE83/00242 Sec. 371 Date Mar. 6, 1984 Sec. 102(e) Date Mar. 6, 1984 PCT Filed Jun. 14, 1983 PCT Pub. No. WO84/00459 PCT Pub. Date Feb. 2, 1984.A method in current feed to a subscriber telephone from a telephone exchange in which there is arranged a voltage source (11). A differential amplifier (1) senses the potential difference between the terminals of the voltage source (11), and after low pass filtering (2) a reference voltage (UREF) is added (3). The thus-obtained sum voltage is allowed to constitute the reference value in the system. The arithmetical mean value of the terminal potentials of the voltage source is utilized as a corresponding actual value. The difference between these reference and actual values is allowed to control a current tap in equal phase from both terminals of the voltage source.
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申请公布号 |
US4617426(A) |
申请公布日期 |
1986.10.14 |
申请号 |
US19840598322 |
申请日期 |
1984.03.06 |
申请人 |
TELEFONAKTIEBOLAGET LM ERICSSON |
发明人 |
JOHANSSON, JAN H.;SUNDVALL, NILS J. |
分类号 |
H04M19/00;(IPC1-7):H04M19/00 |
主分类号 |
H04M19/00 |
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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