| 摘要 |
The device for detecting telephone line seizure performs a measurement of voltage of the telephone line across a first and a second optocoupler connected in series to the telephone line and arranged head-to-tail. The first optocoupler makes it possible to discharge a capacitor connected to the telephone line, the second optocoupler converts the discharge current into an image current in a measurement circuit. This device comprises means ensuring negative feedback of the second optocoupler to the first optocoupler. With this layout, the influence of the transfer coefficients of the optocouplers on the voltage measurement is decreased, so as to increase the accuracy of measurement. |
