| 摘要 |
<p>D-20,721 PROTECTION CIRCUIT FOR CONTROLLING THE EFFECT OF INDUCED CURRENTS ON LINE SIGNAL REPEATERS by Edward T. Ball Operating power for line signal repeaters is fed over a transmission cable pair (signal line) which is susceptible to lightning strikes and, thus, to longitudinally induced currents in the DC power feed circuit. A symmetrical non-linear protection circuit is connected between the signal line and the line signal repeater, and includes a high current shunt regulator which bypasses excessive induced currents. By so doing the adverse effects of these induced currents on the operation of the line signal repeater is minimized. A shunt voltage regulator provides the line repeater with a constant operating voltage when the line current (DC line power feed current plus induced currents) is greater than the minimum required bias current. When the potential at input terminals of the protection circuit exceeds a predetermined value, a portion of the excess current is conducted through a blocking diode to charge an energy storage device. But, when the DC line power feed current and the induced current oppose each other the energy stored in the energy storage device is used to supplement the power feed current to just maintain the required repeater voltage, until the potential decreases below the operating voltage.</p> |
