| 摘要 |
<p>When the power supply 22 fails the impedances at the input and output of an amplifier 12 may not match the impedance of the cables 14 and 16, leading to undesirable reflections in the network. To remedy this problem 75 Ohm resistors 26 and 26 are switched into circuit when the power supply fails, so that constant amplifier impedance and low reflection may be obtained irrespective of whether the amplifier 12 receives a power supply. The amplifier may amplify signals in both directions in a cable television or broadband network.</p> |
