| 摘要 |
<p>PURPOSE:To detect a cable loss in an actual use state by comparing an input power value and an output power value with each other to obtain the power loss of a signal due to a cable by operation. CONSTITUTION:The IF signal generated by a base band processor 1 is transmitted to an outdoor device B by a cable 3 after passing a modulator 2, and at this time, the output power of the IF signal is detected by an output power detecting means 5. Meanwhile, the output power of the IF signal transmitted by the cable 3 is detected by an input power detecting means 7 in the outdoor device B, and the detected value is returned to an arithmetic circuit 6 of an indoor device A through a communication line 9 by an input power communication means 8. The arithmetic circuit 6 compares the output power value and the input power value with each other to calculate the loss due to the cable 3. Thus, the cable loss in the actual use state is detected to surely prevent the malfunction.</p> |
