| 摘要 |
<p>During a carrier sense, a control part (118) shifts the oscillating frequency of a local signal of a local oscillator (117) on a ?f-by-?f basis, thereby shifting by ?f and entering the converted received frequency, which is to be detected, into the signal pass bands of HPFs (109,110) and LPFs (111,112) of a receiving system (100B). The received power is averaged for each of carrier sense intervals, and the averaged power is then compared with a specified power. When the averaged power is greater than the specified power, a communication frequency is established.</p> |
