| 摘要 |
<p>PURPOSE: To reduce loss in a delay circuit, to vary a delay amount and to improve a path diversity effect by providing a frequency conversion means before and behind the delay circuit and operating the delay circuit in a low frequency band. CONSTITUTION: Between the duplexer 100 and antenna 102 of a base station 100, a mixer circuit 131, the delay circuit 133 operated in the low frequency band and the mixer circuit 132 are provided. Signals received by the antenna 102 are mixed with local oscillation signals and converted to the signals of the low frequency band in the mixer circuit 132, delayed by delay timeτin the delay circuit 133 and further, mixed with the local oscillation signals and returned to the signals of a high frequency band in the mixer circuit 131. In the meantime, the signals distributed from a spread spectrum transmitter 110 to the antenna 102 are similarly mixed with the local oscillation signals and converted to the signals of the low frequency band in the mixer circuit 131, delayed by the delay timeτin the delay circuit 133, further mixed with the local oscillation signals and returned to the signals of the high frequency band in the mixer circuit 132 and transmitted from the antenna 102.</p> |
