| 摘要 |
<P>PROBLEM TO BE SOLVED: To switch the gain of an LNA for improving the dynamic range without interrupting the reception of a direct spread spectrum signal during switching. <P>SOLUTION: A DS signal received by an antenna 10' is fetched by a gain variable LNA 11, fetched via an attenuator/delayer 25 as well, converted to an intermediate frequency signal and processed by a Rake receiving part composed of despreaders 21a and 21b, spread code generators 22a and 22b and a Rake synthesizer 24. The gain of the LNA 11 is switched over a plurality of stages corresponding to a gain control signal from a signal level calculator 20 but the interruption of the received DS signal in the LNA 11 during gain switching is compensated by the DS signal received via the attenuator/delayer 25. Besides, in the signal level calculator 20, the threshold for gain switching of the LNA 11 when increasing a signal level is made different from the threshold when decreasing the signal level. <P>COPYRIGHT: (C)2003,JPO |
