| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a low noise amplifier having a high input resistance in an operation off time without deteriorating the quality of a received signal in a receiver such as a radio communication terminal corresponding to a plurality of communication systems. <P>SOLUTION: The receiver includes: an antenna changeover switch 12 for switching a first signal path for transmitting a transmission signal of a GSM (Global System for Mobile Communications) 900 or PCS (Personal Communication Services) communication mode and a second signal path for transmitting a transmitted or received signal of a UMTS (Universal Mobile Telecommunications System)communication mode; a low noise amplifier 15 for amplifying a received signal of the UMTS communication mode; a first witch 21 and a second switch 22 inserted in serial between input and output terminals of the low noise amplifier 15 to be turned on during a strong electric field of the UMTS communication mode; and a third switch 23 inserted between a connection point of the first and second switches, and the ground to be turned on together with the first switch 21 during operation of the GSM 900 or PCS communication mode. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
