| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize dual-mode radio equipment, portable information terminal, base radio station, and radio communication system in simpler constitutions under a communication system the working frequency band of which is widened by providing a TDD mode frequency band additionally to an FDD mode fre quency band. SOLUTION: The radio equipment is constituted to selectively use first and second power amplifiers 105 and 106 and first and second low-noise amplifiers 113 and 114, which are made to adapt to narrower frequency bands and have different working frequency bands by means of high-frequency switches SW4, SW5, SW7, and SW8 for selecting frequency bands, by dividing the power amplifiers of a transmitting system and low-noise amplifiers of a receiving system in the frequency band used by the radio equipment. A transmitting circuit 131 and a receiving circuit 133 are commonly used in both an FDD mode and a TDD mode by switching high-frequency switches SW1-SW3 and SW6.</p> |
