| 摘要 |
PURPOSE: A transmit-receive system for minimizing the power consumption of a battery in a wireless communication terminal is provided to extend the duration time of a battery by reducing the power consumption of a transmitting power amplifier. CONSTITUTION: A dielectric duplexer in an existing transmit-receive system is replaced with a circulator(3). A power amplifier is dividedly replaced with a driver amplifier(42) and a terminating power amplifier(44). A transmitting band pass filter(43) is newly added. Also a receiving band pass filter(45) is added to the front end of a low noise amplifier(4). The circulator(3) is composed of 3 ports with arrow marks rotating in an identical direction. The direction of the arrow marks indicates the forward of signal flow. A forward signal has a very small insertion loss characteristic. However, as a reverse signal has a very big attenuation characteristic, the circulator(3) prevents a signal from being supplied reversely. |
