Abstract: A Time Division Multiple Access FDD/TDD dual mode system includes a switch having first and second common terminals and first and second terminals. Also included are a TDD demodulation circuit for demodulating a TDD received signal from the first common terminal; a FDD demodulation circuit for demodulating a FDD received signal; and a FDD/TDD modulation circuit for modulating and impressing the modulated signal onto the second common terminal. A FDD transmission band selection circuit is connected to the first terminal, and a TDD transmission-reception band selection circuit is connected to the second terminal. The first common terminal of the switch is connected to the second terminal during TDD reception, whereas the second common terminal is connected to the first terminal during FDD transmission and to the second terminal during TDD transmission.

Abstract: The invention presents a high efficiency linear power amplifier of plural frequency bands reduced in the number of parts and elements, simplified in the circuit construction, and saved in the circuit space, and in FIG. 1, signals entering from a common input terminal 1 in frequency bands A and B are matched in both frequency bands A and B in a wide band matching network 2, amplified in a pre-amplifier 3, put into a common terminal 4a of a switch circuit 4, and the signal in frequency band A is put into a changeover terminal 4b, matched in a matching network 5 and amplified in a post-amplifier 6, and its output is matched in a post-matching network 7 and sent out into an output terminal 8, while, similarly, the signal in frequency band B is put into other changeover terminal 4c of the switch circuit 4, matched in a matching network 9, amplified in a post-amplifier 10, and its output is matched in a post-matching network 11 and is sent out into an output terminal 12.

Abstract: A time division multiple access FDD wireless unit has a first local oscillator 8 for oscillating a first frequency; a second local oscillator 12 for oscillating a second frequency; a n-times multiplier 14 for multiplying the second frequency by n; a m-times multiplier 18 for multiplying the second frequency by m; a converter 6 for transmitting frequency of difference between a reception signal and an output of the first local oscillator 8; a converter 11 for transmitting frequency of sum or difference between an output of the converter 6 and an output of the n-times multiplier 14; modulator 19 for modulating an output of the m-times multiplier 18; a converter 22 for transmitting frequency of sum of an output of the modulator 19 and the output of m-times multiplier 18.