Matsushita Electric Industrial Co., Ltd.

Manabu Yamaguchi

Kaoru Ishida

Hiroaki Kosugi

Takashi Enoki

Toshio Obara

Seiichi Yamaguchi

Hidenobu Kato

Keiichi Nakayama

At the time of ordinary communication, up-mixer combines a signal with a frequency f2 from frequency synthesizer with I and Q signals for transmission that are quadrature modulated in quadrature modulator , down-mixer combines the signal with the frequency f2 with a received signal, then only in the case of receiving a signal with a frequency fr&prime; different from a frequency fr, frequency synthesizer that generates a signal with a frequency f3 different from the frequency f2 is operated, and frequency synthesizer and down-mixer are connected with switch , so that down-mixer combines the signal with the frequency f3 with a received signal. It is thereby possible to switch frequencies fast and with low current consumption in receiving a signal with a reception frequency other than a combination of transmission frequency and reception frequency specified in an ordinary radio system.

Radio apparatus and transmission/reception method

A receiving mixer device for a mobile radio transceiver which operates with multiple modulation modes and within multiple frequency bands. The receiving mixer includes a plurality of mixers each for converting a received radio frequency signal to an intermediate frequency, a common connection part to which output terminals of the mixers are connected in common, a plurality of impedance conversion circuits connected to the common connection part, and output terminals for the impedance conversion circuits. The number of mixers is equal to the number of frequency bands of the received radio frequency signal. The number of the intermediate frequencies is equal to the number of modulation modes of the received radio frequency signal. The number of the impedance conversion circuits is equal to the number of intermediate frequencies, and each of the impedance conversion circuits passes only a single predetermined frequency of the intermediate frequencies used by the device.

Receiving mixer circuit for mobile radio transceiver designed to operate

Growing community of inventors

Yokohama, Japan

Manabu Yamaguchi