Matsushita Electric Industrial Co., Ltd.

Hidenobu Kato

Hiroaki Kosugi

Kaoru Ishida

Takashi Enoki

Seiichi Yamaguchi

Hisashi Adachi

Fujio Sasaki

Masayuki Miyaji

Yoichi Morinaga

Keiichi Nakayama

Manabu Yamaguchi

Daisuke Tobise

A multiband PLL frequency synthesizer is disclosed which includes: a reference signal generation circuit for generating a reference signal of which frequency is controlled; a phase comparator for generating a phase difference signal; a low-pass filter circuit for low-pass-filtering the phase difference signal with one of a plurality of cutoff frequencies selected; a VCO for generating and outputting a LO signal according to an output of the low-pass filter; a frequency dividing circuit having an integer frequency dividing mode and a fraction frequency dividing mode to supply the frequency-divided signal to the phase comparator; and a control circuit for supplying the reference frequency control signal to the reference signal generation circuit, a filter control signal to the low-pass filter circuit, and frequency dividing control signal (data) to the frequency dividing circuit in accordance with a frequency command signal. The cutoff frequencies and the frequency dividing mode are selected to control the loop condition in accordance with the frequency command signal.

Multiple frequency band synthesizer using a single voltage control oscillator

A radio communication apparatus is designed for at least first and second radio communication formats which prescribe first and second desired IF pass bandwidths respectively. The first desired IF pass bandwidth is greater than the second desired IF pass bandwidth. The radio communication apparatus includes an IF band-pass filter processing a first IF signal into a second IF signal and having a predetermined pass bandwidth corresponding to the first desired IF pass bandwidth. A demodulator recovers a first baseband signal from the second IF signal generated by the IF band-pass filter. A baseband filter processes the first baseband signal generated by the demodulator into a second baseband signal. The first baseband signal generated by the demodulator is selected as a final output signal when the first IF signal is of the first radio communication format. The second baseband signal generated by the baseband filter is selected as a final output signal when the first IF signal is of the second radio communication format.

Mobile radio communication apparatus

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

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. The invention also presents a power amplifier capable of maintaining a similar high efficiency characteristic if the output power is lowered from the output power of maximum efficiency, and in FIG. 10, first and second power amplifiers 113, 114 are disposed in parallel, and a necessary number of power amplifiers are connected depending on a required output power by switch circuits 115 to 118, and the power source is turned on only in the connected power amplifiers, while the other power amplifiers are turned off, and therefore by the lowering portion of the output power, the current consumption decreases in proportion, so that the equivalent high efficiency operation same as in the case maximum efficiency is realized.

High efficiency linear power amplifier of plural frequency bands and

Growing community of inventors

Yokohama, Japan

Hidenobu Kato