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US 7,454,176 B2Granted
Semiconductor integrated circuit for communication and terminal device for mobile communication
AssigneeRenesas Technology Corp.
InventorsToshiya Uozumi, Ikuya Ono, Jiro Shinbo
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Abstract
The present invention provides a semiconductor integrated circuit for communication (RF IC) operable in a mode for receiving a received signal subjected to phase modulation and amplitude modulation and a mode for receiving a received signal subjected only to phase modulation. In the semiconductor integrated circuit for communication, a frequency band of a loop filter in a PLL circuit is switched and set so as to become large in a reception mode and become small in a transmission mode.
Claims11
A semiconductor integrated circuit for communication, comprising:
- a reception-system signal processing circuit;
- a transmission-system signal processing circuit;
- a down-convert mixer which combines a receive signal and a carrier wave signal;
- an up-convert mixer which combines a transmit signal and the carrier wave signal;
- and
- a PLL circuit common to transmission/reception, which includes a voltage-controlled oscillator and generates a carrier wave signal corresponding to a reception frequency and a transmission frequency and supplies the same to the two mixers,
- said semiconductor integrated circuit being operable in a first communication mode for transmitting and receiving signals subjected to phase modulation and amplitude modulation and a second communication mode for transmitting and receiving the signal subjected only to the phase modulation,
- wherein a frequency band of a loop for the PLL circuit is switched and set so as to be wider than a frequency band in a transmission mode in a reception mode and to be narrower than a frequency band in the reception mode in the transmission mode.
5 more elements
Dependencies are inferred from the claim text.