PLL circuit and radio communication terminal apparatus using...

Details PLL circuit and radio communication terminal apparatus using... PLL circuit and radio communication terminal apparatus using...

2005-11-29

2005-11-29

Matar, Ahmad F. (Department: 2642)

Telecommunications

Transmitter and receiver at same station

With a common signal processing stage

C455S208000, C455S209000, C455S318000, C455S319000, C455S076000, C455S280000

Reexamination Certificate

active

06970683

ABSTRACT:
In a PLL circuit, the number of LPFs is reduced to one to reduce mounting area and pin number, and to simplify design. In one embodiment, the PLL circuit includes a variable-gain phase comparator, a mixer, an LPF, VCOs, couplers, and a control circuit to controlling the on/off operation of the VCOs. The variable-gain phase comparator is capable of varying a phase difference gain. The on/off of the operation of the VCOs is controlled by the control circuit so that one of the VCOs is turned off. The phase difference conversion gain is varied in accordance with the sensitivity of the VCOs so the number of LPFs required for the PLL circuit can be reduced to only one.

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European Search Report dated Feb. 10, 2004.
H. Kuroda, et al., Development of Low-Power Consumption RF/IF Single-Chip Transceiver IC for PHS. Compound Semiconductor Device Division, NEC IC Microcomputer Systems, Ltd., pp 161-167.

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