| 摘要 |
PROBLEM TO BE SOLVED: To provide a high frequency amplifier used both in the GMSK and the EDGE for suppressing fluctuations of a gain also against fluctuations of a power source voltage and prevent deteriorations in receiving band noise characteristic when power of an input signal is variably input from the outside. SOLUTION: A high frequency amplifier using a power source voltage regulating circuit for compensating fluctuations of a power source voltage. It comprises three stages of power amplification circuits 1, 2 and 3 for amplifying an input signal and outputting, a bias circuit 4 for supplying a bias voltage for controlling the power amplification circuits 1, 2 and 3, and a regulating circuit 5 for compensating fluctuations of noise or gain against fluctuations of a power source voltage for driving the power amplification circuits 1, 2 and 3, etc. By the regulating circuit 5, an output voltage Vddc is kept constant with respect to fluctuations of the power source voltage Vdd, the output voltage Vddc kept constant is output and used as a power source voltage of the power amplification circuits 1, 2 and 3. COPYRIGHT: (C)2004,JPO
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