| 摘要 |
A variable gain amplifier includes at least two amplifiers for amplifying a signal, the at least two amplifiers being connected in series with one another, and a variable resistor having a resistance that is controlled in accordance with a voltage applied to a control terminal, the variable resistor being connected between the outputs of two of the at least two amplifiers having opposite output phases. As a result, the variable gain amplifier is capable of a low-gain operation and an attenuating operation in a high-frequency amplifier used in a communications device for transmitting and receiving high-frequency signals.
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