| 摘要 |
<p>A variable-reactance circuit comprising an amplifying section, a first differential section and a second differential section. The amplifying section has first to third bipolar transistors. These transistors are driven by three constant-current sources, respectively. The first differential section receives an output signal of the amplifying section. The first differential section has fourth and fifth bipolar transistors, which are driven by a first variable-current source. The second differential section receives the output signal of the amplifying section. The second differential section has sixth and seventh bipolar transistors, which are driven by a second variable-current source. The output currents of the first and second variable-current sources are controlled by two control signals, respectively.</p> |
