| 摘要 |
A switched gain circuit (350) that employs a plurality of conduction paths (378-384) that provide different levels of signal gain or attenuation to an analog input signal. Each conduction path (378-384) includes a plurality of switching devices (388-402 and 410-424), such as heterojunction bipolar transistors. Further, each conduction path includes a gain device such as a degenerative resistor, that provides gain or attenuation to the analog input signals. A separate control signal is applied to a switching device (410-424) in each conduction path (378-384) to select a particular conduction path to be coupled to the output. The analog input signal can be a differential analog input signal where a first part of the signal is coupled to the base terminal of a bipolar transistor (410-424) in each conduction path (378-384), and a second part of the analog signal is coupled to the base terminal of another bipolar transistor (410-424) in each conduction path (378-384). <IMAGE>
|
