The present invention relates to analogue selectors, also known as analogue multiplexers, for audio equipment input source selection. The present invention provides an analogue input selector for selecting one of a number of analogue source devices. The selector comprises a plurality of input connections for coupling to the input sources, each said input connection being connected to a gain controller having at least zero and one or more non-zero gains, said input connection not including a semiconductor switch. Preferably the gain controllers are implemented using MOSFETs which are held at a voltage which is independent of the signal voltage.
Methods and systems for gain control and power saving in broadband feedback low-noise amplifiers are disclosed and may include controlling gain, power and/or a noise figure by selectively enabling one or more of a plurality of gain stages by activating one or more of a plurality of pairs of switching transistors. Each of the gain stages may comprise complementary inverter pairs, with the gain of each of the gain stages binary weighted and stored in a lookup table. A feedback resistance coupled across the gain stages may be adjusted, and may comprise a plurality of individually addressable resistors, with the resistance binary weighted and stored in a lookup table. The adjusting of the feedback resistance may comprise switching one or more of a plurality of switching transistors, each connected in parallel with one of the individually addressable resistors, which may shunt one or more of the individually addressable resistors.
