The present invention provides a switchable gain amplifier comprising a high-pass
filter pole. The switchable gain amplifier comprises first and second input nodes
for receiving first and second components of a differential input signal. A first
input terminal of a first differential amplifier is coupled to the first input
node, and a first input terminal of a second differential amplifier is coupled
to the second input node. A first variable resistance is coupled between the first
input terminal of the first differential amplifier and a second input terminal
of the first differential amplifier. A second variable resistance is coupled between
the first input terminal of the second differential amplifier and a second input
terminal of the second differential amplifier. A differential capacitor is coupled
between the second input terminal of the first differential amplifier and the second
input terminal of the second differential amplifier.
