Apparatus for reducing DC offset in a signal path of a conversion system
comprising a front end circuit for providing an input signal having an a
DC offset; an amplifier system coupled to the front end circuit to
receive and amplify the input signal; a multi-bit sigma delta modulator
for receiving the input signal from the amplifier system and providing a
first bit quantizer; a DC adapt circuit coupled to the sigma delta
modulator for receiving the first bit quantizer from the sigma delta
modulator and for providing an operation to reduce DC offset; a digital
to analog converter (DAC) coupled to the digital DC adapt circuit to
provide an analog signal representative of the DC offset correction to
the input of the amplifier system, wherein the digital DC adapt circuit
and the DAC form a feedback path originating at the first bit of the
multi bit sigma delta modulator to the input of the amplifier system.