Patent ID: 8199039

Claim:
A delta-sigma analog-to-digital converter comprising: a forward path structure; a feedback structure; and a first subtraction element arranged to receive an input signal to the delta-sigma analog-to-digital converter and a feedback signal from the feedback structure and output a difference signal, which is a difference between the input signal and the feedback signal, to the forward path structure, wherein: the forward path structure comprises: a quantizer arranged to convert an analog input signal to a digital representation; and a forward path filter arranged to input the difference signal and provide an output signal to the quantizer, and the feedback structure comprises a first and a second branch, wherein: the first branch comprises: a first digital-to-analog converter arranged to provide output signals to the subtraction element; and a first feedback filter having a gain to frequency characteristic such that frequencies that are desired in the analog-to-digital conversion, compared to undesired frequencies, are attenuated in the feedback structure, and the second branch comprises: a second digital-to-analog converter, wherein the first and second branches are fed by the digital representation and the outputs of the first and second branches are merged in a second subtraction element arranged to output a signal, which is a difference between the signals from the first and second branches, to the first subtraction element.