An amplifier circuit includes first, second, and third amplifiers each
having an input and an output. The amplifier circuit further includes
first and second capacitances and a resistance. The input of the second
amplifier communicates with the output of the first amplifier. The first
capacitance communicates with the input of the first amplifier and the
output of the second amplifier. The input of the third amplifier
communicates with the output of the second amplifier. The second
capacitance communicates with the output of the third amplifier and the
input of the second amplifier. The resistance directly communicates with
the output of the third amplifier and the input of the first amplifier.