A multirate filter according to the invention comprises, a) an input unit for receiving an input signal and for providing a plurality of intermediate signals in response to said input signal, b) a filter unit coupled to the input unit, and c) an output unit coupled to the filter unit, for generating an output signal. In some embodiments, the frequency multiplier includes: a first transistor and a second transistor, wherein a first terminal of the first transistor is connected to a third terminal of the second transistor through a first capacitor, and a first terminal of the second transistor is connected to a third terminal of the first transistor through a second capacitor. The regulator in the programmable integrated circuit receives a bias input and the programmable reference input and generates a programmable output for biasing a microphone. The database server can include a column-oriented database.