BandPass Sigma-Delta Modulator for Capacitive Pressure Sensor

The paper deals with bandpass sigma-delta modulator (BP SDM), which is used for conversion of signal from capacitive pressure sensor. This approach is absolutely new and unique, because this kind of modulators is utilized only for wireless and video applications. The main advantage of BP SDM is due to its defined band. That is why it is resistant against offsets of its subcuircits. Another important advantage is low power consumption, since the BP SDM digitizes only narrow band instead of whole Nyquist band with similar dynamic range. The paper shows basic ideas of this approach and simulation results with ideal and real modulator. The main stages are implemented in switched-capacitor (SC) technique. The modulator layout is presented as well.