CMOS PLL Synthesizers, Analysis and Design
- K. Shu, E. Sánchez-Sinenco
The paper deals with a 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 modulator 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 sub-circuits. 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. The main stages are implemented in switched-capacitor (SC) technique. The paper presents two possibilities how to design PLL block. The first one is conventional approach and the other one is with digital sigma-delta modulator as generator of input harmonic signal.