@inproceedings { 04_Graaf_Cretu, title = {Quadrature oscillator with pre-distorted waveforms for application in MEMS-based mechanical spectrum analyser}, journal = {ESSCIRC 2004, Proceeding of the 30th European Solid-State Circuits Conference, Leuven, Belgium, 21-23 September 2004}, year = {2004}, month = {September 21-23}, pages = {407-410}, type = {inproceedings}, abstract = {An AC-operated capacitive accelerometer with electrostatic force feedback is employed for direct mechanical spectrum analysis. A suitable electrostatic AC field is used to make the accelerometer selectively sensitive to only the coherent mechanical frequency component. By sweeping the frequency of the drive voltage over a selected range, the mechanical (vibration) spectrum is analysed in the mechanical domain. Operation requires the simultaneous generation of predistorted sine- and cosine-alike waveforms. A DDFS with DAC based on a specially scaled resistive string is designed, fabricated in CMOS and tested. Spurious free dynamic range is 22 dB over a frequency range DC up to 1 kHz. The spectral performance is comparable to FFTbased systems for spectral analysis on a time series supplied by a conventional accelerometer, while the overall system features a reduced complexity, simple spectral in-zooming and potential for low power consumption.}, author = {de Graaf, Ger and Mol, Lukas and Rocha, Luis and Cretu, Edmond and Wolffenbuttel, Reinoud Felix} }