A CMOS Q-Enhancement Bandpass-Filter For Use In Paging Receivers

Paging receivers often have to work in a dense\ud signal environment. This poses high demands on the preselection\ud filter. One of the most difficult aspects is the large\ud image rejection demand, which only can be satisfied by use\ud of a narrow-band or high-Q filter. The practical restrictions\ud for possible filter implementations are the low cost, low\ud power and the small size of the pager. By use of positive feedback\ud around a cheap off-chip low-Q inductor we obtain an\ud enhanced quality factor. We are therefore able to construct\ud selective filters using cheap small-size inductors. The price\ud paid for Q-enhancement is a larger noise and higher sensitivity\ud to component variations. The higher noise influence\ud is eliminated using a high gain in the preceding LNA-stage,\ud which is considered a part of the filter. Simulated results\ud are: Q enhanced from 30 to 100, Image-rejection = 48dB,\ud f0 = 280MHz, Voltage-gain = 20dB, Noise- figure = 2.4dB,\ud IMFDR = 66dB, IDD = 1mA, VDD = 2V. The original contribution\ud of this work is the application of the enhancement\ud principle to off-chip components, which benefits the minimization\ud of size and cost

Towards embedded control for resonant scanning MEMS micromirror

This paper describes the design and realization of an electrostatic actuated MEMS mirror operating at a resonance frequency of 23.5 KHz with a PLL feedback loop. The design is based upon a thorough understanding of the (non-linear) dynamical behavior of the mirror. Using an external position sensitive device (PSD) the proper working of the PLL is demonstrated. Next we study the possibility to replace the PSD sensor with an embedded capacitive phase-angle sensor. We show measurements of capacitance changes with large parasitic influences while actuating the mirror in a feed forward mode. This demonstrates the feasibility of a fully embedded control for a resonant scanning MEMS mirror. Keywords: MEMS micromirror; laser display; raster scanning, capacitive tilt-angle sensor; PLL\ud \u

Development of an integrated am shortwave upconversion receiver front-end

Electrical Engineering, Mathematics and Computer Scienc