Patent
Multiple output allpass switched capacitor filters
TLDR
In this article, the authors proposed two different topologies for implementing a second order allpass function filter which is vital for equalization of the phase of other arbitrary response magnitude shaping filters.Abstract:
This invention comprises two separate topologies for implementing a second order allpass function filter which is vital for equalization of the phase of other arbitrary response magnitude shaping filters. While the allpass response itself does not affect the frequency spectrum of the signal, these topologies have available outputs that have either bandpass or bandstop characteristics. Thus, two types of useful frequency characteristics formed by the filters that have exactly the same resonant frequency and Q (or Quality factor). Using the well known general two amplifier topology to implement a monolithic switched allpass filter with a high Q leads to very high capacitance ratios and hence excessive silicon area in manufacture. Both the topologies described here reduce the required silicon area by either reducing the required capacitance ratios or making the sensitivity to the smallest capacitor extremely small allowing it to violate otherwise necessary area-to-perimeter matching of the capacitor geometries. Reducing the overall silicon area reduces the overall cost of producing the filters and allows more functionality to be integrated on a single silicon chip.read more
Citations
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References
More filters
Journal ArticleDOI
All-MOS charge-redistribution analog-to-digital conversion techniques. II
TL;DR: This second paper describes a two-capacitor successive approximation technique which, in contrast to the first, requires considerably less die area, is inherently monotonic in the presence of capacitor ratio errors, and which operates at somewhat lower conversion rate.
Journal ArticleDOI
Exact design of switched-capacitor bandpass filters using coupled-biquad structures
K. Martin,A. Sedra +1 more
TL;DR: In this paper, the bilinear z-transform is used for the design of switched-capacitor bandpass filters using coupled-biquad structures and employing biquad circuits which are completely insensitive to stray capacitances between any node and ground.
Patent
High pass switched capacitor filter section
TL;DR: In this article, a high-pass switched capacitor biquadratic filter based on bilinear z-transform is proposed, which comprises first and second integrating operational amplifiers connected in series and in combination with a third operational amplifier that serves as a sample and hold.
Journal ArticleDOI
A monolithic dual tone multifrequency receiver
TL;DR: A fully integrated DTMF receiver has been fabricated on a single CMOS chip requiring only three external passive components and combines precision filters, zero crossing detectors and amplitude detectors with digital logic.
Journal ArticleDOI
Switched-capacitor filter design using cascaded sections
TL;DR: In this article, the authors describe a number of simple (first-, second-, or third-order) switched-capacitor circuits, which can be used as simple self-contained filters, or as filter sections in the cascade realization of a higher order transfer function.