DocumentCode :
1478027
Title :
An Active Feedback Interference Cancellation Technique for Blocker Filtering in RF Receiver Front-Ends
Author :
Werth, Tobias D. ; Schmits, Christoph ; Wunderlich, Ralf ; Heinen, Stefan
Author_Institution :
Dept. of Integrated Analog Circuits & RF Syst., RWTH Aachen Univ., Aachen, Germany
Volume :
45
Issue :
5
fYear :
2010
fDate :
5/1/2010 12:00:00 AM
Firstpage :
989
Lastpage :
997
Abstract :
A feedback interference cancellation circuit is presented that uses a control loop to reject blockers in wireless receivers. The concept is based on a feedback translational loop which subtracts a blocker replica from the original blocker signal. In contrast to feedforward methods loop selectivity does not depend on exact gain matching of two paths but on the open loop gain which is easier to adjust. The concept is described including the theoretical derivations of the transfer function and stability. Nonidealities like I/Q mismatch and noise mechanisms are discussed. Finally, measurements from a prototype chip in 65-nm CMOS are presented showing the feasibility of active feedback cancellation. In a desensitization scenario, gain drops by more than 12 dB for a -15 dBm blocker at 20 MHz offset without feedback interference cancellation while a gain degradation of merely 3 dB is measured with feedback interference cancellation enabled.
Keywords :
CMOS analogue integrated circuits; circuit feedback; feedforward; interference suppression; radio receivers; CMOS; RF receiver front-ends; active feedback interference cancellation; blocker filtering; feedback translational loop; feedforward methods; frequency 20 MHz; noise mechanisms; prototype chip; transfer function; wireless receivers; Feedback circuits; Feedback loop; Filtering; Interference cancellation; Noise cancellation; Open loop systems; Radio frequency; Semiconductor device measurement; Stability; Transfer functions; Active filters; CMOS analog integrated circuits; feedback; interference suppression; mixer noise; mixers; nonlinear distortion; receivers;
fLanguage :
English
Journal_Title :
Solid-State Circuits, IEEE Journal of
Publisher :
ieee
ISSN :
0018-9200
Type :
jour
DOI :
10.1109/JSSC.2010.2041405
Filename :
5453300
Link To Document :
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