By Topic

DC offset and IM2 removal in direct conversion receivers

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $33
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

1 Author(s)
M. Faulkner ; Centre for Telecommun. & Microelectron., Victoria Univ. of Technol., Melbourne, Vic., Australia

DC offsets cause interference in homodyne receivers, caused by nonlinearity and imbalances in the receiving amplifier and mixing circuits, as well as local oscillator (LO) leakage into the RF input port and RF leakage into the LO port. The latter causes a squaring action (hence, second order intermodulation distortion (IM2)) in the mixer which generates a DC offset (low frequency) that varies with the amplitude of any high power RF interfering (jamming) signal, whatever its applied frequency. A method for removing this DC offset is described. The signal immediately after the mixer is squared to obtain a distortion estimate of the jamming signal, and then subtracted from the main signal path to remove the interference from the desired signal. The experimental results indicate an 11.5 dB improvement in jamming margin for systems with 30 kHz RF bandwidth. In the experiment an adaptive equaliser is used to equalise the two paths and improve the dynamic response

Published in:

IEE Proceedings - Communications  (Volume:149 ,  Issue: 3 )