Open AccessBaseband tuning of Cartesian delta–sigma RF upconverters
Author(s) -
Sirmayanti S.,
Bassoo V.,
King H.,
Faulkner M.
Publication year - 2014
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2014.0164
Subject(s) - baseband , delta sigma modulation , cartesian coordinate system , sigma , electronic engineering , physics , computer science , mathematics , engineering , telecommunications , bandwidth (computing) , geometry , quantum mechanics
Many digital delta–sigma radio frequency (RF) upconverters exhibit poor performance when the carrier frequency is tuned away from the centre of the band. The offsetting of signals from the nominal carrier frequency position generates unwanted distortion products which are dominated by the image and third harmonics. It is shown that these products can be moved out of the band by the correct choice of intermediate frequency. A novel technique for shifting both the signal and the noise null to the new frequency position is described.