Abstract:
The thesis presents a new algorithm and structure that is to be used in conjunction
with a specially modified CMOS Gilbert cell mixer to remove time-varying DC offsets
in direct conversion receivers. In our approach, the DC offset is detected at the output
of the mixer using a dedicated coarse ADC and tracked using a low gate count digital
structure. The estimated offset is then used to dynamically adjusting the bias of a
specially modified Gilbert cell mixer to cancel the offset in the mixer. This prevents
saturation and desensitization of the analog downstream stages. The presented approach
is suitable for TDMA as well as continuous reception techniques such as W-CDMA and
FH-SS while being fully integrable on-chip.
