A wireless communication receiver is disclosed that operates in a test
mode to determine image correction information that is used to suppress
undesired image signals when the receiver switches to a normal
operational mode. In one embodiment, the receiver includes a frequency
synthesizer coupled by a quadrature divider to an in-phase (I) mixer and
a quadrature mixer. The mixers are coupled by respective analog to
digital converters (ADCs) to respective I and Q channel inputs of a
digital signal processor (DSP). In the test mode, a test tone is provided
to the mixer inputs. The test tone is divided down further and provided
to clock the frequency synthesizer, the ADCs and the DSP. This
configuration locks together the mixers, frequency synthesizer, ADCs and
DSP ratiometrically in frequency during the test mode while image
correction information is being determined. When the receiver switches to
a normal operating mode, the frequency synthesizer, ADCs and DSP are
clocked by a main clock signal instead of the divided down test tone, and
the test tone is removed from the mixers.