We do need to compute phase using a arctan on board, and then unwrap it since sometimes the resonators we are reading out are of poor quality and just rotating them in the IQ plane doesn't solve our phase wrap problem. Sean's drew up the (simple in code, not quite as simple in simulink) algorithm yesterday so we'll test it today.
Ben On Jun 29, 2011, at 11:51 PM, Andrew Martens wrote: > Hi Ben > > Are you trying to do this in software? We don't calculate phase directly on > the ROACH > (i.e compute the arctangent of the imaginary over real component) and the > link shows > how to correct for this, post-ROACH, phase wrapping. > > What we do have in our correlator(s) here in SA (and at the GMRT) is a delay > correction system that removes the phase slope in correlation products caused > by physical signal path length differences. We are not really 'unwrapping' > phase > as described in the link but rather removing the phase slope from the data. I > can > provide more information if this is what you want to know. > > Regards > Andrew __________________________________________________________________ Ben Mazin Phone/Fax: 805-893-3344 Assistant Professor Department of Physics University of California Office: 2015A Broida Hall Santa Barbara, CA 93106 USA http://www.physics.ucsb.edu/~bmazin/
