Marcus Leech wrote:
> > In order to do this, I need to know which samples correspond to "sky" > and which samples correspond to > "calibration source" as I'm processing them. One thought I had was to > synthesize a pair of identical channels, > one called "Sky" and the other called "Calibration", and have the code > that flips the hardware switch set > a multiplier on each of these channels to either 0 or 1. That is: > > when the hardware is switched to "Sky": > > skychan *= 1.0 > calibchan *= 0.0 > > when the hardware is switched to "Calib": > > skychan *= 0.0 > calibchan *= 1.0 > > With the two channels being low-pass filtered separately, then one is > subtracted from the other to produce a > synchronously-detected result. > > How can I make sure that the chanels are properly synchronized with > the hardware state of the switch? > Once inband signalling is done, this shouldn't be hard at all. In the mean time, here is what I would suggest -- Dicke switches have typically used rates in the low hundreds of Hz, with a 50% duty cycle. My understanding is that is not necessary, and was only done to make things easier with the electronics of the time. I think I would switch at a much lower rate, 1 Hz or less, and probably use a calibration duty cycle on the order of 10%. This way you can easily throw out some samples on either side of the switch time without having to worry too much. Matt _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
