Got the first incarnation of the Phased array working now. Had a few hiccups along the way, but managed to get most of them sorted. Main problems included not having enough RAM to store a significant amount of data, so I fixed that using a simple compression technique (I say simple, took me ages to get it working!) and using a circular buffer.
The main problem is that the PIC30F’s can only acquire data sequentially, i.e. not simultaneously. This means that each acquire takes 1Tad to sample, therefore 4 sequential acquires takes 4Tad. This means that the actual sampling speed is Fad/4=50ksps max! Rubbish. So Ive ordered some PIC33f’s to try because they are simultaneous and work up to 1Msps!
Also need to desolder the power lead for the transmits because they should have their own separate power supply. Not the on board one.
Finally, some data!
Errata: Slight cock up, in the second image the pulse labeled reverbaration is not reverbaration. I think it was a reflection from something about 45 degrees out. This poses an interesting question, how do I stop signals that are out of phase by exactly 1 cycle adding up to a large number? I will have to consult the literature to figure this one out!
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