G_gc> Hi, G_gc> I am working on an application where either G_gc> a microprocessor or electronics must measure G_gc> two times. The data comes in a 100 MHz clocked G_gc> A/D. Two pulses are detected, looks like (if it G_gc> looks garbled, use font courier new 8): G_gc> | /\ G_gc> | / \ G_gc> | / \ /\ G_gc> |____/ \___/ \__ G_gc> --------------------- G_gc> The time from 0 to peak 1 and peak 2 are needed. G_gc> The voltages can differ, so the processor must G_gc> look where two peaks are. The time between the G_gc> peaks can be something like 100 nsec to 5 usec. G_gc> The problem is that the processor only has G_gc> 50 usec to measure the two peaks (data will G_gc> probably come through DMA), analyse them and G_gc> send them somewhere (probably flash or to another G_gc> processor through a fifo). We cannot afford G_gc> a expensive environment. G_gc> My question: G_gc> What microprocessor/controller would you recommend? G_gc> Do you think a 'normal' controller would do, or G_gc> would it be an ARM or DSP? Which compilers are G_gc> (low cost) available for those processors? G_gc> I can also try to do it in electronics, that would G_gc> be no problem for me, but software would be more G_gc> intelligent and better in finding the peaks. And G_gc> easier to change... G_gc> Regards, G_gc> Pieter Hoeben
G_gc> Why not use Labview G_gc> Gordon A. Briggs Because of the timescale he is talking about? Signal analysis in real time with at least 100ns resolution is not one of LabView's strongest sides, not even on a very fast machine... I also would go for the hardware solution. I don't know how sharp your pulses are or if it matters whether you trigger on one of the edges or on the top of the pulse. "Egde triggered" appears to be most stable - once you set it up to ignore the noise which you probably also have in your signal. Then you would build a chain of two trigger circuits and a fast counter. The counter setting is latched into a register when the first peak is encountered and into another register upon the second peak. This would work best if run from the analog signal before it went through the ADC, just because analog circuits for edge triggering are much easier to build than digital ones.... Uwe. -- Author: Uwe Zimmermann INET: [EMAIL PROTECTED] Fat City Hosting, San Diego, California -- http://www.fatcity.com --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
