[time-nuts] Very Accurate Delta Time RF Pulse Measurements

Attila Kinali attila at kinali.ch
Fri Jul 29 08:21:10 EDT 2016

On Thu, 28 Jul 2016 23:12:54 +0000
Jerome Blaha <jblaha at polariswireless.com> wrote:

> Hi Guys,
> This is a little outside of time-nuts scope, but not by much.  
> I'm interested in finding the time between two rising edges above a set
> threshold with preferably nS or high ps timing accuracy.  Can this be simply
> done with a few programmed Microchip PICs or with a good short term OCXO
> clock?  The issue I see is that a 10Mhz timing reference with 1 cycle
> difference in time yields 100ns resolution, which is far too large, so maybe
> a PIC can solve this.

I think the easiest way is to implement something like the PICTIC II [1].
That should get you into the order of 100ps with minimal effort.
With a little bit of care, you can make it go down to 20-30ps rms.
But I think, that the pulse generation itself is probably the part
that limits your precision, as the logarithmic amplifiers are usually
quite noisy.

			Attila Kinali

[1] http://www.ko4bb.com/doku2015/doku.php?id=precision_timing:pictic

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