[time-nuts] High rate, high precision/accuracy time interval counter methods

Attila Kinali attila at kinali.ch
Tue May 10 09:17:43 UTC 2016


Hoi Bruce,

On Mon, 9 May 2016 23:34:24 +0000 (UTC)
Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:

> Its probably easier/cheaper to construct a suitable filter for a GSPS ADC
> than to construct a TAC that is fast enough to suit an ADC with a GHz clock.

Probably. 

> Minimising the emitter to emitter inductance of a longtailed pair or
> equivalent is key to achieving a fast enough switching time for a suitable
> TAC. 

How does one minimize this inductance? The only way I am aware of is
to use a package with a pair of transistors with common emiter pin.

> The somewhat heroic measures employed in the Wavecrest counters is
> perhaps the limit of discrete construction techniques.

Are these heroic measures documented somewhere?
So far I have not even seen a block diagram of a Wavecrest counter,
much less a schematic.

			Attila kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson



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