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

[Magnus Danielson]

Hi,

On 05/08/2016 09:53 PM, Attila Kinali wrote:
> On Wed, 4 May 2016 15:26:37 +0200
> Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
>
>> Indeed. ADC conversion speed is not a big issue these days, so the Nutt
>> style of interpolator is just expensive to parallelize for speed, the
>> time-to-voltage system is better and should have a much better
>> recycle-time and thus result in less hardware needs.
>
> True and not true. Yes, there are many ADCs that do high conversion
> rates, but these are optimized for piplined applications where conversion
> happens at a constant rate. Ie they expect a constant conversion clock
> with a constant rate. If you want to trigger conversion at an arbitrary time,
> you either have to build your own sampler or need to  use one of the
> non-pipelined ADCs whic are much slower (IIRC they stop around 5-10Msps
> aka >100ns conversion time). Flash ADCs with direct access to the sampling
> circuitry are basically extinct.

You can let the ADC convert as a continuous process as long as you 
filter out the samples you are interested in.

Cheers,
Magnus