[time-nuts] Thunderbolt schematics

Magnus Danielson magnus at rubidium.dyndns.org
Tue Dec 11 23:38:08 UTC 2012

On 12/12/2012 12:28 AM, Azelio Boriani wrote:
> Magnus, you said it:
>> The GPS front-end chip I haven't been able to find a datasheet for
>> the CPU/GPS-baseband chip seems to be an ASIC
> Quest for the HolyGrail...

On the other hand, it's not all that many pins, so a bit of advanced 
guessing should not be too hard to do.

Tossing a sine in I bet you will find mixed-down versions occuring in 
one or two IF-filtered versions before breaking free as digitized 
version. Most probably as 2 bits and clock going to the GPS baseband chip.

This is what a typical GPS front-end chip does. You toss it a reference 
frequency, and it steps it up, amplifies the GPS signal, mixes it down. 
It will be one or two SAW filters with balanced outputs and inputs.

Fairly trivial stuff.


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