[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.

Cheers,
Magnus



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