Re: programming an rf synthesizer?

On 04-Feb-2003 David Young wrote:
> Duncan,
> 
> Thank you for your rapid response.

No problem.

> ADMtek makes the ADM8211. It is a Tulip-like MAC with an integrated BBP,
> the RFMD RF3000.
> 
> The radio is probably based on an RFMD reference design, so maybe I can
> find out likely values from RFMD.

Possibly - depends on how anal RFMD are wrt NDAs etc. I'm having a look.

The brochure for the chipset gives me some clues. The design is v. similar
to one that has been around for years and is not the best with respect
to integration and cost. There could also be a difficulty with the
reference design because there is an external filter in a metal can that
could well be at a different frequency. The filter is shown in the picture 
in http://www.rfmd.com/uploads/WLAN.pdf. It is the silver topped square
with a white PCB trace around it. Can you locate the same on your PCB and
write down the numbers stamped on the top? The good news is that the
reference board seems to use the SiLabs PLL.

> Suppose that either I cannot find the reference design or I want to
> verify it with the radio: Do you think I can find out the capacitor and
> resistor values by following the traces and measuring with a multimeter?

Unfortunatley, it appears that the loop filter is on chip! However, I've
just reread the data sheet and noticed table 8. It gives some pointers.
We still need to know what to set IF1 to though - this will give
enough info to work out what to set RF2 to.
 
> I would not have guessed that I could not tune the channel center! Thanks
> for bringing the superheterodyne-ness to my attention.
> 
> This project is looking like more fun all the time. =)

Masochist!

> Dave

Duncan

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