[gta02-core] ecn progress

Rene Harder rehar at saweb.de
Mon Sep 28 20:10:46 CEST 2009

Álvaro Lopes wrote:
> We still have a caps with unknown value there.
> I had not the time to compute its proper value (and alas I don't even know if I can do that :P). Maybe someone can help here.

This heavily depends on the GPS antenna and their impedance. If no
information is provided I usually assume that the impedance is 50Ohm
(purely resistive).

So If I'm not mistaken, you would need an inductor to compensate the
capacitive reactance of C7602 and match 50 Ohm input impedance (@
~1.5GHz). However we need C7601to remove the bias voltage from the input
of our GPS amplifier. One possible option to keep the capacitor would be
to add another inductor in parallel to C7602. This will compensate the
effects of C7601 and the result will be a 50Ohm impedance match.


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