Re: Resonator Calculations

"redhat" <aezzat1@xxxxxxxxx> wrote in message
news:1120118141.513702.202160@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Hi Larry,
> how could the capacitors be in series with each other, you haven't
> considered input and output ports?
> Hi Roger,
> you have assumed a frequency of 94MHz to convert the capacitor to
> series, what if i don't know the resonant frequency?

I just took the L7 C7 series resonant frequency to get in the ballpark.
Using the transformed ends I could calculate a new resonant frequency, then
recalculate the ends again etc.

Its quite common to do the transformation at one frequency then use the
result over a narrow band of frequencies.

Easiest to just whack it into SPICE, 50 ohms source and load and look at the
response.

The schematic looks as though non of the components is adjustable. In a
commercial piece of equipment, you just might get away with selecting your
components to give the pass frequency you want and always fitting the same
brand and value parts onto the same PCB. Otherwise, you'd make L7 or C7
adjustable and tune it up.


Roger Lascelles







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