Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: Transistor impedance tolerance for Trimless
VCO ? Posted: Wed Nov 09, 2005 6:32 am
I would like to do away with
the trimmers on an existing VCO design (circa 250 MHz). The analysis
thus far suggests this could work (basic tolerance analysis on passive
parts, Varactor and PCB parasitic tolerance) BUT I have yet to determine
the affect on tuning due to transistor tolerance. Can anyone suggest
how I might approach this ?
The transistor in question is NE85630.
Thanks in advance
OscillatorPosted: Wed Nov 09, 2005 7:23 pm
Unfortunately, the sensitivity
to transistor characteristics of an oscillator is highly circuit-dependent.
You'll need to tell us what kind of circuit you have. Some versions
of SPICE have the ability to do Monte Carlo simulation with tolerances
- that may help.
Post subject: Transistor impedance tolerance for Trimless VCO ?Posted:
Thu Nov 10, 2005 12:25 pm
The oscillator circuit is a bog standard
common emitter colpitt's.Posted