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: Parasitic oscillations Posted: Tue Jul 26, 2005 7:15 am
someone suggest a couple of good references on low frequency parasitic oscillations in microwave amplifiers?
Post subject: Posted: Tue Jul 26, 2005 7:58 am
Mon Jun 27, 2005 2:02 pm
Please try the following:
http://www.semiconductors.philips.com/a ... /LNA97.pdf
Post subject: ThnxPosted: Tue Jul 26, 2005 8:58 am
you very much for the reference. I will have a re-look at the biasing circuitry and the bypass capacitors in my
circuit. From a practical standpoint, how would one determine (when testing the amplifier) if low frequency
products were modulating the suply voltages?
Post subject: Posted: Tue Jul 26,
2005 9:25 am
If you know the bandwidth of your input modulated signal you can see if the voltage
on various points (Base, collector) on the amplifier's circuit has AC components (With high-speed oscilloscope or
with spectrum analyzer don't forget to use DC block for this measurement) if you see these components at these
points, you can estimate by their magnitude if your bypassing is adequate or not.
Alternatively, you can
inject 2 input CW signals with known offset between them and do this measurement.
Should you need more
information, please let me know.