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Parasitic oscillations - RF Cafe Forums
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Guest
Post subject: Parasitic oscillations Posted: Tue Jul 26, 2005
7:15 am
Hello,
Could someone suggest a couple of good references
on low frequency parasitic oscillations in microwave amplifiers?
Top
IR
Post subject: Posted: Tue Jul 26, 2005 7:58
am
Site Admin
Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello,
Please try the following:
http://www.semiconductors.philips.com/a ... /LNA97.pdf
Good
luck!
_________________
Best regards,
- IR
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Guest
Post subject: ThnxPosted: Tue Jul 26, 2005
8:58 am
Hello,
Thank 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?
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Guest
Post subject: Posted:
Tue Jul 26, 2005 9:25 am
Hello,
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.
Posted 11/12/2012
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