Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
IQ phase Error and Image rejection - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: IQ phase Error and Image rejection Posted:
Tue Sep 12, 2006 12:06 pm
Joined: Fri Feb
11, 2005 6:32 am
I have a device (Zero-IF) and an analyzer with IQ inputs , I'd like
to measure- the image rejection. How can I do it?
-what is the
relation between IQerror and image rejection??
Post subject: Posted: Tue Jul 10,
2007 10:53 am
Joined: Tue Jun 26, 2007 10:27
Location: Dallas, TX
For Image Rejection you may need to do a basic theoretical analysis.
You can set up a basic block diagram (signal flow diagram) for an I/Q
receiver. Add some gain mismatch in one path and add some phase mismatch
to the LO path. Then, sum up the outputs of the I and Q paths (you can
take the difference also, and get the same relationship) so that you
end up with a SSB response at the output.
Your expression will
then contain an expression for the desired frequency and for the sideband
frequency. You then take the powers of the desired and undesired and
take the quotient. This will then give you an expression for SBRR based
on amplitude and phase mismatch.
An example of this can be found
http://ieeexplore.ieee.org.ezproxy.tamu ... mber=33037
Hope this helps!