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
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Below are all of the forum threads, including all
the responses to the original posts.
ljoseph Post subject: Multitone IMD Posted: Fri Oct 02, 2009 3:58 pm
Captain
Joined: Tue Sep 04, 2007 7:54 am Posts: 13 Location: Dallas Hi,
This is about IM calculations in case of multitone.
For example take an amplifier with OPI3 of 18.1dBm, gain =11 dB. Two tone IM is 58.2 dBc. Input is -19 dBm Output = -19+11 = -8 dBm. IM = 2(18.1-(-8))+6 = 58.2dBc
Now, I am driving this amplifier with 15 tones each having an input power of -19-10*log(15)=-30.8dBm Total output power for 15 input tones = -8 dBm. What will be the worst case IM in dBC with respect to -8dBm of total output power?
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Kirt Blattenberger Post subject: Re: Multitone IMDPosted: Fri Oct 09, 2009 3:32 pm
Site Admin
Joined: Sun Aug 03, 2003 2:02 pm Posts: 308 Location: Erie, PA Greetings ljoseph:
The link I used to have for a paper titled "A General Algorithm to Calculate Third Order Intermodulation Product Locations for any Number of Tones," by Chris Arnott, has disappeared from it's location on the CED website. So, I just scanned in and OCRed a copy provided to me by Chris back when I worked with him at RF Micro Devices. You can access it here:
http://www.rfcafe.com/references/electrical/calculate-imd-any-number-tones.htm
Hopefully that will get you where you're going.
_________________ - Kirt Blattenberger RF Cafe Progenitor & Webmaster
Posted 11/12/2012
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