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https://designers-guide.org/forum/YaBB.pl Design >> RF Design >> clarification questions about dynamic range https://designers-guide.org/forum/YaBB.pl?num=1264434513 Message started by .matteo on Jan 25th, 2010, 7:48am |
Title: clarification questions about dynamic range Post by .matteo on Jan 25th, 2010, 7:48am Hi everybody I'd like to design an LNA that's gonna receive signals that I both want to detect. One is at -26dBm and the other one at -126dBm, for a total dynamic range of 100dB. However, I've some doubts about my understanding of the dynamic range concept: to require a 100dB dynamic range is the same than a SFDR of 100dB? What's the difference (if there is any)? Thanks a lot and sorry for the "newbie" question Matteo |
Title: Re: clarification questions about dynamic range Post by pancho_hideboo on Jan 26th, 2010, 2:07am .matteo wrote on Jan 25th, 2010, 7:48am:
Your LNA undergoes interference signals ? Or your LNA undergoes only desired signal ? Your receiver is heterodyne scheme with non-zero IF ? Or your receiver is zero IF ? .matteo wrote on Jan 25th, 2010, 7:48am:
If your LNA undergoes inteference signals, SFDR is suitable definition for dynamic range. Here this SFDR is not always defined for IM3 interference. There is a case where you have to define SFDR for IM2 not IM3. If your LNA undergoes only desired signals, suitable dynamic range is simple dynamic range definition which is defined as difference between noise floor and gain compression point. Here this gain compression point is not always 1dB gain compression. There is a case where you have to define gain compression point other than 1dB gain compression, e.g. 3dB gain compression, 6dB gain compression, etc. Again, what defintion for dynamic range has to be used is dependent on your application of LNA. Also see http://www.designers-guide.org/Forum/YaBB.pl?num=1262010372/1#1 |
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