Re: Why IP3 of LNA?
IP3 point and 1dB compression point are two different specification. The term "blocking" means that some strong unwanted signal desensitize the wanted signal gain. Intermodulation means that two interferers' 3rd order product accidently located in our channel.
The following is an analogy example, many people are talking in their native language, someone speeking English, someone speeking Spanish and someone speeking Chinese. If everyone is talking in the same time, the ambient is very noisy, but you can still distinguish your native language if somebody is speeking with that. If I speek Chinese and two other unknown language is so loud that it "sounds like" Chinese, then I might be wonder if there is anybody trying to talk with me or not. This resembles intermodulation(indicated by IIP3). If someone is speeking an unknown language with extra loud volume around me, then it is impossible for me to listen to anyone speeking Chinese because it almost makes me deaf. This resembles gain compression(indicated by 1dB compression point), it is also known as blocking.
The language example is often used as a analogy to explain CDMA.