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Design >> RF Design >> lo-rf isolation units
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Message started by sivacha on Oct 26^th, 2006, 7:35pm

Title: lo-rf isolation units
Post by sivacha on Oct 26^th, 2006, 7:35pm

hi
i got a basic doubt regarding the units of lo-rf isolation.
in the specs for lo-rf isolation it is said that XX dBVrms.
is it same as dB?? otherwise how to convert it into dBVrms??

Thanks a lot............

Title: Re: lo-rf isolation units
Post by ACWWong on Oct 27^th, 2006, 2:11am

dBVrms is dB in reference to 1 Vrms.
so if I have 1V amplitude sine wave signal (ie 1*cos(wt)),
then Vrms=1/sqrt(2)=0.707=-3dBVrms

lo-rf isolation is measured in straight dB (a unitless ratio) NOT dBVrms.
so if 1% of the LO voltage signal leaks to the RF port then one can say the LO to RF isolation is 40dB.