aaron_do
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Hi all,
for the IIP3 simulation, we usually take the inteferrer as very close to the main signal. However, if the adjacent or alternate channel is quite far away, then this simulation method might not apply, especially after the channel select filter. My question is
A) in general can we ignore IIP3 after channel selection?
The channel select filter is also quite difficult to design with very high linearity and low noise/ low power. I'm aiming for IRN <50 nV/sqrt Hz and IIP3 > 1V while power consumption is around 500 uA for a 3rd order BP filter at 2 MHz with around 0 dB gain. I've come up with an architecture which barely meets this, but i'm thinking that since filtering is taking place before the second and third stage of the filter, the IIP3 requirement is not so strict.
B) Is there a way to simulate IIP3 with the interferrer at the adjacent/alternate channel? My frequency is 2 MHz with channel spacing of 5 MHz. I was thinking i could put in 1 tone at 7 MHz, one at 2.01 MHz (fundamental from pac analysis) and one at -3 MHz (if that's possible) and measure at 1.99 MHz...is that right?
thanks, Aaron
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