for direct conversion receivers the iip2 , is also important
so should be simulated , but i don't know how to simulate it
u can check on ADS design guide it may have some setups
yeah , for low IF receivers , the IIP2 is important as well
khouly
Added after 1 hours 25 minutes:
the second order itermodulation if two freq in the RF a , b
if u expand (cos(a)+cos(b))² = cos(a+b)+cos(a-b)+1/2cos(2a)+1/2cos(2b)
then the term a+b is high freq , but a-b . may generate a frequency near ur cahnnel if it low IF or zero IF
in ur simulation check the power of this spectral compoent
then the term a+b is high freq , but a-b . may generate a frequency near ur cahnnel if it low IF or zero IF
in ur simulation check the power of this spectral compoent
khouly
Hi
Dear khouly
thanks for this information.
yes, I accept that IIP2 is important in this case.
I think that the best way is what he said.
I'm not sure but this equation may help you
IIP3=(3Po-IM3)/2
so
IIP2=(2Po-IM2)/2
regards
i agree with u
how to simulate the Ip2 , make 2 tone , and sweep the input power and then plot the output power of the IM2 term , u and extrapolate the curve to intersect with the gain , this is IIP2
my problem is in choosing the second harmonic.
all the frequencies (flo - (f1 + or - f2) will fall out of band.
for IIP3 we choose flo-(2f1-f2) as the third harmonic.
you should not choose (flo - (f1 + or - f2) as the second harmonic the iip2 frequency should be (f1- f2), i think you can detect the power of (f1- f2) at the if port .and calculate the iip2 use the formula "IIP2=Pin+(Pfund,out-p(f1- f2),out)" .Pfund,out is the power at IF port with the Pin in the RF port ,and p(f1- f2),out is the outout power at (f1- f2) frequency at the IF port.