How to measure IIP3 for the circuit- need help

[narendar]

measuring IIP3

how to measure IIP3 for this circuit:
i mean to what resistance the i/p and o/p ports are to be matched?
can i measure it directly ?
or should i have to add any extra circuitry?
the i/p power varies from -85 to -15dBm considering 50ohm and operating freq is 70M
its urgent
thanks in advance

 

[dipnirvana]

Re: measuring IIP3

i don't think you can measure it . it's the theorotical value of amplifier.

 

[narendar]

Re: measuring IIP3

i mean how it can be obtained through cadence simulation?

 

[Grig]

Re: measuring IIP3

Hello
I propose
Use two tone test

For ex. 50 and 52MHz

IIP3(dbm)=Pinput(dbm)+[0.5*dB((Vout(+)-Vout(-))(at 50MHz))-dB((Vout(+)-Vout(-))(at 54MHz))];
Probably You know Pin and You can measure differential output voltage using cadence probing.