Tow tones test with different amplitue level

[passerby]

For 2 tones test with the same amplitude level

IIP3(dBm)=Pin(dBm) + Delta(dB)/2

where Delta = Pout(dBm)-IMD(dBm)

so we can get IMD=3xPin + G - 2xIIP3

What IMD would be if the 2 tones signals are different amplitude levels?

Thanks.

 

[vfone]

Assuming the picture below we get:

PL(dBm) = P1(dBm) - 2*[OIP3(dBm) – P2]
PU(dBm) = P2(dBm) - 2*[OIP3(dBm) – P1]

 

[passerby]

Could also provide the derivation ?

Thanks.

 

[passerby]

PL(dBm) = P1(dBm) - 2*[OIP3(dBm) – P2]
PU(dBm) = P2(dBm) - 2*[OIP3(dBm) – P1]

and OIP3(dBm) = IIP3(dBm)+G(dB)


The G here is the gain @ fundamental frequency ?

or the gain @ f1 or @ f2?

Thanks

 

[vfone]

Yes, G is the gain at fundamental frequency.