Ptotal in 1Tone and 2Tone...why the big difference?

[RFegg]

In MWO, i'm performing 1Tone Loadpull for max. Pout and 2Tone loadpull for IMD.

But the optium loadpull for Ptotal in 1Tone and 2Tone differ by as much as 4dB even at the same bias settings and input power.
It now confuses me what load impedance to follow, because of the big differences.

Any advise?

 

[chuckey]

As you have not given any data on your set up, I can only guess. Your PA is limited to a certain peak voltage out - Vp. With a single tone its power output is proportional to Vp^2. With two tones, Vp is split between the two, So the power output in one tone is (Vp X .5 )^2, so its twice this with the two tone, but the actual RMS power is now 1/2 of the previous, so the PA current is also 1/2 of the single tone, so the PA output impedance rises.
Frank

 

[BigBoss]

There are always compromises between Optimum Max. Power Output or Maximum Efficiency or Minimum Distortion etc.That's why , you should choose a optimum point which is closer to your target.
But you can not consider ALL at the same time,you have to sacrifice a bit from each..