P1 dB and 3-dB back off measurement for power amplifier

We do measure the P1 db and 3-db back for power amplifier. I am confused regarding 3-dB back off measurement. Is it 3-dB back off from output power or is it from input power, from P1-dB point ?

thanks.

Is about 3dB back-off of the output power.
P1dB is the compression point of the output power.

hi there,
i'm designing a power amp as well.
AWR is my simulation software.
may i ask how do u plot them out?
could u pls share those steps?

thanks in advace!

AWR has many examples, I think there should be one example for ploting the P1.

i think 3-dB back off from output power, is that called "out of band 3dB desensitization"? which is the blocker power necessary to desensitize the amplifier by 3dB.
and there is a formula for this, Poblock=P-1dB + 1.2dB.