[HELP] IP1dB analytical equation

[dsjomo]

ip1db

Hi! Does anybody ever seen analytical equation of input 1dB compression point in any reference paper or book?? Many nonlinear Volterra series anaysis is focused on IM3 equation but seldom focused on IP1dB point. Mostly because that IP1dB is in hard nonlinear region, and someone reported that the IP1dB point equation derived in soft nonliear region is not accurate indeed. But I still need the equation anyway, no matter in soft or hard nonlinear region.

Please give me a direction and thx in advance.

 

[Element_115]

ip1db vs ip3

There have been many discussions on these topic. You should always
search the Eboard first . RFcafe has some good notes also look
a Agilents App Notes. Here's a link for IP3 & IM's

h++p://www.rfcafe.com/references/electrical/ip3.htm

Cheers

 

[DonJ]

rf café iip3

Hi

You find some relevante equations in Razavi's RF Microelectronics.

G.L.

 

[VSWR]

amp p1db calculation

As a rule-of-thumb:

P1dB is about 10 dB lower than IP3 for a microwave RF amplifier
P1dB is about 15 dB lower than IP3 for VHF and HF amplifiers.

There is no exact analytical relationship between P1dB and IP3.

 

[DonJ]

ip3 equation

As a rule-of-thumb:

P1dB is about 10 dB lower than IP3 for a microwave RF amplifier
P1dB is about 15 dB lower than IP3 for VHF and HF amplifiers.

There is no exact analytical relationship between P1dB and IP3.

Correct!
You can make circuits with (in theory) infinite IP3 and finite P1dB.
~9.6dB

 

[dsjomo]

ip3 p1db relationship

Thank you guys for your heartily response, and I uploaded 2 IEEE papers talking about IM3 cancellation techniques.



These two papers are discussing IM3 in BJT device, on the other hand, there a technique called "Multi-gate" in MOS device's IM3 cancellation.

Similar to the uploaded two papers, I want to derive the SYMBOLIC equation of IP1dB, just like the volterra series analysis in those papers. If no one has done this work, that means I have to solve the volterra kernels by myself.....

As for IM3 symbolic equation, it is presented and arranged in many different forms, it depends on how the author tries to cancel the 3rd order terms. I know some techniques in both BJT and CMOS, but the above 2 papers are must-read if one wants to learn IM3 cancellation techniques.