2022-09-02 17:59 Status: # IP3 A figure of merit that shows how linear your circuit is (larger means more linear). Increasing A causes fundamental to increase $\propto A$ while the third order IM products increase $\propto A^3$ . Eventually these become equal, producing the equation: ![Pasted image 20220902181723](attachments/Pasted%20image%2020220902181723.png#invert) ![Pasted image 20220902182648](attachments/Pasted%20image%2020220902182648.png#invert) and thus in power form, ![Pasted image 20220902182706](attachments/Pasted%20image%2020220902182706.png#invert) ![Pasted image 20220902181741](attachments/Pasted%20image%2020220902181741.png#invert) ![Pasted image 20220902180937](attachments/Pasted%20image%2020220902180937.png#invert) IP3 is a theoretical idea, it is based on the assumption of a third order system, and the amplifier would be [overloaded](overloaded.md) by the time it reached the IP3 point. Simulations and measurements will extrapolate the data. ## Measuring IP3 Generate the two tone and increase the power. Spectrum analyser looks at the amplitude of output frequencies. --- # References - [Third-order intercept point - Wikipedia](https://en.wikipedia.org/wiki/Third-order_intercept_point) - [Robabeh's Thesis](High%20Resolution%20Integrated%20Passive%20Phase%20Shifters%20for%20Future%20Wireless%20Communications.md#2%201%203%201%20Third%20Order%20Intercept%20Point%20IP3)