Third order intercept point. The point where the output power of the fundamental tones would equal that of the third order intermodulation products if the linear performance of the device would continue for all input power levels. In actual practice, the linear performance degrades starting at the 1dB compression point, so the third order intercept point can never be achieved. Nonetheless it demonstrates the ability of an amplifier, particularly in receivers, to handle strong signal power levels without distortion. The higher the value the better the performance.
See also: Wikipedia article.

Receiver Dynamic Range - Part 2


Robert E. Watson

This Watkins Johnson app note describes dynamic range measurements on receivers. Part 2 discusses "comprehensive measurements," or figures of merit that combine the primary measurements, such as noise figure or IP3, to provide a picture of the range of power levels that a receiver can handle. The app note is hosted on RF Café.

Optimize Dynamic Range for Distortion Measurements


Keysight Technologies

This application note from Agilent describes the challenges of measuring distortion products from your device under test. The challenges arise from the need to measure weak distortion product and harmonic signals in the presence of strong carrier signals, combined with the fact that the analog components in the test instrumentation produce their own unwanted distortion signals.

Measuring the Nonlinearities of RF Amplifiers IP2/IP3



This application note, Measuring the Nonlinearities of RF Amplifiers Using Signal Generators and a Spectrum Analyzer, from Rohde-Schwarz covers the measurement of amplifier nonlinearities. It includes a very useful discussion of the relationship between harmonics and their intermodulation products. Particularly, the ratio between the second harmonic intercept point and IP2 is described. Several useful figures are supplied to aid understanding.

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