I've placed the test description and results of some SDR-IQ linearity tests (in .PDF format) on my website given below. Look in the SDR projects section.
www.scrbg.org/g4jnt/SDRProjects.htm If one thing comes out of this test - it shows that the concept of using Third Order Intercept Point (TOIP) as a measure of performance for wideband digital receivers would appear to be completely flawed. For example, adding in a third tone F3, at a lower level while monitoring the 2.F1 - F2 Intermod product, causes that product to drop in amplitude dramatically. And why does the IMP stay reasonably constant (in level, not dBc) as the input level of the two tones is changed. Explanations please ! We're well into new territory here. Andy G4JNT www.scrbg.org/g4jnt
