On Mon, 27 Nov 2006 06:02:29 GMT, Telamon
wrote:

In article ,
"Robert11" wrote:

To make the measure simple you can set both generators to 0 dB and then
make a measurement of the appropriate mixing products for either IP2 or
IP3. Lets say the IP2 was -66 on the difference and -68 on the plus. The
IP2 would then be 66 dB, which is the worst of the two. Lets say 2 times
generator 1 frequency plus the generator 2 frequency product had the
highest level of -75 dB of the IP3 possibilities. The the IP3 would be
75 dB.

Wrong. IP3 is a theoretical point in space above a graph. What you
have described is the ratio of a single unwanted product to a desired
signal.