We have decided to implement the IP3 value on our new datasheets. This
move forward will give our customers the possibility to measure
competitive products up to ours in a fair and honest way.
The IMD value is important for CATV and wireless connectors. Signals can
get mixed and hereby create new unwanted signals for example by passing
through contact points such as a connector. As the number of channels
increases, minimizing intermodulation becomes more important.
The IMD value describes the relation between the main signal and the
unwanted disturbing signals. We have used 2 ways to describe the IMD: One
describes the relation between the two signals, measured in dBc, typical
for 75-Ohm connectors. Another describes the size of the two signals, both
measured in dBm, typical for 50-Ohm connectors.
The problem with the two mentioned parameters is that they always require
both a specification of the main test signal (dBm) and the disturbing
signal (dBm or dBc), as any change in the main test signal will cause a
triple change in the disturbing signal.
A third way to describe the IMD value is the IP3 (Intercept Point 3rd)
measured in dBm. IP3 is the fictive point where the two signals meet, if
one imagines that the main signal strengthens until the two signals come
together as shown on the illustration below