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IP3-value (IMD) - an important parameter you shouldn’t miss

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


IP3 is the most user friendly way to describe the relation between the main signal and the disturbing signal as this value is immediately comparative to other manufacturers’ IP3 values - if available - no matter the size of the main test signal.

Therefore we now include the IP3 value on our datasheets. We hope this information will support our customers in making a qualified choice of connectors.


 © Corning Cabelcon A/S   Legals  ▪  Last Updated: 5. November 2004 ▪  Go to top