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INTERMODULATION
Intermodulation is often considered
interference in the wireless world. That means that
Intermodulation can create unwanted frequencies
that can interfere with desired radio or cellular
reception.
| Intermodulation to a wireless engineer means
"non-linear mixing". Since non linear mixing within
electronic components such as transistors or even connectors, it
is actually very common. Intermodulation is a very serious
problem for radio engineers. An example of Intermodulation
is the non-intended mixing of two signals that might be in the
same radio product. For example, let us say that this
radio product transmits at 450 MHz, but that it also has a
strong signal either inside of the product itself or nearby that
is at 20 MHz.
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Intermodulation means non-linear mixing, and these two signals are
likely to mix at certain electronic components within the product.
When that happens, not only will there be presence nearby of the first
two signals: 450 MHz and 20 MHz, but also a series of other
frequencies made up of their sum and differences due to non-linear
mixing. Some of those sum and difference products now created
would be: 470 MHz ( 450 + 20), 430 MHz (450 - 20), 920 MHz (450 times 2
+ 20) and 880 MHz (2 times 450 MHz - 20 MHz). As you can see,
the list of frequency products that can be made is endless. While
these new frequencies will be lower in power than the original signal,
they may be high enough in power to interfere with a desired radio
signal nearby.
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