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Instead of spreading the data signal instantaneously (and thinly)
over a wide frequency range, an equally effective method is to rapidly change the position
of the narrow data signal within a much wider bandwidth. This frequency hopping approach means that for some of the time
the signal will fall within a selective fade, but for most of the time, it will be passed
within a non-fading portion of the channel. The result, as for direct sequence spreading,
is that most of the data signal most of the time reaches the receiver with little
distortion, and with extra coding a high integrity communications link can be established.
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