Cliff effect

In telecommunications, the cliff effect or digital cliff describes the sudden loss of digital  reception. Unlike analog signals, which gradually fade when signal strength decreases or electromagnetic interference or multipath increases, a digital signal provides data which is either perfect or non-existent at the receiving end. It is named for a graph (shown at right) of reception quality versus signal quality, where the digital signal "falls off a cliff" instead of having a gradual rolloff.
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