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relatively frequent signal degradation, and a very small change in overall signal quality can have a dramatic impact on the frequency of signal degradation – one incident per hour (not significantly affecting watchability) versus problems every few seconds or continuous problems. Thirdly, in some cases, where the signal is beyond the cliff (in unwatchable territory), viewers who were once able to receive a degraded signal from analog stations will find
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Three particular issues particularly manifest the cliff effect. Firstly, anomalous conditions will cause occasional signal degradation. Secondly, if one is located in a fringe area, where the antenna is just barely strong enough to receive the signal, then usual variation in signal quality will cause
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The phenomenon is primarily seen in broadcasting, where signal strength is liable to vary, rather than in recorded media, which generally have a good signal. However, it may be seen in significantly damaged media that is at the edge of readability.
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digital mode (the official meaning of "HD"). In the future all-digital mode, there is no analog to fall back to at the edge of the digital cliff. This applies only to the main channel
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and coding can provide a compromise by supporting two or more streams with different robustness parameters and allowing receivers to scale back to a lower definition (usually from
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end. It is named for a graph of reception quality versus signal quality, where the digital signal "falls off a cliff" instead of having a gradual rolloff. This is an example of an
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between analog and digital, or the cliff effect will still cause a jump slightly forward or backward in the radio program.
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broadcasting, officially used only in the United States, is one system designed to have an analog
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increases, a digital signal provides data which is either perfect or non-existent at the
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that there is no available signal in rural, fringe or mountainous regions.
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For the effective financial loss resulting from increased income, see
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digital terrestrial television standard. However, layered
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The cliff effect is a particularly serious issue for
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and other weather or atmospheric conditions causing
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