So in high quality networks ( discounting developing countries etc ) the frequency tolerance is pretty strict.
2.
The frequency tolerance was so tight that if encoded audio were recorded during a Phonevision broadcast, and then played back later into a homemade processor running on normal network programming, a slight frequency error could be detected in the restored audio.
3.
Types of auxiliary power services include Class B, a standby power plant to cover extended outages of the order of days; Class C, a 10-to-60-second quick-start unit to cover short-term outages of the order of hours; and Class D, an uninterruptible non-break unit using stored energy to provide continuous power within specified voltage and frequency tolerances.
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