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Вопрос 192

How does a signal that reads 20 dB over S9 compare to one that reads S9 on a receiver, assuming a properly calibrated S meter?

  1. It is 10 times less powerful
  2. It is 20 times less powerful
  3. It is 20 times more powerful
  4. It is 100 times more powerfulПравильный ответ

Объяснение

Decibels of power relate to a ratio by dB = 10 × log₁₀(P₂/P₁), so 20 dB corresponds to a power ratio of 1020/10 = 10² = 100. A reading of 20 dB over S9 therefore represents a signal 100 times more powerful than one reading S9.

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Вопрос 192: How does a signal that reads 20 dB over S9 compare to one… · FCC General Class (Element 3) · Questena