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سؤال 194

What does a receiver noise floor of -174 dBm represent?

  1. The receiver noise is 6 dB above the theoretical minimum
  2. The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperatureپاسخ درست
  3. The noise figure of a 1 Hz bandwidth receiver
  4. The receiver noise is 3 dB above theoretical minimum

توضیح

The figure −174 dBm is the thermal noise power available in a 1 Hz bandwidth at room temperature, which is the floor a perfect receiver would show. It is the theoretical reference itself rather than a level a fixed number of dB above one.

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شروع تمرین
سؤال 194: What does a receiver noise floor of -174 dBm represent? · FCC Amateur Extra Class (Element 4) · Questena