*Question G4D09:
What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?*  

*Correct Answer is  B: 14.347 MHz to 14.350 MHz*  

### AI Response: (may contain errors)  

To determine the frequency range occupied by a 3 kHz Upper Sideband (USB) signal, we need to understand how USB signals work:

1. **Upper Sideband (USB) Basics**:  
   - In USB, the carrier frequency is the lowest frequency in the transmitted signal.
   - The signal extends upward from the carrier frequency by the bandwidth of the signal.

2. **Given Parameters**:  
   - Carrier frequency: 14.347 MHz
   - Bandwidth: 3 kHz (since it's a 3 kHz USB signal)

3. **Frequency Range Calculation**:  
   - The USB signal will occupy frequencies from the carrier frequency up to the carrier frequency plus the bandwidth.
   - Therefore, the frequency range is from 14.347 MHz to \(14.347 \, \text{MHz} + 0.003 \, \text{MHz} = 14.350 \, \text{MHz}\).

4. **Correct Answer**:  
   - **B: 14.347 MHz to 14.350 MHz** is correct because it matches the calculated frequency range.

5. **Why Other Choices Are Incorrect**:  
   - **A: 14.347 MHz to 14.647 MHz**: This range is too wide. It suggests a bandwidth of 300 kHz, which is incorrect for a 3 kHz USB signal.
   - **C: 14.344 MHz to 14.347 MHz**: This range is below the carrier frequency and does not account for the USB signal extending above the carrier.
   - **D: 14.3455 MHz to 14.3485 MHz**: This range is too narrow and does not cover the full 3 kHz bandwidth above the carrier frequency.

By understanding the nature of USB signals and applying the bandwidth to the carrier frequency, we can accurately determine the frequency range occupied by the signal.