*Question G8B04:
What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?*  

*Correct Answer is  D: Multiplier*  

### AI Response: (may contain errors)  

In a VHF FM transmitter, the stage that generates a harmonic of a lower frequency signal to reach the desired operating frequency is called a **Multiplier**.

### Explanation of the Correct Answer:
- **Multiplier**: This stage takes an input signal and produces an output signal at a frequency that is a multiple of the input frequency. For example, if the input frequency is $f$, a doubler would output $2f$, a tripler would output $3f$, and so on. This is essential in VHF FM transmitters to achieve the higher frequencies required for transmission.

### Why the Other Choices are Incorrect:
- **A: Mixer**: A mixer combines two signals to produce new frequencies, specifically the sum and difference of the input frequencies. It does not generate harmonics of a single frequency.
  
- **B: Reactance modulator**: This device varies the reactance in a circuit to modulate the frequency of the signal. It does not generate harmonics but rather changes the frequency of the existing signal.

- **C: Balanced converter**: This is typically used for converting signals while maintaining balance in the circuit, often in the context of RF applications. It does not specifically generate harmonics.

### Useful Formulas or Rules of Thumb:
- For a frequency multiplier, the output frequency can be calculated as:
  $$ f_{out} = n \times f_{in} $$
  where:
  - $f_{out}$ = output frequency
  - $f_{in}$ = input frequency
  - $n$ = integer multiplier (2 for a doubler, 3 for a tripler, etc.)

This understanding of the multiplier's role in generating higher frequencies is crucial for grasping the operation of VHF FM transmitters.