*Question G8A04:
What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?*  

*Correct Answer is  B: Phase modulation*  

### AI Response: (may contain errors)  

To understand the emission produced by a reactance modulator connected to a transmitter RF amplifier stage, let's break down the correct answer and the other options.

### Correct Answer: Phase Modulation

- **Why it's correct**: A reactance modulator works by varying the reactance (inductive or capacitive) in the circuit, which in turn changes the phase of the RF signal. This phase variation directly leads to phase modulation (PM) of the carrier wave. In PM, the information is encoded in the phase of the signal rather than its amplitude or frequency.

### Why the Other Choices are Incorrect

- **A: Multiplex modulation**: 
  - This refers to a technique that combines multiple signals into one for transmission. It does not specifically relate to the modulation of a single RF signal's phase or amplitude.

- **C: Amplitude modulation**: 
  - Amplitude modulation (AM) involves varying the amplitude of the carrier wave to encode information. A reactance modulator does not primarily change the amplitude; it changes the phase, making this option incorrect.

- **D: Pulse modulation**: 
  - Pulse modulation involves transmitting information using pulses of varying width, position, or amplitude. This is not related to the continuous wave modulation that a reactance modulator performs.

### Summary

- A reactance modulator produces **phase modulation** by varying the reactance in the circuit, affecting the phase of the RF signal.
- Other modulation types (multiplex, amplitude, pulse) do not accurately describe the function of a reactance modulator.

This understanding is crucial for the Extra Class exam, as it highlights the specific role of different modulation techniques in radio communications.