🔍 Key Concepts

• FM modulation limits for marine VHF transmitters • Role of the modulator stage vs. later RF stages (like the VCO and power amplifier) • The purpose of pre-emphasis and typical audio frequency ranges in marine VHF

💭 Think About

• Which option directly describes a condition of too much modulation rather than a component failure or misalignment issue? • Marine VHF uses voice audio; what is the realistic audio frequency range involved, and does anything above 25 kHz make sense for normal voice signals? • Is a problem with the voltage controlled oscillator (VCO) usually described as modulator distortion, or would it show up as something else (like frequency instability)?

✅ Before You Answer

• Verify the normal modulation percentage range for FM voice transmitters and what happens when this is exceeded. • Check whether audio pre‑emphasis is normally applied at audio frequencies (e.g., Hz to a few kHz) or at tens of kHz and how that would affect voice quality. • Consider which choices describe general operating conditions (like level of modulation) versus very specific component faults, and which is more likely to be a textbook cause of "distortion in the modulator stage."