🔍 Key Concepts

• Single Sideband (SSB) voice transmitter modulation and what "two‑tone" testing is used for • The meaning of harmonically related vs non‑harmonically related audio tones • Typical audio frequency range used to modulate an SSB marine transmitter

💭 Think About

• Ask yourself: In a two‑tone test, what is the purpose of using two separate audio frequencies on an SSB transmitter (what are we trying to check about the transmitter)? • Which type of tone relationship (harmonically related or not) will give a cleaner, more representative test of linearity and intermodulation? • Look at each option and ask: Would this kind of signal realistically represent normal SSB voice modulation through the transmitter's audio passband?

✅ Before You Answer

• Verify which options mention non‑harmonically related tones versus harmonically related tones and why that matters for intermodulation tests • Check that the tones are within the audio/modulation passband of a typical SSB marine transmitter (around 300–3000 Hz range) • Eliminate any option that would create an unrealistic or distorted test condition, such as phase tricks or square waves that are not typical of normal SSB voice modulation