🔍 Key Concepts

• Minimum Discernible Signal (MDS) definition and what it represents in a receiver test • Relationship between RF input level (from a signal generator) and audio output level when measuring sensitivity • Which test instruments are normally used for sensitivity vs for dynamic range or spectrum measurements

💭 Think About

• Ask yourself: Which procedure actually checks how weak an RF signal the receiver can still pick up as usable audio at the output? • For each option, identify what quantity is really being measured: is it minimum RF input for a specified audio output change, or something else (like frequency components or time behavior)? • Think about which instruments are standard for receiver sensitivity/MDS measurements in marine radio service: signal generator + what kind of audio measurement?

✅ Before You Answer

• Verify which option uses a signal generator at the receiver’s tuned frequency and varies the RF level from very low upward. • Check which choice specifies an objective change in audio output level (such as a 3‑dB change) as the criterion for ‘discernible’. • Eliminate any option that focuses on dynamic range tests or spectrum display instead of minimum usable signal at the audio output.