🔍 Key Concepts

• Radar receiver stages: RF (front end), mixer, IF (intermediate frequency) amplifier • Amplification vs. conversion: which stages mainly amplify and which mainly change frequency? • IF amplifier characteristics: what kind of gain and bandwidth are usually used to detect weak echoes and reject noise/clutter

💭 Think About

• For each statement, ask: does this describe the normal, textbook behavior of that stage in a marine radar receiver? • Think about why a radar needs high gain and selectivity: which stage is best suited to provide most of the gain and narrow bandwidth? • Consider whether the mixer’s main job is to provide large gain or to do something else (what is that?).

✅ Before You Answer

• Review what the front end (RF amplifier) of a radar receiver typically does to very weak incoming echoes. • Confirm the usual role of the mixer: frequency conversion vs. providing significant gain (is 6 dB guaranteed?). • Recall that an IF amplifier in radar is normally designed with high gain and narrow bandwidth to improve sensitivity and selectivity—decide if this is generally true or if “always” makes the statement too strong.