🔍 Key Concepts

• Superheterodyne receiver: how incoming RF is converted to an intermediate frequency (IF) • Relationship between RF frequency, local oscillator frequency, and IF (sum and difference products) • Role of the second detector (demodulator) and what frequency it must receive to recover audio

💭 Think About

• First, figure out which frequency in the set-up is the intermediate frequency (IF) and which one is the incoming radio frequency (RF) carrier. • Ask yourself: in a superheterodyne, is the second detector usually tuned to the RF, the local oscillator, or the IF? • Once you know that, compare that required frequency to each answer choice and decide which makes sense for a detector that is extracting audio from the signal.

✅ Before You Answer

• Verify what IF (intermediate frequency) actually means in a superhet: the fixed frequency produced after mixing RF and local oscillator. • Confirm that the second detector (demodulator) works on the fixed IF signal, not directly on the original RF carrier or the oscillator frequency. • Check which answer choice corresponds exactly to the IF identified in the problem statement before selecting.