🔍 Key Concepts

• Superheterodyne receiver operation (RF, local oscillator, IF stages) • How intermediate frequency (IF) is produced by mixing two frequencies • The relationship between received frequency, oscillator frequency, and IF (sum and difference products)

💭 Think About

• When two frequencies are mixed, what new frequencies are produced from them? Think about both the sum and the difference. • In a typical superheterodyne receiver, which of those products (sum or difference) is usually selected as the intermediate frequency? • Given a received frequency of 1000 kHz and an oscillator at 1500 kHz, calculate both the sum and the difference and decide which one is the IF.

✅ Before You Answer

• Confirm you know that IF = |oscillator frequency − received frequency| in standard high-side injection designs. • Compute 1500 kHz − 1000 kHz and 1500 kHz + 1000 kHz and compare those values to the answer choices. • Verify that the IF should be a fixed, relatively lower frequency compared to typical RF receive frequencies in this context.