🔍 Key Concepts

• Overall noise figure of a receiver and how it is determined • Effect of early vs. later stages in a receiver chain on signal-to-noise ratio (SNR) • Role of gain in the first active stages of a receiver

💭 Think About

• Think about which stage first handles the very weak signal coming from the antenna, before much amplification has occurred. • Consider how noise added early in the chain compares to noise added at later stages that already receive an amplified signal. • Ask yourself: If one stage is noisy, at which point in the chain would that noise most strongly affect the entire receiver performance?

✅ Before You Answer

• Identify which stage in the choices is the first high‑gain stage after the antenna in a typical superheterodyne receiver. • Recall that the earliest active stage usually dominates the total noise figure according to receiver design theory. • Verify which listed stage normally handles audio-frequency, which handles RF (radio frequency), which handles intermediate frequency (IF), and which generates but does not receive the signal (local oscillator).