Ham Radio General Class Practice Test

What circuit is used to process signals from the RF amplifier and local oscillator and send the result to the IF filter in a superheterodyne receiver?

1. Balanced modulator

2. IF amplifier

3. Mixer

4. Detector

The correct answer is: Mixer

In a superheterodyne receiver, the mixer is a crucial component that combines the signals from the RF amplifier and the local oscillator. When these two signals are mixed, they produce new signals at specific frequencies, including the intermediate frequency (IF) which is essential for further processing. This mixing process effectively translates the incoming RF signals down to the IF, simplifying the design and performance of the receiver. The mixer functions by taking the high-frequency RF signal and combining it with the lower frequency local oscillator signal. The result of this mixing process is two new signals: one at the sum of the two frequencies and another at the difference. Typically, the difference frequency is what gets passed on to the IF filter, which further processes this signal by filtering out unwanted frequencies and enhancing the desired signal. For the other options, while they are important components in the overall function of a superheterodyne receiver, they serve different roles. The balanced modulator is used for generating single-sideband signals rather than translating frequencies. The IF amplifier is responsible for amplifying the intermediate frequency signals after they have been processed by the mixer. The detector, on the other hand, is utilized to retrieve the audio or information content from the modulated IF signals after they have been filtered and