Ham Radio General Class Practice Test

What is the simplest combination of stages that implement a superheterodyne receiver?

1. RF amplifier, detector, audio amplifier

2. RF amplifier, mixer, IF discriminator

3. HF oscillator, mixer, detector

4. HF oscillator, pre-scaler, audio amplifier

The correct answer is: HF oscillator, mixer, detector

The simplest combination of stages that implement a superheterodyne receiver is comprised of an HF oscillator, a mixer, and a detector. In a superheterodyne receiver, the purpose of the HF oscillator is to generate a higher frequency signal, known as the local oscillator frequency, which mixes with the incoming radio frequency (RF) signal in the mixer stage. This mixing process produces an intermediate frequency (IF) signal that is easier to process than the original RF signal. The mixer effectively allows for the down-conversion of the RF signal to the IF. Following the mixer, the detector stage is responsible for demodulating the IF signal to recover the audio or data information that was transmitted. The detector converts the IF signal back to a baseband signal, which can then be amplified and processed further if necessary. This combination is essential for the operation of a superheterodyne receiver, as it enables effective frequency selectivity, better sensitivity, and improved overall performance. Other configurations might include additional stages or components, but the combination of an HF oscillator, mixer, and detector represents the fundamental core structure of a superheterodyne receiver, making it the simplest implementation of this type of receiver design.