Which device in the receiver chain is responsible for making the faint signal audible by increasing its level?

Which device in the receiver chain is responsible for making the faint signal audible by increasing its level?

• A. Audio amplifier
• B. Detector
• C. Local oscillator
• D. Antenna

Answer: (A)

The key idea is that you need an amplification stage after demodulation to hear the signal. In a receiver, the antenna picks up the RF signal, the detector demodulates it to recover the audio, but that recovered audio is usually very small. The audio amplifier then boosts this low-level audio so it can drive a speaker or headset and reach a comfortable listening level. The detector’s job is to extract the information, the local oscillator helps convert the signal to a usable form, and the antenna merely collects energy. It’s the audio amplifier that provides the necessary gain to make the faint signal audible.

The key idea is that you need an amplification stage after demodulation to hear the signal. In a receiver, the antenna picks up the RF signal, the detector demodulates it to recover the audio, but that recovered audio is usually very small. The audio amplifier then boosts this low-level audio so it can drive a speaker or headset and reach a comfortable listening level. The detector’s job is to extract the information, the local oscillator helps convert the signal to a usable form, and the antenna merely collects energy. It’s the audio amplifier that provides the necessary gain to make the faint signal audible.