Which component processes the output signal after the radio frequency amplifier in a receiver?

The component that processes the output signal after the radio frequency amplifier in a receiver is a demodulator, which is more commonly referred to as a product detector in this context. After the radio frequency (RF) signal has been amplified, it typically still needs to be converted from its modulated form to an audio signal that can be understood by the operator.

The product detector achieves this by mixing the incoming RF signal with a local oscillator signal. This mixing process translates the frequency of the RF signal down to a lower frequency, which represents the original audio information. Essentially, the product detector extracts the modulation from the carrier wave, allowing for the audio signal to be further processed and understood.

While bandpass filters and audio amplifiers are important in the signal processing chain, their functions are different. A bandpass filter is designed to allow only a specific range of frequencies to pass through, which does not directly convert the modulated signal into audio. The audio amplifier, on the other hand, is responsible for boosting the audio signal so it can be output through a speaker, but it does not demodulate the signal. Therefore, the product detector is the key component that converts the RF output to a format that can be processed as audio.