Detector used in household AM broadcast receivers Which detector topology is most commonly used in standard household AM radio receivers for demodulating the envelope of the received signal?

Introduction / Context:
AM broadcast receivers need a simple, inexpensive, and robust method to recover audio from an amplitude-modulated carrier. The envelope detector (usually a diode detector with an RC load) has been the workhorse solution for consumer radios for decades.

Given Data / Assumptions:

• Standard AM broadcast (medium-wave) receiver.
• Noncoherent detection scheme acceptable (no carrier phase recovery required).
• Low cost and simplicity are desired.

Concept / Approach:

A diode rectifies the RF, and an RC time constant follows the envelope—the audio content—while filtering out the RF carrier. Proper RC selection avoids distortion and diagonal clipping. This method is simple, low power, and adequate for AM fidelity requirements in household radios.

Step-by-Step Solution:

Verification / Alternative check:

Service schematics of classic and modern AM radios show diode envelope detectors. Synchronous or product detectors are used for improved performance or SSB/CW but add complexity and cost.

Why Other Options Are Wrong:

Synchronous and product detectors require carrier/oscillator synchronization; “radio detector” and “none of the above” are not specific or are incorrect in this context.

Common Pitfalls:

Choosing RC values that are too small leads to diagonal clipping; too large causes loss of high audio frequencies.

Final Answer:

Envelope detector