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Example: Sending a simple voice message from Alice to Bob. 1. **Information source**: Alice speaks into a microphone. The sound waves are converted into an electrical signal by the microphone. 2. **Transmitter (modulator)**: The electrical signal is fed into a modulator that changes it into a radio frequency (RF) signal. The modulator may use amplitude modulation (AM) or frequency modulation (FM). 3. **Channel**: The RF signal travels through the air as a radio wave. During transmission, background noise (like wind or other radio stations) may add unwanted signals. 4. **Receiver (demodulator)**: Bob’s radio receiver captures the RF signal. It demodulates the signal, converting the RF back into an electrical audio signal. 5. **Destination**: The audio signal is sent to Bob’s speaker, where it becomes sound again. Bob hears Alice’s voice. This step‑by‑step example shows how each block in the diagram performs a specific job, from converting sound to a signal, sending it through the air, and finally turning it back into sound at the other end.