Carrier Waves in Analog Modulation | Generated by AI
What is a “Carrier” in Modulation Techniques?
In the context of analog modulation (like AM, FM, and PM), the carrier refers to a high-frequency electromagnetic wave or signal that serves as the “backbone” for transmitting information. It’s essentially a steady, continuous waveform (often sinusoidal) at a fixed frequency much higher than the original information signal (e.g., audio or data). The modulating signal (the actual information) is superimposed onto this carrier to make it easier to transmit over long distances, through antennas, or via other channels without losing quality.
Key Characteristics of the Carrier:
- Frequency: Typically in the radio frequency (RF) range (e.g., 500 kHz for AM radio or 88–108 MHz for FM radio) to propagate well through air or space.
- Amplitude and Phase: These are constant in their base form but get altered during modulation (e.g., amplitude changes in AM, frequency in FM).
- Role: Acts like a “vehicle” – the information rides on it, and at the receiver, the carrier is stripped away (demodulated) to recover the original signal.
Without a carrier, low-frequency signals (like voice at 20 Hz–20 kHz) wouldn’t travel far efficiently due to antenna size limits and attenuation.
Simple Analogy:
Think of the carrier as a strong truck (high frequency for speed/distance) carrying a small package (the modulating signal). Modulation loads/unloads the package onto the truck.
For more details:
Carrier Wave Explanation
Modulation Basics