Definition
A radio transmission method in which a steady (continuous) radio-frequency carrier wave is modulated by an audio-frequency tone, so the signal can be heard as a tone in an ordinary AM receiver rather than requiring a special receiver to detect it. MCW is commonly used to transmit Morse code identification signals from navigation aids such as non-directional beacons and VORs.
Plain English
A way of sending a radio signal where a constant tone is added to the carrier wave so that dots and dashes (or other coded sounds) can be heard directly through a normal radio.
Context Anchor
Seen in descriptions of radio, radar, and avionics systems, especially when comparing continuous signals with pulsed signals.
Derivation
Modulated comes from the Latin modulari, meaning to regulate or vary. Continuous Wave refers to an unbroken radio-frequency signal. Together: a steady radio wave whose strength is varied (modulated) by an audio tone so the ear can hear it.
Why Pilots Care
Enables reliable voice and tone transmission over distance in certain radio systems used in aviation.
Grounding Statement
Picture a transmitter that stays on while the shape of its signal is adjusted to carry useful information.
Intuition Check
Do not read continuous as meaning the signal never changes. Here, continuous means the signal keeps being transmitted; modulated means it is still being varied in a controlled way.
Example Sentence 1
The VOR station identifier is sent as Morse code using modulated continuous wave so the pilot can hear it through the audio panel.
Example Sentence 2
Some older navigation beacons used modulated continuous wave to send identification tones.