Editing Continuous wave (section)

===Transition to CW===
It was realized that the ideal radio wave for [[radiotelegraphy|radiotelegraphic]] communication would be a sine wave with zero damping, a ''continuous wave''. An unbroken continuous sine wave theoretically has no bandwidth; all its energy is concentrated at a single frequency, so it doesn't interfere with transmissions on other frequencies. Continuous waves could not be produced with an electric spark, but were achieved with the [[vacuum tube]] [[electronic oscillator]], invented around 1913 by [[Edwin Armstrong]] and [[Alexander Meissner]]. After [[World War I]], transmitters capable of producing continuous wave, the [[Alexanderson alternator]] and [[vacuum tube]] [[oscillator]]s, became widely available.

Damped wave spark transmitters were replaced by continuous wave vacuum tube transmitters around 1920, and damped wave transmissions were finally outlawed in 1934.