Continuous wave, or CW, transmitters, are devices that utilize CW to amplify them for communication purposes. Continuous waves are primarily used for radiotelegraphy. The transmission of short or long pulses of RF energy to form the dots and dashes of the Morse code characters is referred to as interrupted continuous wave. Continuous wave transmission was the first type of radio communication used. This technology is still widely used for long-range communications.
Two of the advantages of CW transmission are a narrow bandwidth, which requires less output power, and a degree of intelligibility that is high even under severe noise conditions such as a crowded intersection in a bustling city or during a thunderstorm. A CW transmitter requires four essential components: a generator, amplifier, keyer, and antenna. Each of these components have an important role involving RF oscillations. Together these components generate, amplify, and turning the RF output on and off the oscillations. Finally, the antenna radiates the keyed output of the transmitter.