In the context of radio broadcasting, the modulation types used in LW (Long Wave), CW (Continuous Wave), SW (Short Wave), and MW (Medium Wave) vary.
LW (Long Wave): Long Wave broadcasting primarily uses amplitude modulation (AM). In AM, the amplitude of the carrier wave is modulated to transmit the audio signal.
CW (Continuous Wave): CW refers to continuous wave transmission, which is typically used for Morse code communication. CW does not involve modulation of either frequency or amplitude. It uses on-off keying, where the carrier wave is turned on and off to encode the dots and dashes of Morse code.
SW (Short Wave): Short Wave broadcasting commonly uses amplitude modulation (AM) for audio transmissions. However, short wave signals can also utilize single-sideband modulation (SSB) or frequency modulation (FM) for some applications, such as amateur radio.
MW (Medium Wave): Medium Wave broadcasting primarily uses amplitude modulation (AM). AM is the standard modulation technique for transmitting audio signals in the medium wave frequency range.
In summary, LW and MW broadcasting use amplitude modulation (AM), CW transmission does not involve modulation, and SW broadcasting can employ a combination of amplitude modulation (AM), single-sideband modulation (SSB), or frequency modulation (FM) depending on the specific application.