amplitude shift keying (Modulation) (ASK)
Amplitude shift keying (ASK) is an amplitude modulation which is used for transmission via modems or also on optical fibers. In amplitude shift keying, the modulating signal is digital and the carrier signal is sinusoidal.
The carrier frequency remains constant with this method, the carrier amplitude changes. By modulating the carrier signal with the digital signal, bursts are generated in the rhythm of the digital modulating signal. The simplest type of amplitude shift keying is done by keying in ("1") and keying out ("0") the carrier signal and is known as On Off Keying( OOK). However, this method has the disadvantage of not being able to distinguish interrupts from zero bits.
Amplitude shift keying is relatively susceptible to interference because noise on the transmission line affects the amplitude of the modulated signal. Therefore, a relatively large carrier amplitude is required for interference-free transmission. Amplitude shift keying is used in EnOcean, among other applications.