Digital Modulation Techniques

  Amplitude Shift Keying The amplitude of the resultant output depends upon the input data whether it should be a zero level or a variation of positive and negative, depending upon the carrier frequency. Amplitude Shift Keying (ASK)  is a type of Amplitude Modulation which represents the binary data in the form of variations in the amplitude of a signal. Following is the diagram for ASK modulated waveform along with its input. Any modulated signal has a high frequency carrier. The binary signal when ASK is modulated, gives a zero value for LOW input and gives the carrier output for HIGH input. Frequency Shift Keying The frequency of the output signal will be either high or low, depending upon the input data applied. Frequency Shift Keying (FSK)  is the digital modulation technique in which the frequency of the carrier signal varies according to the discrete digital changes. FSK is a scheme of frequency modulation. Following is the diagram for FSK modulated waveform along with its input