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Is PAM a Digital Modulation Technique?

 

No

Pulse Amplitude Modulation (PAM) consists of the processes, i.e., sampling, quantization, and amplitude modulation. So, you may think it is an example of a digital modulation technique. Varying the amplitude of a carrier signal in accordance with the message signal amplitude is termed Amplitude Modulation (AM). A similar thing happens in the case of PAM, but here sampling method is included. Only sampling and quantization methods do not make a signal inherently digital. 

I've added the quantization term here because in the cases of 4-level, and 8-level PAM, each pulse can take on one of four or eight discrete amplitude levels. You may confuse PAM with Pulse Code Modulation but they aren't the same. In PCM, an analog signal is first sampled, and then each sample is quantized and represented using PAM. PCM is a digital modulation technique where the quantized PAM samples are encoded into a digital format. PAM is often employed in the analog output stage of a digital-to-analog converter (DAC). In this case, a digital signal is converted into an analog signal using PAM. While both PAM and PCM involve the manipulation of signal amplitudes, PAM is analog modulation with a limited number of discrete levels, while PCM is a digital technique that involves the representation of continuous analog signals by discrete digital values. They serve different purposes and are used in different contexts, such as analog communication systems for PAM and digital audio or telecommunications for PCM.

Digital modulation techniques, on the other hand, involve the modulation of digital signals (which consist of discrete values typically represented as 0s and 1s). Examples of digital modulation techniques include Phase Shift Keying (PSK), Frequency Shift Keying (FSK), and Amplitude Shift Keying (ASK), PCM, among others.
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