Pulse-amplitude modulation (PAM), is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. It is an analog pulse modulation scheme in which the amplitudes of a train of carrier pulses are varied according to the sample value of the message signal.
Pulse amplitude modulation (PAM) is one of several forms of single modulation in which data is transmitted through varying the amplitude of the pulses in regular timed sequence of electrical or electromagnetic pulses. In the case of analog pulse amplitude modulation signals, the number of pulse amplitudes can be infinite. Pulse amplitude modulation is mostly used in digital data transmission with non baseband applications.
Pulse amplitude modulation is used in the popular Ethernet communication standard.
There are two main types of pulse amplitude modulation:
Single Polarity: A fixed direct current level is added to the signal to ensure the pulses are all positive at all times.
Double Polarity: This sort of pulse amplitude modulation has both negative and positive pulses going at once.
