Pulse Amplitude Modulation

PhysicsCommunication system


The Pulse Amplitude Modulation is referred to as a very simple model of signal modulation technique. These are the signals that are further transmitted and are inspected at a very particular interval. On top of it, the modulating signal is proportional directly to the amplitude of the signal

Therefore it general multiple carrier signals like frequency, bandwidth and amplitude which are also its core features. This particular phenomenon is also an outcome because of adding details to the carrier signal in the course of transmission.

What is meant by Pulse Amplitude Modulation (PAM)?

Figure 1: Pam signal

The Pulse amplitude modulation or PAM is denoted as the transmission of data that takes place by changing the amplitudes. Communication has been thoroughly necessary for transmission and this communication occurs through transmitter and receiver with the aid of signals (elprocus, 2022). These signals help carry the information through various modulations. As opined by Khalighi et al. (2017), the aspect of Pulse Amplitude Modulation is one such major type of modulation process that helps in the transmission of signals. This modulation uses an analog to digital signal conversion process; in this case, the information is encoded in the amplitude of signal pulses in a series (stackexchange, 2022). In short Pulse Amplitude Modulation or PAM is used for the conversion of the signal, from analog to a digital version. These signals can be natural and flat top

PAM: types

The Pulse Amplitude Modulation is simply categorized into two distinct sections. This division is done based on the polarity index

  • Single polarity PAM − In this case, a proper fixed DC bias is added with a signal that assures that the pulses that are generated through it are positive.

  • Double Polarity PAM − : In this type of Pulse Amplitude Modulation where there is a prevalence of two distinct polarities. The DC bias that is added to it propagates both positive and negative pulses

However, it is to be noted that there is a new alteration noticed in the PAM, that is, Pulse Code Modulation and Pulse Position Modulation replaces the non-base band application which results in a much faster transfer of digital data that is in practice in recent times.

The Pulse Amplitude Modulation uses three distinct modulation techniques. These techniques are mentioned as follows

  • Pulse Modulation − This aspect is associated with the transmission of signals in pulses (engineersgarage, 2022). These pulses are obtained in either the width type of the pulse or simple Pulse amplitude format

  • Continuous Wave modulation − This case of transmission is a property where the carrier signal modulates the the message signal. This transmission occurs because of the fluctuation of amplitude, frequency and change in the phases.

  • Digital Modulation − The digital modulation are further classified into two distinct categories. The transmission in this modulation occurs in delta modulation or pulse amplitude modulation

PAM sampling techniques

Figure 2: Flat top Pulse Amplitude modulation

Flat top PAM is one of the crucial sampling techniques where the amplitude of the pulses is proportional to modulating signals amplitude in the occurrence of pulses. In Natural PAM during the occurrence of pulses the modulating signal amplitude is proportional to the amplitude

PAM: Advantages and disadvantages


  • The circuit of PAM is very easy to make and the relative operation is quite easy as well

  • In PAM the transmission is quite easy and fast. The amplitude signal reception experiences zero interference from any external factors

  • The Pulse Amplitude Modulation is capable of functioning with two distinct purposes, as this modulation technique can carry various transmitted messages. PAM is also able to produce pulse signals and transmit signals at the same time

  • In PAM, the modulation and demodulation happens automatically and it does not demand any sort of manual activity for its functionality


  • Pulse Amplitude Modulation calls for higher bandwidth for the transmission of a signal

  • It creates extra noises remnants that cause various disturbances.

  • In certain cases, it has been observed that PAM requires a huge volume of power for its functionality

Application of Pulse Amplitude Modulation

  • The Pulse Amplitude Modulation is used in various sections.

  • It is used in Broadband interface communication for connectivity of the Ethernet.

  • It is used in controlling signals of the micro-controllers.

  • Pulse Amplitude Modulation is also used in the graphics cards and the associated high-speed networking and it is also useful in the reduction of the noise to signal ratio.

  • PAM is also used in photobiology for the usage of spectrofluorimetric measurements during photosynthesis.

  • It is also used in LED drivers for efficiency in the energy of the lighting.

  • Pulse Amplitude Modulation is also used to obtain clear pictures and proper signal clarity in digital televisions.


The pulse amplitude modulation is a very critical aspect that is used in terms of communication. The PAM serves effective as an a signal converter that helps in the conversion of analog signals into digital signals. The pulse amplitude modulation is also useful in encoding the pulse amplitude. PAM is highly preferred because of its ease of access. The circuit that utilizes the aspect of PAM is easy to construct and operates pretty easily as well. It can be safely included that the PAM is a necessity in modern times for efficient digital signal transmission without any disturbances


Q1. What is the use of the Pulse Amplitude Modulation?

The Pulse Amplitude Modulation is helpful in the transmission of analog signals with the help of a pulse stream. On top of it, PAM also enables easy analog-to-digital signal conversion

Q2. What are the different types of Pulse modulation?

The most common examples of pulse modulation that are in usage are Pulse Amplitude modulation and Pulse Position Modulation. Pulse Number Modulation and Pulse Width Modulation are classified under pulse modulation

Q3. How many types of PAM are there?

There are two main types of Pulse Amplitude Modulation that use a DC bias. Single Polarity PAM generates positive pulses and Double Polarity PAM that generates negative and positive pulses.

Q4. What are the uses of PAM?

PAM is used in Ethernet connectivity. It s also used for signal clarity in digital television sets

Updated on 13-Oct-2022 11:19:47