Pulse Amplitude Modulation

Communication is an integral necessity for any type of technological transmission. The two primary components of a successful communicable transmission is a transmitter and signal. Further, the signal that transmits is always in wave format. This is where Pulse Amplitude Modulation comes into play. Pulse Amplitude Modulation or PAM acts as a signal converter that helps in encoding the amplitude of the pulse and converts analog signal transmission into a digital version.

pulse amplitude modulation

Introduction to Pulse Amplitude Modulation

Pulse Amplitude Modulation is a simple form of signal modulation. The signals transmitted are inspected at a very specific interval. Moreover, this correlated with the modulating signal as it is categorized to be directly proportional to the amplitude of the signal.

Hence, the various carrier signals emitted like frequency, bandwidth, and amplitude change their core features. This also occurs as a result of the addition of details into the carrier signal during transmission. Thus, some of the common additional details added to carrier signals include videos, audio, texts, and images.  Special cases like Electromagnetic signals use optic or radio laser for modulation.

Pulse Amplitude Modulation broadly divides into two types based on the polarity index. They are:

  • Single Polarity PAM – A DC bias added to the signal transmission to emits only positive pulses.
  • Double Polarity PAM – The added DC bias emits both positive and negative pulse.

Another interesting new change to PAM is the replacement of non-baseband application with Pulse Code Modulation and Pulse Position Modulation. As a result, digital data transfer is much faster today than before.

Kinds of Modulation Used in Pulse Amplitude Modulation

There are primarily 3 specific modulation techniques which come in use in PAM. They are:

  • Pulse Modulation- The signal transmits in the form of Pulses. They can be either pulse width type or in form of Pulse Modulation or as simple Pulse Amplitude format.
  • Continuous Wave Modulation – In this kind of transmission carrier signal modulates the message signal transmission. This transmission occurs due to the fluctuation of amplitude, frequency, and phase change.
  • Digital modulation – This type of modulation has two subtypes. They can transmit in the form of pulse amplitude modulation or delta modulation.

There are two kinds of sampling techniques that also come in use for the transmission of signals. They are:

Flat top PAM- Amplitude of every pulse is proportional to modulating signal amplitude during pulse occurrence.

Natural PAM- The amplitude is proportional to modulating signal amplitude during pulse occurrence.

Application of Pulse Amplitude Modulation

  • Ethernet Connectivity for Broadband interface communication
  • To control signals in Micro-controllers
  • Graphics card for high-speed networking and reduce the noise to signal ratio.
  • In Photo Biology for the purpose of spectrofluorometric measurements during photosynthesis
  • For energy-efficient lighting in LED drivers
  • For better signal clarity and clearer picture in Digital Televisions

Advantages of Using Pulse Amplitude Modulation

  • Very easy and fast transmission and reception of Amplitude signals without interference from external factors.
  • The PAM circuit is easy to construct and operate
  • PAM can function with a dual purpose as it can carry transmitted messages and produce pulse signals simultaneously.
  • The process of Modulation and Demodulation occurs automatically and does not need manual interference.

Disadvantages of Using Pulse Amplitude Modulation

  • Requires a greater amount of Bandwidth for transmission of PAM signal
  • Creates additional noise remnants that can cause disturbances
  • Requires a larger volume of power consumption in many cases

However, all these minor issues can be rectified or avoided altogether if Vestigial Side-band or Single and Double Side-band Suppress Carrier (SSC) is used.

Further, the noise which produces in Amplitude Modulation is one of the reasons why AM radio frequency are not preferrable over Frequency Modulation Radio Signal (FM)

FAQ on Pulse Amplitude Modulation

Question 1: Why do we need to use Pulse Amplitude Modulation?

Answer 1: Pulse Amplitude Modulation helps in the transmission of analog signals through Pulse Stream. Moreover, this enables easy conversion of analog signals into digital ones. The best example is the Phone Call signals that we can convert into Video calls using PAM.

Question 2: What are the types of pulse modulation?

Answer 2: Some of the most common types of Pulse Modulations used are Pulse Amplitude Modulation (PAM), Pulse Position Modulation (PPM), Pulse Number Modulation (PNM), Pulse Width Modulation (PWM).

Question 3: What are the types of modulation signals?

Answer 3: The 4 basic types of Modulation signals are Analog  Signal, Digital Signal, Pulse SIgnal, Spread Signal Method Signal.

Share with friends
Customize your course in 30 seconds

Which class are you in?

Get ready for all-new Live Classes!
Now learn Live with India's best teachers. Join courses with the best schedule and enjoy fun and interactive classes.
Ashhar Firdausi
IIT Roorkee
Dr. Nazma Shaik
Gaurav Tiwari
Get Started
Customize your course in 30 seconds

Which class are you in?

No thanks.