Fourier series in signal and system for GATE/IES/PSU




In this video i am going to explain about Fourier series basics, i am going to make full series of signal and system lectures in which i cover complete syllabus of signal and system mentioned GATE ECE 2018. more more video lectures subscribe our you tube channel ENGINEER TREE. if you have any queries or doubt than you can post it in to our Facebook group, to join our Facebook group link given below in description.





To like us on Facebook page  click here

To join our Face book group  click here 

To follow as on Twitter  click here

To subscribe our YouTube channel click here



Fourier series


In communication system Fourier series is tool which is use to decompose continuous periodic into its sinusoidal component. or we can say it decompose any periodic function or periodic signal into the sum of sin and cosine waves. by our video given above you can get clear idea how it decompose periodic function into sum of sin and cosine wave.

Types of Fourier Series

  • trigonometric or quadrature Fourier Series
  • polar Fourier Series
  • Exponential Fourier Series


Dirichlet condition

  • f(t) should be deterministic in -T/2 ≤ f(t) + T/2
  • Finite number of discontinuities
  • Finite number of minima and maxima
  • f(t) must be absolute integral over period T


important points 


Case 1.  when f(t) is even signal

  • for even signal only cosine functions are present (a0,an ≠ 0) (bn = 0)
  • for odd signal only sin functions are present (a0,an = 0) (bn ≠ 0)


Case 2. when f(t) is half wave symmetry

 f(t) = -f(t ± T/2) 

  • for half wave symmetry only odd harmonics present
  • in Fourier series on sin term with odd harmonics present


Case 3. when f(t) is full wave symmetry 

   f(t ± T/2) = f(t)

  • for full wave symmetry only even harmonics are present



To buy signal and system practice book by kanodia click here

To buy signal and system book by G.K. publication click here

To buy signal and system schaums outline click here

All books mentioned above is very good books for signal and system, we would recommend schoums outline for gate preparation, it is wonderful book to clear basic concepts.


keep visiting for more practice questions


Leave a Reply

Your email address will not be published. Required fields are marked *

error: Content is protected !!
No messages

January 26, 2020

No messages
Clear all