PPT - Frequency domain Analysis and Bode Plot - Electrical Engineering (EE) PDF Download

 Page 1


Frequency domain Analysis
Page 2


Frequency domain Analysis
Introduction
? Time-Domain analysis:
Impulse, unit step, ramp, etc. are used as 
input to the system
? Frequency-Domain Analysis:
Frequency Response of a system is the
response of the system for sinusoidal input
signal of various frequencies
Page 3


Frequency domain Analysis
Introduction
? Time-Domain analysis:
Impulse, unit step, ramp, etc. are used as 
input to the system
? Frequency-Domain Analysis:
Frequency Response of a system is the
response of the system for sinusoidal input
signal of various frequencies
Frequency Response
Linear 
System
X(t)= Xsin(?t)
Y(t)=ßXsin(?t+f)
Page 4


Frequency domain Analysis
Introduction
? Time-Domain analysis:
Impulse, unit step, ramp, etc. are used as 
input to the system
? Frequency-Domain Analysis:
Frequency Response of a system is the
response of the system for sinusoidal input
signal of various frequencies
Frequency Response
Linear 
System
X(t)= Xsin(?t)
Y(t)=ßXsin(?t+f)
Need
• Extraction of Transfer function from Time domain is 
difficult using differential equations
• Using Frequency Response, Transfer Function can be 
easily obtained from the experimental data
• A system may be designed, so that effects of noise are 
negligible
• Analysis & Design are extended to certain non-linear 
control systems
• The design of controller can be easily done in the 
frequency domain method, as compared to time-
domain method
Page 5


Frequency domain Analysis
Introduction
? Time-Domain analysis:
Impulse, unit step, ramp, etc. are used as 
input to the system
? Frequency-Domain Analysis:
Frequency Response of a system is the
response of the system for sinusoidal input
signal of various frequencies
Frequency Response
Linear 
System
X(t)= Xsin(?t)
Y(t)=ßXsin(?t+f)
Need
• Extraction of Transfer function from Time domain is 
difficult using differential equations
• Using Frequency Response, Transfer Function can be 
easily obtained from the experimental data
• A system may be designed, so that effects of noise are 
negligible
• Analysis & Design are extended to certain non-linear 
control systems
• The design of controller can be easily done in the 
frequency domain method, as compared to time-
domain method
Specifications
1. Resonant Frequency ( ?r):
The frequency at which the system has 
maximum magnitude is known as the 
resonant frequency. At this, the slope of 
magnitude curve is zero
2. Resonant Peak (Mr):
Maximum value of magnitude. 
Mr= 1- 1.5