EE-221-L Electrical Network Analysis Lab
PROBLEM BASED LEARNING (PBL)
Submitted By
Name
Reg No
21-EE-16
21-EE-36
21-EE-44
21-EE-48
21-EE-164
Adil Bhatti
Zulkaif Sajjad
Hajra
Ariba Ziafat
Isha Arain
Section: D1
DEPARTMENT OF ELECTRICAL ENGINEERING
UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA
Submitted On:15th June 2023
Task Description:
Design a software based higher-order bandpass filter for a wireless
communication system. The filter should allow signals with frequencies
between 50 GHz and 75GHz to pass through while blocking signals outside
thisrange.
INTRODUCTION TO BANDPASS FILTER:
A bandpass filter is a type of electronic filter that allows signals within a certain
frequency range to pass through while blocking signals outside that range. A
higher-order bandpass filter is a filter with a steeper roll-off than a first-order
filter, which means it can more effectively suppress unwanted signals outside
the passband.
A higher-order bandpass filter can be designed using multiple stages of filters,
each with a specific cutoff frequency and damping ratio. The overall filter
response is the combined response of all the stages.
Higher-order bandpass filters find applications in various fields such as audio
signal processing, telecommunications, and biomedical engineering. For
example, in audio signal processing, higher-order bandpass filters can be used
to eliminate background noise and enhance speech signals in hearing aids and
communication devices.
In telecommunications, higher-order bandpass filters can be used to improve
signal quality and reduce interference from adjacent channels. They can also be
used in radar systems to filter out unwanted signals from the environment and
detect specific signals of interest.
In biomedical engineering, higher-order bandpass filters are used to filter out
unwanted noise in biological signals such as electroencephalography (EEG)
and electrocardiography (ECG) signals. These signals are often contaminated
with noise from surrounding electrical equipment and filtering them out is
critical to accurately diagnose medical conditions.
Overall, higher-order bandpass filters are essential components in various
electronic systems where the precise control of signal frequency is critical
Characteristics:
To design the filter, you need to use an RLC circuit with a higher order than a
simple first-order filter. The circuit must have the following characteristics:
 The cutoff frequencies of the filter must be 1 kHz and 5 kHz.
 The filter must have a steep roll-off with a minimum attenuation of 60
dB/decade.
 The filter must be designed to operate with a maximum voltage of 10 V and
a maximum current of 5 mA.
 The filter must be designed to operate within safe and reliable limits.
Steps to Design:
To Design the higher-order bandpass filter with the given specifications, the
following steps can be followed:
1. Determine the filter order: In this case, the filter order is higher than a
simple first-order filter. A higher-order filter is required to achieve the
steep roll-off and narrow bandpass characteristic. Based on the
requirements, a third-order filter may be suitable for this application.
2. Choose a filter topology: There are different filter topologies that can be
used, such as Butterworth, Chebyshev, and Bessel. Each topology has its own
characteristics and tradeoffs, and the choice depends on the specific application
requirements. In this case, a Butterworth topology may be suitable as it provides
a maximally flat response in the passband.
1. Calculate the component values: The filter component values can be
calculated based on the cutoff frequencies and the filter topology. For a
third-order Butterworth filter, the component values can be calculated
using the following equations:

Resistor: R1 = R2 = R3

Capacitor: C1 = C3 = 1/(2πfc)

Inductor: L2 = L3 = R/(2πfc)
Where fc is the cutoff frequency and R is the resistor value.
Using the given cutoff frequencies of 50 KHz and 75 KHz, the component
valuescan be calculated.
2. Evaluate the filter performance: Once the component values are
determined, the filter can be simulated using circuit analysis software to
evaluate its performance under different signal conditions. The simulation
should confirm that the filter meets the given requirements in terms of the
passband and stopband characteristics, attenuation, maximum voltage,
and current limits.
3. Optimize the filter design: Fine-tune the filter parameters, such as cutoff
frequencies and damping ratios, to optimize its performance. This may
involve adjusting coefficients or other parameters in the filter algorithm
to achieve the desired frequency response and roll-off characteristics.
4. Present the design and results: Finally, a detailed report should be
prepared that outlines the filter design, calculations, simulation results and
performance evaluation. The report should also include recommendations
used, such as Butterworth, Chebyshev, and Bessel. Each topology has its own
characteristics and tradeoffs, and the choice depends on the specific application
requirements. In this case, a Butterworth topology may be suitable as it provides
a maximally flat response in the passband.
5. Calculate the component values: The filter component values can be
calculated based on the cutoff frequencies and the filter topology. For a
third-order Butterworth filter, the component values can be calculated
using the following equations:

Resistor: R1 = R2 = R3

Capacitor: C1 = C3 = 1/(2πfc)

Inductor: L2 = L3 = R/(2πfc)
Where fc is the cutoff frequency and R is the resistor value.
Using the given cutoff frequencies of 50 KHz and 75KHz, the component
valuescan be calculated.
6. Evaluate the filter performance: Once the component values are
determined, the filter can be simulated using circuit analysis software to
evaluate its performance under different signal conditions. The simulation
should confirm that the filter meets the given requirements in terms of the
passband and stopband characteristics, attenuation, maximum voltage,
and current limits.
7. Optimize the filter design: Fine-tune the filter parameters, such as cutoff
frequencies and damping ratios, to optimize its performance. This may
involve adjusting coefficients or other parameters in the filter algorithm
to achieve the desired frequency response and roll-off characteristics.
8. Present the design and results: Finally, a detailed report should be
prepared that outlines the filter design, calculations, simulation results and
performance evaluation. The report should also include recommendations
for the implementation of the filter in the wireless communication system
and any potential tradeoffs or limitations of the design.
PSPICE CIRCUIT:
WAVEFORM:
CONCLUSION:
In this project we learnt to operate and simulate 3rd
order band pass filter for wireless communication of frequency
range 50 KHz to 75 KHz.