ELET4223: Active Filters
Spring 2012
Department of Engineering Technology
The University of North Carolina at Charlotte
Instructor: Dr. Barry Sherlock
Office:
Smith 338
Phone:
(704) 687-2722
Office Hours: TBD
Pre-Requisite:
ELET3222: Electronics II
ETET3113: Network Analysis
ETGR3171: Engineering Analysis I
Catalog Description: This course involves the design, analysis, simulation and implementation
of composite, cascaded and summation filters. Topics include bilinear transfer functions; cascade
design with first-order circuits; biquad circuits; Butterworth lowpass circuits; Butterworth
bandpass circuits; the Chebyshev response; sensitivity; frequency transformations; highpass and
band-elimination filters. This course meets for three (3) lecture hours per week. Three (3) credit
hours.
Course Outcomes: Upon successful completion of this course, students will be able to:
1. Design and analyze filters making use of bilinear transforms.
2. Design active filters by cascading first-order circuits.
3. Demonstrate an understanding of the design and analysis of active filters using the biquad
circuit.
4. Design filters having a lowpass Butterworth response
5. Design filters having a bandpass Butterworth response.
6. Design lowpass and bandpass filters having a Chebyshev response.
7. Perform sensitivity analysis upon a given active filter circuit.
8. Make use of frequency transformation methods to convert prototype lowpass filters into
highpass, bandpass or band-reject filters.
Course Learning Outcomes support achievement of Program Outcome 4: Generate creative and
realistic solutions to defined problems and projects in electrical engineering technology
specifically sub-outcomes
 ELET 4ii: Solve technical problems to satisfy a given set of specifications and
 ELET 4iii: Develop alternate strategies to solve open-ended problems
The outcomes of this course support Program Outcome 4 and are mapped to the following TAC
of ABET Criterion 3 requirements which state that “An engineering technology program must
demonstrate that graduates have: (d) an ability to apply creativity in the design of systems,
components or processes appropriate to program objectives, and (f) an ability to identify, analyze
and solve technical problems”
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Class Topics: The following topics will be investigated in detail:
 Types of Filters: Characteristics and specifications for lowpass, highpass, bandpass, band
reject, and allpass filters.
 Scaling of Circuit Elements: Frequency and Magnitude Scaling of R, L and C elements.
 Cascade Design with First Order Circuits: The bilinear response, When cascading is
permitted, Inverting op-amp circuits, Non-inverting opamp circuits, cascade design.
 The Biquad Circuit: The biquadratic response, Design of each filter type using the TowThomas biquad circuit.
 Butterworth Lowpass Filters: Butterworth response, Butterworth pole locations, the
Sallen and Key circuit, Resistive gain enhancement, RC-CR transformation.
 Butterworth Bandpass Filters: Frequency transformation, the Geffe algorithm, the
Delyiannis-Friend circuit, stagger-tuned bandpass filter design, Q enhancement.
 The Chebyshev Response: Chebyshev response, Chebyshev pole locations, Guillemin’s
algorithm, Chebyshev filter design.
 Sensitivity: Bode sensitivity, Sensitivity analysis, sensitivity of magnitude of T(jω).
 Frequency Transformations: Transformation of prototype response, Foster reactance
functions, transformations from lowpass to bandpass, highpass and bandstop,
transformations of LC circuits, multiple passband transformations.
 Highpass and Band-Elimination Filters: lowpass to highpass transformation, pole
reciprocation, notch filters, generalized notch filters, notch filter design using Bainter,
Boctor and modified Friend circuits.
Textbook:
Analog Filter Design, M. E. Van Valkenburg, ISBN 0-03-059246-1, ISBN-13 978-0-19-5107340.
[Caution: This is NOT the book with a very similar title by Schaumann and Van Valkenburg,]
Examinations: Three 50-minute examinations will be given during the course with the third
given during final exam week. The first two exams are non-comprehensive.
Homework: Homework assignments will be given. These will be graded and will count towards
the final grade for the course. No late homework will be accepted for any reason whatsoever,
including excused absence. In special cases due to excused absence, assignments may be
reviewed by the instructor, but no credit will be given. If you miss a class, you are still
responsible to get and/or turn in any assignments on time. Homework assignments must be
submitted via Moodle, and must be in PDF file format.
Grade calculation:
Exam 1
Exam 2
Final Exam
Homework
Total
30%
30%
30%
10%
100%
Grade Assignment: The following grade thresholds are used:
90% - 100%: A
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80% - 89%:
70% - 79%:
60% - 69%:
0% - 59%:
B
C
D
F
Course/Instructor Policies:
 It is the responsibility of each student to ensure that he or she has successfully completed all
course prerequisites and possesses the necessary background to successfully complete the
current course. It is the responsibility of each student to recognize any potential deficiencies
or problem areas and make arrangements with the instructor for additional assistance.
 Students are encouraged to work on homework assignments in groups; however, each student
must submit an individual homework submission. The content of the submission is entirely
the individual student’s responsibility.
 All material submitted for credit must contain all relevant identification information. Such
information may include, but is not limited to: the course abbreviation, course number and
section; first and last names of individual(s) receiving credit for the assignment; and the
assignment identifier (name and/or number). Multiple page hard copy submissions must be
stapled or firmly attached within a report binder. Failure to comply with all requirements will
result in a zero for the submission.
 Any material submitted for credit must be received and acknowledged by the instructor
before the relevant deadline. Electronic submissions must be date and time stamped as
received before the relevant deadline. Absolutely no material will be accepted for credit after
the posted deadline.
 Submissions must be professional in appearance; i.e., not illegible, illogical, or with missing
information. Failure to comply with these guidelines will result in significant point
deductions for each violation.
 There is a possibility of proctor fees for Distance Learning students who need to use a
proctor. The UNC Online Proctoring Network includes proctors who do not charge as well
as proctors who do charge for their proctoring service. Students are responsible for payment
of any proctoring fees if they choose to use a proctor who charges a fee for this service.
 Makeup exams will not be given except under extraordinary circumstances. If an absence
will occur during a scheduled exam, it is the responsibility of the student to make
arrangements to take the exam before the scheduled date. Emergency absences must be fully
documented before a makeup will be given. Note: Any make-up exam will have a greater
level of difficulty than the original exam.
 Phone calls will not be returned; however, email messages will be responded to as soon as
possible. It is the responsibility of the individual student to arrange an appointment with the
instructor in a timely manner if unable to meet during regularly scheduled hours.
 It is the responsibility of each student to read his or her uncc email and regularly check the
Moodle course site. In accordance with University policy, I will only respond to email from
uncc.edu accounts.
 Attendance is not mandatory, but students are responsible for all material and assignments
provided during class. No accommodations will be made for students not in attendance with
respect to homework submission, makeup quizzes or tests, handouts, or course notes.
Students who are chronically late will be asked to leave the class until the next class session.
 Per university policy, mobile phones, pagers, etc. must be silenced during all lectures and
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
exams. Those not heeding this rule will be asked to leave the classroom immediately so as to
not disrupt the learning environment and will not be allowed reentry during the class session.
If an emergency phone call is expected, the instructor must be notified before the beginning
of class.
The instructor reserves the right to modify information contained in this document.
Academic Integrity:
All students are required to know, observe and enforce the guidelines set forth by the UNC
Charlotte Code of Student Academic Integrity, which may be found the web at
http://www.legal.uncc.edu/policies/ps-105.html. It should be noted that this Code may be
modified and that students are encouraged to contact the Office of the Dean of Students to ensure
they consult the most recent version. This code forbids cheating, fabrication or falsification of
information, multiple submissions of academic work, plagiarism, abuse of academic materials,
and complicity in academic dishonesty. Students should pay particular attention to the standards
involving Complicity and Plagiarism. A complete definition of all terms and a delineation of
procedures to be followed for alleged violations may be found in the complete text of the Code at
the website referenced above.
For this course, students are strongly encouraged to discuss concepts and techniques; however,
with the exception of designated assignments, all material submitted for a grade must be
individual work. The submission of another student’s work, whether written materials or
computer simulation results, will not be tolerated under any circumstances.
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