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 beable 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”

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 Tow-Thomas 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-13 978-0-19-510734-0.

[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 130%

Exam 230%

Final Exam30%

Homework10%

Total100%

Grade Assignment: The following grade thresholds are used:

90% - 100%: A

80% - 89%:B

70% - 79%:C

60% - 69%:D

0% - 59%: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 identificationinformation. Such information may include, but is not limited to: the courseabbreviation, course number and section; first and last names of individual(s)receiving credit for the assignment; and the assignment identifier (name and/ornumber). Multiple page hard copy submissions must be stapled or firmlyattached 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 theinstructor before the relevant deadline. Electronic submissions must be date andtime stamped as received before the relevant deadline. Absolutely no materialwill be accepted for credit after the posted deadline.
  • Submissions must be professional in appearance; i.e., not illegible, illogical, orwith missing information. Failure to comply with these guidelines will result insignificant 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 anabsence will occur during a scheduled exam, it is the responsibility of thestudent 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 toas soon as possible. It is the responsibility of the individual student to arrangean appointment with the instructor in a timely manner if unable to meet duringregularly scheduled hours.
  • It is the responsibility of each student to read his or her uncc email andregularly check the Moodle course site. In accordance with University policy, Iwill only respond to email from uncc.edu accounts.
  • Attendance is not mandatory, but students are responsible for all material andassignments provided during class. No accommodations will be made forstudents not in attendance with respect to homework submission, makeupquizzes or tests, handouts, or course notes. Students who are chronically latewill 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 exams. Those not heedingthis rule will be asked to leave the classroom immediately so as to not disruptthe learning environment and will not be allowed reentry during the classsession. If an emergency phone call is expected, the instructor must be notifiedbefore the beginning of class.
  • The instructor reserves the right to modify information contained in thisdocument.

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 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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