# ELET4223 Active Filters

## SYLLABUS

## ERRORS IN TEXTBOOK

## HOMEWORK ASSIGNMENTS

*Important Note*: I do not accept late homework assignments, and Moodle will not let you submit them late. For homework due times, go to “Homework Submissions” on Moodle.You will notice that the due time is always 3 a.m. You are expected to submit the homework by midnight of the day before. The extra 3 hours until 3 a.m. is an “automatic extension” to let you deal with any technical difficulties you have submitting the homework (such as internet going down, scanner jammed, etc.)

Homework

# 1 :

*Op amps *

**Chapter 3**

Homework

# 2 ,

hints :

*Bode Plots*

**Chapter 4**

Homework

# 3 :

*Cascade design*

**Chapter 5**

Homework

# 4 :

*Biquad filters*

**Chapter 6**

Homework

# 5 :

*Butterworth filters part 1*

Homework

# 6 :

*Butterworth filters part 2(updated)*

**Chapter 7**

Homework

# 7 :

*Butterworth bandpass filters*

**Chapter 8**

Homework

# 8 :

*Chebyshev lowpass filters *

Homework

# 9 :

*Chebyshev bandpass filters *

**Chapter 12**

Homework

# 10 :

*Highpass filters*

Homework

# 11 :

*Bandstop filters*

## HANDOUTS

Semilog paper for Bode plots:

3 decades,

4 decades,

5 decades,

6 decades.

Tue Jan 10:

Lecture notes for today

Thu Jan 12:

Frequency Scaling Notes

Thu Jan 12:

Worked example of magnitude and frequency scaling

Thu Jan 12:

Example: Calculating T(s) of Circuit Containing Op Amps

**Chapter 4**

Thu Jan 12:

When Does Cascading Give T = T1 * T2 ?

Tue Jan 17:

Table 4.2

Tue Jan 17:

Table 4.3

Thu Jan 19:

Example 4.6

**Chapter 5**

Tue Jan 24:

Frequency response of Lowpass Biquad

Tue Jan 24:

Derivation of T(s) for Tow-Thomas Biquad Circuit

Tue Jan 31:

The 4-Op-Amp Biquad Circuit

Tue Jan 31:

Normalized 4-Op-Amp Tow-Thomas Biquad Circuit

Tue Jan 31:

Summary sheet: Tow-Thomas Biquad equations

**Chapter 6**

Tue Jan 31:

Symmetries of T(jw)

Thu Feb 2:

Table 6.1: Butterworth angles and pole locations

Thu Feb 2:

Table 6.3: Q of Butterworth poles

Tue Feb 7:

Derivation of T(s) for Sallen and Key Circuit

Tue Feb 7:

Lecture notes for today’s lecture

Thu Feb 9:

Derivation of T(s) for Resistive Gain Enhancement version of S&K Circuit

**Chapter 7**

Tue Feb 21:

Geffe Algorithm

Tue Feb 14:

Derivation of Geffe Algorithm

Tue Feb 21:

T(s) for Friend Circuit

Thu Feb 23:

|T(jw)| for normalized Friend Circuit

Thu Feb 23:

Example: Stagger Tuned Bandpass Filter Design

Tue Feb 28:

Q enhancement Of Friend Circuit

**Chapter 8**

Tue Feb 28:

Hyperbolic Trig Functions

Tue Feb 28:

Chebyshev functions

Tue Feb 28:

Chebyshev function to magnitude response

Tue Feb 28:

Chebyshev Response Ripples and DC Gain

Tue Mar 13:

Example 8.3

Thu Mar 15:

Example: Even order Chebyshev Lowpass filter

Tue Mar 20:

Example: Odd order Chebyshev Bandpass filter

Tue Mar 20:

Example: Even order Chebyshev Bandpass filter

(Corrected)

**Chapter 12**

Tue April 3:

Bainter Notch Circuit

Tue April 3:

Example 12.3 and 12.6 – Butterworth Band-Eliminate filter

Thu April 5:

Example 12.4 – Chebyshev Band-Eliminate filter

Thu April 5:

Boctor Lowpass Notch Circuit

Thu April 5:

Boctor Highpass Notch Circuit

Tue April 10:

Example 12.5 – Boctor Highpass Notch

Tue April 10:

Example 12.7 – Butterworth BEF using Boctor Notch circuit

Tue April 10:

Friend Lowpass Notch Circuit

Tue April 10:

Friend Highpass Notch Circuit

## EXTRA EXAMPLES

Here are some extra worked examples, in addition to those done in class and homework.

*Chapter 4*

Examples: Cascade design using Tables 4.2 and 4.3 (from Chapter 4 problems)

Examples: Going from circuit diagram to Bode plot (from Chapter 4 problems)

*Chapter 6*

Example: Butterworth Lowpass using S&Key K=1

Example: Butterworth Lowpass using S&Key K=2, with extra attenuation

Example: Butterworth Lowpass using (a) S&Key K=1 (b) S&K Resistive Gain Enhancement

*Chapter 7*

Example: Butterworth Bandpass for n=5

Example: Butterworth Bandpass for n=6

*Chapter 8*

Example: Chebyshev Lowpass for n=7

*Chapter 12*

Example: Butterworth Highpass, n=5

Example: Chebyshev Highpass, n=4

## COURSE PREREQUISITES: REVIEW NOTES AND EXAMPLES

Here are some notes and examples about some of the material that is prerequisite for ELET4223.

Study these to help make sure you are ready for the start of the course.

*Node Voltage*

The Node Voltage Method, plus Special Cases

**Op Amps**

How to Analyze Op Amp Circuits using Node Voltage

(Corrected)

Examples of Analyzing Op Amps by Node Voltage

**Bode Plots**

Building Blocks for Bode Plots

(Corrected)

Straight-Line Calculations on Bode Plots

Examples: Given T(s), draw Bode Plot (from Chapter 3 problems)

Examples: Given Bode Plot, find T(s) (from Chapter 3 problems)

More Bode Plot Worked Examples

## SCREWDOWNS

If I screw something up in class, here’s where I can “screw it down again”.

Thu Feb 9: I’m not satisfied with how I presented the RC-CR example (Problem 6.4) today, so here is

here it is

fully worked in detail.