Filter Design

Syllabus

1. Introduction
   1. Filter, its evolution and importance
   2. Lowpass, highpass, bandpass, bandstop, allpass, passive and active filters
   3. Filter response: Ideal (Brick wall) response and practical response
   4. Filter parameters: Gain, attenuation, passband, stopband and transition band
   5. Filter transfer function, frequency response, poles, zeros and their roles
   6. Normalization and de-normalization in filter design
   7. Impedance (Magnitude) scaling and frequency scaling
2. Approximation Methods
   1. Approximation and its importance in filter design
   2. Low pass approximation methods
   3. Butterworth approximation
   4. Chebyshev (Chebyshev type I) approximation
   5. Inverse Chebyshev (Chebyshev type II) approximation
   6. Cauer (Elliptic) approximation
   7. Bessel-Thomson response
   8. Delay equalization
3. Frequency Transformation
   1. Frequency transformation and its importance in filter design
   2. Low pass to high pass transformation
   3. Low pass to band pass transformation
   4. Low pass to band stop transformation
4. Properties and Synthesis of Passive Networks
   1. One-port passive circuits: properties, positive real functions, lossless functions, synthesis of LC one-port circuits, Foster and Cauer realizations, RC one-port functions
   2. Two-port passive circuits: properties, residue condition, zeros of transmission, zero shifting by partial removal of a pole, synthesis of two port LC and RC ladder circuits
5. Design of Resistively-Terminated Lossless Filters
   1. Properties of resistively-terminated lossless ladder circuit, transmission and reflection coefficients
   2. Synthesis of LC ladder circuits to realize all-pole low pass functions and functions with finite transmission zeros
6. Design of Active Filters
   1. First order active filters (Bilinear)
   2. Second order active filters (Biquads): Tow-Thomas and Sallen-Key biquad circuits
   3. Higher order active filters: cascade of biquads, simulated inductors, gyrator and GIC, FDNR, leapfrog simulation of LC ladders
7. Sensitivity
   1. Sensitivity and importance of sensitivity analysis
   2. Single parameter sensitivity
   3. Centre frequency and Q-factor sensitivity
   4. Sensitivity of biquads and passive filters
8. Other Filters
   1. Switched Capacitor Filters
   2. Current mode filters
   3. Adaptive Filters
   4. Current Conveyors