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Lab 2 – Comments

Filter Design  (from TA Matt Lam)




• A few students asked me for more information about high performance filters in class yesterday.  I pointed a few of them to this handbook published by Analog Devices:
• http://www.analog.com/library/analogDialogue/archives/39-05/op_amp_applications_handbook.html
• The second part of Chapter 5 covers filter realizations (in particular 5-6 gives a bunch of designs for active high-, low- and band-pass filters), but the best part is pp 5.81 to 5.100 where they give diagrams and design equations for a bunch of topologies.
• For this class, the Sallen-Key and Multiple Feedback bandpass topologies look good: They are single-amplifier, second-order and are still simple enough for the students to derive the transfer function on their own. Also, the design rules are simple — however, the fact that the various circuit parameters (midband gain, Q and center frequency) can’t be independently tuned makes this a bit more complicated…for that, however, one would need to build a state-variable or biquad and those take 4 amplifiers to do the same job.