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Mail Spam Filter

A mail spam filtering solution implemented in Matlab.

PDF is in Greek only. If I get enough requests I may be persuaded to translate it in English.


Github repository link.

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Butterworth, Sallen-Key & Chebyshev Filter Analysis, Design and Synthesis

I separate the implementation in several parts as outlined below.

Part A.
A1. Design a normalized low-pass filter with Butterworth response, cutoff rate equal to 18dB/octave and maximum allowed gain deviation in the pass region equal to amax = 1.5 dB.
A2. Implement the normalized filter by connecting in cascade multiple sections. All capacitors must be identical. For the implementation of the second section, use a Sallen-Key filter with identical resistors and identical capacitors (Design II).
A3. Depict the logarithmic gain curve as calculated from the transfer function of the design along with the transfer function of the circuit.
A4. Denormalize the circuit such that the cutoff frequency become f
c = 1.6 kHz and the resisters be at their normal values with dimensions. Sketch the logarithmic gain curve of the denormalized circuit given frequency f (logarithmic axis)....