Flashcards on Digital Signal Processing with MATLAB and Python

Digital Signal Processing with MATLAB and Python Guide

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What is the bilinear transform function call in Python (scipy.signal) to convert an analog filter to a digital one?

[B_z, A_z] = bilinear(B_s, A_s, Fs)

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Digital Filter Design

66 cards

Card 1

Question: What is the bilinear transform function call in Python (scipy.signal) to convert an analog filter to a digital one?

Answer: [B_z, A_z] = bilinear(B_s, A_s, Fs)

Card 2

Question: In the bilinear transform function, what do B_s, A_s and Fs represent?

Answer: B_s and A_s are vectors of prototype numerator and denominator coefficients (highest order first); Fs is the sampling rate.

Card 3

Question: What is the general polynomial form of an analog prototype transfer function F(s) used for bilinear transform conversion?

Answer: F(s) = (b_N s^N + b_{N-1} s^{N-1} + ... + b_0) / (a_N s^N + a_{N-1} s^{N-1} + ... + a_0)

Card 4

Question: After applying bilinear transform, what is the form of the resulting digital transfer function G(z)?

Answer: G(z) = (b_N z^{-N} + b_{N-1} z^{-(N-1)} + ... + b_0) / (a_N z^{-N} + a_{N-1} z^{-(N-1)} + ... + a_0)

Card 5

Question: Which Python function produces the output signal for a designed digital filter given numerator and denominator coefficient vectors and an input signal

Answer: y = lfilter(B, A, x) from scipy.signal

Card 6

Question: Which MATLAB function gives the output signal for a digital filter given coefficient vectors and an input?

Answer: y = filter(B, A, x)

Card 7

Question: What implementation form is commonly used for online implementation of a digital filter and to derive difference equations?

Answer: Canonical form I (to derive a set of difference equations for online implementation)

Card 8

Question: What aspects of a second-order low-pass filter are varied when showing the analog filter frequency response in the content?

Answer: The quality factor Q is varied to show different frequency responses.

Card 9

Question: How does the unit impulse response of a second-order filter change with Q values shown?

Answer: High Q shows damped oscillations; at overdamping limit (double root) it shows critical damping; very low Q shows overdamped (no oscillation); very hig

Card 10

Question: Why is unit step response important in some design applications according to the content?

Answer: Unit step response is important for applications like designing automotive suspension systems.