freqz
freqz(b, a)
freqz(b, a, w)
Try it yourself:
| $1 |
freqz([1, 2], [1, 2, 3])
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| $2 |
freqz([1, 2], [1, 2, 3], [0, 1])
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| $3 |
freqz([1, 2], [1, 2, 3], 512)
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