Q.U.I.N.N. (npub1f8e…zu5u) npub1pu7tyn4lajv927jh9fr6z0w2nvqjscrjf55es0gu5xsgp2nes99qn6pdj6 (npub1pu7…pdj6) that "tan" bit looks like it came from a bilinear transform[1]. Many filters (such as Butterworth) are designed in the S-plane, then discretized to the Z-plane using the BLT.
Generally speaking, I believe the frequency response of most practical filters used in audio can be analytically derived using an equation. Things like non-linear filters are trickier. I think.
1: https://ccrma.stanford.edu/~jos/pasp/Bilinear_Transformation.html
paul /
npub1qw…daf8e
2023-05-19 12:06:26
in reply to nevent1q…x4pk
Author Public Key
npub1qwr4r239yquh0r8xdxk7va7p4gl0wlzc8q69x5vra2yh6jqzjmcq4daf8ePublished at
2023-05-19 12:06:26Event JSON
{
"id": "fd149efe38d384990fad34fc88574de5f6aa818741e296978c16cbae485e6374",
"pubkey": "038751aa252039778ce669ade677c1aa3ef77c583834535183ea897d480296f0",
"created_at": 1684497986,
"kind": 1,
"tags": [
[
"p",
"49f3a746c8d602bb57f2fbcbcec59910fc8742b2c71c4609b3091709fc2a2375",
"wss://relay.mostr.pub"
],
[
"p",
"0f3cb24ebfec98557a572a47a13dca9b012860724d29983d1ca1a080aa79814a",
"wss://relay.mostr.pub"
],
[
"p",
"6c067ee3395bf49d21504349d95f5fff5edf41ec64aa8951334e889dbaf8e31f",
"wss://relay.mostr.pub"
],
[
"e",
"dc2a8d28560402449a573a2774efc583fe643e479186dedce6ecc59cb2e2e501",
"wss://relay.mostr.pub",
"reply"
],
[
"mostr",
"https://post.lurk.org/users/paul/statuses/110395260020705300"
]
],
"content": "nostr:npub1f8e6w3kg6cptk4ljl09ua3vezr7gws4jcuwyvzdnpytsnlp2yd6savzu5u nostr:npub1pu7tyn4lajv927jh9fr6z0w2nvqjscrjf55es0gu5xsgp2nes99qn6pdj6 that \"tan\" bit looks like it came from a bilinear transform[1]. Many filters (such as Butterworth) are designed in the S-plane, then discretized to the Z-plane using the BLT.\n\nGenerally speaking, I believe the frequency response of most practical filters used in audio can be analytically derived using an equation. Things like non-linear filters are trickier. I think.\n\n1: https://ccrma.stanford.edu/~jos/pasp/Bilinear_Transformation.html",
"sig": "a5f1c5098f658204dce06692f0b5ada80a190e2bad9f031cf0087cf333e96184ecccb28a496089b318c473a6424194e4b0a11489c0c820217b507a6a98083754"
}