hi forum-
i'm not much of an engineer or mathematician, but i've become interested in filters for audio purposes. i've read a bit and built a bit, but there are some things that evade me. i was hoping some folks here could explain a few things so that a simpleton might understand them. i will review the ESP page more: http://sound.westhost.com/articles/active-filters.htm
let me see if i'm on the right track - please don't hesitate to correct me:
firstly, my understanding is that there are 5 primary "ideal" categories of analog filters. low-pass, band-pass, high-pass, band-reject (notch), and all-pass.
there is a lot of talk of "filter responses" - these responses are graphed according to higher-level mathematic theory - and they include things like the chebyshev, butterworth, and bessel. i think that these responses can be applied to any of the primary categories (with the possible exception of all-pass), but i'm not totally sure about that point. is there a compilation and summary of all the most popular responses? are there definitive translations of these responses into topologies?
now, these "responses" are neither active nor passive. they're conceptual. i believe they are derived via "transfer function", which involves "polynomials" - but i don't really understand how that stuff works...is there an ultra-basic introduction to that kind of material?
from there, active and passive filters generally refer to specific circuit topologies... there are many. i'm unclear which things are "fixed" and which things are "theoretical." for instance, are there multiple topologies of a state-variable filter?
i notice a lot of the equations for these circuits deal with q and cutoff frequency..usually a ratio-metric relationship...but i am curious about how a filter designer might begin to deal with things like transient response and "ripple" in her or his work.
thanks everyone - i apologize for the broadness.
i'm not much of an engineer or mathematician, but i've become interested in filters for audio purposes. i've read a bit and built a bit, but there are some things that evade me. i was hoping some folks here could explain a few things so that a simpleton might understand them. i will review the ESP page more: http://sound.westhost.com/articles/active-filters.htm
let me see if i'm on the right track - please don't hesitate to correct me:
firstly, my understanding is that there are 5 primary "ideal" categories of analog filters. low-pass, band-pass, high-pass, band-reject (notch), and all-pass.
there is a lot of talk of "filter responses" - these responses are graphed according to higher-level mathematic theory - and they include things like the chebyshev, butterworth, and bessel. i think that these responses can be applied to any of the primary categories (with the possible exception of all-pass), but i'm not totally sure about that point. is there a compilation and summary of all the most popular responses? are there definitive translations of these responses into topologies?
now, these "responses" are neither active nor passive. they're conceptual. i believe they are derived via "transfer function", which involves "polynomials" - but i don't really understand how that stuff works...is there an ultra-basic introduction to that kind of material?
from there, active and passive filters generally refer to specific circuit topologies... there are many. i'm unclear which things are "fixed" and which things are "theoretical." for instance, are there multiple topologies of a state-variable filter?
i notice a lot of the equations for these circuits deal with q and cutoff frequency..usually a ratio-metric relationship...but i am curious about how a filter designer might begin to deal with things like transient response and "ripple" in her or his work.
thanks everyone - i apologize for the broadness.