Hi guys
I'm trying to design a 4th order butterworth filter with fc = 30khz. It's for a loop filter in a Class D amplifier. I want to use a series of 4 integrators to implement the filter. I don't have any software filter package, so by hand I have computed the following Rs on the inverting input of the respective 4 integrators:
R1 = 8.2Kohm
R2 = 27Kohm
R3 = 22Kohm
R4 = 39Kohm
I'm using a 0.01uF cap on the negative feedback path (from the output to the inverting input).
Can someone help me verify that this will in fact have filter response with fc = 30Khz? Or just as well, can someone give me the Rs and Cs for a 4th order butterworth with Fc = 30Khz?
Thanks for the help
I'm trying to design a 4th order butterworth filter with fc = 30khz. It's for a loop filter in a Class D amplifier. I want to use a series of 4 integrators to implement the filter. I don't have any software filter package, so by hand I have computed the following Rs on the inverting input of the respective 4 integrators:
R1 = 8.2Kohm
R2 = 27Kohm
R3 = 22Kohm
R4 = 39Kohm
I'm using a 0.01uF cap on the negative feedback path (from the output to the inverting input).
Can someone help me verify that this will in fact have filter response with fc = 30Khz? Or just as well, can someone give me the Rs and Cs for a 4th order butterworth with Fc = 30Khz?
Thanks for the help
Hi the Anonumous1
thanks for the pointer. that site focuses on passive filters whereas i'm building an active filter. however, i didn't realize there were free tools to be had out there, and I found one on the analog devices site from national instruments, where I can simulate what I plan to build (I am using an ADI differential op amp). I'll let everyone know what I find out about the tool -- I'm a newbie so maybe not so interesting, but I'll but it out there anyway 😉
thanks for the pointer. that site focuses on passive filters whereas i'm building an active filter. however, i didn't realize there were free tools to be had out there, and I found one on the analog devices site from national instruments, where I can simulate what I plan to build (I am using an ADI differential op amp). I'll let everyone know what I find out about the tool -- I'm a newbie so maybe not so interesting, but I'll but it out there anyway 😉
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