Low pass filter, cut off 500 Hz, short response time...

[Viram]

I'm trying to design a LP-filter with a cut off at around 500 Hz. My
problem is getting a short response time and low/no resonance peak. What
order should the filter be? I'm currently trying with a simple
LC-filter...

 

[lloyd]

Viram escribió:

I'm trying to design a LP-filter with a cut off at around 500 Hz. My
problem is getting a short response time and low/no resonance peak. What
order should the filter be? I'm currently trying with a simple
LC-filter...

When you design a LP filter, actually you are limiting the response

time. For 500Hz the time constant is about 0.3 msec.
If you want to limit the resonance peac, you can share the capacitor in
some smaller parallel units and put one resistor in series with one of
them.

 

[Tam/WB2TT]

"Viram" <sorry@.no.spam> wrote in message
news:4c1688b723a5876fcffea18db84efe0f@localhost.talkaboutelectronicequipment.com...

I'm trying to design a LP-filter with a cut off at around 500 Hz. My
problem is getting a short response time and low/no resonance peak. What
order should the filter be? I'm currently trying with a simple
LC-filter...

Unless you like inductors the size of tuna cans, use an active filter.

(Except if you are building a speaker crossover filter).

Tam

 

[Rob Gaddi]

Tam/WB2TT wrote:

"Viram" <sorry@.no.spam> wrote in message
news:4c1688b723a5876fcffea18db84efe0f@localhost.talkaboutelectronicequipment.com...

I'm trying to design a LP-filter with a cut off at around 500 Hz. My
problem is getting a short response time and low/no resonance peak. What
order should the filter be? I'm currently trying with a simple
LC-filter...


Unless you like inductors the size of tuna cans, use an active filter.
(Except if you are building a speaker crossover filter).

Tam


I'll second that one. If you head over to TI's site and check their

analog knowledge base for a program called FilterPro it'll design RC
active filters for you up to 10 poles with either MFB or Sallen-Key
topologies. Though in my opinion they're far too conservative on the
gain-bandwith requirements of the op-amps.