Hello all,
I'm on a project designing a microphone with built-in filtering. We are simply looking to filter out any inaudible frequencies we record. That is, we're looking to design a bandpass filter for which the passband is 20Hz to 20kHz. The filter will be constructed with discrete components on a PCB.
I've been researching some bandpass design methods and wanted some advice on which to choose. We'd like this filter to be fairly selective, so we're hoping for a filter of about the 4th order. The #1 concern, though, is that the passband is as flat as possible.
Thanks in advance!
I'm on a project designing a microphone with built-in filtering. We are simply looking to filter out any inaudible frequencies we record. That is, we're looking to design a bandpass filter for which the passband is 20Hz to 20kHz. The filter will be constructed with discrete components on a PCB.
I've been researching some bandpass design methods and wanted some advice on which to choose. We'd like this filter to be fairly selective, so we're hoping for a filter of about the 4th order. The #1 concern, though, is that the passband is as flat as possible.
- One method would be to cascade 2 bandpass filters that are centered at my high and low cutoff frequencies. This sounds good, but it also looks like the passband's flatness becomes increasingly hard to maintain as the cutoff frequencies separate further.
- The other method that we're considering is just to cascade a low-pass and a high-pass filter (both 2nd- or higher-order) to achieve the bandpass effect. This sounds good to me too – and likely a lot simpler.
Thanks in advance!