Hi,

I would like to design a BPF using ADI filter wizard.

The spec are shown as following.

1.Passband : 100 ~ 3500Hz, -0.3dB, Center Frequency = 1800Hz

2.Low pass filter, cut off frequency : 40KHz, -40dB

3.High pass filter, cut off frequency : 16Hz, -40dB

I perform a example:

https://dl.dropboxusercontent.com/u/26562552/DesignFiles.zip

But it seems the high pass cut off freq cannot achieve 16Hz.

Could someone help me to check it?

Thanks.

Hi Jay,

The filter wizard let's you set the passband bandwidth, the stopband bandwidth, and the center frequency. To set the -40 dB frequencies, do the following:

center frequency should be the geometric mean of your two cutoffs:

center frequency = sqrt(16 * 40k) = 800 Hz

stopband bandwidth should be the result of the subtraction of the two cutoffs:

stopband bandwidth = 40k - 16 ≈ 40kHz

Matt