Forum Post: RE: ADS1198: ADA1198 sampling rate variation and signal attenuation w.r.t. sampling rate

Hi Alex we tried changing sampling frequency to 500Hz and then reading the samples at 250Hz. it definitely improves the frequency response. now the -3dB frequency shifts from originally 65Hz to 130Hz that's that good improvement. however, we have seen some strange issue with output signal quality. i input the pure sinusoidal wave and varied the frequency from 1Hz to 500Hz. at input frequencies which are integral divisor of 500Hz, e.g. 250Hz, 125Hz, etc the shape of the signal really goes bad, looks like it brings aliasing effect or introduces some harmonics of the input or sampling frequency to the oroginal signal. any solution?