Siva, The ADS131E08 is a delta-sigma or oversampling type of converter. This means that the device samples the input many times to give an output data. The ADC input samples at the modulator rate (given by fMOD - which is fCLK/2 or 1.024MHz). These many samples are digitally filtered to give a data rate lower than the sampling rate. For the setting of DR[2:0]=011, the oversampling ratio is 128, which gives a data rate of 8kSPS. This digital filtering also has a frequency response where the input signal continues to attenuate beyond the data rate frequency. You can see the frequency response on page 25 of the datasheet. To prevent aliasing, you need to create a filter that goes out to fMOD/2, not fDATA/2. For this device, it would be out to about 500kHz. Joseph Wu
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