Hi,

How do I calculate the cutoff frequency of the sinc3 filter of the AD7730? I suppose it is linked to the "Output Rate".

I want to use the following settings: "Nonchop Mode" and "Skip ON" (so no active FIR filter).

Regards,

Philippe

Hi Philippe,

Sorry for the delayed response.

The cutoff frequency of the sinc3 filter when the FIR filter is not used is 0.272 x Fadc where Fadc is the output data rate.

For Nonchop mode, the cutoff frequency would be equal to

0.272 x (fCLK IN/16) x (1/SF)

where SF is the decimal equivalent of the data loaded to SF bits in the Filter Register and fCLK IN is the master clock frequency.

RC

Hi Philippe,

Sorry for the delayed response.

The cutoff frequency of the sinc3 filter when the FIR filter is not used is 0.272 x Fadc where Fadc is the output data rate.

For Nonchop mode, the cutoff frequency would be equal to

0.272 x (fCLK IN/16) x (1/SF)

where SF is the decimal equivalent of the data loaded to SF bits in the Filter Register and fCLK IN is the master clock frequency.

Regards,

RC