i am designing a system where i have to pass some strict frequency mask tests on the analog audio inputs/outputs. These tests include unwanted signals that are not within the first nyquist zone of an 192 kS/s ADC and therefore need to be attenuated somewhere. To get an understanding of what anti-aliasing/reconstruction filter i have to provide external to the ADAU1372 i have some questions:
- What is the sample rate of the delta-sigma ADC/DAC? (not the sample rate i get on the serial ports) From the following datasheet plot and from the fact that is is a delta-sigma converter i assume that the sampling frequency is (much) higher than 192 kS/s because otherwise the decimation filter could not provide attenuation at frequencies above 96 kHz.
- Can you provide the decimation filter-response up to the nyquist-frequency of the ADC/DAC?
- Are there any analog anti-aliasing or reconstruction-filters inside the ADAU1372?