QI would like to use your analog front-end AD8283. However, i am facing some
problems looking at the datasheet. The filter cut-off frequency can not be set
exactly to the sample rate / 2 via the register 'FLEX_CHANNEL_INPUT'. Is it
correct and is it done on purpose? Please could you clarify this?
AYou are correct in that there is not fs/2 setting. Settling the cutoff at
exactly fs/2 would result in aliasing of the frequencies just above fs/2 so the
settings we have in the AD8283 are built with some margin in them. The filter
can be manually tuned using the engineering registers to any frequency between
1MHz and 12 MHz (+/-10%). I have attached instructions on how to do this.