My question is about the Xilinx DDS
you can find it's details in this link https://www.xilinx.com/support/documentation/ip_documentation/dds_ds558.pdf
my question is:
A hi resolution phase accumulator is used and then the phase is Quantized to low resolution before using it for the sine look up table,
Why We use high resolution Accumulator and then quantize it to low resolution?
why don't use a low resolution accumulator?
Your answer is clear ,
but to rephrase my question
Didn't we lose the high resolution of the high resolution accumulator- which gives us very precise frequency control- when we quantize it down to low resolution output after the quantizer?
as the quantizer output is what's used to address the lookup table?
You still get the same very precise frequency control even if you connect only some of the phase accumulator bits to the sine ROM. The phase accumulation process determines the frequency, and that's unaffected by how many of its bits you connect to the sine ROM.