Newbie level 5
I am designing a 21bit sigma delta modultor, i want to according to decimate the frequence by sinc3 filter. Now, i want to make the SINC exports 21bit data (input data is onebit) , i need use decimte sample is 128. BUT my quesion is if input data is onebit, using decimte sample=128, the output is 7bit, how i get 21bit data? left shift 14bit??? but the export data by this way is correct? could it make sure the adc's precision?