singh
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In the attached document for 2nd order sigma delta, we have used up down counter approach to implment filter section (page 738 and 739)
the filter stage1 after comparator 1 uses x = x + xx * (n - i +1) where xx is comp1 output and x is output of filter and 1<i <n
the filter stage2 after comparator 2 uses y = y + yy where yy is comp2 output and y is output of filter2 and from summation 1 to n
Now wat i interpret is that in filter 1 there are two stages in series of up-down counters and in filter2 there is only one stage of up down counter. what does this term (n - i +1) means what is the significance. Does it signify the order of filter? how to increase order of these two filters? How can i make the three stage filter from up down counter using above equations any clue about this will be helpful !!
thanks
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