Category: DSP
Tools: Quartus® Prime / Quartus II
device:-


Although it depends on the design specifications, the following countermeasures are available.

• Method 1

Change the sampling clock of the filter to a slower speed than the operating clock

For example, if you set both the operating clock and sampling clock to 100MHz and encounter a fitting error:

Clock Rate: 100
Input Sample Rate (MSPS): 100

In this case, changing the sampling clock to 200 kHz as follows will eliminate the fitting error.

Clock Rate: 100
Input Sample Rate (MSPS): 0.2

The filter's sampling clock is slow enough compared to the operating clock to allow sharing of a minimal number of DSP blocks in a time division manner.

• Method 2

Change to Symmetrical

If the filter coefficients are symmetrical, changing the pull-down menu in the Symmetrical column of the Coefficients tab to Symmetrical halves the number of taps and, as a result, halves the number of DSP blocks used.