MATLAB: Fdatool to fpga

Question

I used fdatool to create VHDL of a lowpass fir filter with Fpass 1KHz and and Fstop 2KHz with sampling freq 20kHz.

I have a 12 bit ADC/DAC with a range from about -1.5V to 1.5V or -2048 to 2048 in signed binary. When I quantize the filter should I make the fraction length 0 so I get the +-2048 range or 10 so I get a range of +- 4V?

I am using a function generator for the input to the ADC.

Answer 1

When you select the 'Set quantization parameters' tool in FDATOOL, in the 'Coefficients' tab, I would recommend checking the 'Best precision fractional length' checkbox. In the 'Input/Output' tab, you can set the 'Input range' to 1.5 V. I think that letting FDATOOL compute the best fractional length is the right way to go.