05-18-2018 11:35 AM
I am designing a digital FIR filter with using the DSP ip core, 50 coefficients. The filter works fine, the cut off frequency is what it supposed to, the problem I am having, is that if I increase the amplitude of my input signal too much, such as the signal will saturate, the output of the filter stays in the previous value, it is like the system will want to prevent saturation or overflow. Is this the case?
05-18-2018 11:47 AM
Did you specify "Maximum Dynamic Range" in the coefficient quantization options? This prevents overflow internally.
05-18-2018 12:24 PM
It's kind of hard to explain the FIR Compiler output, since it doesn't exactly give you source code to play with.
Try this filter I wrote here:
Plug in your floating point coefficients, and it won't overflow.. Promise. It scales the coefficients so that it has unity gain at the frequency with the highest response, using the sum of the absolute value of the coefficients.