I have two signals, $d(t)$ and $p(t)$, respectively the input and the output of the matching filter $w(t)$, i.e. $$ d(t)*w(t)=p(t) $$ where $*$ denotes convolution.The impulse response $w(t)$ may be calculated by going into the frequency domain: $$ w(t)=F^{-1}\left[\frac{F[p(t)]\overline{F[d(t)]}}{F[d(t)]\overline{F[d(t)]}+\epsilon}\right] $$ How can I get the derivative of the the filter $w(t)$ with respect to $p(t)$, i.e. $$\frac{\partial{w}}{\partial{p}}=?$$