A low-pass filter having a frequency response $\mathrm{H}(\mathrm{j} \omega)=\mathrm{A}(\omega) \;e^{j{\phi(\omega)}}$ does not produce any phase distortion, if
- $\mathrm{A}(\omega)=\mathrm{C}\omega^{2}, \phi(\omega)=k \omega^{3}$
- $\mathrm{A}(\omega)=\mathrm{C}\omega^{2}, \phi(\omega)=k \omega$
- $\mathrm{A}(\omega)=\mathrm{C} \omega, \phi(\omega)=k \omega^{2}$
- $\mathrm{A}(\omega)=\mathrm{C}, \phi(\omega)=k \omega^{-1}$