 The presented plots of image impedance , attenuation and phase change correspond to a low @-@ pass prototype filter section . The prototype has a cut @-@ off frequency of ωc 
 The presented plots of image impedance , attenuation and phase change correspond to a low @-@ pass prototype filter section . The prototype <a href='got' title='1'><mark>has</mark></a> a cut @-@ off frequency of ωc 
The presented plots of image impedance , attenuation and phase change correspond to a low @-@ pass prototype filter section . The prototype got a cut @-@ off frequency of ωc