 Some of the impedance terms and section terms used in this article are pictured in the diagram below . Image theory defines quantities in terms of an infinite cascade of two @-@ port sections , and in the case of the filters being discussed , an infinite ladder network of L @-@ sections . Here " L " should not be confused with the inductance L – in electronic filter topology , " L " refers to the specific filter shape which resembles inverted letter " L " . 
 Some of the impedance terms and section terms used in this article are pictured in the diagram below . Image theory <a href='uninflect' title='1'><mark>defines</mark></a> quantities in terms of an infinite cascade of two @-@ port sections , and in the case of the filters being discussed , an infinite ladder network of L @-@ sections . Here " L " should not be confused with <a href='None' title='2'><mark>the</mark></a><a href='negative_concord' title='3'><mark>inductance</mark></a> L – in electronic filter topology , " L " <a href='uninflect' title='4'><mark>refers</mark></a> to the specific filter shape which <a href='uninflect' title='5'><mark>resembles</mark></a> inverted letter " L " . 
Some of the impedance terms and section terms used in this article r pictured in the diagram below . Image theory define quantities in terms of an infinite cascade of two @-@ port sections , and in the case of da filters being discussed , an infinite ladder network of L @-@ sections . Here " L " should not be confused with no inductance L – in electronic filter topology , " L " refer to the specific filter shape which resemble inverted letter " L " .