This paper presents necessary and sufficient conditions on an input impedance function, as a function of

and

, for it to be realized as a cascade of equal-length transmission-line sections terminated in a resistance. The proofs are given in terms of the variable,

, rather than the frequency variable of Richards,

. The method is direct, elementary, and applicable to the realization of the input impendance function of a lowpass ladder network of capacitances and inductances terminated in a resistance. Finally, necessary and sufficient conditions on the input reflection coefficient and then on the insertion-loss function, in terms of

, are given for a cascade of equal-length transmission-line sections terminated in a resistance.