 -cascaded noncommensurable transmission lines, closed on a resistance, are considered. The condition about real positivity of the input admittance is investigated; it is shown that it is partially redundant and can be substituted by a new condition, which verifies the positivity of only
 -cascaded noncommensurable transmission lines, closed on a resistance, are considered. The condition about real positivity of the input admittance is investigated; it is shown that it is partially redundant and can be substituted by a new condition, which verifies the positivity of only  coefficients of the admittance function.
 coefficients of the admittance function.