where Kin(f) = K(f). The zeros of the denominatoirn Eq. (2) determineth e principalm aximaf n = Afon. The frequenciefsn do not dependu ponthe numbero f oscillations to be summedH. owever;
t he greatert he numbero f terms in Eq. (2);
the sharpera re the principal maxima. Detaileda nalysiso f Eq. (2) showst hatt hes pectrumca nbe consideredto be entirelys hapeda fter a few (e.g;
5-6) reflectionsT. his is supportebdy experimentadla ta. AcknowledgemeTnhti:s work was partly supportedb y grants from the Russian Fund of FundamentaRl esearch (No. 95-02-05465aa)n d the ScientificC ouncil 'High Tc Superconductivit(yN'o . 94002);