Hi-Vision is broadcasted via DBS in FM. To examine RF transmission characteristics between receiving antenna and a DBS receiver, it's convenient if we could estimate it from demodulated MUSE baseband signal response. However, it usually has difficulties due to the non-linear distortion caused by phase distortion in RF stage. This paper contains the result of transmission experiments of MUSE-FM signal and clarifies the applicable baseband distortion range within which we can reliably estimate the reflection characteristics of RF transmission line.