DIGITAL MODULATION METHOD, DIGITAL MODULATOR AND DIGITAL BROADCAST RECEIVER

摘要

PROBLEM TO BE SOLVED: To prevent an image from being deteriorated due to A/D conversion and D/A conversion, in the case that a digital broadcast program unique to a local broadcast station is transmitted by the local broadcast station on a radio wave of a nationwide broadcast program. SOLUTION: A nationwide use digital modulation means 21 applies digital modulation to a program of a nationwide broadcast program with a frequency other than that by a local transponder. The modulated signal is transmitted by a transmission means 22 and received by a reception means 23. Then a local digital modulation means 24 applies digital modulation to a program unique to a local broadcast station with a frequency for a local broadcast station transponder by the received modulation signal and the resulting signal is transmitted to each home with the nationwide broadcast program.