Announcement broadcasting system, announcement broadcasting optical receiver used for the announcement broadcasting system, cable television broadcasting system, and optical receiver used for the cable television broadcasting system

摘要

In a subscriber's facility of an announcement broadcasting system utilizing an optical fiber cable TV network, an announcement broadcasting optical receiver receiving an optical transmission signal of audio information and outputting an audio information electric signal for an announcement broadcasting terminal is provided. The announcement broadcasting optical receiver includes: a photo-detection section for converting the optical transmission signal into the audio information electric signal; a photoelectric conversion section, which is connected to the photo-detection section, for converting the optical transmission signal that the photo-detection section receives into electric energy; and an RF signal potential transformation section, to which the electric energy obtained by the photoelectric conversion section is supplied, for potential-transforming the audio information electric signal output from the photo-detection section to one at an input voltage level appropriate to the announcement broadcasting terminal and outputting it.

主权项

1. An announcement broadcasting system comprising:
a network center sending facility including: a mixer for mixing a TV image signal and an audio information signal and outputting a TV electric signal; a TV optical transmitter for converting the TV electric signal output from the mixer into an optical transmission signal and outputting it; a distributor for dividing the audio information signal input in the mixer; and an audio information optical transmitter for converting the audio information signal divided by the distributor into an optical transmission signal and outputting it; an optical transmission line for transmitting the optical transmission signals sent out from the TV optical transmitter and the audio information transmitter of the network center sending facility; and at least one subscriber's facility including: a TV optical receiver for receiving the optical transmission signal transmitted from the TV optical transmitter through the optical transmission line and outputting a TV electric signal; and an announcement broadcasting optical receiver for converting the optical transmission signal transmitted from the audio information optical transmitter through the optical transmission line into an audio information signal and outputting it so that the audio information electric signal is input to an announcement broadcasting terminal for performing announcement broadcasting, wherein the announcement broadcasting receiver of the subscriber's facility includes:
a photo-detection section for converting the optical transmission signal sent out from the audio information optical transmitter of the network center sending facility into the audio information electric signal;a photoelectric conversion section, which is connected to the photo-detection section, for converting the optical transmission signal that the photo-detection section receives into electric energy; and an RF signal potential transformation section, to which the electric energy obtained by the photoelectric conversion section is supplied, for potential-transforming the audio information electric signal output from the photo-detection section to one at an input voltage level appropriate to the announcement broadcasting terminal and outputting it.