Abstract: 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.

Abstract: 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.

Abstract: An optical multiplexer and/or optical demultiplexer for multiplexing and/or demultiplexing a plurality of wavelengths comprises a plurality of optical filters each of which transmits a predetermined wavelength and reflects other wavelengths, said optical filters being arranged so that an optical beam is transmitted or reflected via each optical filter in sequence in a zigzag fashion. A light source or light detector is provided behind each optical filter to project or receive a collimated optical beam. The angle of incidence when a beam is applied to an optical filter is small. And, another optical means is provided to connect the present optical multiplexer and/or demultiplexer with an outside optical fiber. The transmission wavelength of each optical filter is different from the others.

Abstract: A sample pulse generating apparatus is provided having an input signal supply circuit for supply an input signal with a high frequency to be sampled, a saw tooth wave generator for generating a saw tooth wave signal which is in synchronism with the input signal and has lower frequency than that of the input signal, a staircase signal generator for generating a staircase signal of which the voltage level is stepped up in synchronism with the occurrence of the saw tooth wave signal, a voltage comparator for receiving the saw tooth wave signal and the staircase wave signal and comparing them and producing a sampling signal when those signals coincide with each other, and an observation signal generator for generating an observation signal which is analogous in wave shape to the input signal and has lower frequency than that of the input signal, by sampling the input signal by the sampling pulses.