Transmission system for previous-arrangement supervisory signal

Abstract

Abstract PURPOSE:To improve S/N while making it possible to transmit a previous-arrangement supervisory signal by using the same transmission line a main signal by PCM- modulating the previous arrangement supervisory signal and also by amplitudemodulating the main signal by the output. CONSTITUTION:A previous-arrangement supervisory signal applied from terminal 1 consists of an analog signal of 0.3-3.4kHz and is converted by A/D converting circuit 2 into a PCM signal of 64kb/s, for example. On the other hand, a main signal (PCM signal of tens - hundreds Mb/s) applied from terminal 3 is supplied to amplitude modulating circuit 4 for pulse amplitude modulation using the PCM-modulated prearrangement supervisory signal from circuit 2 and after amplification 5, light emitting device 6 is driven to generate and send a photosignal out of 7. On the other hand, the main signal with the superposed previous-arrangement supervisory signal input to terminal 11 is converted at 12 into an electric signal, which is amplified at 13 and discriminated and reproduced at 4 to obtain main signal output 15. Further, the output of amplifying circuit 13 has it peak value detected at 16 and the previous-arrangement supervisory signal PCM-modulated through LPF17 and discriminating circuit 18 is converted at 19 into an analog signal, so that the original previous-arrangement supervisory signal will be reproduced.

Inventors

• 👤 Takashi Kihara
• 👤 Akira Miyata

Bibliographic Details