AUDIO TRANSMISSION THROUGH OPTICAL FIBER USING ADAPTIVE DELTA MODULATION SYSTEM

Abstract

"AUDIO TRANSMISSION THROUGH OPTICAL FIBER USING ADAPTIVE DELTA MODULATION SYSTEM' In this project the audio signal is transmitted through the optical fiber. The whole project consists of mainly three parts. til digitizing the analog audio signal by sampling at regular intervals and coding the difference of the two successsive sampled values for transmission (ii) this signal is then Manchester coded to help the receiver to regenerate the clock and hence work in synchronization with the transmitter. (iii) The coded data is given to the optical driver where the voltage signal is converted into the light signal and then transmitted through the fiber. The reverse operation is done in the receiver block. It is also possible to send some signal waveform of few hundreds of Hz - of frequency. The system uses HFBR-1412 which is an alloy of Ga.AlAs LED which is active in the wavelength range of 820 nm,as driver and HFBR-2412 which is a photodetector and has an inbuilt a.mpl if ier, as the receiver of the optical signal. The fiber used is 4. 3 meter length with overall attenuation of a .bout O.5 dB. The design •of the system and the devices used, makes the system more attractive with very good response. In the end introduction is given to the Wavelength Division Multiplexing and suggested under the improvements that can be made in the same line.