Nabil Abd Rabou

Optical fiber transmission of multi-channel FM audio and video signals

An optical-fiber transmission system with a bandwidth of greater than 100 MHz for transmitting multichannel FM audio and video signals is described. This system for distributing FM audio and video signals on up to five channels to the respective receiver was constructed using a high-speed LED (light-emitting diode) and a wideband amplifier. The differential gain and differential phase were less than 2% and 3 degrees , respectively, and the SNR was 56 dB. The proposed system will be used for high-quality, high reliability distribution of multiple TV channels instead of the coaxial cable distribution systems. >

Optical fiber two way FM video signal transmission for video conferencing applications

This paper describes an optical fiber transmission system to transmit two-way multi-channel FM video signals for video conferencing applications. A two-way optical fiber signal transmission system is built using a pair of optical distributors and a single optical fiber of 1 km for bidirectional communications. A pair of LEDs were used as light sources at 1.3 /spl mu/m and the bandwidth of the optical fiber transmission system was 300 MHz. >

70 MHz fiber optic transmission from satellite DBS receiving antenna

A broadcast satellite signal after conversion into an intermediate frequency (IF) signal at 70 MHz has been transmitted through an optical fiber in order to distribute the signal to the DBS (direct broadcasting satellite) receiver in a remote location. Based on experiments, it was found that a fiber-optic link allowed the designers to have greater flexibility than coaxial cables, and that light emitting diodes were attractive not only in terms of cost-effectiveness but also in terms of simplicity. The optical transmitter and receiver circuits built for experimental use were inexpensive and simple in circuit configuration. The distortion factor of the audio signal was less than 1% with a signal-to-noise ratio (SNR) of 70 dB. The differential gain and differential phase of the fiber-optic transmission system were less than 1% and 1 degree, respectively, and the SNR of the video signal was 46 dB.<<ETX>>

Optical fiber wideband RF signal transmission system for remote data sensing

The authors describe an optical transmission system to transmit the wideband RF signal consisting of remotely sensed data. The RF signal in a frequency band of 30 to 300 MHz was converted into an optical signal by using a high-speed light emitting diode operating at a wavelength of 1.3 /spl mu/m. The RF signal which consists of multiplexed data can be transmitted simultaneously through the optical fiber to the controller, data processor, or monitor. The optical transmission system satisfies the bandwidth required for transmitting many items of data. The optical RF signal was transmitted through an optical fiber (1 km) to the receiver. An application of the optical fiber RF signal transmission system is described for use in areas where high electromagnetic radiation can cause interference to the transmission system.<<ETX>>

New type of DBS receiver utilizing optical fiber as IF transmission line

An optical fiber transmission system that transmits the IF signal for direct broadcasting satellite (DBS) TV channels from a low noise converter to the main chassis of the DBS receiver after the IF signal at 1 GHz is converted into the corresponding second IF signal at 300 MHz (35-335 MHz) is described. The differential gain and differential phase of the video signal are less than 2% and 3 degrees, respectively, and the signal-to-noise ratio (SNR) is 45 dB. >

New type of optical fiber SSB analog data communication system using edge-emitting LEDs coupled to single mode optical fibers

This paper describes a new type of factory communication system using optical fibers. This new type of optical fiber SSB data communication system consists of a pair of optical transmitters, each transmitter constructed using an edge-emitting LED (ELED), a pair of optical receivers and a pair of single-mode-optical fibers, each having a length of 12 km. A pair of 12 channels are assigned to SSB data with frequencies of 12 kHz through 60 kHz in the lower frequency band on the up-going link, and of 72 kHz through 120 kHz in the higher frequency band on the down-going link, respectively. The transmitter and receiver are housed in a transmitter-receiver unit. When the transmission was experimentally carried out, the spurious noise was below -50 dB on each channel, and SNR was more than 60 dB. This system can be used to send status and voice data for the electrical and mechanical machines in place of power line communications.

Optical IF signal distribution circuits for DBS receivers

Describes two optical transmission systems, each of which is designed to transmit the direct broadcasting satellite (DBS) IF signal from the low-noise converter (LNC) to the DBS receiver through optical fiber. One transmits the IF signal for a specific channel from the LNC to the DBS receiver while the control signal is transmitted through the same optical fiber in the opposite direction. The other transmits the IF signal for all the channels with no control signal transmitted, after the DBS IF signal sent from an LNC is converted into an IF wideband signal of 300 MHz (35-335 MHz). The frequency spectrum of the IF signal is shown.<<ETX>>

Optical fiber transmission of data packets multiplexed with digital audio and video signals

Describes a system for transmitting data packets multiplexed with digital audio and NTSC TV signals using optical fibers. Up to 18 channels are allocated for data packets transmitted at a maximum speed of 1.764 Mbps. Digital audio signals are inserted into the horizontal sync period of the NTSC TV signal. In addition to data packet transmission, the digital NTSC TV signal transmission system is used to easily distribute many types of information classified into categories. The proposed system is characterized by: firstly, this system can give a satisfactory picture quality enough to operate it together with video equipment even though the quality of the reproduced pictures is lower than that of normal digital NTSC TV picture codes obtained at a sampling frequency of 4.00/spl times/fsc with a quantizing level of 8 bits. Secondly, NTSC TV picture codes, audio codes, and data packets can satisfactorily be transmitted using inexpensive devices at a transmission rate of as low as 50 Mbps. Thirdly, this system is used for transmitting data packets and audio signal codes which are inserted in the horizontal sync period of the digital NTSC TV signal. Both data packets and audio signal codes can be distributed to the specific receivers specified by device address. A combination of edge-emitting LEDs (ELEDs) and optical fibers enable the transmission system to easily transmit a digital NTSC TV picture signal together with data packets and digital audio codes. A new approach of combining ELEDs and optical fibers to distribute CATV pictures and electronic information via the ISDN is also proposed.

Optical fiber audio and video communication system using AOM and LED

This paper describes the construction and performance of the single-mode (SM) optical fiber communication system utilizing the acousto-optic modulator (AOM) technique for modulation of audio and video signals. An edge-emitting LED (ELED) at an optical wavelength of 1300 nm was used as a light source. The output frequency response for the direct (Oth) and diffracted (1st) beams from the AOM used together with the ELED were flat over the frequency range of 50 Hz to 6 MHz. The differential gain (DG) and differential phase (DP) of the video signal were less than 5%, and 5 degrees, respectively, and the signal-to-noise ratio (SNR) was approximately 56 dB.

Wideband optical fiber signal transmission system of 300 MHz bandwidth using LED

This paper describes a wideband signal transmission system using an LED at an optical wavelength of 1.3 /spl mu/m. The transmission bandwidth was approximately 300 MHz. The linearity of the system was satisfactory at an input signal level of -20 dBm or less for linear operation. The transmission of multi-channel FM video signals is given as an application of this system. The FM signals are transmitted simultaneously from an optical sender to an optical receiver through a GI optical fiber with a length of up to 2 km.