Cable Television Signal Research Articles

Development of a Path Loss Model for Radio Wave Signals for some Selected Routes in Enugu State, Nigeria

Abstract: This research focuses on developing a path loss model for radio wave signals propagating in a wavelength range of 0.37–6.12 m along some selected routes in Enugu state, Nigeria. A cable television signal strength meter was used to measure signal strength at 2 km intervals along the routes. The television signals examined were those from NTA Enugu. Path loss values were derived from the received signal strength for each route. The path loss obtained was plotted against the distance and the result shows that the path loss increases with the distance along each of the routes. A path loss model was developed by analyzing the path loss variation with distance. The path loss values obtained from the developed model were plotted against the distance and compared with the measured path losses for the NTA signals to assess how accurate the model is for the path loss prediction at the study locations. Some statistical tools (RMSE, ME, and SDE) were used to validate the developed model. The model predicted the path loss of NTA-Enugu signals with RMSE very close to zero (0). In addition, the values of the developed path loss model for the NTA signals were compared with the values of other empirical models. The results show that the other empirical path loss models overestimate the path loss of NTA-Enugu signals. Keywords: Nigeria Television Authority (NTA), Path loss, Radio waves, Signal strength, Terrestrial television, Ultra High Frequency (UHF). PACs: 84.40.Ua.

Implementation of Local Area Network (LAN) & Build a Secure LAN System for BAEC Head Quarter

Network security is the process of taking physical and software preventative measures to protect the underlying networking infrastructure from unauthorized access, misuse, malfunction, modification, destruction, or improper disclosure, thereby creating a secure platform for computers, users, and programs to perform their permitted critical functions within a secure environment. A local area network (LAN) is a computer network within a small geographical area such as a home, school, computer laboratory, office building or group of buildings. A LAN is composed of inter-connected workstations and personal computers which are each capable of accessing and sharing data and devices, such as printers, scanners and data storage devices, anywhere on the LAN. LANs are characterized by higher communication and data transfer rates and the lack of any need for leased communication lines. A data network is an interconnected system of computers, peripherals and software over which data files and messages are sent and received. LAN is only one type of computer network. LAN define is Data com system allowing a number of independent devices to communicate directly with each other, within a moderately sized geographic area over a physical communications channel of moderate data rates. Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. This type of communication can transmit voice, video, and telemetry through local area networks or across long distances. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals. Researchers at Bell Labs have reached a record bandwidth distance product of over 100 petabit × kilometers per second using fiber optic communication. Communication between remote parties can be achieved through a process called Networking, involving the connection of computers, media and networking devices. When we talk about networks, we need to keep in mind three concepts, distributed processing, network criteria and network structure. The purpose of this Network is to design a Local Area Network (LAN) for a BAEC (Bangladesh Atomic Energy Commission) Head Quarter and implement security measures to protect network resources and system services. To do so, we will deal with the physical and logical design of a LAN. The goal of this Network is to examine of the Local Area Network set up for a BAEC HQ and build a secure LAN system. Keywords: LAN, Secure LAN, BTCL, UTP, RJ-45, Bandwidth, Wavelength, ISP, Firewall, BAEC

A Bidirectional Fiber-Wireless and Fiber-IVLLC Convergence System with a Dual-Polarization Modulation Scheme and an MZM-OEO-Based BLS

A bidirectional fiber-wireless and fiber-invisible laser light communication (IVLLC) convergence system that adopts a dual-polarization modulation scheme and a Mach–Zehnder modulator (MZM)-optoelectronic oscillator (OEO)-based broadband light source (BLS) for hybrid cable television (CATV)/microwave (MW)/millimeter-wave (MMW)/baseband signal transmission is proposed and experimentally demonstrated. The MZM employed in the MZM-OEO is operated at the minimum transmission point, which results in the format of optical carrier suppression for the y -axis component of the light. Using a dual-polarization modulation scheme, the optical carrier modulated with CATV signal ( x -polarization) and the optical sidebands modulated with MW and MMW data signals ( y -polarization) are separated and polarized orthogonally automatically. Through an in-depth observation, good carrier-to-noise ratio, composite second-order, composite triple-beat, and bit error rate performances are obtained over a 40-km single-mode fiber and a 10-m RF/100-m optical wireless transport. Such a bidirectional fiber-wireless and fiber-IVLLC convergence system is a notable option; it would be attractive for providing broadband heterogeneous services such as CATV, Internet, and big data services.

A hybrid lightwave transport system based on a BLS with an OSNR enhancement scheme

A hybrid lightwave transport system based on a broadband light source (BLS) with an optical signal-to-noise ratio (OSNR) enhancement scheme for millimeter-wave (MMW)/radio-over-fiber (RoF)/cable television (CATV) signal transmission is proposed and experimentally demonstrated. Unlike traditional hybrid lightwave transport systems for signal transmission, in which a transmitting site needs multiple wavelength-selected distributed feedback laser diodes (DFB LDs) to support various services, such proposed systems employ a phase modulator to provide multiple optical carriers for various applications. Over an 80 km single-mode fiber (SMF) transmission, the bit error rate (BER)/carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB) perform brilliantly for hybrid 100 GHz MMW/50 GHz MMW/10 GHz RoF/550 MHz CATV signal transmission. Such a hybrid lightwave transport system would be attractive for fiber trunk applications to provide broadband integrated services.

Hybrid CATV/MMW/BB lightwave transmission system based on fiber-wired/fiber-wireless/fiber-VLLC integrations.

A hybrid lightwave transmission system for cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission based on fiber-wired/fiber-wireless/fiber-visible laser light communication (VLLC) integrations is proposed and demonstrated. For down-link transmission, the light is intensity-modulated with 50-550 MHz CATV signal and optically promoted from 25 GHz radio frequency (RF) signal to 10 Gbps/50 GHz and 20 Gbps/100 GHz MMW data signals based on fiber-wired and fiber-wireless integrations. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 40-km single-mode fiber (SMF) and a 10-m RF wireless transport. For up-link transmission, the light is successfully intensity-remodulated with 5-Gbps BB data stream based on fiber-VLLC integration. Good BER performance is achieved over a 40-km SMF and a 10-m free-space VLLC transport. Such a hybrid CATV/MMW/BB lightwave transmission system is an attractive alternative, it gives the benefits of a communication link for broader bandwidth and higher transmission rate.

A Hybrid CATV/16-QAM-OFDM In-House Network Over SMF and GI-POF/VLC Transport

This letter proposes and experimentally demonstrates a hybrid cable television (CATV)/16-quadrature amplitude modulation (QAM)-orthogonal frequency-division multiplexing (OFDM) in-house network over a combined 40 km single-mode fiber, 1.43 km photonic crystal fiber, and 30 m graded index-plastic optical fiber/5 m visible light communication transport. Good performances of carrier-to-noise ratio, composite second-order, and composite triple-beat are obtained for the CATV signal. A low bit error rate value is achieved for the 16-QAM-OFDM signal.

Cable television transmission over a 1550-nm infrared indoor optical wireless link

We experimentally demonstrate transmission of cable television (CATV) radio frequency signals over a pointed indoor optical wireless link. The length of the optical link was 15 m. Collimators used at both the transmitter and the receiver sides required good alignment before sufficient opti- cal power could be received. The system was placed at a height of 2 m, which is more than average human height, so human movements throughout the room did not obstruct the link. The optical wireless propagation path was almost lossless. The originality in this experimental demonstration is the transmission of full range of CATV signals compared to other works in this area. This experiment of radio over free-space optics showed that point-to-point indoor optical wireless links can be utilized as an alternative means for transmission of multimedia data. © 2013 Society of Photo-Optical

Multi-Service Cable Television System Using a Single Wavelength

This paper presents a multi-service cable television (CATV) system using a single wavelength. The multi-service CATV systems can transmit both CATV and wireless signals by using one external modulator on a single wavelength over a single fiber. Moreover, this multi-service transport system, in contrast to the previously developed systems, does not incur the dc bias drift problem. In addition to satisfying the CATV requirements where excellent performances of carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple beat (CTB) are achieved for CATV signals, the multi-service transport system also satisfies the demand for high-quality wireless signal transmission over a 25-km single-mode fiber (SMF).

An in-building network based on community access television integration with quadrature phase-shift keying orthogonal frequency-division multiplexing

An in-building network based on cable television (CATV) integration with quadrature phase-shift keying (QPSK) orthogonal frequency-division multiplexing (OFDM) transport over a combination of single-mode fibers (SMF) and perfluorinated graded-index plastic optical fibers (GI-POF) is proposed and experimentally demonstrated. In this system, a 1558.5 nm optical signal is directly transmitted along two fiber spans (20 km SMF + 25 m GI-POF). An optimum guard band is carefully established to ensure that no very substantial signal interference is induced between the CATV and QPSK OFDM bands. Error free transmission with sufficiently low bit error rate values was achieved for 1.25 Gbps/771.5 MHz QPSK OFDM signals; also, acceptable carrier-to-noise ratio, composite second-order, and composite triple-beat performances were obtained for CATV signals. This proposed network is significant because it is economical and convenient to install.

Hybrid Cable Television/Radio-Over-Fiber Transport System Based on Polarization Modulation Technique

A hybrid cable television/radio-over-fiber (ROF) transport system with direction modulation of cable television signals and the polarization modulation of ROF signals is proposed and experimentally demonstrated for the first time. When a multicarrier cable television signal in the optical amplitude domain and an ROF signal in the optical polarization domain are modulated, a single optical wavelength can serve these two signal applications simultaneously. This hybrid transport system not only satisfied the cable television requirements, but also satisfied the demand for high-quality ROF transmission over a 20-km single-mode fiber.

15-2 CATV事業用23GHz帯無線システムを用いたデジタルケーブルテレビ信号の伝送実験(第15部門 無線・光伝送2)

15-2 CATV事業用23GHz帯無線システムを用いたデジタルケーブルテレビ信号の伝送実験(第15部門 無線・光伝送2)

Externally modulated CATV/ROF transport systems based on negative dispersion fiber

An externally modulated lightwave cable television (CATV)/radio-over-fiber (ROF) transport system based on negative dispersion fiber (NDF) as the transmission medium is proposed and demonstrated. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO) and composite triple beat (CTB) were obtained for the CATV signals; low bit error rate (BER) and third-order intermodulation distortion to carrier ratio (IMD3/C) values were achieved for ROF applications. The negative dispersion property compensates the positive chirp and results in systems with better transmission performances.

RF Photonics

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In parallel with the development of fiber optics for transmission of digital information, the 1970s and 1980s saw the development of techniques for the transmission of wide-bandwidth analog radio-frequency (RF) signals over optical fibers. The simultaneous need for high linearity and high signal-to-noise in RF photonic links spurred the development of lasers, modulators and detectors matched to the special needs of such links. RF photonics was also explored for the processing of RF signals by means of optically implemented filters and variable-delay lines. Commercial applications of RF photonics included cable television signal distribution and subcarrier-multiplexed digital signals. </para>

Raman Crosstalk Suppression in CATV Overlay Passive Optical Network

In cable television (CATV) overlay passive optical networks (PONs), where a CATV signal copropagates with a downstream baseband signal, the crosstalk components mediated by stimulated Raman scattering (SRS) limit the performance of low-number CATV channels. In this letter, we propose and demonstrate a way of reducing the SRS-induced crosstalk in CATV overlay PONs. The proposed scheme utilizes a high-speed polarization scrambler in the transmitter to make the SRS-induced crosstalk independent of polarization evolution along the fiber and a subtractor module to compensate for the crosstalk. Our demonstration shows that crosstalk can be reduced by 9 dB

A Low-Crosstalk Design of 1.25 Gbps Optical Triplexer Module for FTTH Systems

In this paper, we analyzed and measured the electrical crosstalk characteristics of a 1.25 Gbps triplexer module for Ethernet passive optical networks to realize fiber-to-the-home services. Electrical crosstalk characteristic of the 1.25 Gbps optical triplexer module on a resistive silicon substrate should be more serious than on a dielectric substrate. Consequently, using the finite element method, we analyze the electrical crosstalk phenomena and propose a silicon substrate structure with a dummy ground line that is the simplest low-crosstalk layout configuration in the 1.25 Gbps optical triplexer module. The triplexer module consists of a laser diode as a transmitter, a digital photodetector as a digital data receiver, and an analog photodetector as a cable television signal receiver. According to IEEE 802.3ah and ITU-T G.9833, the digital receiver and analog receiver sensitivities have to meet -24 dBm at BER=10 -12 and -7.7 dBm at 44 dB SNR. The electrical crosstalk levels have to maintain less than -86 dB from DC to 3 GHz. From analysis and measurement results, the proposed silicon substrate structure that contains the dummy line with 100 μm space from the signal lines and 4 mm separations among the devices satisfies the electrical crosstalk level compared to a simple structure. This proposed structure can be easily implemented with design convenience and greatly reduce the silicon substrate size by about 50 %.

RF fiber-optic link performance

Applications that involve point-to-point routing of analog signals have benefited from the excellent propagation characteristics of optical fiber. Fiber-optic links that remote RF signals to and from phased-array radar antennas must meet especially stringent performance requirements. The past decade has seen significant progress in the performance of the fiber-optic links that distribute RF signals in antenna-remoting applications, as well as in cellular communications and cable television signal distribution networks. This article reviews the present state of the art in RF fiber-optic links.

Optical channel upgradability of multiwavelength erbium-doped fiber amplifier for hybrid digital/analog dense wavelength-division-multiplexing systems

We investigate theoretically the impact of optical channel upgradability on the design of erbium-doped fiber amplifier (EDFA), in terms of guard band, channel number and input signal power level for simultaneously amplifying amplitude-modulated vestigial-sideband analog cable television signal and multiple optical digital baseband signals in hybrid dense wavelength-division-multiplexing (H-DWDM) systems. The single-staged forward and backward bidirectional pumping scheme for EDFA without using any inter-staged components is adopted because it is the best amplifier configuration to offer the highest output power with fairly low noise figure and highly satisfied carrier-to-noise ratio performance. In this work, we define the guard band Δλ GB as the channel spacing between the analog channel and the nearest digital channel. We find that various guard bands (Δλ GB =6.45–1.61 nm) do not affect the noise figure (3.36–3.38 dB) and channel gain variation (ΔG D =0.12–0.13 dB) . However, the channel number (10–32, Δλ D =0.8 nm) influences the gain variations (ΔG D =0.12–3.62 dB) evidently. The gain variation of H-DWDM EDFA for a launched 10, 16, 20 and 24 digital channels is 0.12, 0.65, 0.71 and 0.74 dB, respectively, but that for 28 and 32 digital channels is degraded to 2.47 and 3.95 dB, respectively, because the left-most digital channel is very close to the 1530 nm spectrum so as to degrade the gain flattening. This degradation can be improved by shifting the digital channels away from the 1530 nm band.

COMMERCIAL LiNBO_3 INTEGRATED OPTIC DEVICES

The application of LiNbO3 integrated optical devices in the areas of telecommunications, cable television signal distribution, antenna remoting, and fiber optic gyroscopes is reviewed. Emphasis will be placed on significant new devices and device improvements which are presently in commercial and advanced development.

Brillouin scattering in externally modulated lightwave AM-VSB CATV transmission systems

The authors measure the stimulated Brillouin scattering threshold for a CW (continuous wave) laser externally modulated with an AM-VSB (amplitude modulation vestigial sideband) CATV (cable television) signal. The threshold is essentially unchanged from the unmodulated case. For injected powers above the threshold power, substantial degradation of the carrier to noise ratio is seen. >

GENERAL DETERRENCE AND TELEVISION CABLE CRIME: A FIELD EXPERIMENT IN SOCIAL CONTROL*

This research examines the deterrent effect of a written legal threat on a group of persons who are known to be receiving an unauthorized premium cable television signal. The experiment attempts to determine (1) the overall violation rate: (2) the extent to which violators direr from a systematic random sample of cable signal customers (according to age, total household income, and gender); and (3) the deterrent effect of the threat of intervention. Additionally, a six‐month follow‐up was conducted to assess the duration of the threat's effect.Overall, two thirds of the subjects (n=67) reacted to the threat; the major reaction to the threat was an attempt to hide the violation. There were some differences found regarding participation in cable crime and deterrence, but none reached a reliable level of statistical significance. Regarding deterrence, the findings that males heeded the threat least and that the youngest and richest also showed low desistance rates after exposure to the threat are consistent with previous research. Regarding participation in cable crime, the youngest and richest seem to be involved more often in the pilfering of signals. The follow‐up revealed that the deterrent effect of the intervention lasted at least six months. The benefits of using experimentation as a general deterrence research strategy are emphasized throughout.