Improvement of the CATV Coaxial Distribution System Parameters (original) (raw)

Improvement of the HFC System Reverse Path Performance

2005

The paper deals with what causes the signal parameters in the reverse path channel of hybrid fiber-coaxial CATV system to worsen. Besides the analysis, a mathematical model of the channel is also suggested with the funnel effect being taken into consideration. If the carrier-to-noise ratio at the receiver input of the headend is known then the model makes it possible to optimize the topology of the coaxial distribution network and the number of optical nodes whose signals are summarized in the receiver. Experimental and analytical results are shown that enable the engineer to determine the RF signal dynamic range at the modulation input of the reverse path lasers if both the bit error ratio at the receiver output and the acceptable laser clipping are given.

HFC/CATV Transmission Systems (Invited Paper

During the past decade, cable television (CATV) systems have evolved from one-way broadcast of analog video transmission to two-way hybrid fiber/coaxial (HFC) networks delivering both analog and broadband services. The broadband services include high speed internet access, cable telephony, video-on-demand, and digital video. In this talk, we describe HFC transmission systems including the infrastructure, transmission formats, enabling technologies, system performance and impairments. The performance results of some typical HFC/CATV transmission systems are discussed along with the impact of fiber nonlinear effects. The fiber nonlinear effects include stimulated Brillouin scattering, self phase modulation, stimulated Raman scattering, and cross phase modulation. The methods to minimize the effects of fiber nonlinear impairments are also presented.

Fundamental limitations in EDFA-based subcarrier-multiplexed AM-VSB CATV systems

Journal of Lightwave Technology, 1993

This paper presents and discusses fundamental limitations for EDFA-based subcarrier-multiplexed AM-VSB CATV distribution systems. The impairments we consider are fundamental, namely, shot noise, amplifier spontaneous emission noise, and laser, clipping-induced, nonlinear distortion. Treating the amplifier input signal power and pump power as resources, we obtain limits on the number of receivers to which we can deliver, say, 60 (or 80) channels at a carrier-to-noise ratio (CNR) of 55 dB (or 48 dB). Moreover, we present a simple approach that can be used to recalculate the results presented here for different system and amplifier fiber parameters.

On the acceptable perturbation level of CATV distribution amplifiers for mobile DVB-T reception

2015 International Symposium on Signals, Circuits and Systems (ISSCS), 2015

Analog switch-off in television (ASO) Digital transmission DVB-T trial Cable networks in TV distribution Simulation Conclusions ISSCS_2015-Arsinte Analog switch-off in television (ASO) Analog switch-off-total interruption of analog TV (PAL/SECAM) aerial transmission (broadcasting) Analog switch-off is mandatory for EU countries but agreed for non-EU countries Performed already for satellite transmission (since 2012) and previewed for 2015 for all EU countries After June 2015, the analog TV transmission will remain only for a limited time in limited TV band frequencies (eg. In Romania in VHF domain until 31 Dec. 2016) Analog transmission will remain possible in cable networks (most cable operators are private actors) in parallel with digital transmission (DVB-C) ISSCS_2015-Arsinte Digital TV transmission All DVB transmission are replacing the old TV services DVC-T/T2 are replacing the terrestrial transmissions DVB-C are replacing analog channels in cable TV networks Typical spectrum is presented below 50 225 470 790 1050 MHz

A new HFC architecture using return path multiplexing

High Performance Networking, 1998

A Hybrid Fiber Coaxial (HFC) plant is typically configured in a tree topology and covers a large area with tens of thousands of House Holds Passed (HHP) and several return paths into the headend. During initial deployment, it is usually the case that the number of cable modem subscribers is small compared to the HHP, resulting in a small number of modems spread out over the return paths. To operate more efficiently, the return paths should be combined to reduce the port requirement at the headend. A simple upstream RF combiner can be used to merge separate return paths, but that would also funnel the noise of the separate paths and degrade performance. Instead, what is needed is an upstream aggregation device that will multiplex the paths without aggregating the noise. To do so, such a device needs to operate with the HFC's MAC (media access control) layer and employ multiplexing discipline that incurs limited impact on performance under varying modem distribution scenarios. In addition, this device must be simple and transparent to the rest of the HFC system. In this paper, we describe through analysis and simulation how such a return path multiplexing device is possible, and how it impacts the HFC network architecture and upstream performance.

Fundamental limitations in EDFA-based subcarrier timesiplexed AM-VSB CATV systems

J Lightwave Technol, 1993

Simulative Analysis of CATV Systems for Long Haul Transmission

J. Opt. Commun., 2013

In this paper, simulative performance analysis for different modulation formats like NRZ rectangular, NRZ raised cosine, RZ soliton, RZ super gaussian, RZ raised cosine and RZ rectangular, has been demonstrated and analyzed at each node with varying bit rate. It is seen that overall NRZ modulation is performing better among all modulation driving schemes. It is also observed that by using RZ soliton format system can exist up to 90 dB of insertion loss of optical add drop multiplexers with bit rate upto 10 Gbit/s. For 10 Gbit/s of bit rate quality factor drops off below 15 dB after 85 dB of insertion loss for RZ soliton.

Improvement of the CATV Coaxial Distribution System Parameters (original) (raw)

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