Analog Video

Analog video input (either PAL or NTSC) is captured by dedicated hardware, and an FPGA is used for buffering the scanlines between video input and DSP.

From: Multi-Photographic camera Networks , 2009

Electronics Elements (Detailed Discussion)

Thomas Norman CPP, PSP, CSC , in Integrated Security Systems Design (Second Edition), 2014

Capturing and Displaying Analog Video

Analog video is created in a video camera past scanning an electron beam across a phosphor. The beam intensity is determined by the amount of light on each pocket-size area of the phosphor, which itself responds to the light existence focused on it by a lens. That beam is and so transmitted to a recording, switching, or display device. Analog switchers simply make a connexion between devices by closing a relay dry out contact. Recorders but record the voltage changes of the electron beam onto tape, and brandish devices convert the voltage back into an electron beam and aim it at another phosphorus surface, which is the display monitor that is viewed.

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Video Coding: Fundamentals

Mohammed Ebrahim Al-Mualla , ... David R. Bull , in Video Coding for Mobile Communications, 2002

two.3.three Analog Video Systems

There are three principal analog video systems. In most of Western Europe, a 625/fifty PAL arrangement is used. In Russian federation, France, the Middle East, and Eastern Europe, a 625/50 SECAM system is used. In N America and Japan, a 525/lx NTSC organization is used. All iii systems are interlaced with a iv:3 aspect ratio.

The three systems are blended. This ways that the blush components are first bandlimited and then combined (for example, by frequency interleaving) with the luma component. The resulting composite video indicate has the same bandwidth as the original luma signal. For instance, in the 625/50 PAL arrangement, the luma point has a bandwidth of v.v MHz. The blush signals are bandlimited to about 1.v MHz and then QAM (quadrature amplitude modulation) modulated with a color subcarrier at 4.43 MHz above the picture carrier. For a more detailed word of these systems the reader is referred to Ref. 13. There are also other analog video systems that employ separate components (component video) or a dissever luma component and a blended chroma component (S-video) [x].

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Lightwave Analog Video Transmission

Mary R. Phillips , Thomas E. Darcie , in Optical Fiber Telecommunications (Third Edition), Volume A, 1997

2 Analog Lightwave Systems

The analog lightwave system must have multiple frequency-segmentation multiplexed video channels at the input, convert them to an optical signal, and transport them over several tens of kilometers of single-mode cobweb and/or through passive cobweb splitters to an optical receiver where they are converted back to RF. The end-to-terminate link must satisfy strict noise and baloney requirements. Traditional analog lightwave links are intensity modulated/direct detection (IM/DD) systems. In this technique, the analog video channel spectrum only modulates the optical power such that the intensity spectrum of the lite is the same equally the original RF signal (plus a DC component). At the receiver a photodiode converts the modulated intensity back into an RF indicate. The simplicity of the IM/DD arrangement makes it attractive, although it comes at the cost of very stringent operation requirements of the lightwave components. The focus of this chapter is on components for a elementary IM/DD lightwave arrangement that transports a standard band of amplitude modulated–vestigial sideband (AM-VSB) analog video channels. The lightwave system consists of the transmitter, optional optical amplifiers, a fiber transport network, and an optical receiver.

Nosotros discuss the technical requirements of each system component for two exemplary systems. The get-go is an lxxx-channel organisation that is typical of a loftier-performance cable trunk system. The system operation is divers by several parameters that are discussed afterwards. We desire a carrier-to-racket ratio (CNR) of 52   dB or more, composite second-guild (CSO) baloney of –threescore dBc or less, and blended triple beat (CTB) of –65 dBc or less, and we assume that this is accomplished with an optical modulation depth (OMD) of 3.5% per channel. Body systems in use today support betwixt forty and 110 channels with numbers similar to those in our example. These specifications permit additional degradation from a coaxial distribution system with typically 3 coaxial-cablevision amplifiers in pour, while still achieving the following specifications at the tv set: a CNR of 46   dB or more, CSO distortion of –53 dBc or less, CTB of –53 dBc or less, as required by the National Association of Broadcasters [one]. The requirements for the European PAL systems are somewhat less stringent.

Our 2d example is for an FTTC or a PON system where degradation from a coax distribution system demand not be budgeted. Also, given that we envision the analog video to be delivered with a broad variety of other digital (including video) services, nosotros presume that 50 channels of analog video are sufficient. In this instance, the performance at the output of the optical receiver needs to have just a CNR of 47   dB or more than, CSO distortion less than or equal to –56 dBc, and CTB less than or equal to –56 dBc. Given the reduced linearity requirements and reduced channel load, we assume that this is doable with an OMD of five% per aqueduct.

2.i VIDEO FORMATS

The claiming in delivering analog video over fiber systems is in meeting strict noise and linearity requirements. These arrive from the complexity and fragility of the AM-VSB video format. Brilliantly designed many decades agone [ ii] for loftier spectral efficiency, the single-sideband (vestigial sideband [VSB]) amplitude-modulated (AM) format requires 6-MHz channel spacing (viii   MHz in Europe) betwixt video carriers. Baseband video, including intensity and color information, is used to AM a video carrier. This is VSB filtered and frequency multiplexed with a frequency-modulated (FM) audio point, which results in a spectrum equally shown in Fig. 14.1. The dominant feature in the spectrum is the remaining video carrier. Video information appears betwixt the video carrier and the color subcarrier, at power levels many tens of decibels beneath the video carrier. Racket and distortion products must therefore be small in social club non to interfere with picture quality.

Fig. xiv.1. Single-aqueduct amplitude-modulated vestigial-sideband (AM-VSB) video spectrum showing a video carrier, color and audio subcarriers, and time-averaged modulation sidebands at depression levels relative to the video carrier.

Multiple video channels are frequency multiplexed according to a particular programme. The most popular in the United States is the standard National Cable Television Association (NCTA) plan, as shown in Fig. 14.ii. Video carriers are nominally spaced past 6   MHz, simply with irregularities to fit around the FM radio band. As is seen later, the distribution of distortion products that result from the nonlinear mixing between these multiple carriers provides information about the type of nonlinear impairment involved.

Fig. xiv.ii. Multichannel AM-VSB spectrum as transmitted on a typical cable television system. The variation in the video carrier level results from instantaneous differences in amplitude modulation (AM) depth. The features resolved in the spectrum are the video carriers and the frequency-modulated (FM) audio subcarriers.

The time-varying nature of the live video spectrum makes system diagnostics hard. Depending on the luminance of the instantaneous point along the image sweep, and the fourth dimension relative to synchronization and sweep pulses, the magnitude of the instantaneous video carrier varies by upward to 6   dB. This makes accurate carrier measurement with a spectrum analyzer difficult. In improver, modulation sidebands obscure distortion products that class the CSO and CTB distortion. In order to perform stable and accurate measurements, the industry uses a set of continuous unmodulated video carriers every bit a exam signal. In what follows, we consider the performance parameters in the context of these unmodulated examination signals.

Alternative video formats provide much greater immunity to impairment than AM-VSB provides. FM video has been used for decades for satellite and trunk transmission [3], where a high CNR cannot exist achieved. The required 15-dB point-to-racket ratio (SNR) can exist accomplished easily over a diverseness of lightwave systems [four,5]. A typical FM channel requires between 30 and 40   MHz of bandwidth, which makes it unpopular (in the United States) for terrestrial broadcast or cable delivery. Furthermore, the cost of converting between FM and AM-VSB is a disadvantage for systems that deliver FM video to the domicile. The techniques described in this chapter are applicative to FM video manual, merely many of the impairments that are discussed will not be problematic.

Emerging compressed digital video (CDV) technology will eventually displace AM-VSB and FM. CDV eliminates inter- and intraframe redundancy to compress National Television System Committee (NTSC)-like video into less than v   Mb/south [6]. When CDV is combined with avant-garde modem engineering science, the issue is high-quality video with a college spectral efficiency than that of AM-VSB, and with a much lower required CNR. Simply, every bit with FM video, the conversion cost and the embedded base of analog equipment will forestall this new technology from displacing AM-VSB rapidly.

When used with advanced modem technology, CDV allows a trade-off between spectral efficiency and required bandwidth [7,8]. The required CNR increases from less than twenty   dB for uncomplicated modems like quadrature phase-shift keying (QPSK) (2 $.25/south/Hz), to close to 30   dB for 64-QAM (quadrature aamplitude modulation) (6 bits/southward/Hz). As even higher spectral efficiencies are employed, the digital video channel becomes more like an analog video channel, in terms of transmission requirements. Much of this chapter is therefore applicative to these digital–RF channels. Manual of both analog and digital–RF channels simultaneously from the same laser has received considerable attention, primarily considering of the onset of clipping-induced impulse dissonance [9,10]. This topic is not discussed in this chapter.

ii.2 HFC SYSTEMS

As mentioned in the introduction, the availability of high-performance analog lightwave technology has had a great impact on the cable manufacture. The fundamental was to be able to replace cascades of dozens of coaxial amplifiers, as shown in Fig. 14.iii, with cobweb, as shown in Fig. xiv.four . Rather than suffering the accumulated dissonance and distortion of the amplifier chain, high-fidelity analog video could be interjected at distributed points throughout the serving area [ 11]. These fiber nodes (FNs) contain the optical receivers and electronic amplifiers needed to bulldoze relatively brusk coaxial distribution systems. In improver to improved picture quality, many factors came together to effect in the rapid credence of this system arroyo inside the cable industry. Because the FNs serve typically between 200 and 2000 subscribers, the lightwave cost per subscriber is pocket-sized. By eliminating the long amplifier cascades, transmission failure due to amplifier failure is less frequent and affects far fewer subscribers. Finally, because the maximum length of coax serving any subscriber is relatively brusk, the total bandwidth that tin be supported on the coax is increased significantly. Practical amplifier and equalization (to compensate for the frequency-dependent loss of coaxial cablevision) technology would at present enable system bandwidths close to 1   GHz, whereas long amplifier cascades were limited to less than typically 450   MHz.

Fig. 14.3. Prelightwave customs-antenna television set (CATV) arrangement with long cascades of electronic amplifiers and coax, showing a typical carrier-to-noise (C/N) ratio deposition along spans.

Fig. xiv.4. Fiber overlay to the CATV system, in which fiber nodes are used to subdivide serving areas. Loftier-quality signals are delivered far into the serving area using linear lightwave.

Diverse specific HFC systems take been implemented, simply the near popular system with both LECs and cablevision operators has approximately 500 subscribers served from each FN. This is accomplished with typically three or fewer coaxial amplifiers in cascade. This is a reasonable trade-off betwixt present-twenty-four hour period cost and operation. An instance is shown in Fig. 14.five. More aggressive system designs seek to eliminate all amplifiers outside the FNs past serving fewer than 200 subscribers per FN. These passive coax systems cost more than simply take better reliability and lower racket in the upstream band (typically from v to twoscore   MHz).

Fig. xiv.5. Hybrid fiber coax (HFC) broadband access system. Broadband analog video, broadband digital video, and switched phonation and information services are delivered past analog lightwave to fiber nodes. Fiber nodes convert analog optical signals to electrical and drive coaxial distribution systems that serve between 200 and 2000 subscribers. Various network interface units (NIUs) provide the required digital-to-RF conversion.

Analog lightwave is used in three main manners in HFC systems. Showtime, the price of converting from digital or FM video formats that can exist delivered over long distances and satellite networks to the AM-VSB formats for cablevision transmission is high. It is therefore desirable to minimize the number of head ends or central offices in which this is done. This head-cease consolidation requires that the multichannel AM-VSB spectrum exist distributed over long distances between head ends. This requires extremely high-fidelity operation over distances in the range of 50   km, which tin can exist achieved using linearized high-power lasers and/or optical amplifiers.

The 2nd grade of analog application in HFC is for the trunk systems between head ends and FNs, as shown in Fig. 14.5. This requires transmission over ordinarily less than 30   km, with performance as discussed in our 80-channel example system. Direct modulated DFB lasers, normally at 1.3 μm, are generally used for these links. 1 of these lasers can back up multiple (typically four) FNs using passive optical splitters.

The third application is the commitment of narrow band digital data betwixt the head finish and the FNs. This includes telephony or switched digital services. These are generally converted to RF channels using modems at the head end or subscriber and transported as RF through the fiber and coax. Separate lasers are often used for these services, as shown in Fig. 14.v, so that spare lasers can be provisioned in the consequence of failures. Robust modem techniques like QPSK are used to ensure amnesty to dissonance, especially in the upstream ring, so that a high CNR (compared with AM-VSB) generally is not required. These narrowcast lasers can be relatively cheap, because the requirements tin be met past low-performance DFB lasers or in some cases even Fabry–Perot lasers. Depression cost is critical because many more of these lasers are required than are required for AM-VSB commitment.

2.3 LOOP FIBER SYSTEMS

HFC provides a low-cost medium for combined analog video and narrow band digital services, but problems with ingress dissonance and cable deterioration lead many to prefer more than fiber-intensive alternatives. Various systems that deploy FTTC or fiber to the domicile (FTTH) are attractive, including PONs and several FTTC systems in which a curbside switch serves multiple subscribers. In all cases, one claiming is to evangelize the broadcast spectrum of multiple analog video channels to the optical network unit (ONU) at the curb or home.

Figure 14.half-dozen shows an FTTC organisation that uses a point-to-point fiber feeder, and a point-to-multipoint PON, in which a cobweb feeder is shared by multiple ONUs. Either system can be FTTC or FTTH, if feasible economically. The difficulty for analog lightwave in these applications is that each optical receiver serves a small number of subscribers (1–24), then that the price of analog lightwave components is not shared by every bit many subscribers as with HFC (typically 500). This constraint is offset somewhat past the reduced performance requirements, as described in our 50-channel instance system.

Fig. 14.6. Typical (a) point-to-point and (b) indicate-to-multipoint subscriber loop access systems. P represents points in the network at which ability must exist supplied (in addition to the primal function [CO]). Each optical network unit (ONU) continued to the host digital concluding (HDT) can serve multiple subscribers in a fiber-to-the-curb configuration, or only one subscriber, for cobweb to the home. The indicate-to-multipoint organisation uses a cobweb splitter or wavelength-partitioning multiplexer (WDM).

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Digital Set-Superlative Terminals and Consumer Interfaces

Walter Ciciora , ... Michael Adams , in Modernistic Cable Television Engineering (Second Edition), 2004

BB Video

This is the common baseband analog video interface described in Chapter 2 and Appendix B. Sound is not included. The meaning frequencies extend from virtually 0 to 4.2 MHz for NTSC video and from most 0 to 5 MHz for PAL video. Composite video (including sync, equally described in Appendix B) is transmitted at a level of 1 volt p-p, with a source and load impedance of 75 ohms. Normally, the common "RCA" connectors are used, though occasionally other connectors, such as BNC, are employed. Impedance matching is important if the connecting cable is long, to preclude ringing or ghosting. The quality of the interface is better than that of the Ch. 3/iv interface described next but not as good as the other analog interfaces described, because the chrominance data is combined with the luminance, and the ii must be separated before they can exist processed. The filters used to separate the two are imperfect; even if perfect filters were available, there would be some inevitable interference.

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Alive HDR Video Broadcast Production

I.Chiliad. Olaizola , ... J. Gorostegui , in High Dynamic Range Video, 2017

1.i SDTV, HDTV, and UHDTV

Digital Goggle box and video technologies were originally based on analog video formats. Therefore, standard definition Tv set (SDTV) takes its visual characteristics from NTSC (480/60i) and PAL/SECAM (575/50i) as it is defined past the ITU Recommendation BT.601 [ 1] as well as by SMPTE 259M [2]. High definition Idiot box (HDTV) introduces a big change in spacial resolution (720p, 1080i, 1080p) only the color gamut is like to SDTV and other aspects as the frame rate is not increased. HDTV is defined past the ITU-R BT.709 [3] and shares the same color primaries as sRGB. While the resolution in HDTV can be considered as acceptable for usual distances between the TV screen and the viewer, both, the color gamut (Fig. 1) and dynamic range of the human visual system (HVS) are far beyond the capabilities of HDTV. Therefore, ultra-loftier definition TV (UHDTV) improves all the dimensions involved in video: resolution, frame rate, color gamut, and dynamic range. UHDTV has been divers by ITU in ITU-R BT.2020 [4]. This recommendation can by summarized as:

Fig. 1. BT.2020 color space (creative commons BY-SA iii.0).
•

Aspect ratio: 16:ix (foursquare pixels)

•

Resolution: 4K (3840 × 2160) or 8K (7680 × 4320)

•

Frame charge per unit (Hz): 120, 120/1.001, 100, lx, 60/one.001, 50, 30, thirty/1.001, 25, 24, 24/1.001

•

Only progressive browse way

•

Coding format: 10 or 12 bits per component

•

Wide color gamut

•

Opto-electronic transfer

•

High dynamic range (not defined yet)

Regarding the HDR capabilities of BT.2020, fifty-fifty if there are not specific details virtually how to process and represent HDR data, there is a real constraint introduced by the 12 bits per component divers as the maximum bit-depth.

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Video Interfaces

Keith Jack , in Digital Video and DSP, 2008

Publisher Summary

This chapter focuses on video interfaces. Video interfaces make it possible to commutation video data betwixt devices. Interface standards are classified into analog video interfaces and digital video interfaces. Analog video interfaces types include S-Video, SCART, SDTV RGB interface, HDTV RGB interface, SDTV YPbPr interface, HDTV YPbPr interface, D-Connector interface, and VGA interface. Nigh consumer video components in Europe support i or two 21-pin SCART connectors. These connectors permit analog R'G'B' video or S-video, composite video, and analog stereo audio to be transmitted between equipment using a single cable. Some HDTV consumer video equipment supports an analog R'One thousand'B' video interface in which 3 separate RCA phono connectors (consumer market) or BNC connectors (pro-video and PC marketplace) are used. Nigh HDTV consumer video equipment supports an analog YPbPr video interface in which 3 separate RCA phono connectors (consumer market) or BNC connectors (pro-video market) are used. This chapter explains the features of digital video interfaces such as pro-video component interfaces pro-video transport interfaces, IC component interfaces, consumer component interfaces, and consumer transport interfaces.

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Video Surveillance Systems

James Sinopoli , in Smart Edifice Systems for Architects, Owners and Builders, 2010

Video Transmission

Transmission of the video signal captured from a surveillance camera to the security control center has typically occurred through coaxial cable, the traditional cable for analog video. With changes in the technology more installations are using unshielded, twisted-pair copper cable, fiber optic cable and wireless solutions. Unshielded twisted pair is even being used with analog cameras, with baluns (an interface betwixt balanced signals and unbalanced signals) or a manufacturer'south proprietary technology, which may allow signaling over long distances.

With IP cameras transmission is accomplished through unshielded, twisted-pair cabling as part of a structured telecommunications cabling system. Fiber optic cablevision is utilized for exceptionally long cable runs or for outside cameras where lighting protection is a concern. The distance between the camera and the headend equipment, as well as cost, security of signal, and resolution, may be considered in selecting the physical transmission media.

Wireless transmission tin can be used for cameras where cablevision is impractical or costly. Wireless can exist deployed chop-chop but information technology may require power and line of sight between locations; it may also be susceptible to interference. Wireless technologies include "Wi-Fi," infrared, microwave and free-span optic (FSO) systems.

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Disc and Tape Recording

Ian Sinclair , in Electronics Simplified (Third Edition), 2011

Video and Digital Recording

The recording of audio on tape presented difficulties enough, and at one time the recording of video signals with a bandwidth of upwards to five.5   MHz, and of digital sound, would have appeared to be totally impossible. The main problem is the speed of the record. For high-quality sound recording, a tape speed of fifteen   i.p.s. was one time regarded as the absolute minimum that could be used for a bandwidth of 30   Hz to almost 15   kHz. Improvements in record and recording head applied science fabricated information technology possible to achieve this bandwidth with speeds of effectually 1   i.p.s., simply there is nonetheless a large gap between this operation and what is required for video or for digital sound recording. This amounts to requiring a speed increase of some 300 times the speed required for audio recording. Early video recorders in the 1950s used tape speeds every bit high as 360   i.p.s. forth with very large reels of tape.

Analog video recording, even at present, does not cope with the total bandwidth of a video signal, and various methods of coding the bespeak are used to reduce the bandwidth that is required. In addition, the luminance (black and white) video signals are frequency-modulated on to a carrier, and the color signals that are already in this form take their carrier frequency shifted (see Affiliate eight for more details of luminance and colour signals).

For domestic video recorders, the maximum bandwidth requirement can be decreased to about three   MHz without making the picture quality unacceptable, but the main problem that had to be solved was how to accomplish a tape speed that would accommodate even this reduced bandwidth. In fact, the frequency of the carrier ranges betwixt three.8 and 4.8   MHz as information technology is frequency-modulated to avoid the problems of uneven amplitude when such high frequencies are recorded on record.

The bright solution evolved by Alexander Poniatoff (founder of the Ampex corporation) was to motility the recording head across the tape rather than move the record over a head. Ii (now often four) heads are used, located on the surface of a revolving drum, and the tape is wound circular this drum then that the heads follow a slanting path (a helical scan) from 1 edge of the tape to the other (Figure 7.13). The signal is switched from caput to caput then that information technology is ever applied to the head that is in contact with the tape. At a drum rotation speed of around 1500 rotations per second, this is equivalent to moving the tape past a head at about 5 meters per second.

Figure 7.thirteen. Principle of rotary-caput video recording. The two (or more) heads are mounted on a drum, and the record is wrapped at a slight angle. This makes the head trace out a sloping track across the tape as the drum revolves and the record is pulled around it at a boring charge per unit

Though the way that the caput and the tape are moved is very different from that used for the older tape recorders, the principles of analog video recording remain unchanged. The block diagram for a video cassette recorder is very dissimilar from that of a audio recorder of the older type, just the differences are due to the signal processing that is needed on the video signals rather than to differences in recording principles.

Note

Videotape is, at the time of writing, almost obsolete (equally attested by the huge stacks of videotapes in clemency shops) and has been superseded by digital versatile disc (DVD), the digital arrangement that uses the same principles as CD. This is particularly suited to digital television signals, and in the United kingdom has been used mainly for players of unnecessarily expensive discs (it costs less to press out a DVD than to tape a record). DVD recorders with a recordable and reusable disc are readily bachelor and of good performance, and some other answer to the need for domestic recording and replay has been to utilise a computer hard drive (magnetic disc) along with conversion circuits and then that ordinary analog television signals (as well equally digital signals) can exist recorded digitally.

These hard drive units have typically a chapters of up to 45 hours, and so that a single unit tin can cope with most domestic recording needs. With the switch to digital television set in the UK complete in 2011 the use of hard-drive video recorders will exist almost universal. A particular reward of these hard-drive recorders is that (using buffer stages) they can record and replay simultaneously, and so that when the unit is switched on it is possible to view a live programme, place on hold while answering a telephone telephone call or having a meal, and resume viewing later. The facility is available besides for digital radios in the areas where reception is possible. Ideally, we might have a difficult-drive recorder along with a DVD recorder so that really useful recordings could be preserved.

Afterward sound recorders (before the extensive use of CD recorders) for very high-quality applications used digital audio record (DAT). This operated by converting the audio into digital codes (see Chapter 9) and recording these (wide-band) signals on to tape using a helical browse such equally is used on video recorders. The main problem connected with DAT is that the recordings are too perfect. On earlier equipment, successive recording (making a copy or a copy of a copy) results in noticeable degradation of the sound quality, but such copying with DAT equipment causes no detectable degradation even after hundreds of successive copies. This would make it easy to copy and distribute music taken from CDs, and the record manufacturers succeeded in preventing this misuse of DAT (though not in the Far East). DAT recorders that were sold in the UK were therefore fitted with circuits that limited the number of copies that could be made, and the DAT system disappeared when recordable CDs and, subsequently, DVDs were adult.

Summary

Record as a recording medium hardly seems acceptable for sound recording, and its use for video and for digital sound has been a triumph of technical evolution. As and then often happens, however, the relentless progress of technology has made tape-based systems obsolescent just as they seemed to accept reached their pinnacle of perfection.

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Overview

Ivan P. Kaminow , in Optical Fiber Telecommunications (Third Edition), Volume B, 1997

A Survey of Fiber Optics in Local Access Architectures (Chapter 13)

The Telecommunication Act of 1996 has opened the local access marketplace to contest and turmoil. New applications based on switched broadband digital networks, besides as conventional telephone and broadcast analog video networks, are adding to the mix of options. Furthermore, business organization factors, such as the projected customer have charge per unit, far outweigh engineering science issues.

In Chapter 13, Nicholas J. Frigo discusses the economics, new architectures, and novel components that enter the access fence. The architectural proposals include fiber to the home (FTTH), TDM PON, WDM PON, hybrid fiber coax (HFC), and switched digital video (SDV) networks. The disquisitional optical components, described in Book IIIB, include WDM lasers and receivers, waveguide grating routers, and low-cost modulators.

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Introduction to Cable Television

Walter Ciciora , ... Michael Adams , in Modern Cable Television Engineering science (Second Edition), 2004

1.i Introduction

Cablevision television is an industry and a engineering science that has outgrown its historical proper name. Modernistic "cablevision television set" networks are used to provide a broad range of services, including analog and digital video, digital audio, high-speed data, and telephony.

The essential distinguishing characteristics of cable tv set networks are that they include broadband (typically 0.v-1 GHz of total bandwidth), highly linear distribution systems designed to carry many modulated radio frequency (RF) signals with a minimal amount of common interference between a central point and many customers, where signals are delivered via coaxial cables to and from terminal equipment. Because of these characteristics, the networks are service-agnostic to the extent that they volition carry whatsoever data that tin can be modulated on a compatible RF carrier. Modern cablevision television networks are near always two-way, use optical fiber extensively, and are segmentable so as to allow simultaneous frequency reuse in various network sections.

Historically, the cable tv set business was based exclusively on delivery of television programming, and it has been very successful in that regard. Every bit of 1999, nearly 97% of U.S. television households had cable idiot box service available, and approximately 66 million households subscribed to at least the lowest tier of video service, representing almost 67% of U.Due south. television households. 1 Those levels have changed just slowly over the by few years.

Because cablevision television receiver has been so successful and has enjoyed such vigorous growth and credence, it has spawned video competitors, including prerecorded media, direct broadcast satellite (DBS), video streaming over the Internet, as well as the involvement of the telephone industry. Increasing revenue streams from connected households, made possible by multiple service offerings, has also inverse the economics of the manufacture sufficiently that customers in some markets at present have a selection between two cable television operators who accept constructed parallel distribution networks serving the same homes. In the mutual terminology of the cablevision industry, the company building the second network is known as an overbuilder. Overbuilders may offering service as a 2nd, franchised cable tv set operator or as an open video system (OVS) operator. Taking advantage of new technologies and, in detail, the falling prices of electro-optical components, these networks typically use optical fibers to carry signals closer to subscribers than legacy cable operators, in some cases all the way to subscriber homes.

In the earth of loftier-speed information communications, and Cyberspace access in particular, services offered by cable operators have codeveloped with other wired and wireless options. For residential users, Internet access was historically provided almost exclusively through punch-upward modems straight to Internet service providers (ISPs). Many applications, nonetheless, run discouragingly slowly at the data rates that are possible through standard telephone connections, and this has led cable companies to develop connection services that are 10–100 times faster. In the competition amidst broadband service providers, cable has outsold its competitors by virtually 2:1, with a telephone technology known as digital subscriber line (DSL) providing the strongest competition to date. Competing satellite and wireless terrestrial data transport technologies are still developing market share.

In offering voice telephone service, it is the cable operator who is the over-builder, since residential phone service was bachelor to virtually every household in the United States earlier cable television operators entered that market segment. When offered by cable tv operators, phone service is regulated past the same agencies who regulate the incumbent telephone companies, leading to completely different regulatory authorities for services that share the same concrete network.

Cable-offered telephony comes in at least two technical versions and ii product classifications. Initially, telephone offerings utilized dedicated indicate-processing equipment that was advisedly engineered to meet the high reliability expectations of this service. As of early 2003, that type of equipment was nevertheless used to service the large majority of installed phone customers. The newest version, known as vox-over-IP (VoIP), shares terminal equipment with the high-speed data service, offering the potential for reduced equipment costs.

Regardless of how the signals are handled technically, cable operators may offer a primary-line service or just a secondary-line service. Primary-line service competes straight with the incumbent phone operator for all residential telephone business, merely it requires that the cable network and equipment meet the reliability standards to be the "life-line" communications link for customers in the case of an emergency (while non mandated past regulatory agencies, this voluntary requirement is generally defined as a service that is bachelor at least 99.99% of the time). Secondary-line service cedes the commencement line in each home to the incumbent but competes for boosted lines. The supposition is that the availability needn't be as high, saving the cable operator capital upgrade cost and assuasive it to offer a lower price.

In the post-obit capacity, you lot volition gain a solid agreement of the technologies required to evangelize broadband services to and from homes. You will see how the pieces fit together to make up a complete system for the transmission of data and entertainment choices to consumers. If yours is a related business organisation, you will amend empathise how it fits with the cablevision industry. If you lot are already knowledgeable in some aspects of the broadband networks used by cable, this volume volition fill in the gaps.

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