Digital Technologies Come Of Age

Digital Technologies Come Of Age

Speech digitisation was driven by the need to manage long-distance transmission systems more effectively. But the result of this drive also affected end users because, thanks to digital technologies, the random level of speech quality that had plagued telephony since its early days began to have less consequences on communication. Later the CCITT adopted the Group 3 facsimile standard that offered considerable improvement to end users, business first and general consumers later. Then Philips and Sony on the one hand, and RCA on the other, began to put on the market the first equipment that carried bits with the meaning of music to consumers’ homes. 

As in the case of speech digitisation, digital technologies in the CE space were not primarily intended to offer end users something really new. The CD was just another carrier, more compact and lighter to distribute records with a quality claimed to be indistinguishable from the studio’s. The opinion of some consumers, however, seems to indicate that CD quality is not necessarily the issue because some claim that the sound of the Long Playing (LP) record is better. In other words, the drivers to both digital speech and digital music were the stability, and reduced manufacturing and maintenance cost offered by digital technology, not quality. This last feature was just a by-product. 

In the same years of the CD (1982) the CCITT, with the publication of its Recommendation H.100, enabled videoconferencing through the use of 1.5/2 Mbit/s primary multiplexers as carriers of compressed videoconference streams. Videoconferencing was not unknown at that time because several telecommunication operators, and broadcasting companies as well, had videoconference trials – all using analogue techniques – but there was hope that H.100 would eventually enable a diffused use of a business communication form that at that time was little more than a curiosity. This was followed in the mid 1980s by the beginning of the standardisation activity that would give rise to CCITT Recommendations H.261 (video coding at px64 kbit/s) and H.221 (media multiplex) together with other CCITT Recommendations for coding speech sampled at a bitrate less than or equal to 64 kbit/s, in some cases with a wider speech bandwidth than 4 kHz. These activities were synergistic with the huge CCITT standardisation project known as ISDN that aimed to bring 144 kbit/s to subscribers using existing telephone lines. 

In the mid 1980s several CE laboratories were studying methods to digitally encode audio-visual signals for the purpose of recording them on magnetic tapes. One example was the European Digital Video Recorder (DVS) project, originally a very secretive project that people expected would provide a higher-quality alternative to the analogue VHS or Betamax videocassette recorder, as much as the CD was a higher-quality alternative to the LP record. Still in the area of recording, but for a radically new type of application – interactive video on compact disc – Philips and RCA were studying methods to encode video signals at bitrates of 1.4 Mbit/s fitting in the output bitrate of their CDs. 

Laboratories of broadcasting companies and related industries were also active in the field of audio and video coding for broadcasting purposes. The Commission Mixte pour les Transmission Télévisuelles et Sonores (CMTT), a special Group of the ITU dealing with issues of transmission of radio and television programs on telecommunication networks and now folded into ITU-T as Study Group 9, had started working on transmission of compressed digital television for “primary contribution” (i.e. transmission between studios). At the end of the 1980s RAI and Telettra, the latter an Italian manufacturer of telecommunication equipment, had developed an HDTV codec for satellite broadcasting that was used for very impressive demonstrations during the Soccer Worldcup hosted by Italy in 1990. Slightly later, General Instrument (GI) had showed its Digicipher II system for terrestrial HDTV broadcasting in the very narrow bandwidth of 6 MHz used in American terrestrial television. 

This short list of examples shows how, at the end of the 1980s, the telco, CE and broadcasting industries had already embarked in implementations, some of them at research level and some of an industrial value, that were based on digital technologies and provided products and services to end users with the intention of consolidating or extending their own positioning in the communication and media businesses. People who are fancied by the “convergence” idea have probably noticed that the computer industry is missing from the list of canonical “converging” industries. The reason is that, even if the computer industry has been the first to make massive use of data processing techniques, in the second half of the 1980s the computing machines within reach of end users – mostly Macintoshes and IBM compatible Personal Computers (PC) in the office, and Atari, Commodore 64 and Amiga at home – still needed at least one order of magnitude more processing power to be able to provide their users with natural moving video of acceptable size and natural sound of acceptable quality. In January 1988, the IBM representatives at the JPEG meeting proudly showed how an IBM AT could decode in real time a DCT-encoded still picture at the bitrate of 64 kbit/s. 

This snapshot describes what technology could achieve in the 1980s, but says nothing of the mindsets of the people who had masterminded those developments. Beyond the superficial commonality of technological solutions, there were and, to a considerable extent, still exist today, fundamental differences of traditions, strategies and regulatory concerns among the different industries and, within each of these industries, in the different countries or regions of the world. 

The telco industry placed great value in the existence of standard solutions, but was typically weak in end-user equipment. These were forced, on the one hand, to adhere to standards if they were intended to be connected to the “public network” and, on the other, had to be left to the goodwill of the manufacturing industry, because terminal equipment was outside the telcos’ purview. Manufacturers, however, had scarce inclination to invest in new terminal equipment because they were accustomed to receive guaranteed orders from operators at prices that could hardly be described as the result of fierce competition. The interest in digital solutions was linked to the digitisation prospects of the telephone network: basic-access ISDN (144 kbit/s) for the general user and at most primary-access ISDN (1.5 or 2Mbit/s) for the professional user, but there continued to be an underground clash between those who were driven by the need to foster the evolution of the network – here and now – and those who assumed that the world would stay unchanged and cherished the dream of bringing optical fibres to end users with virtually unlimited bandwidth some time in the future. 

The CE industry did not feel particularly constrained by the existence of standards, as shown by the adoption of 44.1 kHz as the sampling frequency of compact disc audio, selected because analogue video recorders provided an easy means to digitally encode audio in the early phases of development. That industry, however, had the culture and financial muscle to design and develop user equipment for mass-market deployment that often required sophisticated integrated circuits, when market needs so dictated. The weak point of that industry showed when equipment from several manufacturers that were functionally similar but technically incompatible appeared almost simultaneously in the market. Just the names V2000, Betamax and VHS, the three formats of home video cassette recorders and the battles that raged around them, should suffice to explain the concept. 

Even more complex was the attitude of the broadcasting industry. This was rigidly regulated in Europe and Japan and less visibly, but equally, if not more so, rigidly regulated in the USA. In Europe the Commission of the European Communities (CEC) had laid down the policy of evolution of television through Multiplexed Analogue Components (MAC) towards the European version of HDTV transmission called HD-MAC, both via satellite. In the USA and Japan the policy was one of evolution from analogue NTSC to analogue HDTV. In Japan, the introduction of HDTV was expected to happen via satellite while in the USA this was expected to happen as an evolution of the terrestrial network.

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