PART FOUR: COMMUNICATION AND CALCULATION
742
exhibited the device in 1893–4, but thought of it as a mere novelty and failed
to patent it in England. However, his choice of film width (35mm) and
perforation design have become standard for normal-width motion pictures
down to the present time.
Robert Paul, finding the kinetoscope unpatented in Britain, copied the
device and sold several to Charles Pathé in France. Edison, realizing his
mistake, refused to allow Paul to use his films, stimulating Paul to build his
own camera. Paul also constructed a projector with a Maltese-cross
intermittent-motion system (the French astronomer, P.J.C.Janssen had used a
revolver camera with a Maltese cross to photograph the transit of Venus in
1874). However, credit for the first successful motion-picture projection system
is usually given to the brothers August and Louis Lumière of Lyons, who in
1895 designed a combined camera and projector to which they gave the name
cinematographe. They used the same size film as Edison, but with only one
round perforation at the margin of each picture, instead of the four square ones
used by Edison. They also were the first to give an exhibition for which the
public had to pay admission, in 1895.
In 1896, Lumière films were projected in London by the magician Trewey,
who was soon giving regular cinema shows; the films were only about 15m
long (49ft), so frequent reel changes were necessary. In 1897, Pathé separated
the cinématographe into two distinct parts: camera and projector. The
Lumières were quick to capitalize on this new entertainment medium, buying
up film manufacturers in France and creating production units in the United
States and in Russia. Edison, reluctantly abandoning his kinetoscope, was
persuaded by his distributors to buy the rights to a projector so his films could
be shown before an audience, and not just remain a curiosity—the ‘peep-show’.
Edison then threw his great organizational talents into the battle, and his
company made 1700 movies. He also built the first studio, a rambling affair
which could be rotated to follow the sun; it was called the Black Maria,

because it was covered with tar paper to increase contrast.
Even though Edison was also the inventor of the phonograph, and had
been able to synchronize film and disc in his laboratories in 1889, the system
was too awkward for commercial application. A sound-on-film system was
patented by Eugène Augustin Lauste in France in 1906 and demonstrated in
1910, and a more advanced system shown by Lee de Forest of the US in 1923,
but they did not have any commercial success. What many critics consider the
golden era of the motion picture, the silent era, had a chance to flourish for
quarter of a century.
Another desired innovation was colour, and attempts were made from as early
as 1898. Some films were hand-coloured using stencils, and the French tried
tinting certain scenes for dramatic effect. However, although a number of two-
colour processes were devised in the early part of the twentieth century, the first
commercially viable full-colour film was not made until 1932 (see p. 736).
INFORMATION
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FACSIMILE AND TELEVISION
While the practice of transmitting pictures over the air is relatively recent, the
basic principles behind facsimile and television can be observed in nature, and
have been used by man in his art for thousands of years. Many insects have
compound eyes; that is, instead of just one lens to focus a scene on the optic
nerve, their eyes are composed of thousands. This is the mosaic principle: a
multiple of similar, tiny elements composes a single, meaningful whole. The
great advantage of using fragments of minerals, glass or shells in art is that
they are small, light and multi-coloured, yet can be used to cover immense,
multiply curved surfaces with intricate designs, more brilliant than any painted
surface, yet far more durable. Hence, mosaics were a natural choice in
decorating early Christian churches.
A mosaic design is another example of optical illusion; the eye is tricked
into seeing the whole when it cannot distinguish individual elements. In

today’s communications terminology, digital elements are used to represent an
apparently continuous pattern. The same principle was applied to painting in
the nineteenth century, particularly by Georges Seurat who used tens of
thousands of different-coloured paint dots to depict outdoor scenes. The
breaking up of a whole into tiny segments is also the basis of half-tone printing
processes (see p. 679), and the underlying mechanism of video cameras.
Another method of dissecting a whole into simpler elements is scanning,
which transforms a spatial pattern into a temporal one. This is the technique
we use in reading the printed page, and underlies facsimile and television
transmission. The eyes move across a line of type, and ‘fly back’ to the
beginning of the next line; similarly, the electron beam in a television receiving
tube sweeps across it 625 times every 1/50 second to compose images, a
sequence of which, due to persistence of vision, we interpret as a moving
image, the close simulation of reality. However, the invention of television had
to wait until the principles underlying motion pictures were better understood.
Facsimile
In contrast, facsimile ideas were being considered soon after the invention of
photography and even before electric telegraphy; the basic inventions for the
transmission of documents and still pictures were made 30 years before the
telephone. In 1817 the element selenium was discovered by Berzelius in
Sweden. In 1843, Alexander Bain, the Scottish watchmaker who invented the
electric clock (see p. 696), patented an electrochemical recording telegraph, and
in 1847, Frederick Bakewell devised the cylindrical mechanism on which
images for transmission are placed for scanning, which also provided
synchronization. Cylindrical scanning became the basis of most facsimile
PART FOUR: COMMUNICATION AND CALCULATION
744
machines up to the 1980s. During 1861–2, Giovanni Casseli in Italy devised
the pantelegraph, which was used by the French PTT to transmit images
between Paris and Marseilles during the latter part of the decade. Willoughby

Smith of the Telegraph Construction Company in England discovered in 1866
that light would lower the electrical resistance of a selenium rod. This, the
photoelectric effect, is the basis of all facsimile and television systems. In 1877,
Constantin Senlecq in France published a paper on his telectroscope, the first
device to use selenium for scanning.
Facsimile seems to have had a slow but steady evolution from that time, but
during the early part of the twentieth century the major use was in
transmitting photographs for newspaper publication, a process called
wirephoto. It was not until after the Second World War that facsimile devices
became available in offices. These desktop transceivers, called telefax, required
six minutes to transmit a page over the public switched telephone system; in
contrast, large centrally located systems known as bureaufax work at higher
speeds between post offices, and use separate transmission and reception
devices. In the 1970s the Japanese turned their attention to facsimile, after long
frustration with attempting to use telex with the large character sets of their
language. They now have a virtual monopoly on the manufacture of facsimile
machines, which are capable of unattended transmission and reception at
speeds of less than a minute per document.
Television
It was not long after the invention of the telephone in 1876 that imaginative
writers and artists were dreaming of the next step, which they called by such
names as ‘telephonoscope’ or ‘electric vision’. The French artist Albert Robia
was especially entranced, and drew scenes of families watching a war ‘live’ in
their living-rooms, people taking courses without going to school, and
housewives window-shopping from an armchair.
In 1884, eight years after the invention of the telephone, a German, Paul
Nipkow, patented his ingenious disc, which had 24 holes evenly spaced along a
spiral. While the disc spun at 600rpm a lens focused the light samples on a
selenium photocell. The output of this cell was a varying electric current; to
reassemble the now dissected image, Nipkow proposed using an identical,

synchronously rotating disc and a Faraday-effect (magneto-optical) light
modulator. Nipkow did not actually build this system (no suitable technology
was available at that time), but the Nipkow disc was to become the basis of
early mechanical television systems.
In 1897 in Strasbourg, Ferdinand Braun constructed the first cathode-ray
oscilloscope, the basis of all present television receivers. In 1907, Boris Rosing at
the Technological Institute in St Petersburg proposed using Braun’s tube to
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receive images, and A.A.Campbell-Swinton in a letter to Nature in 1908, ‘Distant
Electric Vision’, proposed using cathode-ray tubes (CRT), as they became
known, for both transmission and reception. Vladimir K.Zworykin, who had
emigrated to the USA from Russia, joined the Westinghouse company in 1919,
bringing with him ideas about using CRT devices for television. However, it was
not until 1923, after having left and returned to Westinghouse, that he
constructed the first practical storage camera tube, the iconoscope. The image
was projected on to a mosaic of photosensitive elements inside the tube. This
mosaic was then scanned by a beam of electrons which, by a process called
secondary emission, released charged elements to form the picture signal.
During the period 1923–4, Charles Francis Jenkins, who had contributed to
the evolution of motion-picture projectors in the 1890s, experimented with the
Nipkow disc. About the same time, but independently, John Logic Baird in
Scotland was engaged in similar experiments. Baird, and Jenkins shortly after,
made demonstrations of their systems in 1925, as did Ernst F.W.Alexanderson
at the General Electric (GE) Company’s headquarters in Schenectady. In 1927,
Philo T.Farnsworth, an independent inventor, demonstrated the first complete
electronic television system, based on his invention of the image-dissector tube.
However, Zworykin, now with the Radio Corporation of America (RCA),
contested Farnsworth’s patent, and only after long litigation did each receive
basic patents on their systems.

These experiments came to preliminary fruition in 1927, when the
presidential candidate, Herbert Hoover, appeared in an experimental AT&T
telecast. GE put the first home TV set on the market in 1928, and the same
year broadcast the first dramatic production, the sound going out over WGY
while the picture was transmitted from experimental station W2XAD. This
was followed by a science-fiction drama, giving its audience a missile-eye’s
view of an attack on New York City. In 1929 the British Broadcasting
Corporation (BBC) began an experimental, low-definition TV broadcast; and
in the US, the Bell Telephone Laboratories transmitted a television image in
colour between Washington and New York, using three separate channels to
transmit the lightprimaries, red, green and blue.
In 1932, Zworykin, now at RCA, supervised the installation of television
equipment in their flagship NBC studios in the Empire State Building, and in
1935, RCA’s president, David Sarnoff, announced that they would spend a
million dollars for TV programme demonstrations. Also in 1935, a station in
Berlin began low-definition broadcasting, and in 1936 the BBC began the
world’s first high-definition TV broadcasting service. In 1937 a mobile TV
unit roved the streets of New York City for live pickups. The pre-war
development of television technology culminated in the conception of the
shadow-mask colour tube in 1938 by W.Flechsig in Germany, and the
invention of the first large-screen television projector, Eidophor, by Professor
Fischer at the Swiss Federal Institute of Technology in 1939.
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The year 1939 also saw the opening of the New York World’s Fair, at which
Sarnoff premiered commercial television. RCA also demonstrated a complete
home TV set; a peculiarity of this set was that viewers did not look directly
into the CRT, but saw the tiny images in a mirror—whether this was done
because of concern about irradiating the public, or for technical reasons is not
known. A few of these sets were sold to enthusiasts; others, more technically

minded, built their own to receive the experimental broadcasts, but the war
delayed regular television broadcasting.
Television broadcasting
After the war ended in 1945, the US Federal Communications Commission
(FCC) resumed television licensing, displacing FM radio’s allocation in the
frequency spectrum. By mid-1946, 24 new licenses had been issued. The
Columbia Broadcasting System (CBS), long RCA’s main rival, demonstrated a
colour system invented by Peter Goldmark. Although giving a brilliant image, it
was incompatible with the existing black-and-white sets which RCA had just
placed on the market. Therefore, RCA wanted to delay approval, and in 1947
the FCC postponed any colour decision. It was not until 1953 that the FCC
adopted a compatible colour system, called NTSC (National Television Systems
Committee). In 1956 an improved system called SECAM (Sequentiel Couleur à
Memoire) was devised in France; and in 1962, PAL (Phase Alternance Line)
appeared in Germany. All these systems are incompatible, and in consequence
no world-wide television system is possible without conversion until a new, high-
definition, all-digital replacement is introduced, probably in the 1990s.
In the US, 1947–8 saw the beginning of television entertainment as well as
news, pitting NEC and CBS against each other for the flood of advertising
revenue. In 1949 the first TV set to appear in Sears, Roebuck’s mail-order
catalogue was offered for $149.95.
By 1956–7, 40 million (85 per cent) of all US homes had TV sets; there
were 500 TV stations; and families were spending five hours a day before the
‘tube’. Advertisers flocked to take advantage of the immense persuasive power
of the medium, even experimenting with such Orwellian devices as subliminal
perception.
In 1962, the first transatlantic television transmission was achieved, using
the communications satellite Telstar I (see below).
COMMUNICATIONS SATELLITES
The basic principle under which satellites function is due to Kepler, who first

elucidated the laws under which planets orbit the sun (celestial mechanics).
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However, the notion of an artificial satellite was apparently first conceived in
an 1870 science-fiction story, The Brick Moon by Edward Everett Hale. The
story featured the use of a visible, 60m (200ft) diameter body orbiting the
earth to assist navigators. In 1870, Asaph Hall discovered two natural satellites
revolving around Mars, and told Hale that from what he could see, one might
be such a ‘brick moon’.
Jules Verne’s novel From the Earth to the Moon (1865) was remarkably
prophetic, not in the mechanism used—a train-like projectile shot out of a huge
cannon—but in his choice of geographical locations. Verne picked Florida for
his launch site (a hundred years later, the first manned moon rocket left from
Cape Canavaral), and the cannon was designed in Baltimore (home of the
Glenn L.Martin company, which built the Viking rocket, an early
improvement to the Second World War V2). However, it was not until 1924
that Hermann Oberth described the potential advantages of artificial satellites
in detail, including space stations and huge space mirrors to control weather, in
his book Wege zur Raumschiffahrt (‘Ways to Space flight’).
After the Second World War serious work on artificial satellites accelerated.
In 1945, Arthur C.Clarke published his prophetic article on the advantages of
a geostationary orbit for satellites to be used for radio and television
communications. Wernher von Braun published in 1952 a popular article
advocating the use of a manned space station for military purposes. Other,
more peaceoriented proponents wanted small, instrument-carrying satellites for
scientific purposes (see Chapter 13).
The first satellite designed specifically for communications was launched in
1960. Dubbed ECHO 1, it was nothing but a huge reflecting sphere for
relaying voice and television signals. However, it was soon followed by the first
active repeater satellite, Courier 1B, and the communications satellite era

began in earnest. In 1962, Telstar I became the first communication satellite
which could relay not only on data and voice, but also TV. Although NASA, a
US government agency, provided the launch, a private corporation, AT&T,
owned the satellite; a few months later, Congress authorized the creation of
COMSAT (Communications Satellite Corporation) as a private corporation.
In 1963, the first satellites to be placed in geosynchronous orbit—with all the
advantages that Clarke had foreseen—were launched. These, the Syncom
series, were built by the Hughes Aircraft Corporation. Because their on-board
power was low, and because the Syncoms had to be placed in an orbit 37,000
km (23,000 miles) from the earth’s surface, ground stations had to employ
30m (100ft) diameter parabolic antennas (called ‘dishes’ from their
appearance), which cost $3–5 million each. In 1959, Clarke, again foreseeing
the next step, published a popular article advocating satellites of great power,
whose signals could be received by low-cost antennas connected to ordinary
TV sets; in the late 1980s, several such direct-broadcast satellites (DBS) have
been put into orbit.
PART FOUR: COMMUNICATION AND CALCULATION
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From 1960 thousands of satellites were launched by the US and the USSR
for a variety of military and civilian purposes; and by them for other countries.
The West, under the multinational consortium Intelsat, preferred geostationary
orbits for its communications satellites, three of which are enough to provide
world-wide coverage. The East, under Intersputnik, preferred close-in,
nearpolar orbits, although this means that many satellites are required to
provide 24-hour coverage; also, they must be continuously tracked as they
flash from horizon to horizon. However, much less power is needed aboard,
and smaller earth-station antennas can be employed.
The launch monopoly held by the two superpowers has been challenged
since 1979 by the European Space Agency (ESA), using their Ariane rocket,
and other countries including China and India have the capability. Also, these

countries and Japan have built their own satellites. In the 1980s, the US
became more and more dependent on NASA’s manned space shuttles for
satellite placement, but a launch disaster in 1986 gave new impetus to
conventional rockets.
Back to ‘wire’?
By the mid-1980s, Intelsat had so many satellite circuits available over the
north Atlantic for telephone, data and television transmission that it had
surplus capacity. Furthermore, a rival technology, transatlantic fibre-optic
cables, was threatening satellites with severe competition. Laser beams,
travelling in two pairs of glass fibres, are capable of carrying the equivalent of
37,800 simultaneous telephone conversations. Even greater capacity is in the
offing, AT&T’s Bell Laboratories having achieved a record of 20 Gbits (1
gigabit= 10
9
bits) per second over one hair-thin fibre using optical
multiplexing, the equivalent of 300,000 conversations.
The idea of beaming TV programmes directly into homes by means of very
high-power direct broadcast satellites (DBS) is being challenged by co-axial and
hybrid fibre-coax distribution systems. Thus, we may come full circle, back to
the original concepts of telegraphy—a ‘wired world’, rather than one principally
dependent upon space technology.
INFORMATION STORAGE TODAY
In principle, any physical phenomenon can be used for recording information,
but until the scientific revolution information always remained readable by the
naked eye. Only after optical (photographic), electromechanical (telegraphic
and phonographic) and magnetic recording methods were developed did we
extend our storage capacities to the submicroscopic level.
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Also, with the exception of telegraphy, information was recorded in

analogue form. The alternative, digital recording, is much simpler in principle:
finger-counting and tally sticks were among the earliest digital techniques. The
development of the electric telegraph, which used a pulse-code system from the
beginning, led to theoretical studies of digital systems and analogue-digital
conversion technologies.
Digital systems for data storage are only two centuries old. However, the
inventions of Jacquard, Babbage and Hollerith (see pp. 699, 701) were
mechanical, and even when they became electromechanical they were
relatively slow in operation. The acceleration of science and technological
development during the Second World War provided practical electronic,
magnetic and optical data storage systems.
Pulse-code modulation and information theory
In 1926, Paul M.Rainey of the United States was granted a patent on a
pulse coding system, but nothing seems to have come of it until Alec
H.Reeves, an Englishman working in the Paris laboratories of the
International Telephone and Telegraph Company (ITT) reinvented it in
1937; the fundamental PCM (Pulse Code Modulation) patents were
granted to him in 1938 and 1942. However, no available electronic
components were capable of implementing PCM at a reasonable cost.
During the Second World War a team headed by Harold S. Black at the
Bell Telephone Laboratories designed the first practical PCM system for the
US Army Signal Corps to safeguard telephone conversations. Civilian
applications had to wait until relatively recently, when semiconductor
technology—particularly the integrated circuit (see p. 705) —made them
economically attractive. The first significant PCM application was in
digitizing voice communications for telephony. For PCM, soundwave
amplitude is sampled 8000 times every second and each sample encoded to
a 7-bit accuracy (1 part in 128), with an extra bit added for signalling
purposes. Thus 64,000 pulses per second (64 kbits per second in today’s
units) are necessary for intelligible speech transmission.

In 1948, Claude E.Shannon of the Bell Telephone Laboratories published a
seminal paper, ‘The Mathematical Theory of Communication’, which for the
first time provided a sound theoretical basis for understanding information and
communication phenomena of all kinds. He outlined a ‘universal’
communication system: a source, producing messages; a transmitter, encoding
them into suitable signals for transmission; a channel, through which the signals
travel; a receiver, decoding the signals; and a message destination. Sender and
receiver are usually human beings, the other elements being mechanical,
optical, electronic or other artificial means. Another element, a source of noise,
PART FOUR: COMMUNICATION AND CALCULATION
750
is always present in real communications channels. This general model applies
from the simplest to the most complex communication systems.
Another part of Shannon’s theory gives a precise measure of information,
based on the concept of uncertainty (entropy in thermodynamics; information
has been called negentropy by some information theorists). A bit (a neologism
formed from ‘binary’ and ‘digit’) can represent the uncertainty between ‘yes’
and ‘no’ when both are equally likely; the message content, the storage
capacity, the transmission rate, and the channel capacity can all be measured in
terms of bits. For example, a telephone channel which has a band-width of
3000Hz has a channel capacity of about 60,000 bits per second, and
commercial television, with a 6MHz band-width, requires a channel capacity
approaching 100 Mbits per second—more than a thousand times greater.
The work of Reeves, Shannon and many others will culminate in a totally
digital switched public telecommunications system known as ISDN (Integrated
Services Digital Network), which will replace the existing analogue networks
which have been the only public carriers for more than a century. ISDN will
transmit voice, data, text and images using multiple 64kbit-persecond channels.
Image and data storage and retrieval systems
Starting in the 1950s, many attempts have been made to use

electromechanical—essentially phonographic—techniques to store and play back
images, such as Phonovid, a still-picture TV system (Westinghouse, mid-
1960s); and Teldec, a full-motion, black-and-white TV system (AEG-
Telefunken and Decca, 1970). They failed: Phonovid required an expensive
scan converter; and Teldec, even though attaining a storage density 100 times
greater than that of LP records, could only play 7-to 15-minute programmes.
About 1970, EG&G Inc. introduced their Dataplatter, an adaptation of 7in
(18cm) diameter, 45rpm phonograph technology which could store up to 5
megabits (Mb) of data. The reasons for the failure of this innovative
technology in the marketplace are unclear—perhaps it was too far ahead of its
time, coming five years before the microcomputer.
Optical means have been used almost from the invention of photography,
but only for images, not for digital data. However, in 1945, Vannevar Bush
published a seminal article, ‘As We May Think’, in a popular American
magazine, the Atlantic Monthly. Bush had developed the Differential Analyzer in
1931, one of the earliest analogue computers, for solving differential equations.
During the war he became director of the US Office of Scientific Research and
Development. Looking forward to a conversion of the massive wartime
scientific effort to peacetime uses, he pointed out how primitive were our
methods of accessing the research literature. After predicting the inventions of
dry photography, ultramicrofiche and the voice-operated typewriter, he
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conceived an automatic system for the mass storage and rapid retrieval of
documentary information, which he called ‘memex’. Memex was based on an
extrapolation of imaging technology, but the selection principle was associative
indexing, which only now is coming into the realm of the possible as a
technique of ‘artificial intelligence’.
It was not long after Bush’s detailed prophecy that automatic retrieval of
photographically reduced documentary information was embodied in working

hardware. The Filmorex system, invented by Jacques Samain in France early in
the 1950s, used 70×45mm (23/4×13/4in) film-cards (or microfiche, which
French word has been adopted into English). Each Filmorex fiche contained
two moderately reduced page images, together with a grid of tiny squares on
which was encoded up to 500 bits of index information. When the fiche
passed by an array of photocells in the Filmorex selector, code-combinations
matching the search request would trip a release mechanism and divert the
selected fiche to a bin for viewing. A similar system, Minicard, was developed
in the 1950s by Kodak’s Recordak Division. This was based on tiny fiche cut
from 16mm microfilm, each of which could store up to six pages at a 60:1
reduction, together with more than 1500 bits of data. Roll microfilm was used
for optical data storage in FOSDIC (Film Optical Scanning Device for Input to
Computers) to speed up the processing of the vast amount of data collected for
the 1960 US census; data were reduced images of punched cards, compressed
vertically by photographing them through an anamorphic lens.
Videotape
In 1956, Alexander M.Poniatoff demonstrated the first videotape recording
(VTR) device; and in 1958 his Ampex Corporation installed the first VTR in
American television studios. This invention radically changed TV programme
production and dissemination. The first VTR machines used 2 inch-wide
(5cm) tape and were very expensive, but programmes could be recorded and
played back immediately, unlike film; this capability was of incalculable value
for television production. The public could no longer tell whether it was
watching a programme ‘live’ or ‘canned’. Attempts had been made to store
television on tape before, but these had been brute force systems based on tape
speeds hundreds of times greater than used for audio—with concomitant
mechanical problems. Poniatoff saw that the required megahertz band-width
could be achieved without these penalties by using magnetic heads rotating at
right angles to the linear tape motion. Ampex also realized that VTR
technology could store high-resolution still images. In the 1960s they marketed

Videofile, which could store facsimiles of 250,000 pages (about 5Gbits: 1
gigabit=10
9
bits) on a reel of videotape. These systems cost several million
dollars and only a few were purchased by government agencies and