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BROADCAST NEWS of April 1961

Die ausgewählten Artikel stammen aus der RCA Firmen-Zeitung vom April 1961 - Die Einführung beginnt hier.



Hier gab es noch kein Editorial wie in früheren und den späteren Ausgaben.  Es beginnt gleich mit dem ersten Artikel von JOHN H. ROE, Broadcast Television Engineering.


Increase Reliability, Cut Cost of Operation, Make Programming More Versatile and Assure a Higher Quality Color TV Picture - by JOHN H. ROE, Broadcast Television Engineering
The increasing importance of color in television programming is placing a great deal of emphasis on improvements in equipment to permit easier, more flexible, more reliable operation and at the same time bring about a reduction in cost of producing programs.

Engineers working in the many branches of the electronics industry are rapidly breaking down barriers which confined the designers of television equipment only ten short years ago when color television was in its infancy.

Utilization of new techniques, materials, and components has had a significant effect on the cameras and other gear used in television stations in the direction of simplification and stabilization.
The idea of improvement is being applied basically toward easier and less costly operation.

In some cases the equipment itself may be much simpler, but in others it may be more complex in order to assure greater stability with consequent lessening of attention from operators. Another result of this trend is better reliability; therefore, less cost in operation and maintenance.

In the period since the previous color television issue of "Broadcast News" 1*) in early 1954, there have been numerous significant changes and additions in the color studio product line. Many of these are described here.
1*)  "Broadcast News", Vol. No. 77, Jan.-Feb. 1954.

Color Studio Camera

The TK-41C Color Studio Camera is an embodiment of the most modern construction and features in live color cameras. It is the third generation from the TK-40A, the first practical color studio camera made available for the "compatible color system".
Anmerkung : Es gab minidestens 10 verschiedene Denk- und Forschungs- Ansätze, ein farbiges Bild zu übertragen und mit einem Fernseher darzustellen. Die FCC hat irgendwann das zum s/w Bild kompatible System ausgesucht und es USA weit festgeschrieben.

It is interesting to trace the transitions from this early model to the present modern TK-41C to illustrate the character of the modernization which has appeared throughout the line.

All versions of the color studio camera are alike in the use of three 3-inch image orthicon tubes, with color-separating optics, to generate the three primary color signals required in the compatible color system.

Also, basic electronic functions performed in the circuits are the same. The differences lie in details of execution, details which represent a tremendous simplification in the rack and console-mounted portions of the chain.

In the TK-40A, three and a half racks and two 13-inch console sections were required to house the control and processing equipment assocated with each camera. Two of the racks were nearly filled with 11 regulated power supplies, a total of 136 1/2 !!! inches of rack space, while a third rack was filled with signal-processing and cable terminal units.

Processing Amplifier Introduced

The transition to the TK-41A camera chain involved a series of very significant changes in both signal processing techniques and power supply design which resulted in reducing space requirements to one 13-inch console, one 22-inch console, and about one half of one cabinet rack.

All of the signal processing circuits, formerly occupying a full rack plus a console section, were compressed into a single unit, called a processing amplifier. This amplifier occupies only 10 1/2 inches of space in a console.

Not only has space been reduced, but performance is greatly improved. Application of highly stabilized circuits removed some of the drift problems in the TK-40A that required constant attention from operators. A reduction of about 50% in power required for the camera chain led to reduced air-conditioning costs.

Electro-Optical and Stability Improvements

The succeeding transitions, now embodied in the TK-41C, have introduced important features into the camera itself. These include precision yokes for assuring accurate image registration, and new color splitting optics (prisms instead of flat plates) which eliminate spurious reflections in the received pictures.

Very significant improvements in electrical stability of the amplifiers and image orthicon control circuits have been developed recently, and are incorporated in the TK-41C. They have eliminated much of the daily setup routine and warm-up period formerly required to put a color camera on the air.

RCA - Precision Image Orthicons for Color

An associated improvement in camera tubes was made available at the same time as the precision deflecting yokes. This was the RCA-7513 precision image orthicon for color which also contributes to better image registration and picture quality.

More recently, the sensitivity of precision color image orthicons has been increased to a point where it is now possible to make color telecasts in studios where lighting is only slightly greater than what is needed for monochrome cameras. The greater sensitivity is available in the RCA-4415 and RCA-4416 image orthicons, the latter being especially designed for use in the blue channel.

Anmerkung : Das sind typische Werbesprüche. Im Vakuum-Labor in Darmstadt waren ebnsolche Spezialisten am Werk, die sich mit dem prinzipiellen Mikrofonie-Effekt der Ortikons beschäftigen mußten und diese Probleme nie gelöst hatten. Das wird hier einfach verschwiegen, weil die Kamera an die 180 Kilo wog und so nicht zu erschüttern war. Die Fese Konstrukte lagen aber nur bei 60 Kilo samt Optik und bei der geringsten Berührung fing das Farbbild an zu schwimmen. Die (angeblich waren es nur acht Exemplare) FESE Ortikon Farbkameras wurden am Ende verschrottet.

Color Film Chain

The introduction of the RCA TK-26 3-Vidicon Film Camera Chain in 1954 brought a practical solution to color tv programming from film. Since this time the "3-V"- system has consistently outperformed any other experimental approaches employing flying-spot scanners and special projectors.

Its two great virtues are the ability to function with standard intermittent types of TV film projectors as well as the ability to produce pictures of excellent quality from film having a wide range of densities. The appearance of this equipment on the market coincided with that of the processing amplifier described earlier. The film chain performance correspondingly benefited from the characteristic stability of the new processing equipment.

Optical and Camera Tube Advances

Important and more recent improvements in the TK-26 equipment include a prism type of color-splitter designed along the same principles as the similar parts of the studio camera (TK-41C), and having the same beneficial effects in eliminating unwanted reflections.

Improved camera tubes have also become available. The RCA 7038 vidicon (announced in 1958) is especially useful in the TK-26 camera because of its precision face plate (helping optical accuracy and registration) and its freedom from spurious edge flare and resultant freedom from unnatural color shading.

Projectors and Multiplexers

The steadily growing importance of film as a program source indicates the need for providing the very best in projectors. To meet this need, the TP-6A 16mm professional projector was introduced in 1953, establishing an unmatched level of excellence, long life, and reliability.

A special feature for color was added in the later model, TP-6CC, in the form of a remotely controlled neutral-density disk for adjusting the light output. This feature may be used with either manual or automatic control to aid in handling wide variations in film density without disturbing color fidelity. The current TP-6EC model features greater light efficiency (longer application time) and a new and improved driving motor.

One of the most important pieces of equipment in many stations is a projector for handling 2" by 2" slides, color or monochrome, which constitute a large portion of the material for station breaks and commercials.

The announcement of the TP-7A dual-drum slide projector in 1956 solved a prolonged problem of inadequate performance in the previous types of slide projectors used in stations. This new projector not only provides the convenience, slide-holding capacity, ruggedness, and reliability needed, but it fulfills the requirement for consistent color balance in color programming. The companion TP-8A model goes beyond the flexible remote control features of the TP-7A by providing for random selection of slides.

Flexible programming for either monochrome or color, or for combined operation, in the film room is now easily accomplished with the TP-15 multiplexer. This rugged equipment provides for remote switching of the light paths from as many as four projectors into either of two film cameras. It is especially tailored for use with the TK-26 color film camera chain and RCA film and slide projectors.

Television Tape Recording

The advent of magnetic tape recording as a medium for television programming took place after the establishment of the compatible color system.

The necessity for including color recording within the capabilities of the new medium was accepted from the very first. In that it was essentially born in full color, tv tape recording is distinct from the earlier techniques in telecasting which grew up in drab hues of gray before acquiring colorful garb.

The advantage, inherent in magnetic recording, of immediate play-back has brought about much more effective use of the most desirable program hours in all the time zones by permitting repetition of important programs on an hourly basis. Also, the pre-recording of many of the big-name shows has become almost a universal practice through the use of TV tape. The ability of tape systems to record compatible color has been an important factor in the wide acceptance of both delayed broadcasts and pre-recording.

The comprehensiveness of RCA's TRT-1 TV Tape recording equipment in meeting the demands for negligible distortion, inter-changeability of tapes and recording heads, and simplicity and reliability of operation is establishing the highest standards in this important phase of the industry.

Color Monitor

The studio color monitor is the "yardstick" by which final performance of cameras and other studio equipment is judged. The TM-21B color monitor is an outgrowth of experience with earlier monitors such as the TM-10 and the whole line of color studio equipment.

It was designed from the beginning to serve as a precise measuring instrument with unusual accuracy and stability. It contains built-in features for self-checking and calibration, which provide ease in rechecking its accuracy quickly - requiring no external equipment other than a source of color bar signal.

All-Glass Color Kine

The earlier TM-21A was designed to use a specially selected 21-inch metal cone kinescope. The more modern version, TM-21B, uses the newer all-glass color kinescope without special selection. This is the same type of tube that is used in all new color receivers. Its use provides increased brightness and clarity of color.

Program Switching Equipment (Bild- und Trickmischer)

Continuing growth in the art of television programming has dictated steadily increasing flexibility, variety, and sophistication in the means for assembling the desired sequence of events in a program.

The TS-40 is a new "studio switching system" (hier ierst mal nur der Umschalter der Quellen) which handles color and monochrome signals with equal ease. It produces negligible distortion and provides for a wide variety of applications from the simplest to the most complex. Precise control with minimum operating effort and versatility of switching modes and effects enable the programmer to enhance the attractiveness of both programs and commercials.

The TS-40 is a transistor switching system where the new solid-state devices are used to carry out the actual switching function with accuracy and simplicity - impossible with mechanical relays.

This feature alone greatly reduces the space requirements. It also permits handling color signals with so little distortion that several trips through the system do not produce noticeable degradation.

Special Effects System

Transitional fades and wipes (Überblendungen) have been standard devices in motion pictures for adding atmosphere and relieving monotony in changing from one scene to another. The possibilities for producing a large variety of special effects by electronic means are almost unlimited. One of the most intriguing aspects of the electronic approach is the ease and speed with which selection and execution can be accomplished.

The RCA Special Effects System provides electronic circuitry and controls capable of selecting over 150 different kinds of picture transitions. This system is especially designed to be integrated with the TS-40 switching equipment to provide the most flexible and complete facility for the program assembly function. It works equally well with monochrome or color signals, or with switching from monochrome to color signals and vice versa. It also permits the production of composite scenes using the travelling-matte technique.

Microwave Relay Equipment

The characteristics of color TV signals are much more demanding on the transmission capabilities of station equipment than the simpler monochrome signals.

Critical evaluation of such capabilities is especially important in intermediate links where it is important that no appreciable degradation be added no matter how many links are involved.

While the early TTR / TRR 0.1 watt microwave equipment did an excellent job with monochrome signals, it fell short of the distortionless performance required for color.

This is not surprising when it is remembered that it was designed in the mid-1940's when monochrome equipment was undergoing its early growing pains.

The arrival of color in the early 1950's made undeniable demands for improved relay systems, and the TVM-1A 1.0 watt system was announced in 1958 to meet these needs. The fundamental soundness of its design has been demonstrated in wide usage by both broadcasters and common carriers, and by constant improvement leading to broader applications in multiple-hop systems. It is presently in use in systems as large as eight hops where it is delivering color signals so nearly like the originals that it is difficult to measure the difference.

Transmitters and Antennas

Because of the large amounts of power involved, the television broadcast transmitter is probably the most difficult link in the system with respect to keeping distortion within reasonable limits.

It is interesting to note, therefore, that advances in the art of tube and circuit design have permitted the power of transmitters to advance from about 5 to 100 kilowatts with no sacrifice in quality of performance and with increasing reliability. The demands of color are even more difficult to meet than in other parts of the system, particularly with respect to differential phase and gain, characteristics which largely determine color fidelity.

However, the color years have witnessed the development of a complete line of transmitters for UHF and VHF bands. VHF transmitters providing up to 100 kw of actual power and ERP of 316 kw, the maximum permitted by the FCC, and UHF transmitters providing up to 25 kw of actual power and the maximum allowed ERP of 1000 kw, are standard products. Simple air-cooled tubes are used throughout the VHF line.

In the field of transmitting antennas great strides have been made in new types which provide simple, rugged construction, reliability over long periods of time regardless of climatic conditions, and ability to accommodate the large amounts of input power delivered by modern transmitters.

The familiar superturnstile or "batwing" antenna has become a "hallmark" of the VHF station. It is available for both upper and lower bands with power gains as high as 17.5, and power input capacity up to 100 kw.

The sleek looking travelling wave antenna is also available for high band VHF stations with gains up to 18 and input ratings up to 50 kw. For UHF stations the pylon antenna is available for all channels with input ratings up to 60 kw and power gains up to 60.

Matched Color TV System

The contribution of a matched system of quality equipment to the successful operation of a TV station is inestimable. At RCA, the developments which have lead to improved color TV equipment have progressed hand-in-hand, each contributing to the success of the other.

By setting the matched system as the goal, all of the improvements in studio and film cameras, projectors, control and monitoring equipment, switching and special effects systems, TV tape recorders, microwave, transmitters and antennas, have been completely integrated to produce a color TV system for easiest, most flexible, most reliable operation.


FIG. I. RCA advanced Color TV Tape recorders are designed from the ground up ior color. This equipment meets the demands for negligible distortion, interchangeability of tapes and recording heads, and simplicity and reliability of operation.

FIG. 2. TK-41C Color Studio Camera is embodiment of the most modern features in color cameras.

FIG. 3. New optics for 1C incorporate prisms for color separation.
the TK-41C incorporate dfe'

FIG. 4. Processing amplifier has compacted signal processing circuits resulting in minimum rack space and 50 per cent power reduction.
FIG. 5. Transistor switching and special effects equipment handle color and monochrome signals with equal ease, maximum quality.

FIG. 6. TK-26 3-Vidicon Film Camera chain brings a practical solution to color TV film programming.

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