TELEVISION Volume VI (1949-1950) TELEVISION Volume VI (1949-1950) TELEVISION Volume VI (1949-1950) Edited by ALFRED N. GOLDSMITH ARTHUR F. VAN DYCK ROBERT S. BURNAP EDWARD T. DICKEY GEORGE M. K. BAKER AUGUST, 1950 Published by RCA REVIEW RADIO CORPORATION OF AMERICA RCA LABORATORIES DIVISION Princeton, New Jersey Copyright, 1950, by Radio Corporation of America, RCA Laboratories Division Printed in U.S.A. INDUSTRIAL TELEVISION TRICOLOR KINESCOPE -v- TELEVISION, Volume VI PREFACE TELEVISION, Volume VI, covering the years 1949 to June, 1950, is the twelfth volume in the RCA Technical Book Series, and the sixth volume devoted exclusively to television. The first television volume was published in 1936 followed by Volume II in 1937. Volumes III and IV appeared in 1947. Original plans called for the publication in 1950 of a volume cover- ing the years 1947-1949. Because of the extraordinarily large amount of work done in television during this period, too many valuable papers would have had to be excluded for lack of space in a single volume. For this reason, two volumes are being published simultaneously, covering the periods 1947-1948 (TELEVISION, Vol. V) and 1949- June, 1950 (TELEVISION, Vol. VI). Even with the two -volume presentation, the large number of ex- cellent papers on the subject of television has made necessary a very stringent selection process.All the available material can not be in- cluded in full form. A number of papers are, therefore, presented herein in summary form only; it has been necessary to omit others entirely. Suitably balanced presentation of the various phases of tele- vision was the major criterion in deciding which papers to include in full and which in summary. The presentation of a paper in summary form (or the non -inclusion of any particular paper) is not intended to indicate any deficiency in technical accuracy, literary merit, or importance. The papers in this volume are presented in six sections: pickup, transmission, reception, color, UHF, and general. RCA Review gratefully acknowledges the courtesy of the Institute of Radio Engineers (Proc. I.R.E.), the McGraw-Hill Book Company, Inc. (Electronics), Caldwell -Clements, Inc. (Tele-Tech) and the Grad- uate School of Business Administration, Harvard University (Harvard Business Review) in granting to RCA Review permission to republish material by RCA authors which has appeared in their publications. The appreciation of RCA Review is also extended to all authors whose papers appear herein. RCA Laboratories The Manager, RCA REVIEW Princeton, N. J. July 18, 1950 - NTH - TELEVISION Volume VI (1949-1950) CONTENTS PAGE FRONTISPIECE -V - PREFACE The Manager, RCA Review -vii- PICKUP Development and Performance of Television Camera Tubes . R B JANES, R. E. JOHNSON AND R. R. MOORE A New Image Orthicon 1 ..... R . B. JANES, R. E. JOHNSON AND R. R. HANDEL 34 The Vidicon - Photoconductive Camera Tube P K WEIMER, S. V. FORGUE AND R. R. GOODRICH 41 Summaries: The Image Isocon - An Experimental Television Pickup TubeBased on the Scattering of Low Velocity Electrons . P. K. WEIMER New TV Studio Relay Switching System 49 . W E.TUCKER AND C. R. MONRO 49 Mixing Local and Remote Television Signals W. E. WELLS AND J. M. WEAVER 50 Television Photometry and Optical Background R L Kum NI 50 TRANSMISSION Standardization of the Transient Response of Television Transmitters . R. D. KELL AND G. L. FREDENDALL 51 Phase and Amplitude Equalizer for Television Use . ... ... E. D. GOODALE AND R. C. KENNEDY 69 Artificial Lines for Video Distribution and Delay . .A. H. TURNER 77 RECEPTION Development of a Large Metal Kinescope for Television . H. P. STEIER, J. KELAR, C. T. LATTIMER AND R. D. FAULKNER 90 Reversible -Beam Antenna for Twelve -Channel Television Reception . ........ 0. M WOODWARD, JR.106 Characteristics of High -Efficiency Deflection and High -Voltage Supply Systems for Kinescopes 0. H. SCHADE123 Automatic Frequency Phase Control of Television Sweep Circuits . E. L. CLARK156 A Study of Cochannel and Adjacent -Channel Interference of Tele- vision Signals, Part I- Cochannel Studies 164 A Study of Cochannel and Adjacent -Channel Interference of Tele- vision Signals, Part II - Adjacent -Channel Studies . 186 ULTRA -HIGH FREQUENCIES Method of Multiple Operation of Transmitter Tubes Particularly Adapted for Television Transmission in the Ultra -High -Frequency Band G. H. BROWN, W. C. MORRISON, W. L. BEHREND AND J. G. REDDECK195 -ix- PAGE Experimental Ultra -High -Frequency Television Station in the Bridge- port, Connecticut Area . ....... R F GUY, J. L. SEIBERT AND F. W. SMITH 207 An Experimental Ultra -High -Frequency Television Tuner . T MURAKAMI220 Ultra -High -Frequency Antenna and System for Television Trans- mission 0. 0. FIST232 A New Ultra -High -Frequency Television Transmitter . J R BENNETT AND L. S. LAPPIN248 COLOR A Six -Megacycle Compatible High -Definition Color Television System270 An Analysis of the Sampling Principles of the Dot -Sequential Color Television System 291 A General Description of Receivers for the Dot -Sequential Color Tele- vision System Which Employ Direct -View Tri-Color Kinescopes. 338 Summaries: Mixed Highs in Simultaneous Color Television 343 Colorimetric Analysis of RCA Color Television System 344 A Simplified Receiver for the RCA Color Television System . 344 Recent Developments in Color Synchronization in the RCA Color Tele- vision System 345 GENERAL Television: Techniques and Applications. .A. N. GOLDSMITH346 Simplified Television for Industry . R. C. WEBB AND J. M.MORGAN 387 Theater Television A. N. GOLDSMITH396 APPENDIX-TELEVISION BIBLIOGRAPHY 403 DEVELOPMENT AND PERFORMANCE OF TELEVISION CAMERA TUBES'," BY R. B. JANES, R. E. JOHNSON AND R. S. MOORE Summary-Three new television camera tubes have resulted from an intensive development program extending over several years.These are (1) the well-known 2P28 image orthicon which is especially suited for remote pickups where a wide range of illumination is encountered and versatility is of the greatest importance; (2) the 5655 image orthicon which is capable of producing pictures of studio quality when the illumina- tion can be controlled; (3) the 5769 image orthicon which may be used for either remote or studio pickups. The construction and operation of these tubes are described in detail. The development of image orthicons is traced by an examination of their limitations and the improvements which have resulted from changes in their construction. INTRODUCTION -DURING the past fifteen years a number of television camera tubes have been developed. The first to be considered here is the iconoscopel. This tube is still used for the transmission of motion picture films and has been extensively used in studio work. When carefully used with the needed complicated correcting circuits, bias and frame lighting, it is capable of producing a high -quality pic- ture. Its resolution is satisfactory and its half -tone response is good. It is also completely stable at all light levels.However, in order to obtain satisfactory pictures, incident light levels of 800 to 1,200 foot- candles are needed on the subject. Even under these conditions "dark spot" and "flare" can be troublesome, particularly for rapid changes of illumination and for scenes that contain dark areas near the bottom of the picture. Although the signal-to-noise ratio may be satisfactory at lower light levels, shading becomes nearly impossible to correct unless the scene is evenly lighted.Lowering the beam current to decrease dark spot is of little help because the signal output drops nearly as rapidly as the dark spot and the tube becomes unusable be- cause of low signal-to-noise ratio. The type of iconoscope presently available is the 1850-A, which has a diameter of VA inches and a mosaic area of 17 square inches. * Decimal Classification: R583.6. t Reprinted from RCA Review, June, 1949. V. R. Zworykin and G. A. Morton, TELEVISION, John Wiley and Sons, Inc., New York, N. Y., 1940. 1 2 TELEVISION, Volume VI The signal output in microamperes for a typical tube is shown in Figure 1 plotted against illumination on the mosaic in foot-candles for two values of beam current. These two values of 0.15 and 0.2 micro- ampere are, in general, the values used in operation. As the operating personnel become more conscious of dark spot and flare, they tend to use the lower value of beam current. However, some may prefer the greater signal and signal-to-noise ratio obtained from the higher value. With a beam current of 0.2 microampere and a mosaic illumination of 6 foot-candles, a signal-to-noise ratio(assuming 3 X 10-3 micro- amperes of amplifier noise) of 60 can be obtained. Because this is "peaked -channel noise",i.e., noise of high frequency which conse- 1 a quently appears to the eye as fine trr grain, it is not objectionable; it is qttr equivalent to a flat -channel noise ;1*ii ratio' of 180 to 1. The use of "high peaking" to improve resolution may reduce this ratio to about 100 to 1. NKNLIGNY ILLY.NNATION ON MOSNOC,OT-CONO,CO It should be noted that these signal- Fig.1 - Typical signal outputto-noise ratios are expressed as the characteristics for iconoscopes type 1850-A and type 1848. ratio of highlight signal to root - mean -square noise. Another type of iconoscope which has been manufactured is the 1848.It has a 41/2 inch diameter and a mosaic area of a little over 6 square inches.The signal output in microamperes is shown in Figure 1 plotted against illumination on the mosaic in foot-candles for 0.15 and 0.2 microampere beam current. At 6 foot-candles and with the same amplifier noise as for the 1850-A, the value of signal to peaked -channel noise is about 30 to 1. To many users this perform- ance has not been acceptable when compared with that of the 1850-A.