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Above, pictures of the 10 inch Emiscope tube used in Victors working reproduction pre-war television receiver, similar to the tube used in the H.M.V. table model 10" receiver of 1939.

        Marconi-E.M.I                         

    How original was their system?

The question that must be asked is :- How original was the M-E.M.I. system of television?

     It is well documented and beyond doubt that E.M.I. were in possession of many patents relating to the practice of television engineering by the mid 1930's , not all however were originated in house, quite a few were the product of their American associate The Radio Corporation of America, just how important the R.C.A. patents were in shaping the system of t.v. employed by E.M.I. we shall now attempt to determine.

             First of all we will look into the two most outstanding components without which the system could not possibly operate and which separates it from the mechanical system advocated by Baird.

             There can be no doubt that the two most important items that characterise the M-E.M.I. system are the cathode ray tube for use in the receiver and the Emitron camera tube, of the two devices perhaps the most important is the cathode ray tube because there is was no other method available then to display high definition television pictures, despite the claims of one British company of the time who attempted to devise a mechanical system*1, it should also be noted that a cathode ray tube could be used employed to scan either transparencies or motion film for television signal generation instead of using an Emitron camera and was in fact the preferred method for many years after W.W.2. Rank Cintel a British company sold this type of film scanner to countries all over the world it was of course the flying spot scanner possibly first demonstrated by the Mssrs. A.C. Cossor of London.

             The first cathode ray tube  or close predecessor is probably the Braun tube invented by Braun a German physicist towards the end of the nineteenth century, following this Campbell Swinton in his now famous address to the Rontgen Society in 1911  postulated his ideas on distant electric vision or television. Campbell Swinton's idea clearly envisioned cathode rays in both transmitter and receiver and also utilised electro-magnetic scanning, all of this at a time prior to useful thermionic amplification or high vacuum technology became available.

            On the other side of the Atlantic R.C.A. scientists were also looking for a method of displaying television pictures  and it was Zworykin an emigre Russian employed by Sarnoff *2 who first patented the present form of cathode ray tube, he called it a "KINESCOPE". R.C.A. began making kinescopes in small quantities for experimental purposes and supplied E.M.I. with a number of such devices, E.M.I. under the leadership of Isaac Schoenberg directed Dr. McGee*3 to try developing tubes of their own, McGee succeeded in producing high vacuum tubes that were specifically designed for t.v. rather than instrumentation tubes that were becoming available  from other manufacturers. E.M.I. now began filing patents of their own for variations and improvements on R.C.A's original kinescope. E.M.I's cathode ray tube was named EMITRON but was never the less basically a Kinescope. 

Above, an early E.M.I. valve type DL82. Note, this is not a directly heated output pentode but an indirectly heated double diode triode, E.M.I.'s type numbers bear no relationship to the Mullard and European valve numbering system.

1*  Schophony , a small but enthusiastic television company operating during the mid 1930's  characterised by little working capital,a highly innovative British concern eventually to be taken over by the Ostrer Bros.and operated as Scophony Baird Television Ltd.

Scophony proposed a number of methods of displaying high definition television without employing a cathode ray tube, non of their systems or designs were a commercial success.

2* Sarnoff, head of R.C.A. from the 1920's until the late 1960's

3*Dr. McGee, graduate from Cambridge University , physicist specialising in high vacuum technology, worked for E.M.I. in the development of the Emitron camera tube and directed and helped Dr. Broadway in the development of E.M.I.'s version of the KINESCOPE it was aptly named  EMISCOPE.

    Zworykin's Iconoscope and E.M.I.'s Emitron camera tube are without doubt the creation of one mind, that of Zworykin, he patented and demonstrated the tube in the 1920's and passed on the principle of operation to E.M.I. there is no question that the team lead by Isaac Schoenberg refined the tube as it was in the late 1920's but to suggest that they invented it would appear to be as erroneous as suggesting that a modern day electric lamp manufacturer had invented the incandescent light bulb when it is accepted that it was invented by Edison (despite Swans claim).

      The major scanning innovation employed by E.M.I. was that of interlacing and E.M.I. did not claim it as one of their inventions, in fact Schoenberg fully and rightfully acknowledges it's inventor BALLARD of R.C.A., again patented during the 1920's, without this the 405 line system would not have been practical due to bandwidth constraints if flicker was to be avoided.

     M-E.M.I. inventions.

     One must in all fairness give credit to E.M.I. for their system of d.c. working that is retaining accurate black level throughout the entire transmit-receive chain, line clamping, flyback energy recovery employed in magnetic horizontal scan circuitry, the actual television waveform employing twice horizontal rate broad pulses for vertical sync generation, for pulse counters as used in frequency dividers found in early sync pulse generators, the long tailed pair and many other circuits essential to television.

       Many of the above inventions are due to Britains electronics genius Allan Blumlein who died so tragically during a test flight in a Halifax bomber over Wales whilst developing radar systems for the allied war effort.

      The leading figure in the development of M-E.M.I.'s television system was undoubtedly Isaac Schoenberg later to become Sir Isaac Schoenberg, under his leadership a team was brought together who complemented each other with a minimum of personality clashes, the team worked together with enthusiasm, dedication, loyalty and professionalism, each member possibly being indispensable to the team as a whole due to the enormous time constraints they were working under, one must realise that when Schoenberg committed M-E.M.I. to delivering a working 405 line electronic television system to the B.B.C. his proposed system was still in the laboratory stage yet he had sufficient confidence in his team to not only propose the system but to guarantee delivery of the system in no less than twenty six weeks from the placement of orders, he also promised that receivers would be available for the start of the television service, it being no later than the end of 1936, as we are aware the service began on November 2nd. 1936. Some items did not meet the twenty six week delivery date but the system was up and running in time for it's trade debut at Radio Olympia on August 23rd.1936.

              E.M.I and M-E.M.I. surely did such a splendid job in the development of the 405 line television system that to credit them with other companies inventions for patriotic or  personal aggrandizement is at best insulting, their work is amply rewarded by it's own success and longevity.