Kurt Schlesinger

Progress in the Development of Post-Acceleration and Electrostatic Deflection

Electrostatic deflection from a common center is possible by the use of electrostatic yokes, or Deflectrons. These consist of a 4-terminal pattern, printed on the inside of glass cylinders or cones. An analysis of the pattern geometry is presented which gives simple expressions for deflection factor of electrostatic yokes. The theory also accounts for a small residual noncircularity of scan, and gives clues as to its correction. Equipment to test tube performance is described, including ultraviolet mapping and electronic detection of the axis. The most suitable type of post-accelerator for use with Deflectrons employs a long drift space, bounded by a metallic mask, and confines the high gradient to a narrow region close to the screen. It is shown that this mask intensifier suffers from secondary emission. This effect can be effectively suppressed by an insulating coating of the first surface of the mask, while connecting the support metal to a lower potential than the drift space. The resulting double layer of charges prevents the escape of secondaries towards the screen. This barrier-mask intensifier permits post-acceleration ratios of 10 to 1 without loss of deflection.

Continuous All-Electronic Scanner for 16mm Color Motion-Picture Film

The methods of converting the 24 frames/sec film standard to the 30 frames/sec television standard are discussed. The disadvantage of using storage-type devices is brought out in order to show the need for a flying-spot scanner in televising film in color. The reasons for choosing the jump-scan method in the Motorola scanner are given with emphasis on the advantage of the large optical aperture realized with this method. This is possible since no moving optical parts are needed between the tube and the film and the full opening of the lens can be used. — The various factors affecting registry both in time and space are enumerated. The solutions used to minimize the errors and the final results obtained are given. The use of a signal derived from the leading edges of the sprocket perforations to control the position of scan on the tube face to minimize bounce is described in detail. The use of this signal for continuous correction of film shrinkage is also shown. Other features of the scanner to be described are the anastigmatic deflection yoke and single-control adjustable gamma.

Transfer Characteristics and Mu Factor of Picture Tubes

An attempt is made to explain, analytically, the observed shape of the characteristic of kinescopes, which seems to follow a simple power law with an exponent between 2 and 2.5. The difference from Langmuir-Childs law is due to the fact that the active-cathode area varies with grid voltage according to another power law. The theory is applied to the modulator section of a conventional TV picture tube and also to various structural modifications thereof. As to the emission characteristic, gamma is consistently found to lie between 2.4 and 2.5 and seems to be little affected by structural alterations. The mu factor, on the other hand, is strongly influenced by any one of the changes in the four system parameters. An experimental tube was built to check some of the predictions of the above theory. For the cathode current, a gamma value of 2.43 was observed. The useful screen current followed a power law with an exponent of 1.9. The mu factor of this tube was found to fall within two per cent of the value computed from (15) of this paper.

The Synchrotector, A Sampling Detector for Television Sound

The paper describes an efficient and economic demodulator for intercarrier television sound. The circuit uses the method of sampling near zero passage of the carrier. This is accomplished in one-half of a double triode. The other half operates as a locked oscillator, whose cathode output is used to drive the sampler cathode. The phase angles between grid and cathode of the sampler are not in quadrature. A centering method to obtain coincidence between optimum fm detection and best AM rejection is described.

Pulsed Envelope Detection of Color Signals

The paper deals with a method for synchronous detection employing half-wave rectifiers, rather than product demodulators, for the decoding of NTSC color signals. Two basic circuits are presented illustrating the balanced and unbalanced envelope detector and using conventional diodes and triodes, respectively. The ultimate phase accuracy is found to be ± 2 degrees for the unbalanced type, and better than ± 1 degree for the balanced type. However, these errors occur only at specific angles and vanish on others.

The Vectorscope and its Applications in Color Tv, Fm and Radio Navigation - Second Edition

The Vectorscope is an oscillograph for the display of signals which consists of amplitude and/or phase modulation of a carrier at some specific center frequency. The Vectorscope displays amplitude-modulation as the radial distance of the scanning spot from center screen, and instantaneous phase as the angle counted from a fixed phase reference, say North, on the Vector screen.