U.S. Philips Corporation

Marinus Cornelis Van Buul

Sing L Tan

Leendert J Van De Polder

Claude J Le Can

Jan August Hofman

Pieter M Van Den Avoort

Jean P Michel

The use of a field interpolation circuit which interpolates by means of equal amplitudes of the information from two successive fields results in a television line standard doubler capable of furnishing a very good picture quality.

Line standard conversion circuit

An analog-digital converter supplying a digital output signal in natural or reflected binary code, having an input stage, n consecutive conversion stages comprising two parallel channels of identical structure, in each of which there are two current paths in accordance with the result of a comparison of currents effected in the preceding stage and an output stage to which the switched currents proceed. In the complete converter there are 2.sup.n current paths corresponding to 2.sup.n quantization levels. Conversion is effected by means of a number of stages as small as the number n of bits of the desired digital signal. This converter is simple, fast, asynchronous, has a lower power consumption and its symmetry provides excellent automatic temperature compensation.

Binary analog-digital converter

Indicated as hybrid D-PCM a new transmission system is given which is based on differential pulse code modulation (DPCM) with signal compression at the transmitter end and signal expansion at the receiver end. In the transmitter defined auxiliary information is fed to the DPCM code groups to obtain composite code groups, while in the receiver a local auxiliary signal derived from a reconstruction device is subtracted in a separating device from the received composite signal. With a particularly simple construction hybrid D-PCM is distinguished as compared with DPCM by effective perturbation reduction, in addition to which a pulse can be saved in the transmitted code groups.

Transmission system by means of time quantization and trivalent

When the information of a continuous-motion video record is displayed in the stop-motion mode by repeated display of two fields which form an interlaced picture, motion in the scene gives rise to a frame-frequency flicker phenomenon in the stop-motion picture. By forming suitable video signal combinations in discrete groups which each comprise two associated fields and by recording these combinations in the video record, the flicker phenomenon in a stop-motion picture is eliminated without continuous display being perceptibly affected.

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Eindhoven, Netherlands

Marinus Cornelis Van Buul