U.S. Philips Corporation

Edward M Ponte

Dirk J Teuling

Hendrik Ten Pierick

Alko F De Vries

Steven J Van Raalte

A field deflection circuit in a picture display device including a sawtooth generator for generating an essentially sawtooth-shaped voltage. The circuit is provided with a storage element in which information is stored under the influence of applied clock pulses. Per field period the number of times when the content of the storage element is changed is reduced to a predetermined number, e.g. because a number of clock pulses is omitted. The clock pulses applied to the sawtooth generator are then distributed as regularly as possible.

Field deflection circuit in a picture display device

A field deflection circuit for use in a picture display device, comprising an amplifier to whose output the series network of a field deflection coil, a separated capacitor and a negative feedback resistor is disclosed. A circuit is provided in parallel with the separating capacitor for fixing the d.c. component of the voltage across the capacitor at a more less constant value. Frequency-dependent negative feedback networks may therefore be omitted.

Field deflection circuit for use in a picture display device

A circuit arrangement for generating a sawtooth-shaped signal for the field deflection in a picture display device with an amplitude which is substantially independent of the field frequency is disclosed. The value of the sawtooth-shaped signal during the occurrence of a sampling pulse is compared with a reference value for generating a control signal controlling the slope of the sawtooth-shaped signal. To eliminate instability in amplitude, which might result from phase jitter of the incoming field synchronizing signal and might cause an interlace error, sampling pulses are applied whose repetition frequency is substantially equal to the nth part of the field frequency, where n is an integer which is larger than 1, preferably a small multiple of 2.

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Eindhoven, Netherlands

Edward M Ponte