DE2116405A1 - Circuit arrangement for setting the picture grid in a television receiver - Google Patents

Description

BLAUPUNRT-WERKE GMBH * »h.loe.ne.m,

Pll Rl / Po 2.4.1971

R. No. 1135

Circuit arrangement for setting the image grid in a television receiver

The invention relates to a circuit arrangement for setting the image grid in a television receiver with a hori-; ζontal deflection circuit, which is constructed with controllable semiconductors, the horizontal deflection windings in series with; a capacitor parallel to the primary winding of a horizontal deflection transformer are connected in series with a further capacitor and the horizontal deflection windings are supplied with a variable direct current from a direct current ^source, through which the image grid can be shifted.

In television receivers, it is known that by Pertigungs-. tolerances of the deflection systems and the picture tubes displacements; of the image grid on the screens. Here- j as a result, the image center of the image grid is not in the geometric center of the screen, which some viewers find annoying feels. It is therefore desirable to compensate for these tolerances. In order to achieve this, it is known to add a variable current to the deflection windings in addition to the sawtooth-shaped deflection current Feed direct current, with the help of which the center of the image grid is aligned with the geometric center of the screen v / can earth. In conventional deflection circuits in which the deflection windings are fed via a deflection transformer can be the changeable direct current in easier; V / else are fed in at a point of the deflection windings, ι

209841/0549

BLAUPUNKT-WERKE GMBH

PLI Rl / Fo - 2 - 2.4.1971

R. No. 1135

In the case of new deflection circuits that use controllable semiconductors are constructed and in which the deflection windings are in series with a capacitor in parallel with the primary winding of a deflection transformer are connected in series with another capacitor, is the supply of a variable direct current associated with some difficulties to adjust the image grid. These difficulties are primarily to be seen in that one end of the deflection coils is no longer related to ground potential and thus also none to ground potential related G-lei.chstromq.ueHe, which in every TV receiver is present, can be used.

In order to enable the picture grid to be set in these circuits, which can compensate for the production tolerances and their effects on the position of the picture grid on the picture tube screen, it was proposed (DT-OS 1.811.138) to add an additional first winding to the deflection transformer provided, which is followed by a sliding circle; is. The equilibrium circle contains a potentiometer, des- ^; sen tap at the connection point of the series connection of a

Capacitor and the deflection windings is placed. The ^x circuit arrangement must now be designed so that between a center tap of the additional first winding of the deflecting transformer; and the connection point to which the tap of the potentiometer is placed, no potential difference admits. This is done by; a further additional second winding is reached, which on the one hand = · "■ on the one hand with the center tap of the additional first winding and on the other hand with the" upper end ^{11 of} the primary winding of the deflection; transformer, or »the deflection coils is connected. In this ^way: there is a series connection of the deflection coils, the to-■ sätzlichen second winding and CKLeichriehterkreises that; is connected to ground via the capacitor, which is connected to the deflection ■ ^! gen is connected in series, so that the potential across the capacitor

209841/0549

BLAUPUNKT-WERKE GMBH »ηι«. «. *, * ·«. *** »***» ». * »

PLI Rl / Fo - 3 - 2.4.1971

R. No. 1135

equal to the potential at the center tap of the additional first winding. The return pulses of the deflection circuit are inductively transmitted to the additional first winding and rectified by the rectifier circuit in such a way that a positive DC voltage is applied to one end of the potentiometer and a negative DC voltage to the other end of the potentiometer. By moving the potentiometer tap, an additional direct current can flow through the deflection coils, by means of which the picture position of the displayed picture on the j screen of the picture tube can be adjusted. The additional equal ^! current can be changed between the two extreme values, the j given by the potentiometer and its applied voltages; are. In this circuit, two additional capacitors are required for filtering. Furthermore, the additional second winding is required to prevent the return pulses from occurring at the center tap of the additional first winding. This is achieved in that the primary winding 'of the deflection transformer and the additional second winding are connected in opposite directions. As a result, the back lifts; running impulses on. The additional second winding could also be designed as a separate choke coil, which would have to be dimensioned in such a way that the return pulses are blocked. It's him- . It is evident that this additional circuit arrangement is associated with considerable effort and requires a considerable amount of power from the output stage of the deflection circuit. Due to the additional windings and the additional power required, the deflection transformer is also relatively large.

It is therefore an object of the invention to overcome the disadvantages of the known To avoid circuit arrangement and to build a circuit arrangement for setting the image grid, which is I characterized by little effort and without additional performance

209841/0549

BLAUPUNKT-WERKE GMBH «H ₁ L ₀₆₈ Mt ₁ *. r «« ^ »« a «

PLI rtl / Fo. - 4 - April 2, 1971

R. No. 1135

j from the output stage of the deflection circuit, or with a small amount of power.

'. This object is achieved by the invention in that the! the horizontal deflection and the primary winding of the Ho- '- rissontal Ableriktraneformators downstream capacitors are combined and connected in the supply line before the parallel line of the windings, and that the direct current source delivering the variable direct current to a positive point: the windings connected*

¹ The inventive measure it iet possible to use a ground referenced DC power source that is present in any television receiver. Such a source will be

^: For example, needed to feed other receiver stages. The power consumption of a circuit according to the invention is also significantly lower than that of the known additional ones

! Circuit. In addition, the horizontal deflection transformer is considerably smaller, as no additional windings have to be applied. Also the use of an expensive choke coil is there not necessary anymore.

With the aid of a drawing, an example of a circuit arrangement according to the invention for setting the image grid is shown in more detail; purifies.

The drawing shows a highly simplified horizontal deflection circuit that is fed from a regulated power supply unit 1. The storage capacitors 4, 5 are charged within a line trace interval via a charging inductance 2 and a further inductance 3, which serves as a commutation coil. During this charging phase, a first switch 6 is closed and a second switch 7 is open. The switches 6, 7 exist

209841 / OS49

BLAUPUNKT-WERKE GMBH »h.lde ₈ he.m.

PLI Hl / Po - 5 - 2.4.1971

R. No. 1135

each consisting of a thyristor and an anti-parallel connected to it Diode. A capacitor is connected to the first switch 6 and is in the supply line before the horizontal deflection windings are connected in parallel 9 and the primary winding 10 of the horizontal deflection transformer 11 is located. A secondary winding of the horizontal deflection transformer 11 is a voltage multiplier circuit 13 downstream, by means of which the high voltage required to operate a picture tube is generated.

The base point 14 of the primary winding is connected to a direct current source 15 connected, from which a variable direct current can be seen. By a capacitor 16 the puss point 14 is the Primary winding connected to ground potential in terms of alternating current. From the direct current source 15 can now, depending on the requirements, a direct current can be fed into the horizontal deflection windings 9, for example to reduce the manufacturing tolerances of the deflection systems equalize and adjust the picture grid on the screen of the picture tube according to the geometric center. as DC power source 15 can be any power source referenced to ground potential, and for example primarily serves other levels of the television receiver to dine.

This uncomplicated, advantageous generation and supply of an additional direct current for setting the image grid in a television receiver is possible that the Capacitors used in the well-known horizontal deflection circuits the windings 9, 10 are connected downstream, are combined to form the capacitor 8, which is then in the supply line before the Parallel connection of the windings 9, 10 is connected.

E3 can be seen that through the circuit arrangement according to the invention in a simple way and without great effort

209841/0549

BLAUPUNKT-WERKE GMBH »,

PLI Rl / Fo - 6 - 2.4.1971

■ position of the picture grid in a television receiver with a Horizontal deflection circuit built with controllable semiconductors is, is possible.

209841/0549

Claims (1)

BLAUPUNKT-WERKE GMBH » PLI Rl / Fo - 7 - 2.4.1971 R. No. 1135 Patent entitlement ¹ 1, circuit arrangement for setting the image grid in one; Television receiving apparatus with a horizontal deflection circuit; which is constructed with controllable semiconductors, the Ho-; Vertical deflection waves in series with a capacitor j parallel to the primary winding of a horizontal deflection transformer in series with another capacitor and the horizontal deflection windings are supplied with a variable direct current from a direct current source, through which the image position can be shifted , characterized in that the horizontal deflection windings (9) and the primary winding (10) of the horizontal deflection transformer (11) . downstream probes are summarized and in the supply line are connected upstream of the parallel connection of the windings (9, 10), and that the variable direct current supplying direct current source (15) is connected to a Pußpunkt (14 ·) of the windings. 209841/0549 L e r s e i t e