DE2008656C3 - Circuit arrangement for the horizontal shifting of the picture position in a television receiver - Google Patents

Description

The invention relates to a circuit arrangement for the horizontal displacement of the image position in a Television receiver, the capacitor of the AC integrator. which is the phase comparison stage the line synchronization circuit with the comparison pulse source connects via a means of a Control voltage adjustable first resistor is connected to ground

Such a circuit is the subject of the earlier patent 15 37 924.

In known television receivers, permanent magnets are used to shift the image position are arranged adjustable on the picture tube neck.

This relatively difficult to adjust device is another known arrangement preferable when adjusting the image position by adjusting the size and / or direction of one of the Deflection coils supplied DC voltage is made, which produces a premagnetization corresponding to the desired image position in the deflection coils calls. This setting can be done easily and precisely with the help of a potentiometer respectively.

Such circuits are used in black-and-white receivers and in color television receivers 90 ° deflection used, whereby the adjustment range for the image position is sufficient to compensate for all examples of deviations in deflection systems and picture tubes, without disturbing distortions of the television picture.

Since, however, in color television receivers with 110 ° deflection because of the larger deflection angle among other things a stronger pincushion distortion occurs, the adjustment range of the known circuit must be reduced if a specified allowable pillow ver without higher demands on the tolerances of the deflection systems and picture tubes used there must be provided.

According to the invention, this object is achieved by that the control voltage for the adjustable first resistor is an adjustable second resistor taken is arranged in the direct current path of the line deflection coils and at a constant DC supply voltage source is connected.

Advantageous embodiments of the invention are described in the subclaims.

An exemplary embodiment of a circuit arrangement according to the invention is shown in the drawing jo and is explained in more detail below.

In the drawing, 1 shows the part of the line output stage of a television receiver that is essential for the horizontal position shift, in particular of a color television receiver for 110 ° deflection. Here, the part of a line output transformer which is located in the deflection circle and has two windings 3, 4 is shown with 2. Two electrolytic capacitors 5 and 6 are provided for the alternating current medium-voltage earthing of the windings 3 and 4. The outer connections of the windings 3 and 4 form the transformer output for the horizontal deflection coils 7 and 8 connected in parallel in the present exemplary embodiment. 9 denotes a potentiometer that is connected to a preferably stabilized positive DC supply voltage source + Ub or ground via resistors 10 and 11, respectively located. A fixed tap 12 and an adjustable tap 13 of the potentiometer are each connected to one of the ends of the windings 3 and 4 which are earthed in terms of alternating current.

In the drawing, a known phase comparison circuit 14 is also shown to which line sync pulses taken from a pulse separation stage 16 (not shown in detail) are fed via a coupling capacitor IS. Via a further coupling capacitor 17 and an RC integrator 18, 19, the phase comparison stage 14 is simultaneously supplied with comparison pulses, which in the present exemplary embodiment are taken from the horizontal oscillator 20, to which the control DC voltage resulting from the phase comparison stage 14 is then fed via a connection 21. In another embodiment, the comparison pulses can also be taken from a winding of the line output transformer. The output signal of the horizontal oscillator 20 reaches the line output stage 1, which is only partially shown, via a connection 22.

The capacitor 19 of the integrator is a resistor adjustable by means of a control voltage,

50

55

for example, a diode 23 connected in the forward direction is connected downstream, the cathode of which with the Connection point between the potentiometer 9 and the resistor 11 is connected. The diode 23 is a Resistor 24 connected in parallel whose ends with the s anode of the diode 23 or with the adjustable tap 13 of the potentiometer 9 are connected.

The function of the circuit arrangement according to the invention will now be described below.

A direct current supplied by the supply direct voltage source + Ub flows through the potentiometer 9. An additional direct sirom also flows through the deflection coils 7 and 8, which can be adjusted in size and direction with the potentiometer 9 and allows the image position to be shifted horizontally in both directions. However, the amount of this shift is too small to meet the requirements at 110 ° -Color television receivers to be sufficient.

The additionally required amount of the horizontal image shift is according to the invention by a Shift of the phase position of the horizontal oscillator, based on the line sync pulse sequence, obtained. For this purpose, the forward resistance of the diode 23 is changed by changing the diode as a function of the position of the potentiometer 9 flows through the resistor 24 from a larger or smaller current will. The parallel connection of the resistor 24 and the forward resistance of the diode 23 thus forms a variable base point resistance for the ÄClntegrier member 18, 19. By changes this Resistance also changes the size of the time constant of the tfC integrator 18,19, by the the shape and size and thus the phase position of the comparison pulses and thus also the horizontal ones Image position is essentially determined.

The properties of the horizontal oscillator are not influenced by the shift in the phase position of the comparison pulses

The simultaneous shift of the horizontal image position due to the changing bias of the Deflection coils and by changing the phase position of the comparison pulses by means of the Potentiometer 9 increases the adjustment range of the horizontal image position to such an extent that the The circuit arrangement also meets the requirements for 110 ° color television receivers additional circuit complexity is very low. The setting is easy because for the one you want Shift only the potentiometer 9 must be adjusted.

1 sheet of drawings

Claims (4)

Patent claims: 1. Circuit arrangement for horizontal displacement the image position on a television receiver, with the capacitor of the SC-IntegraiJonsgfiedes, which the phase comparison stage of the line synchronizing circuit with the comparison pulse source connects via a first resistor that can be adjusted by means of a control voltage is connected to ground, characterized in that that the Steeerspannuog for the adjustable & jeraen Widerstaijcl (23) ι Her Im drawing must not be exceeded. However, the adjustment range rekfit djwn is no longer sufficient, mn at 110 ° -Ab | entoH ^ sä ^ icae specimen scatter Deflection systems nip ifldröhren to balance it out because, one would have higher demands on the Set the tolerances of the deflection systems and picture tubes, which, however, would lead to an undesirable increase in production costs The invention was based on the issue, while avoiding the disadvantages mentioned, a simple and inexpensive circuit arrangement for the horizontal displacement of the image position in a television receiver. to be built up. The adjustment range is extended in such a way that it can also be used to shift the ^o Fbfhfä barenzv ^ fflMWiderstand ^) entomrnteriisi ^ -w-,. "", _.,, _f _ DC path of the Zeüe ^ deflection coils (7, 8) 15 image position in HO color television receivers right arranged and at a constant Speisegleicbspan- without disturbing raster distortions and power source is connected 2. Circuit arrangement according to claim 1, characterized in that the first resistor (23) has a forward-connected diode and the second resistor (9) is a potentiometer 1 circuit arrangement according to claim 2, characterized in that instead of a diode the Collector-emitter path of a transistor is used 4. Circuit arrangement according to claim 2, characterized in that the instead of a diode Source-drain path of a field effect transistor is used.