JPH0520050Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a horizontal deflection linearity correction circuit used in various devices using cathode ray tubes (picture tubes).

(Prior Art) One of the problems with devices that display images using a picture tube that is deflected at a relatively wide deflection angle is that It is mentioned that the output reproduced image is stretched at both ends.

Generally, to horizontally deflect the electron beam of a picture tube using the electromagnetic deflection method, a sawtooth wave current for horizontal deflection is passed through a horizontal deflection coil attached to the neck of the picture tube. However, the manner in which the sawtooth wave current for horizontal deflection supplied to the horizontal deflection coil changes on the time axis is the eighth
As shown in curve a in the figure, if the electron beam of the picture tube changes at a constant rate on the time axis, the deflection angle per unit time of the electron beam of the picture tube is 9th.
As illustrated in the figure, the beam is deflected at a constant angle α.

On the other hand, the image display surface of a picture tube is curved with a large radius of curvature so that it is as close to a flat surface as possible, so the distance from the center of deflection of the picture tube to the image display surface is not constant. Therefore, when the deflection angle per unit time of the electron beam is constant as described above, the moving distance of the electron beam per unit time on the image display surface is the 9th
Since the moving distance at the periphery, exemplified by l' in the figure, is larger than the moving distance l at the center, even if you try to project an image with a constant grid spacing pattern on the image display surface, As illustrated in FIG. 10, the image projected on the image surface is in a state where the peripheral portion is elongated compared to the center portion.

The most common conventional solution to the above problem is to install a horizontal deflection coil 2 in series with a horizontal deflection coil 2 to which a sawtooth wave current for horizontal deflection is supplied from a horizontal deflection circuit.
A so-called S-shaped correction capacitor, which also serves as a direct current blocker, is connected to appropriately adjust the resonance period between the S-shaped correction capacitor and the horizontal deflection coil. The conventional method used uses the resonance effect between the S-shaped correction capacitor and the horizontal deflection coil to correct the waveform of the horizontal deflection current.
Good correction can be made when the horizontal deflection frequency is constant, but when the horizontal deflection frequency is switched to multiple levels, multiple S-shaped capacitors are used in response to the change in the horizontal deflection frequency. is required to be switched by a changeover switch.

However, because a large current flows through the S-shaped capacitor, the above-mentioned changeover switch is prone to arcing between the contacts each time the current is cut off, so in order to safely and reliably change the changeover switch, it is necessary to turn off the power to the device. This requires a complicated operation, such as having to switch the switch once it has been disconnected, and it is difficult to change the linearity of a part of the image, for example, the left edge of the image. Even if there were such demands, there was a problem in that they could not be easily met.

Therefore, in order to solve the above-mentioned problem, including the case where the horizontal deflection frequency is switched to a plurality of levels, the applicant company has developed a system that starts from the horizontal deflection circuit 1 as shown in FIG. In series with the horizontal deflection coil 2, which is supplied with a sawtooth current for horizontal deflection, there is a horizontal deflection linearity corrector LCA, i.e. one permanent magnet, as shown in FIGS. 4 to 6. 9, and a permanent magnet 9 arranged in such a manner that the magnetic flux generated by the permanent magnet 9 can be circulated in series.
Two saturable magnetic cores 7 and 8 are respectively provided in contact with the two magnetic poles forming a pair and are spaced apart from each other, and are wound around the two saturable magnetic cores 7 and 8, respectively. When the windings 10 and 11, which are respectively wound around the two saturable magnetic cores 7 and 8 described above, are connected in series and a current is passed through them in a certain direction, the two The magnetic flux generated by the respective windings 10 and 11 wound around the saturable magnetic cores 7 and 8, respectively, is added to the magnetic flux generated by the permanent magnet 9 in one saturable magnetic core, and in the other saturable magnetic core. 2 wound around the two saturable magnetic cores 7 and 8 so as to be subtracted from the magnetic flux by the permanent magnet 9.
The connection polarity of the two windings 10 and 11 is determined, and the series-connected windings are connected to the horizontal deflection coil 2 of the picture tube.
By connecting a horizontal deflection linearity correction device LCA, which is essentially connected in series with the horizontal deflection linearity correction device LCA, the sawtooth wave current for horizontal deflection has a steep slope in the center like the waveform b shown by the dotted line in Fig. 7. The specification of Japanese Patent Application No. 182,574/1983 proposes a solution in which the above-mentioned problem is avoided by making the inclination gentle at both ends.

In FIG. 3, which shows a block diagram of a horizontal deflection circuit to which the horizontal deflection linearity correction device LCA, which has been proposed by the applicant company and is configured as shown in FIGS. 4 to 6, is connected. 1 is a horizontal deflection output circuit, 2 is a horizontal deflection coil, and LCA is a horizontal deflection linearity correction device.

Further, c and d in the figure are terminals of the horizontal deflection linearity correction device, and these terminals c and d are used in the horizontal deflection linearity correction device LCA shown in FIGS. 4 to 6, respectively. They correspond to terminals c and d, respectively.

Reference numeral 5 in FIG. 3 is a capacitor for blocking the DC component, and this capacitor 5 is connected to the horizontal deflection coil 2.
Its capacitance value is selected to be a large value so that its impedance is sufficiently small at the frequency of the horizontal deflection current applied to it. That is, in the circuit arrangement shown in FIG. 3, the waveform of the horizontal deflection current is not corrected by the resonance effect between the capacitor and the horizontal deflection coil 2, as in the conventional circuit described above, but by the correction of the waveform of the horizontal deflection current. The waveform is corrected by the horizontal deflection linearity corrector LCA.

Now, in the previously proposed horizontal deflection linearity correction device shown in FIGS. 4 to 6, 7 and 8 are drum cores made of a ferromagnetic material having saturable magnetic properties, such as ferrite. , also 9
1 is a permanent magnet, and 10 and 11 are windings wound around the drum cores 7 and 8 described above.

The drum cores 7 and 8 described above are individually in contact with the two magnetic poles N and S forming a pair in the permanent magnet 9 in an arrangement such that the magnetic flux generated by one permanent magnet 9 can be circulated in series, The windings 10 and 1 are provided in a spaced apart state and are wound around the two drum cores 7 and 8, respectively.
1 are connected in series.

The connection polarity of the two windings 10 and 11 wound on the two drum cores 7 and 8, respectively, is the same as that of the two windings 7 and 8 that are connected in series.
When a current i in a certain direction is passed through the two drum cores 7 and 8, magnetic fluxes φ1 and φ2 are generated in the windings 10 and 11 respectively wound on the two drum cores 7 and 8, and as for one drum core 7, the magnetic fluxes φ1 and φ2 are generated as described above. magnet 9
The magnetic flux φ3 is added to the other drum core 7.
is determined to be subtracted from the magnetic flux φ3 caused by the permanent magnet 9. is the opposite, the magnetic fluxes φ1 and φ2 generated in the respective windings 10 and 11 wound around the two drum cores 7 and 8 are equal to the magnetic flux φ1 of one drum core 7 and the magnetic flux φ1 of the drum core 7, respectively. For the other drum core 8, the magnetic flux φ2 of the other drum core 8 is added to the magnetic flux φ3 of the permanent magnet 9}.

In any of the previously proposed horizontal deflection linearity correction devices shown in FIGS. 4 to 6, the magnetic flux φ3 generated from one permanent magnet 9 is divided into two The magnetic flux φ1 generated by the current i flowing through the winding 10 wound around the drum core 7 is configured to flow back to the drum cores 7 and 8 in series, so that the magnetic flux φ1 does not flow back to the drum core 8. The magnetic flux φ2 generated by the current i flowing through the winding 11 wound around the drum core 8 is prevented from flowing back to the drum core 8.

Therefore, the inductance L10 of the winding 10 wound around the drum core 7 and the inductance L10 of the winding 11 wound around the drum core 8 are
L11 changes as shown by curves L10 and L11 in FIG. 7 in response to changes in the polarity and magnitude of the current i passed through it.

That is, when the current i flowing through the winding 10 is positive, the inductance of the winding 10 wound around the drum core 7 increases as the drum core 7 becomes saturated as the current i increases. The inductance L10 of the winding 10 being turned is
It decreases as the current i flowing through the winding 10 increases, and when the current i flowing through the winding 10 is negative, the magnetic flux density in the drum core 7 decreases as the current i increases. The inductance L10 of the winding 10 wound around the drum core 7 is
The inductance of the winding 11 wound around the drum core 8 increases as the current i flowing through the winding 10 increases.On the other hand, when the current i flowing through the winding 11 is negative, the inductance increases. Since the drum core 8 becomes saturated as i increases, the inductance L11 of the winding 11 wound around the drum core 8 decreases as the current i flowing through the winding 11 increases. When the flowing current i is positive, the inductance of the winding 11 wound around the drum core 8 decreases because the magnetic flux density in the drum core 8 decreases as the current i increases.
L11 increases as the current i flowing through the winding 11 increases.

Therefore, the series inductance of the two windings 7 and 8 described above, that is, the inductance L between terminals c and d in the horizontal deflection linearity correction device
(10+11) is the minimum inductance at the point where the current i is zero, as shown in the curve L(10+11) in FIG. 7, which is a combination of the curves L10 and L11 in FIG. It increases as the current increases regardless of whether it increases in the positive or negative direction, and a sawtooth shape as shown in the lower part of FIG. When a wave current i is applied, the inductance value between terminals c and d of the horizontal deflection linearity correction device LCA becomes the largest corresponding to the positive and negative peak values of the sawtooth wave current, and is the largest in the center. Changes to become smaller.

Therefore, in the horizontal deflection linearity correction circuit shown in FIG. 3, where the previously proposed horizontal deflection linearity correction device LCA shown in FIGS. The sawtooth wave current flowing through the deflection coil 2 has a slope that becomes gentler at the beginning and end of the sawtooth wave, as shown by the dotted curve b in FIG. By using the horizontal deflection linearity correction device LCA, the occurrence of image distortion as shown in FIG. 10 can be effectively prevented.

(Problem to be solved by the invention) However, since the horizontal deflection current that actually flows through the horizontal deflection circuit is not a perfect straight line as shown by the broken line c in FIG. When an image is displayed on an image display screen by performing electromagnetic deflection using a horizontal deflection current whose horizontal deflection linearity has been corrected using the proposed horizontal deflection linearity correction device LCA, the reproduced image obtained will not be symmetrical. That became a problem. In order to solve the above-mentioned problems, for example, by adjusting the number of turns of the windings 10 and 11 individually wound around the drum cores 7 and 8, the manner of correction of the waveform of the horizontal deflection current can be adjusted arbitrarily. It is also possible to change it. However, even when the solution described above is applied, fine adjustments may be required due to variations in the sets and windings. This is done by unwinding or adding windings to the deflection linearity coil, but since such fine adjustment is impossible, the windings individually wound around the drum cores 7 and 8 are The fine adjustment described above can be achieved by winding a secondary winding around one or both of the wires 10 and 11, connecting a load circuit to it, and changing the current value flowing to the load according to the set variations. A solution was proposed to do this.
By the way, the scanning standards to be applied when reproducing images, for example, in the case of television receivers, often differ depending on the standard system of the television system that is being received. When it comes to display devices used in various information devices, the scanning standards are often so different that each device manufacturer sets their own scanning standards. If the scanning standards are different, as in the case of different scanning standards, the configuration of the deflection circuit will naturally be different. As is well known, many types of deflection circuits that can be used for multiple scanning standards have been proposed, since production is carried out in small quantities with a wide variety of products, which is disadvantageous in terms of production control and cost. be.

In the horizontal deflection circuit that can be used for multiple scanning standards as described above, one of the windings 10 and 11 individually wound around the drum cores 7 and 8, as described above, Alternatively, if you wind a secondary winding around both, connect a load circuit to it, and change the current value flowing to the load depending on the set variation to perform the fine adjustment described above, a certain horizontal deflection can be achieved. Even if the load circuit described above is compatible with the frequency, the load circuit described above may become incompatible when the horizontal deflection frequency is switched to another frequency, so a solution is needed. It was done.

(Means for Solving the Problems) The present invention includes one permanent magnet and a pair of permanent magnets arranged in such a manner that the magnetic flux generated by the permanent magnet can be circulated in series. The two saturable magnetic cores are provided in contact with the two magnetic poles individually and are spaced apart from each other, and the windings are respectively wound around the two saturable magnetic cores. When the windings respectively wound around the saturable magnetic cores are connected in series and a current is passed through them in a certain direction, the magnetic flux generated by the windings respectively wound around the two saturable magnetic cores is , the two saturable cores are wound so that in one saturable core, the magnetic flux is added to the magnetic flux by the permanent magnet, and in the other saturable core, it is subtracted from the magnetic flux by the permanent magnet. The connection polarity of the two windings being turned is determined, and the series-connected windings are substantially connected in series with the horizontal deflection coil of the picture tube, and are wound respectively around the two saturable magnetic cores. Horizontal deflection linearity is achieved by winding a secondary winding around one or both of the windings, and connecting a load circuit for changing linearity to the secondary winding via a switch. The above-mentioned problems are solved by providing a correction circuit.

(Example) Hereinafter, specific contents of the horizontal deflection linearity correction circuit of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a circuit diagram of one embodiment of the horizontal deflection linearity correction circuit of the present invention, and FIG. 2 is a circuit diagram for explaining the operation of the horizontal deflection linearity correction circuit shown in FIG. The horizontal deflection linearity correction circuit according to the invention includes the windings 10 and 10 respectively wound around the two saturable magnetic cores 7 and 8 in the previously proposed horizontal deflection linearity correction device described with reference to FIG. 1
A horizontal deflection linearity correction circuit having a configuration in which a secondary winding is wound around one or both of 1 and a load circuit R for changing linearity is connected to the secondary winding 14 via a switch SW. It is. The above-described on/off operation of the switch SW is performed, for example, by a switching control signal supplied from the control signal generation circuit CC to the switch in correspondence with the switching operation of the horizontal deflection frequency.

In FIG. 1, 7 and 8 are drum cores made of a ferromagnetic material having saturable magnetic properties, such as ferrite, 9 is a permanent magnet, and 10 and 11 are the drum cores 7, The winding 8 is wound around, and the numeral 14 is a secondary winding.

In the horizontal deflection linearity correction circuit shown in FIG. 1 and FIG. Although it is shown as being wound on the winding 11, when implementing the present invention, the above-mentioned 2
The next winding may be wound on a winding 10 which is wound on a drum core 7 made of a ferromagnetic material having saturable magnetic properties (e.g. ferrite) or The winding 11 is wound around the drum core 8 made of a ferromagnetic material having saturable magnetic properties, and the coil wound around the drum core 7 made of a ferromagnetic material having saturable magnetic properties. Both the wire wound on the winding 10 being turned and the wire wound on the winding 10 may be used.

The drum cores 7 and 8 mentioned above are arranged in such a manner that the magnetic flux generated by the permanent magnet 9 can be circulated in series, and are in contact with the two magnetic poles N and S forming a pair of the permanent magnet 9, respectively, and are mutually connected. The windings 10 and 11 wound around the two drum cores 7 and 8, respectively, are connected in series.

The connection polarity of the two windings 10 and 11 wound around the two drum cores 7 and 8, respectively, is the same as that shown in the fourth diagram, and the two windings connected in series are the same as those shown in the fourth diagram. When a current i in a certain direction is passed through the drum cores 7 and 8, 1 is applied to each of the windings wound around the two drum cores 7 and 8, respectively.
The magnetic fluxes φ1 and φ2 generated at points 0 and 11 are added to the magnetic flux φ3 caused by the permanent magnet 9 described above for one drum core 7, and subtracted from the magnetic flux φ3 generated by the permanent magnet 9 described above for the other drum core 7. {If the direction of the current i flowing through the two series-connected windings 7 and 8 is opposite to that described above, the two drum cores 7 and 8 The magnetic fluxes φ1 and φ2 generated in the respective windings 10 and 11 are the magnetic flux φ1 of one drum core 7 and the magnetic flux φ3 due to the permanent magnet 9 described above.
and for the other drum core 8, it is added between its magnetic flux φ2 and the magnetic flux φ3 from the permanent magnet 9}.

Now, the switch SW in the horizontal deflection linearity correction circuit of the present invention shown in FIG. 1 is turned off, and the linearity change load circuit R connected to the secondary winding 14 Considering the horizontal deflection linearity correction circuit of the present invention in a state where no current flows through the secondary winding 14, in this case, the inductance L10 of the winding 10 wound around the drum core 7 and the inductance L10 of the winding 10 wound around the drum core 8 are The inductance L11 of the winding 11 is the seventh
The inductance of the winding 10 wound around the drum core 7 changes as shown by curves L10 and L11 in the figure. When the current i flowing through the winding 10 is positive, the drum core 7 increases as the current i increases. The winding 10 wound around the drum core 7 in order to become saturated
The inductance L10 decreases as the current i flowing through the winding 10 increases, and when the current i flowing through the winding 10 is negative, the inductance L10 decreases with the magnetic flux density in the drum core 7 as the current i increases. In order to achieve this, the inductance L10 of the winding 10 wound around the drum core 7 increases as the current i flowing through the winding 10 increases, and on the other hand,
The inductance of the winding 11 wound around the drum core 8 is such that when the current i flowing through the winding 11 is negative, the drum core 8 becomes saturated as the current i increases. The inductance L11 of the winding 11 decreases as the current i flowing through the winding 11 increases, and when the current i flowing through the winding 11 is positive, the inductance L11 in the drum core 8 decreases as the current i increases. As the magnetic flux density decreases, the inductance L11 of the winding 11 wound around the drum core 8 increases as the current i flowing through the winding 11 increases. 8 series inductance, i.e. terminal c in the horizontal deflection linearity corrector,
The inductance L (10+11) between d is the curve L in Figure 7, which is a composite of curves L10 and L11 in Figure 7.
As shown in (10+11), the inductance is the minimum at the point where the current i is zero, and when the current i is positive,
Regardless of whether the increase is negative, it will increase as the current increases, and the horizontal deflection linearity correction circuit when a sawtooth wave current i as shown in the lower part of FIG. The inductance value between the terminals c and d changes so that it becomes the largest corresponding to the positive and negative peak values of the sawtooth wave current and becomes the smallest at the center.

The operation of the horizontal deflection linearity correction circuit of the present invention when no current flows through the secondary winding 14 is the same as the operation of the previously proposed horizontal deflection linearity correction device LCA described with reference to FIGS. 4 to 6. However, in the horizontal deflection linearity correction circuit of the present invention, either one of the windings 10, 11 wound on the two saturable magnetic cores 7, 8 in the horizontal deflection linearity correction device or A load circuit R for linearity change is connected to the secondary winding 14 wound on both of the windings via a switch SW, and the switch
When the SW is turned on, the linearity change load circuit R is connected to the secondary winding 14 via the switch SW, and a current is caused to flow through the linearity change load circuit R. Ensure that adjustments are made.

FIG. 2 is a circuit diagram for explaining the operation of the horizontal deflection linearity correction circuit of the present invention shown in FIG. 1, and the windings 10 and 1 shown in FIG.
The black circles near the ends of the windings 1 and 1 indicate the polarity of each winding. In the horizontal deflection linearity correction circuit shown in FIG.
The polarity of the windings is determined so that when the magnetic fluxes flow into the windings 10 and 11, a magnetic flux is generated in the direction in which the magnetic flux exits from the end on the black circle side.

2 which is wound on the winding 11 in FIG.
A load circuit R for linearity change is connected to the secondary winding 14 via a switch SW, and a current flows through the secondary winding 14.
When i2 flows, the self-inductance of the winding 11 is L11, the induced voltage generated in the winding 11 is E,
The mutual inductance between the winding 11 and the secondary winding 14 is M, the current flowing through the winding 11 is i1, and the secondary winding 14 is
Assuming the self-inductance L14 of 2) The formula holds true.

{(L11)di1/dt}-(Mdi2/dt)=E......(1) −{Mdi1/dt}+{(L13)di2/dt}+Ri2=0
...(2) Equation (2) above shows that the current i2 can be changed freely by changing the resistance R, and if the current i2 is changed, the second term on the left side of the equation (1) {-Mdi2/ dt} changes, changing the resistance R equivalently changes the inductance L11 of the winding 11.

2 wound on the winding 11 as described above.
A load circuit R for linearity change is connected to the secondary winding 14 via a switch SW, and a current i2 is applied to the secondary winding 14.
When the self-inductance L11 of the winding 11 is changed equivalently by flowing the 7th
It is possible to change the linearity of the screen on one half of the screen corresponding to the + side, which is the dominant region of L11 in the figure, and also, contrary to the above, winding the secondary winding 14 toward the winding 10, A switch SW is installed in the secondary winding 14.
Connect the load circuit R for linearity change through 2.
When current is passed through the next winding 14, as shown in Fig. 7,
It is possible to change the linearity of one side of the screen corresponding to the - side, which is the dominant area of L10.

In addition, in implementing the present invention, windings 10 and 11
A secondary winding is provided for each of the
Alternatively, it is natural that a large number of windings may be provided, and as an example where the circuit of the present invention is applied to a device in which multiple horizontal deflection frequencies are switched. In this case, a plurality of loads having different resistance values are provided in the load circuit R for linearity change, and the plurality of loads described above are selectively changed into two by the switch SW.
It may also be implemented as a configuration in which it is connected to the next winding 14. And the switch mentioned above
SW switching control is performed by a switch from the control signal generation circuit CC corresponding to the horizontal deflection frequency switching operation.
The switching may be performed using a switching control signal supplied to the SW.

(Effect of the invention) As is clear from the above detailed explanation, the horizontal deflection linearity correction circuit of the invention serially circulates the magnetic flux generated by one permanent magnet and the permanent magnet. The two magnetic poles are arranged in such a manner that they are in contact with the two magnetic poles of the pair in the permanent magnet, and are spaced apart from each other.
The windings each wound around the two saturable magnetic cores are connected in series, and the windings each wound around the two saturable magnetic cores are connected in series. When current is applied, the magnetic flux generated by the respective windings wound around the two saturable magnetic cores is added to the magnetic flux generated by the permanent magnet for one saturable magnetic core, and is added to the magnetic flux generated by the permanent magnet for the other saturable magnetic core. The connection polarity of the two windings wound around the two saturable magnetic cores is determined so that the magnetic flux generated by the permanent magnet is subtracted in the saturated magnetic core, and the polarity of the two windings connected in series is determined. A winding is connected substantially in series with the horizontal deflection coil of the picture tube, and a secondary winding is wound around one or both of the windings respectively wound around the two saturable magnetic cores. The horizontal deflection linearity correction circuit of the present invention has a horizontal deflection can be switched to multiple types, and a load circuit R for linearity variation having a load with an appropriate resistance value is connected to the secondary winding in accordance with each horizontal deflection frequency via a switch SW. Winding 1 of the horizontal deflection linearity corrector is
By switching the equivalent inductance of 0.11 to an appropriate value, it is easy to ensure that the linearity of the screen is always in good condition even when the horizontal deflection frequency is switched. According to the present invention, the above-mentioned problems can be satisfactorily solved.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of one embodiment of the horizontal deflection linearity correction circuit of the present invention, Fig. 2 is a circuit diagram for explaining the operation of the horizontal deflection linearity correction circuit shown in Fig. 1, and Fig. 3 is a circuit diagram of an embodiment of the horizontal deflection linearity correction circuit of the present invention. Block diagrams of horizontal deflection linearity correction circuits using horizontal deflection linearity correction circuits, Figs. 4 to 6
The figure shows the configuration of the previously proposed horizontal deflection linearity correction device.
FIG. 7 is an example of a characteristic curve, FIG. 8 is a waveform diagram of a sawtooth wave current, FIG. 9 is an explanatory diagram of problems in a wide deflection angle picture tube, and FIG. 10 is an explanatory diagram of image distortion. 1...Horizontal deflection output circuit, 2...Horizontal deflection coil, 5...Capacitor, 7, 8...Drum core,
9... Permanent magnet, 10, 11... Winding wire, LCA...
...Horizontal deflection linearity correction device, 14...Secondary winding,
R...Load circuit for linearity change, SW...Switch.

Claims (1)

[Scope of utility model registration request] one permanent magnet, each of which is in contact with the two magnetic poles of the pair of the permanent magnet in an arrangement such that the magnetic flux generated by the permanent magnet can be circulated in series, and is spaced apart from each other; two saturable magnetic cores provided in a state of When the two saturable magnetic cores are connected and a current is passed through them in a certain direction, the magnetic flux generated by the respective windings wound around the two saturable magnetic cores is the magnetic flux generated by the permanent magnet for one of the saturable magnetic cores. The connection polarity of the two windings wound around the two saturable magnetic cores is determined so that the flux is added to the magnetic flux generated by the permanent magnet in the other saturable magnetic core. , the series-connected windings are substantially connected in series with the horizontal deflection coil of the picture tube, and one or both of the windings are respectively wound around the two saturable magnetic cores. A horizontal linearity correction circuit is formed by winding a secondary winding around the secondary winding and connecting a load circuit for changing linearity to the secondary winding via a switch.