JPS5850864A - Method and device for measuring correction signal - Google Patents

Abstract

PURPOSE:To obtain the accurate waveform of a correction signal through simple constitution by measuring the level, etc., of the correction signal with a signal from a photodetector. CONSTITUTION:A horizontal and a vertical deflection signal from a deflecting circuit 1 are supplied to the deflection coil 3 of a picture tube 2. Then, part of the vertical deflection signal is supplied to a parabolic wave generating circuit 4, a parabolic wave signal Sa from which is supplied to a deflection coil 5 for correction. This parabolic wave signal Sa is supplied to a two-phenomenon oscilloscope 6. Further, a detection signal Sb from a photodetector 7 is supplied to the oscilloscope 6 through an attenuator 8. So as a point where the photodetector 7 is in contact is an accurate landing state, the parabolic wave generating circuit 4 is adjusted and the level B at the intersection of the rising signal Sb and signal Sa is read to measure the necessary amount of correction at the point. Further, the distance l from the beginning of the parabolic signal Sa to the rising point of the signal Sb is measured to obtain the accurate position of a measurement point on the deflection signal.

Description

DETAILED DESCRIPTION OF THE INVENTION In the picture tube of a television receiver, [1] For example, when correcting pincushion distortion, conventionally, vertical and horizontal period parabo waves are superimposed on the aII deflection signal and the horizontal deflection signal. I was going. However, in a large-sized picture tube, complete correction cannot be performed with a mere parabolic wave.

For example, by projecting a raster image and correcting the deflection signal so that the beam will land correctly at an arbitrary point on the fluorescent image,
The amount of correction required at that time is fixed, the same operation is repeated over the entire surface of the phosphor screen, and the amount of correction at each point is plotted to obtain the waveform of the necessary correction signal.

By the way, when performing such measurements, it is necessary to know the position of the shelf fixed point. Therefore, in the past, a school was placed on the phosphor screen to measure its position.

However, in a picture tube, the raster is thicker than the phosphor screen (
, so-called overscanning.

Therefore, even if the position is measured on the phosphor screen, the position does not match the position on the intralateral signal. Also, since the deflection is measured visually, it is difficult to obtain accurate values.Therefore, even if the correction signal obtained by plotting a fixed amount is superimposed on the deflection signal, it is difficult to perform correct correction. I couldn't.

The present invention is based on the point K, and with a simple configuration, it is possible to obtain an accurate correction signal IIty#.
It is something that

An embodiment of the present invention will be described below with reference to the drawings. In this example, a case will be described in which the correction signal for the pincushion distortion number in the normal direction is constant.

At #C in FIG. 1, horizontal and direct deflection signals from the deflection path (1) are supplied to the deflection coil (3) of the receiving tube (2). In addition, a part of the -direct polarization signal is transmitted to the parabolic wave generation circuit (
4) The paraponic wave signal S from the generation group (4) is supplied to the correction deflection coil (5).

Also% this parabolic wave, signal am tie fA II
Elephant Oshida scope (6)k supplied. Detection signal 4#8b from the photoreceiver (7) is supplied to the amplifier (6) through the amplifier (8).

Therefore, in this circuit, the oscilloscope (6) is projected with a parabonic wave signal 8m as shown in the second m1k.At the same time, the oscilloscope (6) is capable of projecting the received light II (7) to any point on the fluorescent image. When the electron beam passes through, the light emission is detected, and this is displayed as a detection signal 8b. In this case, the time axes of the parameter wave signal 8a and the detection signal 8b match.

Then, adjust the parapolar wave generation circuit (4) so that the point at which the photoreceiver ff) is pulsating becomes an accurate tunde Y waveform, and then compare the rising point of the signal 8b and the signal 8a at that time. By adjusting the level B of the intersection point, it is possible to keep the necessary correction amount at that point constant.

Also, since the parabonic wave signal 8F is synchronized with the deflection signal, the position of the measurement point on the deflection signal can be determined by keeping the distance 1 from the beginning of the signal qa to the rising point of the signal 8b constant. Write what you know exactly.

The waveform of the necessary correction signal can be obtained by sequentially carbonizing the measurement points and plotting the measured level B and distance curve.

In addition, l! Ilk is to sequentially change the measurement points and put the intersection points on the oscilloscope:l-1.
It is also possible to directly obtain the required waveform.

In this way, the H-shape of the correction signal can be kept constant, and according to the present 1 PLK, the fixed point can be accurately known, so the waveform of the fixed correction signal becomes accurate.

The present invention can also be used to fix correction signals for ν nearness, ν ginder, misconvergence, etc. without focusing on pincushion distortion.

Furthermore, in the above example, the case where the period is constant is 1, but when the horizontal period is constant, the waveform of the signal 8b becomes dull.
Therefore, in the case of measuring the horizontal period, the detection signal sb is supplied to a differentiating circuit, and the differentiated signal is further sliced to obtain a clear waveform.

Furthermore, the signal of 8 m is supplied to the digital constant meter, and the signal from the receiver triggers the measuring device to display the level.
kL, good.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an example of the present invention, and FIG. 2 is a waveform diagram for explaining the same. (5) A deflection coil for C correction, (6) an oscilloscope, and (7) a light receiver.

Claims (1)

[Claims] 1. The correction signal from the correction signal generator that generates a correction signal for correcting the beam scanning position of the picture tube is supplied to the waveform constant device, and the correction signal is supplied to the waveform constant device at any point on the front surface of the picture tube. A method for measuring a correction signal, comprising: supplying a signal from a photoreceiver to the waveform measuring device, and fixing the level of the correction signal at the arbitrary point using the signal from the photoreceiver. λ A correction signal generator, a waveform measuring device, and a light receiver that generate a correction signal for correcting the beam scanning position of the picture tube, and the light receiver is placed at an arbitrary position in front of the picture tube, and the correction signal is generated by placing the light receiver at an arbitrary position in front of the picture tube. A correction signal measuring device, wherein a generator and the light receiver are connected to the waveform measuring device, and the level of the correction signal at the arbitrary point is measured based on the signal from the light receiver.