JPS6052632B2 - Correction signal measurement method and measurement device - Google Patents

Description

Detailed Description of the Invention When correcting, for example, pincushion distortion in a picture tube of a television receiver, conventionally, parabolic waves with vertical and horizontal periods are superimposed on vertical and horizontal deflection signals. It was on.

However, in a large-sized picture tube, complete correction cannot be performed with a simple parabolic wave. So, for example, we blow out a raster, correct the deflection signal so that the beam will land ink correctly at an arbitrary point on the phosphor screen, measure the amount of correction needed at that time, and repeat the same operation over the entire surface of the phosphor screen. The waveform of the necessary correction signal is obtained by plotting the correction amount at each point.

By the way, when performing such measurements, it is necessary to know the position of the measurement point.

Conventionally, therefore, the position was measured by placing a scale on the phosphor screen. However, in a picture tube, the raster is larger than the phosphor screen, and is so-called overscanned.

Therefore, even if the position is measured on the phosphor screen, the position does not match the position on the deflection signal. It is also difficult to obtain accurate values because the scale is measured visually. Therefore, even if a correction signal obtained by plotting such a measured quantity is superimposed on a deflection signal, correct correction cannot be performed. In view of these points, the present invention is designed to enable obtaining accurate correction signal waveforms with a simple configuration.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In this example, a case will be described in which a correction signal for vertical pincushion distortion is measured. In FIG. 1, horizontal and vertical deflection signals from a deflection circuit 1 are applied to a deflection coil 3 of a picture tube 2. In FIG.

Further, a part of the vertical deflection signal is supplied to a parabolic wave generation circuit 4, and a parabolic wave signal Ba from this generation circuit 4 is supplied to a correction deflection coil 5. Further, this parabolic wave signal Ba is supplied to a two-phenomenon oscilloscope 6.
Further, a detection signal Sb from the light receiver 7 is supplied to the oscilloscope 6 through an attenuator 8. Therefore, in this circuit, a parabolic wave signal Sa is displayed on the oscilloscope 6 as shown in FIG.

At the same time, by applying the light receiver 7 to an arbitrary point on the phosphor screen, the light emitted when the electron beam passes through that point is detected, and this is displayed as a detection signal Sb. In this case, the parabolic wave signal Sa and the detection signal Sb have the same time axis. Therefore, by adjusting the parabolic wave generation circuit 4 so that the point on which the light receiver 7 is applied is in an accurate landing state, and reading the level B at the intersection of the rising point of the signal Sb and the signal Sa at that time, the The required correction amount of the point can be determined.

Furthermore, since the parabolic wave signal Sa is synchronized with the vertical deflection signal, by measuring the distance from the beginning of the signal Sa to the rising point of the signal Sb, the position of the measurement point on the deflection signal can be accurately determined. You can know. Then, by sequentially changing the measurement points and plotting the measured level B and distance', the waveform of the necessary correction signal can be obtained.

In reality, by changing the measurement points sequentially and plotting the intersection points on the oscilloscope,
You can also directly obtain the required waveform.

In this way, the waveform of the correction signal can be measured. According to the present invention, the measurement point can be accurately known, so the waveform of the correction signal to be measured becomes accurate.

Note that the present invention is not limited to correction of pincushion distortion, but can also be used to measure correction signals for linearity, ringing, misconvergence, and the like.

Furthermore, although the above example deals with the measurement of the vertical period, in the case of measuring the horizontal period, the waveform of the signal Sb becomes dull and difficult to measure.

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 Sa may be supplied to a digital measuring instrument, and the measuring instrument may be triggered by the signal from the light receiver to display the level.

[Brief explanation of the drawing]

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 is a deflection coil for correction, 6 is an oscilloscope, and 7 is a light receiver.

Claims (1)

[Scope of Claims] 1. The correction signal from a correction signal generator that generates a correction signal for correcting the beam scanning position of the picture tube is supplied to a waveform measuring device, and the signal is placed at an arbitrary point on the front surface of the picture tube. A method for measuring a correction signal, wherein a signal from a light receiver is supplied to the waveform measuring device, and the level of the correction signal at the arbitrary point is measured using the signal from the light receiver. 2. 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.