| 摘要 |
PURPOSE:To correct the fog of a picture circumferential part with simple constitution by constituting the device with an auxiliary deflection coil having a coil axis in parallel with an axis of a horizontal deflection coil, an OR circuit inputting a color signal, a differentiation circuit of the said circuit and an amplifier circuit for the output. CONSTITUTION:The auxiliary horizontal deflection coil 5, the OR circuit 6, the differentiation circuit 7 comprising a resistor and a signal delay element and an amplifier circuit 8 constitute the picture quality adjusting device 9, which is added to a conventional picture display circuit section. The coil 5 is arranged coaxially with the horizontal deflection coil of a parallel coil unit 4. If any of color signal output circuits 1, 1a and 1b outputs an unsharpened signal (Fig. a), the OR circuit 6 outputs a rectangular wave signal shown in Fig. (b). In differentiating this signal, a differentiated waveform (Fig. c) with less unsharped component is obtained by selecting the circuit constant. The differentiated output is amplified and fed to the coil 5. On the other hand, a linear horizontal deflection current as shown in Fig. (d) is applied to the horizontal deflection coil from a synchronism deflection circuit 3. Thus, the horizontal deflection magnetic field (Fig. e) of a cathode ray tube 10 is the sum of electric fields by the said two currents and the time change of the strength of electron beam is as shown in Fig. (f).
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