JPH1065933A - Contour correction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the contour correction device at a low cost by modulating a primary differentiation signal of a video signal with a parabolic waveform. SOLUTION: A video signal differentiated by a primary differentiation circuit 1 is given to an amplitude modulation circuit 2 by using a horizontal parabolic waveform signal 7 within a horizontal scanning period, in which the video signal is amplitude-modulated. The modulated primary differentiation signal voltage is converted into a current by a conversion circuit 3, and a velocity modulation coil 4 applies velocity modulation to an electronic beam scanning a CRT in the horizontal direction, and the effect of the velocity modulation is enhanced at both sides of a screen of the CRT to improve the sharpness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contour correction circuit (IPC) for modulating a signal of a speed modulation circuit by a parabola waveform.
H04N 3/32).

[0002]

2. Description of the Related Art In recent years, as the deflection angle of a CRT increases, the sharpness of the peripheral portion has become an issue, and the technology in this field is disclosed in Japanese Utility Model Application Laid-Open No. 62-1468 shown in FIG. Means for modulating a secondary differential signal of a video signal with a parabolic waveform has been employed.

[0003]

However, when modulating the second-order differential signal of the video signal as described above, it is necessary to control a very large current portion, and it has been difficult to construct an inexpensive structure. .

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an inexpensive contour correcting device by modulating a first-order differential signal of a video signal with a parabolic waveform. It is a feature.

According to the present invention, since the modulation by the parabola waveform signal is performed by the primary differentiating circuit performing the low voltage and low current driving as described above, a large power component is not required and the configuration can be performed at low cost. .

[0006]

According to a second aspect of the present invention, there is provided a contour correcting circuit for converting a video signal into a first-order differential circuit, and the first-order differential circuit converts the first-order differential video signal into a horizontal rate within a horizontal period. A modulation circuit that performs amplitude modulation with a parabola waveform, a conversion circuit that performs voltage-current conversion of an output voltage of the amplitude modulation circuit, and a speed modulation coil that is mounted on a neck portion of a CRT connected to the conversion circuit. The amplitude of the primary differentiated video signal is modulated by a horizontal parabolic waveform signal within a horizontal scanning period, the modulated primary differential signal voltage is converted to a current, and an electronic screen for scanning a CRT is provided. (2) to improve the sharpness which tends to deteriorate by performing the speed modulation in the horizontal direction of the camera and enhancing the effect of the speed modulation on both sides of the screen of the CRT.

According to a fourth aspect of the present invention, in the contour correction circuit, a first-order differentiating circuit of the video signal and the first-order differentiating circuit converts the first-order differential video signal into a parabolic waveform having a horizontal rate within a horizontal period. A variable circuit that varies the amount of coring of the differentiated waveform; a conversion circuit that performs voltage-current conversion of the output voltage of the coring amount variable circuit; and a CR connected to the conversion circuit.
And a velocity modulation coil mounted on the neck of the T. The first-order differentiated video signal is converted into a first-order differentiated video signal according to the horizontal parabolic waveform signal amplitude within a horizontal scanning period. By changing the coring amount, converting the changed first-order differential signal voltage into a current, and modulating the speed of the electronic beam for scanning the CRT in the horizontal direction, and increasing the speed modulation effect on both sides of the screen of the CRT. Improves sharpness that tends to deteriorate.

According to a sixth aspect of the present invention, in the contour correction circuit, a first-order differentiating circuit of the video signal and the first-order differentiating circuit converts the first-order differential video signal into a parabolic waveform having a horizontal rate within a horizontal period. A variable circuit for varying the frequency characteristics of the differential waveform,
A conversion circuit for performing a voltage-to-current conversion of the output voltage of the frequency characteristic variable circuit; and a velocity modulation coil mounted on a neck portion of a CRT connected to the conversion circuit. The frequency characteristic of the video signal obtained by firstly differentiating the obtained video signal according to the horizontal parabola waveform signal amplitude within the horizontal scanning period is changed, and the changed first-order differential signal voltage is converted into a current to scan the CRT. The speed of the electronic beam is modulated in the horizontal direction to enhance the effect of the speed modulation on both sides of the screen of the CRT, thereby improving the sharpness which tends to deteriorate.

An outline correction circuit according to claim 8, wherein a primary differentiating circuit using a delay circuit, a variable circuit for varying the delay time of the delay circuit in the primary differential circuit with a horizontal parabolic waveform, A conversion circuit for performing a voltage-to-current conversion of the output voltage of the primary differentiating circuit; and a speed modulation coil mounted on a neck portion of a CRT connected to the conversion circuit. In a primary differentiating circuit configured by subtraction from the video signal input to the delay circuit, the delay time of the delay circuit is changed by a horizontal parabolic waveform signal, and the changed primary differential signal voltage is converted into a current. Shi CR
The speed of the electron beam for scanning T is modulated in the horizontal direction, and
By improving the speed modulation effect on both sides of the RT screen, sharpness that tends to deteriorate is improved.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 is a schematic configuration diagram of a contour correcting apparatus according to embodiments 1 and 2 of the present invention. In FIG. 1, an image signal that has been first-differentiated by a first-order differentiating circuit 1 is amplitude-modulated by an amplitude modulating circuit 2 using a horizontal parabolic waveform signal 7 within a horizontal scanning period, and the modulated first-order differentiating signal is obtained. A speed modulation coil 4 converts a signal voltage into a current by a conversion circuit 3 and performs horizontal speed modulation of an electronic beam for scanning a CRT.
By increasing the speed modulation effect on both sides of the screen of the CRT, the sharpness, which tends to deteriorate, is improved.

(Embodiment 2) FIG. 2 shows a third embodiment of the present invention.
FIG. 9 is a schematic configuration diagram of a contour correction device according to Embodiments 4 and 4. The video signal that is first-order differentiated by the first-order differentiation circuit 1 is
In the horizontal scanning period, the coring amount of the video signal that has been first differentiated according to the signal amplitude of the horizontal parabola waveform 7 is varied by the coring variable circuit 5, and the varied first differential signal voltage is supplied to the conversion circuit 3. Electronic beam that scans the CRT by converting it to a current
Speed modulation in the horizontal direction of the
By increasing the speed modulation effect on both sides of the RT screen, sharpness that tends to deteriorate is improved.

(Embodiment 3) FIG. 3 shows a fifth embodiment of the present invention.
FIG. 9 is a schematic configuration diagram of a contour correction device according to the embodiments of FIGS. The video signal that is first-order differentiated by the first-order differentiation circuit 1 is
In the horizontal scanning period, the frequency characteristic of the video signal that has been first differentiated according to the signal amplitude of the horizontal parabola waveform 7 is varied by the frequency characteristic variable circuit 5, and the changed primary differential signal voltage is converted by the conversion circuit 3. The velocity modulation coil 4 performs horizontal velocity modulation of the electronic beam which converts the current into a current and scans the CRT.
By increasing the speed modulation effect on both sides of the screen of T, sharpness that tends to deteriorate is improved.

(Embodiment 4) FIG. 4 shows a seventh embodiment of the present invention.
FIG. 9 is a schematic configuration diagram of a contour correction device according to the eighth and eighth embodiments. In the primary differentiating circuit 8 configured by subtracting the video signal and the video signal input to the delay circuit 9, the delay time of the delay circuit 9 is varied by the horizontal parabolic waveform signal 7. Conversion circuit 3 for next differential signal voltage
The velocity modulation coil performs horizontal velocity modulation of the electronic beam for scanning the CRT by converting the current into a current, thereby enhancing the effect of the velocity modulation on both sides of the screen of the CRT, thereby improving the sharpness which tends to deteriorate. .

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0015]

As described above, according to the present invention, since the modulation using the parabola signal waveform is performed in the primary differentiating circuit section which performs low voltage and low current driving as described above, a large power component is required. And can be configured at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a contour correction device according to embodiments 1 and 2 of the present invention.

FIG. 2 is a schematic configuration diagram of a contour correction device according to the third and fourth embodiments of the present invention.

FIG. 3 is a schematic configuration diagram of a contour correction device according to embodiments 5 and 6 of the present invention.

FIG. 4 is a schematic configuration diagram of a contour correction device according to embodiments 7 and 8 of the present invention.

FIG. 5 is a schematic configuration diagram of a conventional contour correction device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary differentiation circuit 2 Amplitude modulation circuit 3 Voltage-current conversion circuit 4 Speed modulation coil 5 Coring amount variable circuit 6 Frequency characteristic variable circuit 7 Horizontal parabolic waveform 8 Primary differentiation circuit 9 Delay circuit

Claims (8)

[Claims] An electronic beam for amplitude-modulating a first-order differentiated video signal with a horizontal parabolic waveform signal within a horizontal scanning period, converting the modulated first-order differential signal voltage into a current, and scanning a CRT. Contour correction device that performs horizontal velocity modulation to enhance the effect of velocity modulation on both sides of the CRT screen to improve sharpness. 2. A primary differentiation circuit for a video signal, an amplitude modulation circuit for performing amplitude modulation on the primary differentiation video signal by the primary differentiation circuit with a parabolic waveform of a horizontal deflection circuit, and an output of the amplitude modulation circuit. A contour correction device comprising: a voltage-current conversion circuit for performing a voltage-current conversion on a signal; and a velocity modulation coil mounted on a neck portion of a CRT connected to the conversion circuit. 3. The primary differentiated video signal is obtained by varying the coring amount of the primary differentiated video signal according to the horizontal parabola waveform signal amplitude within a horizontal scanning period, and An electronic beam that converts a voltage to a current and scans a CRT
A contour correction device that performs velocity modulation in the horizontal direction of the system and enhances the effect of velocity modulation on both sides of the screen of the CRT to improve sharpness. 4. A primary differentiating circuit for a video signal, and coring for varying a coring amount of the primary differential waveform in the primary differential circuit with a parabolic waveform of a horizontal deflection circuit in the primary differential circuit. An amount variable circuit, a voltage-current conversion circuit that performs voltage-current conversion on an output signal of the coring amount variable circuit, and a speed modulation coil mounted on a neck portion of a CRT connected to the voltage-current conversion circuit. Contour correction device provided with 5. A frequency characteristic of a video signal obtained by primary-differentiating a video signal obtained by primary differentiation according to a horizontal parabola waveform signal amplitude within a horizontal scanning period, and a variable primary differential signal voltage A contour correction device that converts the speed of the electronic beam into a current and performs horizontal speed modulation of an electronic beam that scans the CRT, thereby enhancing the effect of speed modulation on both sides of the screen of the CRT and improving sharpness. 6. A primary differential circuit for a video signal, and a variable frequency characteristic for varying the primary differential video signal in the primary differential circuit with a parabolic waveform of a horizontal deflection circuit. A voltage-current conversion circuit for performing voltage-current conversion on an output signal of the frequency characteristic variable circuit; and a speed modulation coil mounted on a neck portion of a CRT connected to the voltage-current conversion circuit. Contour correction device. 7. A first-order differentiating circuit configured by subtracting a video signal and the video signal input to a delay circuit, wherein the delay time of the delay circuit is varied by a horizontal parabolic waveform signal. A contour correction device that converts a primary differential signal voltage into a current and modulates the speed of an electronic beam for scanning a CRT in the horizontal direction, thereby enhancing the effect of speed modulation on both sides of the screen of the CRT and improving sharpness. 8. A primary differential circuit using a delay circuit, a delay time variable circuit for varying a delay time of a delay circuit in the primary differential circuit with a horizontal parabolic waveform, and an output of the primary differential circuit A contour correction device comprising: a voltage-current conversion circuit for performing a voltage-current conversion on a signal; and a velocity modulation coil mounted on a neck portion of a CRT connected to the voltage-current conversion circuit.