JPH07336705A - Image correction device - Google Patents

Abstract

PURPOSE:To provide an image correction device in which convergence, focus, deflection distortion and luminance or the like are corrected with high accuracy corresponding to various signal sources of a television receiver. CONSTITUTION:A synchronizing signal of a video signal is inputted to a deflection section 27, from which deflection waveform is generated. A frequency discrimination section 28 discriminates the scanning frequency of the video signal from the deflection waveform and gives it as voltage information to a phase control section 29. The phase control section 29 generates a deflection synchronizing pulse delayed from a change point of the deflection waveform by a prescribed time. A correction waveform generating section 30 uses the deflection synchronizing pulse to generate a correction waveform and it is added to a deflection waveform of the deflection section 27. Then convergence is corrected by a video signal of a certain standard and even when a video signal of other standard is received, an image is corrected with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for uniformly correcting the convergence, focus, deflection distortion, brightness and the like of a color television receiver, and more particularly to a highly accurate image correction device that is compatible with various signal sources. Is.

[0002]

2. Description of the Related Art In a general television receiver (hereinafter, referred to as a television), the flatness of a phosphor screen increases as the deflection angle of a picture tube increases, and color shift, focus shift, deflection distortion, and brightness on the screen occur. Change occurs. These various corrections are performed by synchronizing with horizontal and vertical scanning to create an analog correction waveform and adjusting the amplitude and shape of this waveform. In such a correction method, there is a problem that it takes a long time to adjust because the deviation on various screens is visually observed and the correction is manually performed.

Further, when there are various input video signal sources such as HDTV broadcasting which is HDTV in Japan and HDTV in the United States or Europe, the position of the video signal with respect to the video display area and the synchronizing signal is different. In this case, in order to perform accurate correction, it is necessary to optimally adjust the deflection synchronization signals of various corrections for each input video signal source. Therefore, as a method capable of supporting various input video signal sources and having high convergence accuracy, a digital convergence apparatus as disclosed in, for example, Japanese Patent Laid-Open No. 2-32693 has been proposed.

FIG. 11 is a block diagram showing the configuration of this conventional digital convergence correction apparatus. In FIG. 11, the horizontal sync signal (H-SYNC) and the vertical sync signal (V-SYN)
C) is input to the address generator 1. Address generator 1
Outputs an address corresponding to the screen display position to the adder 2 and the center address detector 7. Further, the zero-cross comparators 6a and 6b respectively input a horizontal sawtooth wave (H-SAW) and a vertical sawtooth wave (V-SAW), generate a timing pulse indicating a deflection center point, and output it to an AND circuit (AND). To do.
The AND circuit detects the screen center point from the two timing pulses and outputs a screen center signal to the center address detector 7. The center address detector 7 latches the address from the address generator 1 with this screen center signal to detect the center address.

The comparator 8 compares the center address with the fixed address output from the correction center fixed address generator 9, and outputs the shift amount of the adjustment point to the adder 2 as a center offset value. And the adder 2 is the address generator 1
The address of the comparator 8 is added to the address output in step 3 to give the frame memory 3 an offset address. In this way, the address of the frame memory 3 always outputs the correction signal at the timing synchronized with the center of the screen.

The addresses of the crosshatch generator 10 and the marker generator 11 are supplied from the adder 2 and always generate the crosshatch and the marker at the timing synchronized with the center of the screen. The digital correction signal held in the frame memory 3 is converted into an analog signal by the D / A converter (DAC) 4, and the low pass filter (LPF) 5
Is output to the display device via. When the correction device incorporated in the television is operated as described above, convergence correction can be performed in synchronization with the deflection center, and a high-quality image with less misconvergence can be obtained.

[0007]

However, in the conventional configuration as described above, although it is possible to adjust the convergence with high accuracy at the time of normal convergence adjustment, when the horizontal and vertical scanning frequencies change, the convergence yoke that passes the convergence correction current scans. Since a constant delay time is generated regardless of the frequency, there is a drawback that the phase of the convergence correction current is different and the convergence on the screen is shifted.

The present invention has been made in view of the above conventional problems, and does not require readjustment even when various video signals are input, and can cope with various input signal sources with high accuracy. An object is to realize an image correction device.

[0009]

According to a first aspect of the present invention, there is provided deflection means for generating a deflection waveform from a synchronizing signal of a video signal, and frequency discrimination for discriminating a scanning frequency of the video signal by the deflection waveform from the deflection means. Means for controlling the phase based on the frequency discrimination result from the frequency discriminating means and producing a deflection synchronizing signal for generating a correction waveform, and a correction waveform based on the deflection synchronizing signal from the phase controlling means. And a correction unit that corrects an image.

In the invention of claim 2 of the present application, the frequency discriminating means is based on the output of the delay circuit and the delay circuit which outputs a pulse when a certain time is delayed from the change point of the deflection waveform output by the deflecting means. And a sample / hold circuit for sampling the deflection waveform of the deflection means and outputting voltage information.

According to the invention of claim 3 of the present application, the deflection means for generating the deflection waveform from the synchronizing signal of the video signal, the frequency discriminating means for discriminating the scanning frequency of the video signal from the synchronizing signal of the video signal, and the frequency discriminating means. Phase control means for controlling the phase according to the frequency discrimination result of 1 to generate a deflection synchronization signal for generating a correction waveform, and correction means for producing a correction waveform based on the deflection synchronization signal from the phase control means to correct an image. And are provided.

According to the invention of claim 4 of the present application, the frequency discriminating means divides the synchronizing signal of the image and outputs a pulse whose polarity changes in the cycle of the synchronizing signal, and a pulse width of the dividing circuit. And a time-voltage converter for converting the voltage into voltage information.

[0013]

According to the inventions of claims 1 and 2 having the above characteristics, the frequency determining means determines the scanning frequency of the input video signal from the deflection waveform and outputs the voltage information. The phase control means generates a deflection synchronization signal from the deflection waveform based on the frequency discrimination result. Then, the correction means creates a correction waveform using the deflection synchronization signal and corrects the image.
Even if the scanning frequency of the input video signal changes after the image is adjusted once, the phase control means outputs the deflection synchronization signal by the voltage information from the frequency determining means and the voltage information of the scanning frequency adjusted once. Occur. Therefore, deflection synchronization signals corresponding to various scanning frequencies can be obtained. This eliminates the need to readjust the image correction when the scanning frequency of the video signal changes.

According to the third and fourth aspects of the present invention, the frequency discriminating means discriminates the scanning frequency of the inputted video signal from the synchronizing signal of the video signal and outputs the voltage information. The phase control means generates a deflection synchronization signal from the deflection waveform based on the frequency discrimination result. Then, the correction means creates a correction waveform using the deflection synchronization signal and corrects the image. Even if the scanning frequency of the input video signal changes after the image is adjusted once, the phase control means outputs the deflection synchronization signal by the voltage information from the frequency determining means and the voltage information of the scanning frequency adjusted once. Occur. Therefore, deflection synchronization signals corresponding to various scanning frequencies can be obtained. This eliminates the need to readjust the image correction when the scanning frequency of the video signal changes.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image correction apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the image correction apparatus 20 in the first embodiment. In the figure, an input terminal 21 is an input terminal to which a video signal of various standards is supplied, and an input terminal 22 is an input terminal for a horizontal (H) and vertical (V) synchronizing signal of the video signal. The signal processing unit 23 controls the amplitude of the video signal of the input terminal 21 using the correction waveform of the correction waveform creation unit 30 described later, and also amplifies the power and outputs the video signal to the cathode of the cathode ray tube (CRT) 24. Is.

A convergence yoke 25 and a deflection yoke 26 are provided on the electron gun and the neck portion of the CRT 24. When the synchronizing signal is given from the input terminal 22, the deflection unit 27 receives the convergence yoke 25 and the deflection yoke 26.
On the other hand, the deflection means outputs various correction waveforms by superimposing them on the deflection waveform. The deflection waveform of the deflection unit 27 is the frequency discrimination unit 2
8 and the phase control unit 29. Frequency discriminator 2
Reference numeral 8 is a frequency discriminating means for discriminating the scanning frequency by the deflection waveform and outputting the value as voltage information to the phase controller 29. The phase control unit 29 is a phase control unit that creates a deflection synchronization signal having a correction waveform when the voltage information and the deflection waveform are input. The correction waveform generation unit 30 is a correction unit that generates various correction waveforms when the deflection synchronization signal is input and outputs the correction waveforms to the deflection unit 27 and the signal processing unit 23.

FIG. 2 is a block diagram showing the configuration of the frequency discriminating section 28. As shown in the figure, the frequency discrimination unit 28
It has a delay circuit 31 and a sample / hold circuit 32. The delay circuit 31 is a circuit that generates a sampling pulse at a time delayed by a certain time from the falling portion when a sawtooth-shaped deflection waveform is input from the deflection unit 27. The sample / hold circuit 32 is a circuit that samples the deflection waveform with the sampling pulse from the delay circuit 31, holds the sample voltage, and outputs the sample voltage to the phase controller 29.

FIG. 3 is a block diagram showing the configuration of the phase controller 29. As shown in the figure, the amplifier circuit 33 is a circuit that amplifies the voltage information of the frequency discriminating unit 28 by x times, and its output is given to the adder 35. The time-voltage converter 36 is a circuit that, when the deflection waveform is input from the deflection unit 27, generates a ramp signal having a predetermined slope and converts the scanning period of the deflection waveform into voltage information. The memory / arithmetic circuit 34 is
A circuit that stores the voltage information of the frequency discriminating unit 28 and the voltage information of the time-voltage converter 36 and converts the voltage based on a predetermined arithmetic expression, and the arithmetic result is given to the adder 35. The comparator 37 uses the output of the adder 35 as a reference voltage, compares the amplitudes of the deflection waveforms output from the deflection unit 27, and outputs a pulse of H level as a deflection synchronization signal if higher than the reference voltage, and the correction waveform generation unit 30. Is a circuit to give to.

The operation of the image correcting apparatus of the first embodiment having the above-mentioned structure will be described with reference to the signal waveform charts of FIGS. 4 and 5. When a video synchronizing signal (V, H) is input to the input terminal 22 of FIG. 1, the deflection unit 27 generates a deflection current for raster-scanning the screen of the CRT 24 and supplies it to the deflection yoke 26 and the convergence yoke 25. Then, the scanning speeds of V and H are controlled.

When a video signal of a certain standard is input from the input terminal 21, the signal processing unit 23 performs various signal processing and power amplification for driving the cathode of the CRT 24. Further, the deflection waveform generated by the deflection unit 27 is used as the frequency discrimination unit 28.
And the phase controller 29. The frequency discriminating unit 28 converts the repetitive frequency of the deflection waveform into voltage information and gives it to the phase control unit 29. Then, the phase control unit 29 creates a deflection synchronization signal corresponding to the scanning frequency. Correction waveform creation unit 3
0 is synchronized with the deflection synchronization signal from the phase controller 29, and generates a parabolic waveform or a sawtooth waveform for analog correction. The correction waveform from the correction waveform creation unit 30 is supplied to the deflection unit 27 and the signal processing unit 23, and the output waveform is corrected.

Next, regarding the operation of the frequency discriminating section 28,
This will be described with reference to the block diagram of FIG. 2 and the waveform diagram of FIG. First, as shown in FIG. 4A, it is assumed that the deflection waveform of the scanning frequency fa is output from the deflection unit 27 as the first input video signal. The delay circuit 31 outputs a pulse delayed from the deflection pulse (not shown) obtained at the falling edge of the deflection waveform shown in FIG. 4A by a constant time T0 regardless of the scanning frequency as shown in FIG. 4B. To do. Here, the deflection pulse is synchronized with the deflection current and has the same phase as the start of the blanking period of the deflection current. When the output pulse of the delay circuit 31 is applied to the sample / hold circuit 32 as a sampling pulse, the sample / hold circuit 32 outputs the voltage V as the voltage information as shown by the broken line portion in FIG.
Output a. The inclination of the sawtooth portion of the deflection waveform is la
And

Next, it is assumed that a video signal of another broadcasting standard is input from the input terminal 21. In this case, as shown in FIG. 4C, as the second input video signal, the scanning frequency fb =
A deflection waveform of k · fa is output from the deflection unit 27. The delay circuit 31 outputs a pulse delayed by the time T0 from the deflection pulse as shown in FIG. 4 (d). The output timing is the same as the pulse shown in FIG. At this time, the inclination of the scanning period of the deflection current is lb = k · la. CRT
When the screen size of 24 is constant, that is, when the amplitude of the deflection current is constant, the inclination of the deflection waveform is proportional to the scanning frequency.
The relationship between the scanning frequency and the inclination has a proportional relationship as shown in FIG. Sample / hold circuit 32 in this case
If the output voltage of V is Vb, then Vb = k.Va. Therefore, the frequency discriminator 28 can output the voltage information Va and Vb proportional to the scanning frequency.

Next, the operation of the phase controller 29 will be described with reference to the block diagram of FIG. 3 and the waveform diagram of FIG. Figure 5
As shown in (a), consider a case where a deflection waveform of the scanning frequency fa is input and various corrections are performed. Frequency discriminator 2
When the voltage information Va is supplied from 8, the amplifier circuit 33 outputs x
The voltage is multiplied and the voltage of x · Va is given to the adder 35. The voltage Va is also given to the memory / arithmetic circuit 34 and temporarily held. The time-voltage converter 36 is connected to the deflection unit 27 as shown in FIG.
When the deflection waveform as shown in (a) is input, a ramp voltage is generated and the voltage V0 is output at the end of the scanning period Ta of the deflection waveform. This voltage V0 is temporarily held in the memory / arithmetic circuit 34.

The memory / arithmetic circuit 34 includes a frequency discriminator 28.
Let Vin be the input voltage from V and Vout be the operation output. Based on the held voltages Va and V0, the operation formula Vout = V
0- (V0 /Va).Vin is created and the voltage Vout is output to the adder 35. The voltage at the scanning frequency fa is Vout =
Since it becomes 0, the voltage x · Va (= v
a) is supplied. Therefore, the deflection synchronization signal as shown in FIG. 5C is output from the comparator 37. Here, the time difference ta between the synchronizing pulse of the phase controller 29 and the deflection pulse shown in FIG. 5B is ta = (V0-x.Va
) / La.

Next, a video signal of another standard is input, and FIG.
Consider the case where a deflection waveform of the scanning frequency fb is input as shown in (d). At this time, the image adjusting device 20 incorporated in the television enters the adjusting mode. In the memory / arithmetic circuit 34, the voltage information Vb (= k · Va) from the frequency discriminating unit 28
Is supplied to perform calculation, and the control voltage Vout = V0- (V
Outputs 0 / Va) · Vb. This voltage Vout and the voltage x · Vb multiplied by x by the amplifier circuit 33 are added by the adder 35, and the voltage x · Vb + V0− (V0 is supplied to the comparator 37.
/Va).Vb (= vb) is supplied. Therefore, the comparator 37 generates a deflection synchronization signal as shown in FIG. 5 (f) from the deflection current, using the voltage added by the memory / arithmetic circuit 34 as a threshold.

Of the output voltage of the adder 35, the scanning frequency f
The voltage at a is va, and the voltage at the scanning frequency fb is vb
And FIG. 5 (e) shows the deflection pulse at the scanning frequency fb, and the time difference from the deflection synchronization signal from the phase controller 29 is tb. Here, the time difference tb is tb = (V0-
Since vb) / lb, when tb is represented by va and la, tb = (V0-va) / la = ta. In this way, the phase control unit 29 can generate the deflection synchronization signal such that the time difference from the deflection pulse is always constant by the voltage information from the frequency determination unit 28 even when the scanning frequency changes.

Next, as a concrete correction example, a method of creating a convergence correction waveform will be described. FIG. 6 is an explanatory diagram showing the relationship between the correction wave and the correction change on the screen. In FIG. 6, for example, when the correction waveform such as (1) is a sawtooth waveform of 1 V (vertical scanning) period, when this correction waveform is added to the vertical convergence coil, vertical amplitude correction is performed. . When this correction waveform is applied to the horizontal convergence coil, orthogonal correction of vertical lines is performed. In addition, the correction waveform is set to 1 as in (4).
When the parabolic waveform of H (horizontal scanning) period is used, when this correction waveform is applied to the vertical convergence coil, the bending of the horizontal line is corrected. Also, when this correction waveform is applied to the horizontal convergence coil, horizontal linearity correction is performed.

Such correction waveforms are shown in FIGS. 5 (c) and 5 (f).
It is created by the deflection synchronization signal shown in FIG. 2, but the windings of the convergence yoke 25 and the deflection yoke 26 are L component and C
It has a component, and even if the correction waveform is applied to these yokes, a certain delay occurs. Therefore, even if the correction waveform is given from the time when the deflection pulse is generated, the convergence correction does not operate properly for the video signals having different scanning frequencies. Therefore, the correction waveform must be applied in anticipation of the delay time. This delay time is constant as long as the convergence yoke 25 and the deflection yoke 26 are the same. Therefore, by applying the correction waveform in advance of the generation timing of the deflection pulse for a fixed time, various correction waveforms can be automatically generated under the optimum conditions even if the scanning frequency changes due to the difference in the broadcast standard. .

In this way, the deflection unit 27 can output a correction waveform for color misregistration so that, for example, the display areas of respective colors are located at the same position over the entire screen, and optimal convergence correction is performed. In addition, the signal processing unit 23 performs the brightness correction so that the brightness and the brightness of each color are always constant,
A video signal is supplied to the CRT 24.

As described above, according to the first embodiment, the frequency discriminating section for discriminating the scanning frequency of the input video signal from the deflection waveform and outputting the frequency information as the voltage information is provided,
A phase controller that generates a deflection synchronization signal based on the frequency discrimination result is provided. For this reason, even if the scanning frequency of the input video signal changes after the adjustment is performed once, the deflection synchronization signal is generated by the voltage information from the frequency determination unit in the phase control unit and the voltage information of the scanning frequency adjusted once. By controlling, it is possible to generate correction waveforms corresponding to various scanning frequencies. Further, since the deflection synchronization signal is created from the deflection waveform from the deflection unit, pulse jitter due to noise contained in the power supply voltage does not occur, and a stable synchronization signal can be generated. A correction waveform synchronized with this deflection synchronization signal is created by the correction waveform creation unit and various corrections are performed, so there is no need for readjustment even if the scanning frequency changes, and it is possible to handle various input video signal sources with high accuracy. It is possible to perform various image corrections.

Next, an image correction apparatus according to the second embodiment of the present invention will be described with reference to FIGS.
FIG. 7 is a block diagram showing the overall configuration of the image correction device 40 in the second embodiment. The image correction apparatus 40 of FIG. 7 includes input terminals 21 and 22, a signal processing unit 23, and a CRT2.
4, the convergence yoke 25, the deflection yoke 26, the deflection unit 27, and the correction waveform generation unit 30 are provided as in the first embodiment, and detailed description thereof will be omitted.

The difference from the configuration of the first embodiment is that the frequency discriminating section 41 discriminates the scanning frequency from the synchronizing signal of the video signal.
Is provided, the phase control unit 42 generates a deflection synchronization signal based on the voltage information output from the
That is to output to.

FIG. 8 is a block diagram showing the configuration of the frequency discriminating section 41. The frequency discriminating unit 41 includes a frequency dividing circuit 43 and a time-voltage converter 44. The frequency dividing circuit 43 is composed of, for example, a flip-flop (FF) which inverts with a synchronizing signal, and generates a pulse having a pulse width of the same time as the period of the synchronizing signal. Then, the pulse width on the positive side is output to the time-voltage converter 44 as time information. The time-voltage converter 44 is a circuit which, when a pulse is input, generates a ramp signal from the rising point of the pulse and converts the time interval up to the falling point of the pulse into voltage information.

FIG. 9 is a block diagram showing the structure of the phase controller 42. As shown in the figure, the phase controller 42 includes a memory / arithmetic circuit 45, a time-voltage converter 46, and a comparator 47. The memory / arithmetic circuit 45 is a circuit that stores the voltage information from the frequency discriminating unit 41 and the voltage information of the time-voltage converter 46, and performs an arithmetic operation described later based on these voltage information. The comparator 47 is a circuit that uses the voltage supplied from the memory / arithmetic circuit 45 as a reference voltage, discriminates the level of the deflection waveform output from the deflection unit 27, and generates a deflection synchronization signal.

The operation of the image correcting apparatus according to the second embodiment thus constructed will be described with reference to the signal waveform diagram of FIG. When the synchronizing signal of the video signal is input to the input terminal 22 of FIG. 7, the deflection unit 27 generates a deflection current for raster-scanning the screen of the CRT 24. The deflection current is supplied to the deflection yoke 26 and the convergence yoke 25 to control the scanning speed. When the video signal is input from the input terminal 21, the signal processing unit 23 performs various signal processing and amplification for driving the cathode of the CRT 24. Also,
The deflection waveform of the deflection unit 27 is supplied to the frequency discrimination unit 41,
The frequency information is converted into voltage information and given to the phase controller 42.

The phase control section 42 creates a deflection synchronization signal corresponding to the scanning frequency based on the input voltage information. The correction waveform creation unit 30 is synchronized with the deflection synchronization signal from the phase control unit 42 and generates a parabolic waveform or a sawtooth waveform for analog correction. The correction waveform from the correction waveform creating unit 30 is output to the deflection unit 27, is superimposed on the deflection waveform, and is supplied to the deflection yoke 26 and the convergence yoke 25. The correction waveform is also output to the signal processing unit 23 to control the amplitude of the video signal and the like.

Next, the operation of the frequency discriminating section 41 will be described. First, when a synchronizing pulse of frequency fa is input as shown in FIG. 10 (a), the frequency dividing circuit 43 divides the synchronizing pulse and outputs a pulse as shown in FIG. 10 (b). The pulse width on the positive side at this time is Ta. Next, this time information Ta is input to the time-voltage conversion circuit 44, and by generating a ramp signal, the time information Ta is converted into voltage information of the voltage Va and output as shown in FIG. 10 (e). .

Next, as shown in FIG. 10 (c), when a synchronizing signal of frequency fb (= k · fa) is input, the frequency dividing circuit 43 outputs the pulse shown in FIG. 10 (d). In this case, the time information Tb becomes (1 / k) · Ta, and the voltage information Vb of the time-voltage converter 44 becomes 1 / k · Va. Therefore, the voltage information inversely proportional to the scanning frequency can be output from the frequency determination unit 41.

Next, the operation of the phase controller 42 will be described with reference to FIG.
And FIG. 5 will be described. First, assume that a deflection waveform with a scanning frequency fa is input as shown in FIG. The deflection waveform of the scanning cycle Ta (= 1 / fa) is applied to the time-voltage converter 46 to generate the ramp signal of the slope la, and the scanning cycle Ta is converted into the voltage information of V0 (= la.Ta). Output. The memory / arithmetic circuit 45 stores the voltage information V0 and the voltage information Va from the frequency discriminating section 41 to determine the arithmetic expression. The calculation formula here is Vout = x.Va. (Va /
Vin) + V0-V0. (Va / Vin).

Therefore, the voltage information Va from the frequency discriminating section 41 is obtained.
Is input, the voltage va (= x
・ Va) is output. Therefore, the comparator 47 is shown in FIG.
The deflection synchronization signal shown in (c) is output. The time difference between the deflection pulse of FIG. 5B and the deflection synchronization signal of the phase controller 42 is ta (= (V0 -va) / la).

Next, it is assumed that the deflection waveform of the scanning frequency fb (= k · fa) is input as shown in FIG. 5 (d). The memory / arithmetic circuit 45 receives the control voltage V
b (= 1 / k.Va) is input and calculation is performed, and the voltage vb = x.Va. (Va / Vb) + V is applied to the comparator 47.
Outputs 0-V0. (Va / Vb). Therefore, the comparator 47 generates the deflection synchronization signal shown in FIG. 5F from the deflection waveform by using the added voltage vb as a threshold. Figure 5
(E) is a deflection pulse, and the time difference from the synchronization signal of the phase controller 42 is tb. Here, the time difference tb is tb =
Since (V0-vb) / lb, this can be expressed by using va and la, and tb = (V0-va) / la = ta.

As described above, the phase controller 42 generates the deflection synchronization signal such that the time difference from the deflection pulse is always constant according to the voltage information from the frequency discriminator 41 even when the scanning frequency of the video signal changes. To do. Here, the method of creating the correction waveform is the same as that of the first embodiment, and thus the description thereof is omitted. As described above, according to the image correction apparatus of the second embodiment,
A frequency discriminating unit for discriminating the scanning frequency of the input video signal from the synchronizing signal of the video signal and outputting the frequency information as voltage information is provided. Then, the phase controller generates a deflection synchronization signal according to the frequency discrimination result. Therefore, when a video signal having a different standard is received after the image is adjusted once, even if the scanning frequency changes, the phase control unit detects the voltage information of the scanning frequency that has been adjusted once, and the frequency determination unit outputs the voltage information. The deflection synchronization signal is controlled by the voltage information. Therefore, it is possible to automatically generate a deflection synchronization signal corresponding to various scanning frequencies. Further, since the synchronizing signal is created from the deflection waveform from the deflecting unit, the problem that the synchronizing signal is jittered by noise contained in the power supply voltage is solved. In addition, the correction waveform creation unit creates correction waveforms in synchronization with this deflection synchronization signal and performs various corrections, so there is no need for readjustment even when the scanning frequency changes, and it is possible to use various input video signal sources with high accuracy. It is possible to perform compatible image correction.

[0043]

As described above, according to the first and second aspects of the present invention, the frequency discriminating means for discriminating the scanning frequency from the deflection waveform generated by the deflecting means is provided, and the voltage information from the frequency discriminating means is used. The deflection control signal whose phase is controlled is output by the phase control means. By doing so, even if the scanning frequency of the input video signal changes, a deflection synchronization signal suitable for the time constant of the yoke of the CRT can be obtained, and the convergence and the like can be corrected with high accuracy. Therefore, even when one type of television receiver receives video signals of different standards, the adjustment work can be completed with one adjustment. Further, the deflection synchronization signal, which is the generation source of the correction waveform, is less likely to be affected by the pulsed noise included in the power supply, etc., and the image correction is stabilized.

According to the third and fourth aspects of the present invention,
A frequency discriminating means for discriminating the scanning frequency from the synchronizing signal included in the video signal is provided, and the phase synchronizing means outputs the deflection synchronizing signal whose phase is controlled by the voltage information from the frequency discriminating means. By doing so, even if the scanning frequency of the input video signal changes, a deflection synchronization signal suitable for the time constant of the yoke of the CRT can be obtained, and the convergence and the like can be corrected with high accuracy. Therefore, with one type of television receiver, the adjustment work can be completed only once for the video signals of different standards. Further, the deflection synchronization signal, which is the generation source of the correction waveform, is less likely to be affected by the pulsed noise included in the power supply, etc., and the image correction is stabilized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an image correction apparatus in a first embodiment of the present invention.

FIG. 2 is a block diagram of a frequency discriminating unit in the image correction apparatus of the first embodiment.

FIG. 3 is a block diagram of a phase control unit in the image correction apparatus of the first embodiment.

FIG. 4 is a waveform diagram showing the operation of the frequency discriminating unit of the first embodiment.

FIG. 5 is a waveform diagram showing the operation of the phase controller of the first embodiment.

FIG. 6 is an explanatory diagram showing a relationship between a correction waveform and a correction change in the image correction apparatus.

FIG. 7 is a block diagram showing an overall configuration of an image correction apparatus according to a second embodiment of the present invention.

FIG. 8 is a block diagram of a frequency discriminating unit in the image correction apparatus of the second embodiment.

FIG. 9 is a block diagram of a phase control unit in the image correction apparatus of the second embodiment.

FIG. 10 is a waveform diagram showing the operation of the frequency discriminator of the second embodiment.

FIG. 11 is a block diagram of a conventional digital convergence device.

[Explanation of symbols]

 21 and 22 Input terminal 23 Signal processing unit 24 CRT 25 Convergence yoke 26 Deflection yoke 27 Deflection unit 28,41 Frequency discrimination unit 29,42 Phase control unit 30 Corrected waveform generation unit 31 Delay circuit 32 Sample / hold circuit 33 Amplification circuit 34, 45 memory / arithmetic circuit 35 adder 36, 44, 46 time-voltage converter 37, 47 comparator 43 frequency divider circuit

Claims (4)

[Claims] 1. A deflection means for generating a deflection waveform from a synchronizing signal of a video signal, a frequency discrimination means for discriminating a scanning frequency of a video signal based on the deflection waveform from the deflection means, and a frequency discrimination result from the frequency discrimination means. A phase control means for controlling the phase by means of the control means to generate a deflection synchronization signal for generating the correction waveform, and a correction means for producing a correction waveform based on the deflection synchronization signal from the phase control means to correct the image. An image correction device comprising. 2. The frequency discriminating means outputs a pulse when a certain time is delayed from a change point of a deflection waveform output by the deflecting means, and a delay circuit of the deflecting means based on an output pulse of the delay circuit. The image correction apparatus according to claim 1, further comprising a sample / hold circuit that samples the deflection waveform and outputs voltage information. 3. Deflection means for generating a deflection waveform from the synchronizing signal of the video signal, frequency discriminating means for discriminating the scanning frequency of the video signal from the synchronizing signal of the video signal, and phase based on the frequency discriminating result from the frequency discriminating means. And a phase control means for generating a deflection synchronization signal for generating a correction waveform, and a correction means for producing a correction waveform based on the deflection synchronization signal from the phase control means to correct an image. An image correction device characterized by the above. 4. The frequency discriminating means divides a synchronizing signal of an image and outputs a pulse whose polarity changes in a cycle of the synchronizing signal, and a pulse width of the dividing circuit into voltage information. The image correction apparatus according to claim 3, further comprising: a time-voltage converter that operates.