JPH05316380A - Pin cushion distortion correction circuit and television receiver - Google Patents

Abstract

PURPOSE:To attain more accurate deflection distortion correction with respect to the pin cushion correction circuit having a corner distortion correction circuit separately for lower and upper parts of a CRT. CONSTITUTION:The television receiver is provided with an amplitude adjustment circuit 6 adjusting an amplitude of a correction signal to correct corner distortion at a lower part of a screen, an amplitude adjustment circuit 8 adjusting an amplitude of a correction signal to correct corner distortion at an upper part of the screen, and a multiplier circuit 13 generating a parabolic wave signal to correct horizontal pin cushion distortion on the screen, and better deflection distortion correction is attained and factory adjustment is simplified by the provision of the circuits interlocking the amplitudes to interlock corner distortion correction and pin cushion correction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical / horizontal deflection circuit of a television receiver (hereinafter referred to as TV), and more particularly to an improved pincushion correction circuit of a horizontal deflection distortion correction circuit.

[0002]

2. Description of the Related Art FIG. 3 shows a block diagram of a conventional horizontal deflection pincushion distortion (hereinafter referred to as pincushion distortion) correction circuit. In FIG. 1, reference numeral 21 indicates the charging / discharging timing of an external capacitor. A vertical sawtooth voltage signal generated by taking a synchronizing signal, 22 is a differential comparison circuit for extracting a portion corresponding to the lower part of the screen when the vertical sawtooth signal of 21 is used for vertical deflection, and 23 is the vertical sawtooth of 21. When used for vertical deflection, a differential comparison circuit that extracts a portion corresponding to the upper portion of the screen, 24 is a multiplication circuit that multiplies the waveform extracted in 22 above, 25 is a multiplication circuit that multiplies the waveform extracted in 23 above, and 26 is the above A circuit for adjusting the amplitude of the secondary waveform output from 24, 27 is a circuit
Control voltage input terminal (hereinafter referred to as DAC) for adjustment of 2
8 is a circuit for adjusting the amplitude of the secondary waveform output from 25, 29 is the DAC for adjusting 28, and 30 is the above 2
The lower corner correction wave signal output from 6 and the above 2
8. An adder circuit for adding the corner correction wave signals output from the upper part of the screen to form a corner distortion correction wave, 31 is a voltage / current converter for converting the vertical sawtooth wave voltage signal of 21 into a current, and 32 is a voltage converter of 31. DAC for changing the distribution ratio of the current signal output from the voltage / current converter to change the phase of the pincushion distortion correction parabolic wave signal,
33 is the vertical sawtooth current output from 31
A multiplier circuit for multiplying to form a pincushion distortion correction parabola wave, 34 is a DAC for controlling the amplitude of the parabola wave signal output from 33, and 35 is a pincushion correction wave signal output from 33 and 30 An amplifier circuit that receives the output corner distortion correction wave signal, and 36 is a pincushion correction wave signal that has been subjected to corner distortion correction. The 27, 29, 32, and 34 DACs receive data signals from a microcomputer or the like. In the block diagram of this embodiment configured as described above, its operation will be described below with reference to FIG.

When a signal as shown in FIG. 4 (a) is input to 21, the portion corresponding to the lower corner of the vertical sawtooth signal is taken out at 22 as shown in FIG. As shown in (c), the amplitude of the signal is adjusted by 26 and added to the amplifying circuit of 35 to correct the corner distortion at the bottom of the screen. Also, at 23, the vertical sawtooth signal as shown in FIG. The part corresponding to the upper corner of is taken out and multiplied by 25 to be as shown in FIG. 4 (e). The amplitude of the signal is adjusted by 28 and added to the amplifier circuit of 35 to correct the corner distortion of the upper part of the screen. , A correction waveform as shown in FIG.

The pincushion correction circuit configured as described above can correct not only the usual pincushion distortion but also the distortion of the screen corner caused by the variation of the deflection yoke and the CRT.

[0005]

However, in the above configuration, the amplitudes of the distortion correction signals at the upper and lower corners are not interlocked with the amplitude of the pincushion correction parabolic wave. However, since the amplitude of the corner correction wave does not change, and the corner correction is too effective or insufficient, the amplitude of the corner correction wave must be changed again. The upper corners referred to here are the left and right corners of the upper part of the CRT, and the lower corners are the left and right corners of the lower part of the CRT, which correspond to the broken lines in FIG. 4 (f) on the waveform.

In view of the above point, the present invention interlocks the amplitude of the corner distortion correction wave with the amplitude of the pincushion correction parabolic wave so that the left and right pincushion distortion can be corrected more accurately and at the time of factory adjustment. The purpose is to reduce the loss of.

[0007]

In order to solve the above problems, a pincushion correction circuit according to the present invention comprises a circuit for interlocking the amplitude of a parabola wave for pincushion correction and the amplitude of a corner distortion correction wave shown in FIG. It has a configuration with.

[0008]

According to the present invention, with the above-described structure, the corner distortion correction can be performed in conjunction with the pincushion correction. By doing this, the deflection distortion of the screen can be corrected more accurately, and the loss during factory adjustment is reduced.

[0009]

FIG. 1 is a block diagram of a horizontal deflection pincushion distortion correction circuit including a circuit for interlocking a corner correction wave amplitude and a pincushion correction wave amplitude surrounded by a broken line in an embodiment of the present invention. In FIG. 1, reference numeral 1 is a vertical sawtooth voltage signal generated by taking charge / discharge timing of an external capacitor by a video vertical synchronizing signal, and 2 is a lower portion of a screen when the vertical sawtooth signal of 1 is used for vertical deflection. Differential comparison circuit that extracts the part that hits
Reference numeral 3 is a differential comparison circuit for extracting a portion corresponding to the upper part of the screen when the vertical sawtooth wave of 1 is used for vertical deflection, 4 is a multiplication circuit for multiplying the waveform extracted in 2 and 5 is a waveform extracted in 3 above. 6 is a circuit for adjusting the amplitude of the secondary waveform output from 4; 7 is the DAC for adjusting 6; 8 is the amplitude of the secondary waveform output from 5; Circuit, 9 is a DAC for adjusting 8 mentioned above, 1
Reference numeral 0 is an adder circuit that forms a corner distortion correction wave by adding the screen bottom corner correction wave signal output from 6 and the screen top corner correction wave signal output from 8 above.
Reference numeral 1 is a voltage / current converter for converting the vertical sawtooth voltage signal of 1 into current, and 12 is a distribution ratio of the current signal output from the voltage / current converter of 11 to change the phase of the pincushion distortion correction parabolic wave signal. DA to change
C and 13 are multiplier circuits that square the vertical sawtooth current output from 11 to form a pincushion distortion correction parabolic wave; 14 is a DAC that controls the amplitude of the parabolic wave signal output from 13; Is a differential circuit that adjusts the outputs of the 7 and 9 DACs in conjunction with the 14 DACs and links the amplitudes of the upper and lower corner correction waves with the amplitude of the pincushion correction parabolic waves, and 16 is the pin output from 13 above. An amplifier circuit receives the cushion correction wave signal and the corner distortion correction wave signal output from the above 10, and 17 is a pincushion correction wave signal subjected to corner distortion correction.
The data signals are sent from the microcomputer, etc. to the 7, 9, 12, and 14 DACs. By doing this, the amplitude of the corner correction wave changes in conjunction with the amplitude of the pincushion correction wave, and even if the amplitude of the parabola wave changes, the corner correction does not become too effective or insufficient, and better pincushion distortion correction can be achieved. It is possible. 2 is a specific circuit of the block shown by the broken line portion in FIG. The corner correction wave current is mirrored by Q1 and Q2, changed in amplitude by the differential circuit of Q5 and Q6, and output from the collector of Q5. Q in front of DACD1 that changes the amplitude of the corner correction wave
A differential circuit composed of 7 and Q8 is inserted, the collector of Q7 is connected to the base side of Q5, the collector of Q8 is connected to the base side of Q6, and DACD2 is also connected to the base side of Q6. The current distribution is determined by the balance of DACD3 and D4 that change the amplitude of the pincushion correction parabolic wave. That is, by doing so, the current ratio of D3 and D4 becomes D3> D.
If the amplitude of the pincushion parabolic wave is reduced at 4, the collector current of Q8 increases and the collector current of Q7 decreases, so that the amplitude of the corner correction wave decreases in conjunction. Conversely, when the current ratio is D3 <D4 and the amplitude of the pincushion parabolic wave increases, the collector current of Q7 increases and the collector current of Q8 decreases, so the amplitude of the corner correction wave increases in conjunction.

[0010]

As described above, according to the present invention, by providing a pincushion distortion correction circuit having a function in which the corner distortion correction is linked with the pincushion correction as shown in FIG. It can be done in conjunction with. By doing so, the deflection distortion of the screen can be corrected more accurately, and the loss at the time of factory adjustment can be reduced, which has a great practical effect.

[Brief description of drawings]

FIG. 1 is a block diagram of a pincushion correction circuit including a circuit for interlocking upper / lower corner distortion correction and pincushion correction according to the present invention.

FIG. 2 is a specific circuit diagram of an interlocking circuit for corner distortion correction and pincushion correction according to the present invention.

FIG. 3 is a block diagram of a conventional pincushion correction circuit.

FIG. 4 is a conceptual diagram of forming a corner distortion correction wave signal.

[Explanation of symbols]

 1 Sawtooth signal of one vertical cycle 2, 3 Differential comparison circuit 4, 5 Multiplier circuit 6, 8 Amplitude adjusting circuit 7, 9, 12, 14 DAC 10 Adder circuit 11 Voltage / current converter 13 Multiplier circuit 15 Corner / pin cushion Interlocking circuit 16 Pincushion correction parabolic wave amplifier circuit

Claims (2)

[Claims] 1. A differential comparison circuit a for taking out a portion corresponding to a lower corner of a CRT of a color television receiver and a portion corresponding to an upper corner thereof by taking a sawtooth voltage signal having a cycle of one vertical period of a video signal as an input. A differential comparison circuit b, a multiplication circuit a that multiplies the output signal from the differential comparison circuit a, a multiplication circuit b that multiplies the output signal from the differential comparison circuit b, and an output from the multiplication circuit a. An amplitude adjusting circuit a for adjusting the amplitude of the signal, and an amplitude adjusting circuit b for adjusting the amplitude of the output signal from the multiplication circuit b.
And an adder circuit for adding the outputs from the amplitude adjusting circuit a and the amplitude adjusting circuit b as inputs, and a voltage / current converter for converting the current by inputting a sawtooth voltage signal having a cycle of one vertical period of the video signal. And a multiplication circuit c that forms a left and right pincushion distortion correction quadratic curve wave signal of a CRT using the output signal of the voltage / current converter as an input signal, an output signal from the multiplication circuit c, and an output from the amplitude adjustment circuit a. A differential circuit for interlocking a signal with the output signal from the amplitude adjusting circuit b; a left and right pincushion distortion correcting quadratic curve wave signal output from the multiplying circuit c; and a corner distortion correcting wave signal output from the adding circuit. A pincushion correction circuit that has an amplifier circuit as an input and that aims to control the upper and lower corner distortion correction and the left and right pincushion distortion in conjunction with each other. 2. A television receiver including the pincushion distortion correction circuit according to claim 1.