CN1050299A

CN1050299A - The pulse generator that is used for lattice in the television equipment

Info

Publication number: CN1050299A
Application number: CN 90107772
Authority: CN
Inventors: 古恩特·格雷姆; 杰克斯·考文
Original assignee: Deutsche Thomson Brandt GmbH
Current assignee: Deutsche Thomson Brandt GmbH
Priority date: 1989-08-23
Filing date: 1990-08-22
Publication date: 1991-03-27
Also published as: AU6156590A; WO1991003134A1; DE3927676A1; DD297289A5

Abstract

The pulse generator that is used for lattice in the television equipment.Because grid image is made up of with vertical bright line (SH, SV) level, the brightness of vertical line is not as horizontal line.The objective of the invention is in order to eliminate this luminance difference, and need not to change the parts in the circuit.With respect to the amplitude (AH) of the pulse train (H) of horizontal line (SH), the amplitude (AV) of the pulse train (V) of vertical line (SV) is increased.It is specially adapted to have the projection television apparatus of big projection plane.

Description

The pulse generator that is used for lattice in the television equipment

According to the preorder of claim 1, the present invention is the pulse generator that is used for lattice in the television equipment.

Above-mentioned lattice (grid wire) is general with judge and the correction of do to the display error of the screen of presentation of displayed picture, for example, with the gamma correction of oppose south-north or Dong-Xi distortion, deflection, or with the correction of doing three-beam electron-beam R, G on the projection plane of TV projection equipment, B convergence.

For TV projection equipment or system, for three primary colors R, G, B provide three picture tubes, each picture tube produces a monochrome image with primary colours separately.Be projected on the projection plane of (photography) screen or frosted glass form at these three images on three picture tube image screens, and superimposed there.Because the picture tube of three local detachment of deflection unit produces by having separately for R, G, three images that are formed by stacking of B, so the special measure of needs remains on the convergence on the projection plane.

As everyone knows, in order to check and adjust convergence, utilize these three picture tubes of pulse-triggered, produce a network pattern in the image on projection plane, this lattice is made of with vertical bright line (bar) in vertical direction side by side horizontal brightness (bar), and promptly the direction corresponding to line is a quadrature.Therefore, horizontal pulse train includes the pulse of approximate-line duration, and has corresponding to desired brightness value, i.e. the highest white level or the 80%-90% amplitude of high white level for example.Delegation the duration, the pulse train of vertical line is made up of independent short pulse.Because horizontal and vertical lines should have identical brightness, so both pulse train has identical amplitude.

Although have identical amplitude, the brightness trace of vertical line is all low than horizontal, and this has been clearly.Because this situation will occur having on the horizontal and vertical lines of iso brightness as far as possible, so be disadvantageous for inspection and the correction assembled.

The objective of the invention is for the luminance difference between elimination of level and the vertical line, and guarantee that two lines have identical visible bright trace, and need not to change the parts in the circuit.

The present invention that claim 1 limits finishes above-mentioned task, and the present invention further improves and provided by dependent claims.

The present invention is based on following result of study and design.Be used to control the pulse train of picture tube by being used to trigger the video amplifier of picture tube.Because electric capacity exists inevitably, this video amplifier presents a kind of frequency response, also promptly has the low-pass characteristic in the upper frequency decay.This means that because their high frequency characteristics, impulse hits can not correctly be transmitted, but is flattened slow.This is actually inoperative to being used for horizontal first pulse train, because corresponding pulse extends to the whole line sweep phase, and impulse hits always is positioned at the outside of visible image.Yet the pulse that is used for second pulse train of vertical line all drops within the zone of visible image fully.Therefore, the frequency response of the video amplifier makes these pulses be deformed into so degree, so that the bright trace that they produce is darker.This defective can remedy by the amplitude that increases consciously corresponding to these pulses of first pulse train.This scheme has and in fact need not advantage that circuit is changed.Pulse generator only is that the pulse in second pulse train presents under the situation of higher amplitude and just is adjusted.Like this, use the present invention, by taking favourable measure aspect the amplitude, make the defective that is occurred, for example aspect frequency, and the shape of curve is compensated.

The present invention can be used for the HDTV(high definition TV in particularly advantageous mode) correction that projection is assembled, its line frequency is increased to 32KHz.Because use such system, the pulse of second pulse train only continues about 50ns.The present invention generally can be applicable in the television equipment, is used for inspection and correction to screen aspect deflection parameter, for example, is used for south-north or Dong-Ding distortion.The inspection and the correction of the distortion of non-linear and other geometry of deflection, the present invention both can be applicable to the general TV that has picture tube and in, also can be applicable in the projector equipment with three picture tubes.In above-mentioned all situations, pass judgment on and proofread and correct and preferably undertaken by above-mentioned lattice.

The present invention illustrates by the instance graph that utilizes the projection television apparatus convergence correction.In this diagram:

Fig. 1 shows the lattice on the projection plane substantially,

The impulse waveform of first and second pulse trains that Fig. 2 produced and

Fig. 3 illustrates to be used for controlling always the circuit block diagram of a picture tube generation according to Fig. 1 and lattice.

Fig. 1 shows the projection plane 1 of a television projection facility, utilizes three picture tubes with on the image projection plane 1.Picture tube is Be Controlled by this way, promptly produces the lattice with horizontal brightness SH and vertical bright line SV in order to assemble inspection on the plane 1 with assembling to be adjusted at.Thus, the width a of line SH only is a delegation, and is approximately equal to the width b of vertical line SV.

Fig. 2 shows the delegation's control signal that is used for picture tube between two horizontal synchronizing pulse z.Horizontal line SH is produced by the first pulse train H, and the pulse of this pulse train extends to the whole scan period of delegation always, and has amplitude A H.Amplitude A H represents white value (the white Value), perhaps the gray value of a corresponding expectation.Therefore, inoperative by the brightness that 2 couples of horizontal line SH of the frequency response transient state effect that cause, that dotted line shows of the video amplifier show, because it occurs in the outside in visible image zone.Vertical line SV is produced by the second pulse train V.This pulse train V was made up of several short pulses in the duration scanning of delegation.Adjust opportunity for the convergence that the best is possible, lattice must be very intact.Therefore, the pulse of vertical line only is very short pulse, and they produce the lines that have an about line width accordingly.At first, first pulse 3 of supposing pulse train V also has amplitude A H.Yet, by the frequency response of the video amplifier, this pulse become the pulse 3 of dotted line '.Though, pulse 3 ' have an amplitude that is reduced, thereby caused the bright trace of vertical line SV to weaken.

For this reason, the pulse 4 of the second pulse train V of generation has an amplitude that increases, and pulse 4 stands the distortion the same with the frequency response function of the video amplifier, thus also produced the pulse 4 of distortion '.Yet, owing to increased its amplitude, thus pulse 4 ' produced the bright trace the same for line SV with the pulse H of horizontal line SH.Like this, pulse distortion from 3 to 3 ', and from 4 to 4 ' be compensated, by amplitude is increased to 4 from 3, consistent until the bright trace of the line SH, the SV that occur.

Fig. 3 shows a circuit block diagram.For obtaining the lattice according to Fig. 1, circuit 5 is used to produce pulse train H and V.The signal that produces in circuit 5 is fed to picture tube 7 through the video amplifier 6 always, and this amplifier also is to be used to handle represent this visual signal.Cause frequency response according to the video amplifier 6 of the pulse distortion of Fig. 2 by 8 expressions of RC assembly.Circuit 5 comprises a pulse generator 9 that produces digital signal HD and VD.Above-mentioned digital signal is transformed into corresponding analog signal in two D/As 10,11, i.e. pulse train H and V.Analog signal is addition in addition unit, and is fed to the video amplifier 6.The video amplifier 6 produce according to the pulse train H of the glitch-free transient process 2 of having of Fig. 2 and increased the distortion pulse 4 of amplitude '.

From AH to AV, also promptly from pulse 3 to pulse 4, the degree that amplitude increases is to be that promptly the beholder feels that line SH and SV have same brightness according to what determine with the experiment by such mode.Showed already that in fact increasing degree was approximately 20% to 30% and just can makes horizontal and vertical lines have identical bright trace.The degree that amplitude increases depends on the frequency response of the width and the video amplifier of actual pulse.The increase of amplitude is to carry out in numeric area in principle, promptly carries out in generator 9.Yet also can carry out in simulated domain, promptly the output at D/A 11 carries out.

The present invention who is used for horizontal and vertical lines is described above.The present invention is also applicable to the line with other orientation, i.e. level and oblique line.Owing to be oblique line, the pulse 3 or 4 of pulse train V is moved respectively slightly a line one line.The width a of horizontal line SH also can be equivalent to the width of several lines, and is best, and it is equal that a among Fig. 1 and b always keep.

Claims

1, the pulse generator that is used for lattice (grid wire) in the television equipment, this pulse generator produces one and is used for going up first pulse train (H) that generates horizontal brightness (SH) at image plane (1), and second pulse train (V) that is used for going up the vertical bright line of generation (SV) at image plane (1), it is characterized in that: compare with the amplitude (AH) of first pulse train (H), the amplitude (AV) of second pulse train (V) is increased, and directly causes horizontal and vertical lines (SH, SV) that identical visible bright trace is provided.

2,, it is characterized in that amplitude (AV) is added to original 1.3 times according to the pulse generator of claim 1.

3,, it is characterized in that the degree that amplitude increases is artificial adjustable according to the pulse generator of claim 1.

4,, it is characterized in that this pulse generator produces a pulse train that is used at the lattice of projection television apparatus convegence correcting device according to the pulse generator of claim 1.