JPH01194784A - Television receiver - Google Patents

Abstract

PURPOSE:To display a video software different in aspect ratio in vivid video by delaying a read starting time of a line memory circuit than a write starting time by one horizontal scanning period or below. CONSTITUTION:To reproduce video on a screen with aspect ratio of 9:16 without any lacks, an image is reduced 3/4 both vertically and horizontally. Switches 22, 23, 24 operate associatively and are set in contacting point (b). The frequency of a clock generated by a read clock generator 11 is made 4/3 of that of a clock generated by a write clock generator 10. Accordingly, a video read from a line memory 4 and displaced on a cathode-ray tube 7 is reduced to 3/4 in the horizontal direction (time base). In the meantime, vertical amplitude is made 3/4 or normal value through a vertical amplitude adjustment variable resistor 18b. Therefore, on the tube 7, a video reduced to 3/4 both vertically and horizontally can be displayed. In this case, the starting time of a read from the line memory 4 is delayed for a certain length of time in order to eliminate an outstrip phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a television receiver in which the effective screen of the image displays an image having an aspect ratio different from that of a standard television image (3:4). It is related to.

BACKGROUND OF THE INVENTION In recent years, television receivers (hereinafter referred to as television receivers) have been used not only to receive broadcasts, but also to receive videotapes,
It is increasingly being used as a display device for packaged software such as video discs.

Also, among recent packaged software, for example, in order to display the entire image of a movie, many have added blanking (black bands) at the top and bottom while maintaining the movie's aspect ratio. .

By the way, the aspect ratio of television receivers is 3:4, but it is known that in order to create more powerful images for CinemaScope and high-definition television, it is better to make the image more horizontal. There is.

The aspect ratio of conventional television receivers is 3:4, and when playing a video with a wider effective image aspect ratio, black bars are displayed at the top and bottom, and the aspect ratio of the display remains 4:3. Therefore, the conventional aspect ratio of the display section was insufficient to produce more powerful images.

Furthermore, as high-definition televisions (with an aspect ratio of 9:16) have recently become more practical, proposals have been made to display standard television images on screens with different aspect ratios in order to maintain compatibility with standard television broadcasting. ing.

The conventional television receiver described above will be described below with reference to the drawings.

FIG. 4 is a system diagram of a conventional television receiver that converts aspect ratios. In Fig. 4, 3o indicates a receiving circuit including from a tuner to a video detection circuit, and from now on, depending on the broadcasting format, a high-quality luminance signal Yw or a standard luminance signal Y
s is retrieved.

In the case of high-definition television broadcasting, the brightness signal Yw from the receiving circuit (the high-definition side contact W of the changeover switch 31
The signal is further supplied to the picture tube 33 through the video amplifier 32. The aspect ratio of this picture tube 33 is 9:16, which is the aspect ratio of a high-definition television.

On the other hand, in the case of standard television broadcasting, the standard luminance signal Ys from the receiving circuit 3° is transmitted to the memory circuit 34a consisting of a COD or the like.
, 34b. Further, the horizontal synchronization pulse ph from the horizontal synchronization separation circuit 35 is supplied to the write/read pulse forming circuit 36, and write pulses φ at predetermined intervals are formed during the effective horizontal scanning period of the standard luminance signal Ys. A readout pulse φ, whose interval is compressed by 3/4 of the horizontal size ratio of a high-definition television screen and a standard television screen, and whose number is the same as that of the pulse φ8 and located at the center of the effective horizontal scanning period, is used. It is formed. These pulses φ8. φ is supplied to the switch circuits 37 and 38, and the horizontal synchronization pulse ph from the horizontal synchronization separation circuit 35 is also supplied to the flip-flop circuit 39 to form a rectangular wave signal sh that is inverted every horizontal period. , the pulses φ□ and φ2 are alternately supplied to the memory circuits s4a and s4b every horizontal period by controlling the switch circuits 37 and 38. Therefore, the memory circuit s4a,
In 34b, writing and reading of the signal Ys are performed alternately every horizontal period.

Furthermore, in this case, the number of read pulses φ is equal to that of write pulses φ8, and the interval (period) thereof is compressed to 3/4, so that the memory circuit 34a.

The time axis of the signal Ys read from 34b is 3/34b.
It is compressed to 4. Note that this compressed luminance signal Ys
was set as the signal Ye. In this way, the memory circuit 34a,
The luminance signal Yc alternately read out from the flip-flop circuit 34b is supplied to the switch circuit 40, and the signal sh from the flip-flop circuit 39 is supplied to the switch circuit 4o as its control signal.

Therefore, from the switch circuit 4o is the memory circuit 34a.

The signal Yc from 34b is sequentially taken out.

The signal Yc from this switch circuit 40 is transmitted to the synthesis circuit 41
At the same time, the horizontal synchronization pulse ph from the horizontal synchronization separation circuit 35 is supplied to the valid signal generation circuit 42, and the valid signal generation circuit 42 distinguishes between the valid horizontal scanning period and the ineffective horizontal scanning period of the luminance signal Yc. An inverted signal sb is formed and supplied to the synthesis circuit 41. In this way, the synthesis circuit 41 outputs a luminance signal Yc whose ineffective horizontal scanning period is set to the black level. And this luminance signal Yc
is connected to the amplifier 3 through the standard side contact S of the switch 31.
2 to the picture tube 33.

Therefore, an image based on the luminance signal Yc is reproduced on the picture tube 33, but in this case, the signal Yc has its time axis compressed to 3/4 of the original luminance signal Ys for each horizontal period, and the received image The screen of the tube 33 has an aspect ratio of 9:16, and the horizontal size is 4/3 times that of a standard screen (3:4 aspect ratio), so the image of the luminance signal Yc is In other words, the standard luminance signal Y8 is reproduced with the correct aspect ratio (Japanese Unexamined Patent Publication No. 53-51922).

Problems that the invention sought to solve: However, in the above configuration, the read clock has a higher frequency than the write clock, so two line memories were required, and writing and reading had to be switched alternately. . In particular, in the case of a color television receiver, not only a luminance signal but also five color signals are required, so at least three sets of the above-mentioned line memories are required, resulting in a problem of high cost.

In view of the above problems, the present invention allows video software with different aspect ratios to be displayed with impressive images, and images with normal aspect ratios can be compressed at low cost without losing information. The present invention provides a television receiver that displays images.

Means for Solving the Problems In order to solve the above problems, the television receiver of the present invention includes:
a display section having an aspect ratio different from that of a standard television screen;
It is equipped with a line memory circuit that stores a video signal of a horizontal period, a write-in clock generation section for writing into this line memory circuit, and a read clock generation section that generates a clock having a frequency υ higher than the write clock, The read start time of the line memory circuit is delayed by one horizontal scan or less from the write start time.

Effect: With the above-described configuration, the present invention prevents an overtaking phenomenon from occurring even if the video information of the line memory is read at a faster speed than the write clock or with a lock. With the line memory of
The compression function is configured and can be realized at low cost.

Embodiment Hereinafter, a television receiver according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a television receiver according to a first embodiment of the present invention.

In FIG. 1, a composite video signal is supplied to terminal 1,
The luminance signal and the color signal are separated and demodulated in the Y/C separated single color demodulation circuit 2, converted into a digital signal by the A/D converter 3, and stored in the line memory 4a. 5 is a D/A converter for converting the digital video signal read from the line memory 4 into an analog signal, and the video signal that has become an analog signal is amplified by an amplifier θ,
The image will be displayed. In order to project powerful images, the picture tube 7 is longer in width than a standard television receiver, and its aspect ratio is the Vista size, which is often used in movies, and is being standardized as a high-definition television. The score was 16 vs.

Further, the composite video signal supplied from the terminal 1 is sent to a horizontal synchronization separation circuit 8 to form a horizontal synchronization signal, which is supplied to a write start pulse generator 9 and a write clock generator 1o to control the writing of the line memory 4. . Further, the horizontal synchronization signal from the horizontal synchronization separation circuit 8 is also supplied to a read start pulse generator 12 and a read clock generator 11 to control read from the line memory 4. Further, the delayed horizontal synchronizing signal generator 13 generates a delayed horizontal synchronizing signal by delaying the horizontal synchronizing signal supplied from the horizontal synchronizing separator 8 by a certain period of time, and outputs the delayed horizontal synchronizing signal to the deflection coil 21 through the horizontal drive circuit 14 and the horizontal output circuit 16. to drive.

The vertical synchronization separation circuit 16 forms a vertical synchronization signal from the composite video signal from the terminal 1, and the vertical oscillation circuit 21 generates a sawtooth wave synchronized with this composite video signal. The switch 24 is a switch for switching the vertical amplitude, and is a vertical amplitude adjustment polyurethane 18a.

18b, the deflection coil/
Drive L'27.

Also, Figure 3 shows the projected screen when an image is projected on a display screen with an aspect ratio of 9:16, but when a standard TV image is played back as shown in Figure fa1, the vertical The video in the area indicated by the dotted line is missing.

In this way, in order to reproduce a standard video on a display screen with an aspect ratio of 9:16 without image loss, the vertical amplitude must be set to 3/4 of the normal value to prevent image distortion. ,
The horizontal direction (time axis) must also be compressed to 3/4. Figures 3(b) and fc) show the projected screen when both the vertical and horizontal dimensions are compressed to 3/4.

Furthermore, when displayed on a standard television receiver, an image with blanking (black bands) at the top and bottom can be played back as a horizontally long and powerful image if the image is displayed without compression. An example is shown in FIG. 3(d).

The operation of the television receiver configured as described above will be described below with reference to FIGS. 1 and 2.

The composite video signal supplied from terminal 1 is separated and demodulated into a bright V signal and a chrominance signal by a Y/C separation/color demodulation circuit 2.
It is converted into a digital signal by the /D converter 3 and written to the line memory 4, but the line memory 4 is a FiFO
It consists of (first in, first out). In this line memory 4, when the write start pulse ω□ is @Ln level, the write address is set to the initial address (address 0), and the write start pulse ω is set to “H”.
” level, the digital video signal obtained by the A/D converter 3 is stored while sequentially incrementing the address one by one using the write clock ω.Furthermore, the line memory 4 can be read out asynchronously with writing. , when the read start pulse RR is at the w L Jl level, the read address is set to the initial address (address 0), and when the read start pulse RR becomes the ``H# level'', the addresses are sequentially changed one by one according to the read clock RC. While increasing, the stored digital video signal is read out.

By the way, as mentioned above, in order to play the video without any loss on a display screen with an aspect ratio of 9:16, the image must be resized to 3/3 in both the height and width.
It needs to be reduced to 4.

In FIG. 1, switches 22 and 23 are interlocked;
When the contact is set to the b side, the read start pulse (RR) of the line memory 4 is supplied from the read start pulse generator 12, and the read clock (RC) is supplied from the read clock generator 11. The frequency (fr) of the clock generated by the read clock generator 11 is 4/3 times the frequency CfW of the clock generated by the write clock generator 1o, and is read from the line memory 4. The image projected on the picture tube 7 through the D/A converter 5 and amplifier 6 is horizontally (time axis)
It has been reduced to 3/4. Further, the switch 24 is also linked to the switches 22 and 23, and the vertical amplitude is set to 3/4 of the normal amplitude by a vertical amplitude adjustment volume 18b connected at the contact point on the b side. Therefore, an image reduced to 3/4 in both the vertical and horizontal directions is displayed on the picture tube 7.

Also, as mentioned above, when the switches 22 and 23 are set to the b side, the read clock (RC) has a frequency 4/3 times higher than the write clock (ω), so writing and reading start at the same time. Then, a phenomenon occurs in which reading overtakes writing (called overtaking phenomenon),
A normal image cannot be obtained.

Therefore, the present invention eliminates the overtaking phenomenon described above by delaying the start of reading from the line memory 4 for a certain period of time.

Figure 2 shows the video signal, write start pulse, write clock, delayed horizontal synchronization signal, read start pulse,
This shows the timing of the read clock.

The write start pulse (ωR) is formed in synchronization with the horizontal synchronization signal (cycle is set to Th) of the video signal, and when this write start pulse (ωR) reaches the 11 HJ level, writing to the line memory 4 starts. and is written at the cycle (1/fW-) of the write clock (ω0). Then, reading starts when the read start pulse becomes "H" level, and is read at the cycle (1/fr) of the read clock (RC).

Here, in order to prevent an overtaking phenomenon, the read start time (the time when the read start pulse goes to "H" level) is changed from the write start time (the time when the write start pulse goes to "H" level).
It is necessary to delay by Td from the time when the signal reaches the level.

Here, Td must be Td(Th) since it satisfies the tracking condition and uses line memory. Therefore, T
d is set in the range of 1/4 Th<Td<Th. In addition, in order to display the reduced image in the center of the screen as shown in Figure 3(b), the horizontal synchronization signal is delayed as shown in Figure 2 to form a delayed horizontal synchronization signal. Deflection coil /l/21 is driven by a delayed horizontal synchronization signal. The delay time for starting reading at this time is Tdl.

Also, as shown in FIG. 3(C), in order to display the reduced image at the left edge of the screen, the readout start time delay is set to Ta2, and T
This is possible by making it less than dl.

Similarly, in order to move the reduced image to the right, it is sufficient to increase the delay time at the start of reading. Such a delay in the read start time can be easily formed by counting read clocks with reference to the horizontal synchronization signal supplied from the horizontal synchronization separation circuit 8.

Furthermore, by configuring as described above, the left and right parts of the compressed image (hatched areas 25, 26, . . . in FIG. 3)
2a) It is possible to display channel numbers, volume levels, etc., allowing effective use of the screen.

Also, when receiving a video with an effective screen aspect ratio of 9:16 as shown in FIG. 3(d), the contacts of the interlocking switches 22 and 23 in FIG. By setting it to the a side, the write start pulse and the read start pulse, the write clock and the read clock are the same, and an image that is not compressed in the horizontal direction (time axis) can be obtained. Further, the vertical amplitude adjustment polyurethane 18a which has been switched by the switch 24 is adjusted to the normal vertical amplitude. In this way, the interlocking switch 22
．． By setting the contact points of 23 and 24 to the b side, an uncompressed image can be obtained, and the aspect ratio is also 9:16, so a powerful image can be projected.

As described above, according to this embodiment, there is a display section having an aspect ratio different from that of a standard television receiver, a line memory circuit that stores video for one horizontal period, and a clock (frequency) for writing to the line memory circuit. a write clock generating section that generates a clock with a higher frequency than the write clock (frequency m/nfw, where m)n); One horizontal scanning time (Th
), a compressed image can be obtained with 1/2 the number of line memories of the conventional method by delaying the time by at least (1-n/m)Th.

Furthermore, by changing the delay time for starting reading, the position of the display screen can be easily moved left and right.

Effects of the Invention As described above, according to the present invention, by delaying the start of reading from the line memory circuit from the start of writing, the image compression function can be configured at low cost, and furthermore, the image compression function can be configured at low cost. It is also possible to easily position the image to the left or right.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a television receiver in an embodiment of the present invention, FIG. 2 is a waveform diagram showing timing in the embodiment, and FIG. 3 is a screen of the television receiver in the embodiment. FIG. 4 is a block diagram of a conventional television receiver. 4... line memory, 7... picture tube,
9...Writing start pulse generator, 1o...
... Write clock generator, 11 ... Read clock generator, 12 ... Read start pulse generator, 13 ... Delay horizontal synchronization signal generator, 18a, 1 sb... Vertical amplitude adjustment polyum, 22.23.24... Interlocking switch. Name of agent: Patent attorney Toshio Nakao and one other person
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Claims (2)

[Claims] (1) A display unit having an aspect ratio different from that of a standard television screen, a line memory circuit that stores video signals for one horizontal period, and a write clock (frequency f_r) for writing video signals into the line memory circuit. A write clock generator generates a write clock, and a read clock (frequency m/n・f_r, m
>n);
The reading start time of the above line memory circuit is one horizontal scanning period Th or less than the writing start time and (1-n/m)T
A television receiver characterized by a delay time of more than h. (2) The television receiver according to claim 1, wherein the position of the displayed image is moved from side to side by changing the delay time for the start of reading.