JPH08265666A - Display device for television signal - Google Patents

Abstract

PURPOSE: To provide the display device at a low cost in which a standard and a high definition television signal whose number of scanning lines, horizontal scanning frequency and aspect ratio or the like differ are displayed efficiently and image quality of the standard television signal is remarkably improved while eliminating various types of disturbance. CONSTITUTION: An NTSC signal is written in a memory 12 in the unit of lines for each field, and the NTSC signal written in the memory 12 is read in the unit of lines for each field based on a read clock RCP whose frequency is nearly twice that of a clock WCP from a pulse production circuit 22, a double speed horizontal synchronizing signal HD1 and a double speed vertical synchronizing signal VD1 from the pulse production circuit 22. The signal compressed into nearly 1/2 on time base from the original NTSC signal is outputted from the memory 12 and the horizontal scanning frequency fH is nearly twice as high as the original frequency fH1 and the number of scanning lines is an odd number being nearly twice that of the original television signal. A high definition television signal from input terminals 2, 3, 4 is fed to a changeover circuit 18 and selected and displayed on a display device 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for efficiently displaying a standard television signal such as the NTSC system or both the standard television signal and a high definition television signal such as the high definition system. The present invention relates to a display device for television signals.

[0002]

2. Description of the Related Art NT is the conventional television system.
There are standard television systems such as SC system (or ED system), PAL (or PAL plus system), and SECAM system. In the case of NTSC system, the number of scanning lines N1 per frame is 525, and the field frequency fV1 is 59. 94
Hz (in frame frequency fV1 / 2 = 29.97H
z), the horizontal scanning frequency fH1 is set to 15.73 kHz, and the aspect ratio is set to 4: 3.

On the other hand, in recent years, the definition of images has been improved by improving the television system, and a high-definition system which has about twice as many scanning lines as the standard television system and which dramatically improves the image quality, High-definition television systems (HDTV: High Definition TV) such as the ATV system have been devised, and broadcasting is about to start.

In the case of the high-definition system, the number of scanning lines N2 per frame is 1125, and the field frequency fV2
Is 60.0 Hz (frame frequency fV2 / 2 = 3
0.0Hz), horizontal scanning frequency fH2 is 33.75kHz
z and aspect ratio are set to 16: 9.

For this reason, it is expected that the future television system will coexist with the high-definition television system of a completely different format in addition to the current standard television system, and display of future television signals. It is desirable that the device and the recording / reproducing device can selectively display both of these types of television signals by one device or can selectively record / reproduce by one device.

[0006] An example of a device that fulfills such needs, that is, a device capable of recording and reproducing both types of television vision signals, has been disclosed by the inventors of the present invention.
It is proposed in Japanese Patent Publication No. 334289.

In recent examples, a practical example can be seen in a device for selectively displaying the standard television signal and the high-definition television signal in a high-definition television receiver or the like.

For example, in the "television device" disclosed in Japanese Patent Laid-Open No. 6-225269, an NTSC signal is non-interlaced by writing twice in one field in a television device compatible with high-definition signals. . Then, although it is written twice in the next field, the scanning lines are scanned so as to alternate with the scanning lines of the previous field. As a result, both the high-definition signal and the NTSC signal can be displayed with a simple structure.

[0009]

However, in the above-described conventional television signal display device for selectively displaying the standard television signal and the high-definition television signal,
In order to switch and display the standard television signal and the high-definition television signal having different signal formats (in particular, horizontal scanning frequency), it is necessary to individually operate the deflection systems which are greatly different in these two modes, which results in a low device It was difficult to reduce costs.

On the other hand, although the cost of the apparatus increases, even if the current standard television signal is displayed, only the image quality comparable to the conventional one can be obtained, and the size is increased, the brightness is increased, and the definition is increased (CRT). On the display, various aliasing interferences such as flicker interference and scanning line interference are conspicuous, and on the contrary, there is a drawback that image quality is deteriorated and cost performance is deteriorated.

Further, as in the example described in Japanese Patent Laid-Open No. 6-225269, in a high-definition image receiver or the like,
In a device for selectively displaying a standard television signal and a high-definition television signal, although a high-definition television receiver is used, in the case of a standard television signal, only conventional image quality is still obtained. There wasn't. Therefore, in a television signal display device using a high-definition television receiver, there is a demand to improve the quality of standard television signals.

It is an object of the present invention to efficiently display with a single device even if the number of scanning lines, horizontal scanning frequency, aspect ratio, etc. are different, such as standard television signals and high definition television signals. It is also an object of the present invention to provide a device which can eliminate the various interferences and significantly improve the image quality at the time of displaying a standard television signal at a low cost.

[0013]

In order to achieve the above object, the present invention is configured as follows. A signal input means for inputting a television signal having a field frequency of fV1, the number of scanning lines in one frame being N1, and a horizontal scanning frequency of fH1 (= N1 × fV1 / 2), and a television signal from the signal input means. The field frequency fV is twice as high as the television signal (fV = 2 × fV1), and the number of scanning lines N is an odd value in the vicinity of twice the television signal within one frame period of the television signal. And a signal converting means for converting the horizontal scanning frequency fH into a display signal given by fH = N × fV / 4, and the display signal from the signal converting means is deflected at a field frequency fV and a horizontal scanning frequency fH. Display means for displaying via a deflection system.

Preferably, in the above television signal display device, the signal converting means includes a memory into which a composite signal including a color signal and a luminance signal is written at a first timing, and a composite signal written into the memory. Is read at a timing almost twice as high as the first timing.

The field frequency is fV1, the number of scanning lines in one frame is N1, and the horizontal scanning frequency is fH1.
(= N1 × fV1 / 2) first television signal, the number of scanning lines is larger than that of the first television signal, the field frequency is fV2, and the number of scanning lines in one frame is N2.
When the horizontal scanning frequency is fH2 (= N2 × fV2 / 2) and the second television signal, at least one of the television signals is input, and the first television signal is input, The first television signal from the signal input means is scanned within the period of one frame of the first television signal when the field frequency fV is twice as high as the first television signal (fV = 2 × fV1). Number of lines N is first
Of the television signal, a signal converting means for converting the horizontal scanning frequency fH into a display signal given by fH = N × fV / 4, and a display signal from the signal converting means, A display for displaying via a deflection system that selectively switches and deflects the field frequency fV and the horizontal scanning frequency fH or the second television signal is deflected at the field frequency fV2 and the horizontal scanning frequency fH2. And means.

Preferably, in the above television display device, the signal converting means converts the first television signal into
The number of scanning lines N is converted into a display signal having an odd value (N.apprxeq.N2) near the number N2 of scanning lines of the second television signal within the period of one frame of the first television signal.

[0017]

With the above configuration, for example, in the case of the current NTSC system, the number of scanning lines is N1 (= 525) and the fields are interlaced so that the scanning line interval is 1 / N1 (= 1).
/ 525) television signals are interlaced between fields with almost twice the number of scanning lines N (= 1051 or 1125), and the scanning line interval is 1 / N (= 1/1).
(051 or 1/1125) signals are displayed and then the scanning line structure is less likely to be detected, and visually, scanning line interference is removed, line flicker is reduced, and the image has a glossy texture. Higher image quality can be obtained.

Also, the field frequency is doubled (fV≈1
Since it is converted into 20 Hz) and displayed, flicker interference, which was conventionally conspicuous in a large area of the image, is removed, and a visually stable image is obtained.

As described above, since the number of scanning lines is approximately doubled and displayed, the horizontal scanning frequency fH is almost the same as the horizontal scanning frequency fH2 of a high definition television signal (N =
In the case of 1125, fH ≈ 33.72 kHz or a value close to it (in the case of N = 1051, fH ≈ 31.50 kHz)
z), the deflection system of the receiver can be commonly used for displaying a standard television signal and for displaying a high-definition television signal, so that the cost of the device can be easily reduced. .

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an apparatus for selectively displaying a video signal of a standard television system and a video signal of a high definition television system will be described with reference to the drawings.

FIG. 1 is a block diagram of a display device showing an embodiment of the present invention. In the example of FIG. 1, the number of scanning lines N1 = 525, the field frequency fV1 = 59.94 Hz, the frame frequency fV1 / 2 = 29.97 Hz, and the horizontal scanning frequency fH1 = 1 as a standard television system video signal.
The number of scanning lines N2 = 1125 as an NTSC signal of composite format (5.73 kHz, interlace ratio 2: 1 and aspect ratio 4: 3 (hereinafter referred to as standard NTSC signal)) and a high definition television image signal. Book,
Field frequency fV2 = 60.0 Hz, frame frequency fV2 / 2 = 30.0 Hz, horizontal scanning frequency fH2 = 33.
75 kHz, interlace ratio 2: 1, aspect ratio 1
This is an example of a display device of a television signal capable of displaying both a high-definition signal of a component format of 6: 9 (hereinafter, referred to as an HD signal).

In FIG. 1, the input terminal 1 has a standard NT
The SC signal is input. Since the standard NTSC signal input to the input terminal 1 is in the composite format, the carrier color signal C in which the two color difference signals (RY) and (BY) are orthogonally multiplexed becomes the luminance signal Y. It is frequency multiplexed.

Further, a luminance signal Y of the HD signal is input to each of the component format HD signal input terminals 2, 3, and 4.
2 and two color difference signals Pb and Pr are input. The NTSC signal input to the input terminal 1 is sent to the A / D conversion circuit 11
Is supplied to the memory 12 via. And memory 1
The output signal from 2 is supplied to the YC separation circuit 13 and the color decoding circuit 14, and the output luminance signal from the YC separation circuit 13 is passed through the D / A conversion circuit 15 to the signal switching circuit 18
Is supplied to.

Further, the color difference signal from the YC separation circuit 13 is supplied to the color decoding circuit 14, and the color difference signal (B-
Y) is the signal switching circuit 18 via the D / A conversion circuit 16.
And the color difference signal (RY) is supplied to the D / A conversion circuit 1.
It is supplied to the signal conversion circuit 18 via 7. The signal switching circuit 18 includes a matrix circuit.

The NTSC signal from the input terminal 1 is
It is supplied to the sync separation circuit 21, and the burst signal BS1 and the sync signal SY1 are supplied from the sync separation circuit 21 to the pulse generation circuit 22. From this pulse generation circuit 22,
A write clock signal WCP described later is supplied to the A / D conversion circuit 11 and the write control circuit 23. Also,
The double speed vertical synchronizing signal VD1 and the double speed horizontal synchronizing signal HD1 from the pulse generating circuit 22 are supplied to the deflection switching circuit 23. Further, the write clock signal RCP from the pulse generation circuit 22 is supplied to the read control circuit 24.

Further, H input to the input terminals 2, 3, 4
The D signals (Y2, Pb, Pr) are supplied to the signal switching circuit 18. The signal Y2 supplied to the input terminal 2 is supplied to the sync separation circuit 31, and the sync separation circuit 31 supplies the sync signal SY2 to the pulse generation circuit 32. Then, from the pulse generation circuit 32, the deflection pulse VD2,
HD2 is supplied to the deflection switching circuit 41.

Then, the signal from the signal switching circuit 18 is supplied to the cathode ray tube 50, and the signal from the deflection switching circuit 41 is supplied to the deflection system 42. The deflection system 42 includes both vertical deflection and horizontal deflection.

First, the H of the above high definition television system.
The operation of displaying the D signal on the cathode ray tube 50 will be described. The component signals Y2, Pb, Pr from the input terminals 2, 3, 4 are sent to the signal switching circuit 18 respectively.
When an external command is issued to display a high-definition television signal, each of these component signals Y is generated by the signal switching circuit 18 based on the command.
2, Pb, Pr are selected and switched so that the three primary color signals R, G, B of the high-definition television signal are decoded.

On the other hand, the luminance signal Y2 from the input terminal 2
The sync information included in the sync signal is separated by the sync separation circuit 31, and a sync signal SY2 based on the sync information is output from the sync separation circuit 31 and supplied to the pulse generation circuit 32. The synchronizing signal SY2 has vertical synchronizing signals VS2 and fH2 = of which frequencies are fV2 = 60.0 Hz, respectively.
A horizontal synchronizing signal HS2 of 33.75 kHz is included. The pulse generation circuit 32 generates the vertical deflection pulse VD2 based on the vertical synchronization signal VS2. Further, the pulse generation circuit 32 generates a horizontal deflection pulse HD2 based on the horizontal synchronization signal HS2.

These deflection pulses VD2 and HD2 are supplied to the deflection switching circuit 41, and based on the display instruction of the high definition television signal, these deflection pulses VD2 and HD2 are supplied.
2 and HD2 are selectively switched and output to the deflection system 42.

By the above operation, the signal switching circuit 18 is
The three primary color signals of the high-definition television signal from the above are supplied to the display device 50, and fV2 = 60.0 Hz in the deflection system 42 based on the deflection pulse of the high-definition television signal from the deflection switching circuit 41. Vertical deflection and fH2 = 33.
Horizontal deflection of 75 kHz is performed, and a color image of a high definition television is displayed on the display device 50.

Next, the NT of the above standard television system
The operation for displaying the SC signal will be described. The composite standard NTSC signal from the input terminal 1 is converted into a digital signal by the A / D conversion circuit 11. The standard NTSC signal from the input terminal 1 is also supplied to the sync separation circuit 21, which separates the sync information contained in the standard NTSC signal from the burst information of the color subcarrier. Synchronization signal SY1 based on synchronization information and burst signal BS1 based on burst information
Are output and supplied to the pulse generation circuit 22.

The sync signal SY1 has a frequency fV1 = 5.
Vertical sync signal VS1 of 9.94 Hz and frequency fH1 = 1
A horizontal synchronizing signal HS1 of 5.73 kHz is included. The frequency of the burst signal BS1 is fSC = 3.58 MHz, like the color subcarrier frequency.

In the pulse generation circuit 22, the frequency is, for example, fW = 4 × fSC = 14.32M based on the burst signal BS1 by the first PLL circuit described later.
A write clock signal WCP of Hz is generated. The write clock signal WCP is fW = 910 × fH1 (=
Since the relationship of 14.32 MHz) is established, it may be generated based on the horizontal synchronizing signal HS1 of the frequency fH1.

In this embodiment, the first PLL circuit generates the color subcarrier signal SC which is continuous at the same frequency as the burst signal BS1. The color subcarrier signal SC may be a pulse signal whose amplitude is limited and binarized into a rectangular wave shape. For example, the write clock signal WC is used.
It may be a signal obtained by dividing P by 1/4.

In the pulse generating circuit 22, the frequency is, for example, fV = 2 × fV1 = 1119.88H based on the vertical synchronizing signal VS1 by the second PLL circuit described later.
z double speed vertical synchronizing signal VD1 and fH = (1051/4)
A double speed horizontal synchronizing signal HD1 of × fV = 31.50 kHz is generated. Furthermore, in this pulse generation circuit 22,
The frequency is, for example, fR = 910 × fH based on the double speed horizontal synchronizing signal HD1 by a third PLL circuit described later.
= 28.66 MHz read clock signal RCP is generated.

The read clock signal RCP is f
R = (1051/525) × fw (= 28.66MHz)
Since the above relationship is established, it may be generated based on the write clock signal WCP having the frequency fW. Alternatively, fR = (4 × 1051/525) × fSC (= 2
8.66 MHz), the frequency f
It may be generated based on the burst signal BS1 of the SC (or the color subcarrier signal SC). Moreover,
fR = (910 × 1051/525) × fH1 (= 28.
66 MHz) is established, it may be generated based on the horizontal synchronizing signal HS1 of the frequency fH1, or fR = (1051 × 455) × fV1 (= 28.
66 MHz) is established, it may be generated based on the vertical synchronizing signal VS1 having the frequency fV1.

The double speed vertical synchronizing signal VD1 and the double speed horizontal synchronizing signal HD1 are output as a vertical deflection pulse and a horizontal deflection pulse for displaying a standard television signal, respectively, and are supplied to the deflection switching circuit 41.

The write clock signal WCP generated by the pulse generation circuit 22 is supplied to the A / D conversion circuit 11 as an A / D conversion clock signal. Then, the analog standard NTSC signal is sequentially converted into a digital signal. The write clock signal WCP is also supplied to the write control circuit 23. This write clock signal WC
Writing to the memory 12 is controlled based on P, and the digitized standard NT from the A / D conversion circuit 11 is controlled.
The SC signal is sequentially written in the memory 12.

Writing to the memory 12 is performed in units of lines for each field of the standard NTSC signal. In order to control the writing in units of lines, the horizontal synchronizing signal HS1 and the vertical synchronizing signal VS1 are appropriately supplied from the pulse generating circuit 22 to the writing control circuit 23.

Further, this standard NTSC signal memory 12
The color subcarrier signal SC from the pulse generation circuit 22 is also written in another area of the memory 12 in synchronization with the writing to the memory 12. When the color subcarrier signal SC is binarized as described above, one bit in the amplitude direction is sufficient for writing to the memory 12. Therefore, for example, if the number of bits of the A / D conversion circuit 11 is m, the number of bits (in the amplitude direction) of the memory 12 is (m +
1) is sufficient.

Next, the read clock signal RCP generated by the pulse generation circuit 22 is supplied to the read control circuit 24. Then, based on the read clock signal RCP signal, reading from the memory 12 is controlled, and the standard NTSC signal written in the memory 12 is sequentially read line by line for each field. In order to control the reading on a line-by-line basis, the pulse generation circuit 22 outputs the double speed horizontal synchronizing signal HD1 and the double speed vertical synchronizing signal VD1.
And are appropriately supplied to the reading control circuit 24.

Here, the frequency ratio between the write clock signal WCP and the read clock signal RCP is expressed by the following equation (1).
Given in. fR / fw = 1051 / 525≈2.0-(1) Therefore, from the memory 12, the original standard NTSC
A signal obtained by time-compressing the signal on a line-by-line basis to about 1/2 (hereinafter referred to as a double speed NTSC signal) is output,
The horizontal scanning frequency is fH = (1051/525) × fH1 = 31.50 of the double speed horizontal synchronizing signal HD1.
given in kHz. From this, the original horizontal scanning frequency f
The ratio with H1 is given by the following equation (2) and is almost doubled. fH / fH1 = 1051 / 525≈2.0 --- (2) Also, from the memory 12, the color subcarrier signal SC described above is read together with the reading of the double speed NTSC signal, and its frequency is double speed. Similar to the color subcarrier frequency of the carrier color signal C included in the NTSC signal, it is almost doubled (7.
17 MHz) and output (hereinafter, this output is referred to as a double speed color subcarrier signal).

The double-speed NTSC signal and the double-speed color subcarrier signal read and output from the memory 12 are each Y
It is supplied to the C separation circuit 13 and the color decoding circuit 14. Y
The C separation circuit 13 separates the luminance signal Y and the carrier color signal C, which are frequency-multiplexed into the double speed NTSC signal. The separated luminance signal Y is supplied to the D / A conversion circuit 15 and converted into an analog signal, and then supplied to the signal switching circuit 18 as the luminance signal Y1.

The separated carrier color signal C is supplied to the color decoding circuit 14. Then, in the color decoding circuit 14, two color difference signals (BY) and (RY) that are orthogonally multiplexed to the carrier color signal C are generated based on the double speed color subcarrier signal from the memory 12. Decoded, separated and output. These two color difference signals (BY)
And (RY) are D / A conversion circuits 16 and 17, respectively.
And the color signal C after being supplied to and converted to an analog signal
1 and C2 are supplied to the signal switching circuit 18.

When an external command is issued to display the above standard television signals on the cathode ray tube 50,
Based on the command, the signal switching circuit 18 selectively switches the component signals Y1, C1 and C2 of the double speed NTSC signal based on the original standard television signal, performs matrix calculation as appropriate, and three primary colors based on the double speed NTSC signal. The signals R, G, B are decoded.

On the other hand, the vertical deflection pulse VD1 and the horizontal deflection pulse HD1 from the pulse generation circuit 22 are selectively switched by the deflection switching circuit 41 on the basis of the display command of the standard NTSC television signal, and the deflection system. 42 is output.

As described above, the double-primed three-primary-color signal based on the original standard NTSC television signal from the signal switching circuit 18 is supplied to the display unit 50 and deflected based on the deflection pulse from the deflection switching circuit 41. FV = in system 42
Vertical deflection of 119.88 Hz and fH = 31.50 kHz
Horizontal deflection is performed to display a color image of a standard NTSC television signal at double speed.

Here, the memory 12 which is the key to the present invention.
A method of reading the signal from the above will be described in detail below with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing a timing of reading a signal from the memory 12 in one embodiment of the present invention,
FIG. 3 is a diagram showing a scanning line structure between fields of a double speed NTSC signal obtained by this.

In FIGS. 2 and 3, numerals indicate line numbers, the scanning state of the standard NTSC signal is shown in (a) of FIG. 2 (a) and FIG. 3 (a), and the waveform diagram of this standard NTSC signal is shown. Is shown in FIG. Further, the scanning state of the double speed NTSC signal according to the embodiment of the present invention is shown in (b) and (b) of FIG. 2A, and the waveform diagram of the double speed NTSC signal is shown in FIG. ).

First, as shown in FIG. 2 (b) (and FIG. 3 (a)), the standard NTSC signal has N1 = 525 lines and 1 field within one frame period (1/30 seconds). In the period (1/60 second), 262.5 scan lines are included. That is, the first field of the standard NTSC signal includes the 1st to 263rd lines, and the next second field includes the 263rd to 525th lines.

On the other hand, the double speed NTSC signal has a field period of 1/2 (1/120) of the standard NTSC signal, as shown in FIG. 2C (and FIG. 3B).
, Which includes 262.75 scan lines in one field period of 1/120 second, and scan line N in the four field period (that is, one frame period of the standard NTSC signal). = 262.75 × 4 = 1051
Including books.

That is, as shown in FIG. 2C, during the period of the first field of the double speed NTSC signal, the signals of the 1st to 263rd lines of the first field of the standard NTSC signal are read from the memory 12 at the double speed. It is read and output as a signal on lines 1 to 263, and again during the following second field period, the standard NTSC
The signals of the 1st to 263rd lines of the first field of the signal are read and output as the signals of the 1'to 263 'lines.

In the next third field period, the signals of the 264th to 525th lines of the second field of the standard NTSC signal are read from the memory 12 at a double speed and output as the signals of the 264th to 525th lines. In the subsequent fourth field period, the signals of the 264th to 525th lines of the second field of the standard NTSC signal are read again and output as the signals of the 264 'to 525' lines.

At this time, at the boundary between the third field and the fourth field, an arbitrary signal (for example, the signal on the 263rd line of the standard NTSC signal) is appropriately read and output as a signal on the 263 "line. To be done.

The boundary between the first field and the second field, the boundary between the second field and the third field,
The boundary between the third and fourth fields, or the fourth
The boundary between the field and the first field of the next frame is
Both of them are ineffective periods of blanking in the case of displaying an image, so that the reading of the signal from the memory 12 is temporarily suspended over the period of one line or a plurality of lines before and after these boundaries. No signal is output,
A so-called blanking period may be formed.

As described above, the control of the line-by-line reading and the inter-field reading from the memory 12 is based on the double speed horizontal synchronizing signal HD1 and the double speed vertical synchronizing signal VD1 generated by the pulse generating circuit 22. Therefore, it is possible to reliably obtain the desired double speed NTSC signal as shown in FIG. Examples of the waveforms of the double speed horizontal synchronizing signal HD1 and the double speed vertical synchronizing signal VD1 are shown in (d) and (e) of FIG. 2, respectively.

With the above configuration, the number of scanning lines is N between the horizontal scanning frequency fH and the vertical scanning frequency fV of the double speed signal obtained in the embodiment of the present invention. Generally, the following relational expression (3) ) Is established. fH = N.times.fV / 4 --- (3) By the way, the scanning line structure of the standard NTSC signal is shown in FIG.
As shown in (a) of the above, since the interlaced scanning structure is completed by shifting 1/2 line in the vertical direction between 1/60 second fields to complete two fields, the scanning line interval in the vertical direction is 1 between fields. / 525.

On the other hand, the double-speed converted N
As shown in FIG. 3B, the scanning line structure of the TSC signal has a scanning structure in which the fields are shifted by 1/4 line in the vertical direction between fields of 1/120 seconds and completed in 4 fields. Vertical scan line spacing is 1 between fields
It becomes / 1051 and it can be seen that the scanning line interval can be reduced to about 1/2 as compared with the case of the standard NTSC signal.

In the scanning line conversion according to the embodiment of the present invention, the fields are interpolated in the time axis direction to double the number of fields per frame, and the scanning lines are interpolated in the vertical direction between the fields. Is performed to bring about the effect of doubling the number of lines per frame.

As long as the effects of the present invention are brought about, for example, in order to obtain the signal of the second or fourth field (interpolated) shown by the broken line in FIG. 3B, the arrow shown in FIG. Thus, the first field (eg line 1) signal and the third field (eg line 264)
It is also possible to perform a process of interpolating as a signal of the second field (for example, of line 1 ') by using a signal obtained by adding and averaging the signal of (. According to this method, an effect of band limitation in the vertical direction is generated, and as will be described later, it is possible to reduce interference such as line flicker due to folding, and it is effective in improving image quality.

As described above, the signal of one field and the third field
When the signal averaged with the signal of the field is used as the signal of the second field, a buffer memory is provided in the subsequent stage of the memory 12 of FIG. 1 and a signal directly output from the memory 12 without passing through this buffer memory. An adder circuit that performs arithmetic averaging and a further memory are arranged in the subsequent stage of this adder circuit. Then, the adder circuit adds and averages the signals of the first field and the signals of the third field and stores them in the memory, and the signals stored in this memory and the signals of the first field from the memory 12 If it is configured to be output between the signal of the 3rd field and the signal of the 3rd field, the method using the above-mentioned averaged signal can be executed.

The difference in image quality between the standard NTSC signal described above and the double speed NTSC signal obtained by the embodiment of the present invention is
The two-dimensional spectrum of FIG. 4 is shown for comparison. In FIG. 4, the horizontal axis represents the time frequency (λ), the vertical axis represents the vertical spatial frequency (ν), and the portion surrounded by the broken line is made larger and has higher brightness and higher definition like a high-definition television. It shows the area displayed on a new TV receiver. The figure (a) shows the two-dimensional spectrum of the standard NTSC signal, and the figure (b) shows the two-dimensional spectrum of the double speed NTSC signal.

As shown in FIG. 4A, in the standard NTSC signal, the spectrum appearing at (λ, ν) = (0,525) causes scan line interference (disturbance in which the scan line structure is visible), and (λ, The spectrum appearing at ν) = (60,0) causes flicker interference (interference that causes flicker in a large area). Furthermore, it can be seen that various image quality deteriorations such as interference (line flicker) that folds back to the vicinity of (λ, ν) = (30,0) occur.

On the other hand, in the above double speed NTSC signal,
As shown in FIG. 4B, (λ, ν) = (0,525)
Since the spectrum of is eliminated, the above-mentioned scanning line interference is removed, and the effect of improving the image quality is obtained such that the scanning lines become inconspicuous and the image becomes glossy and the texture is enhanced. Also,
Since the spectrum of (λ, ν) = (60,0) is also extinguished, the above-mentioned flicker interference is eliminated, and the flicker is eliminated, and a visually stable image is obtained. Further, due to the vertical band limitation effect by the scanning line interpolation described above, the interference returning to the vicinity of (λ, ν) = (30,0) is reduced, the line flicker is improved, and the overall image quality is improved. The effect is obtained.

As is clear from the explanation of the operation of FIG. 1, in the embodiment of the present invention, the standard NTS is used.
Even when the C television signal is displayed, the same deflection as in the case of displaying the high definition television signal is performed, so that the deflection system can be easily shared by both, and the cost of the device can be reduced. It will be possible.

Next, P used in the pulse generation circuit 22 is used.
An example of the LL circuit is shown in FIGS. FIG. 5 shows the first
An example of the PLL circuit is shown, and FIG. 6 shows an example of the second PLL circuit and the third PLL circuit.

In FIG. 5, the burst signal BS1 input to the input terminal 101 is supplied to the phase comparator 111 and the phase adjuster 114. The output signal from the phase comparator 111 is supplied to the first voltage control oscillator (VCO) 112 that oscillates at 14.32 MHz, and the output signal of the first voltage control oscillator 112 is output by the frequency divider 113. After being divided into 1/4, the phase comparator 11
At 1, the phase is compared with the burst signal BS1 from the input terminal 101. The output of the phase comparator 111 controls the voltage of the oscillator 112. As a result, the oscillator 112 outputs the burst signal BS with a frequency of fW = 4 × fSC.
A write clock signal WCP phase-locked to 1 is generated,
It is output to the terminal 102.

A continuous signal having a frequency of fSC is obtained from the frequency divider 113, and its output is the phase adjuster 114.
At the same time, the signal is phase-synchronized with the burst signal BS1 from the terminal 101, and after being properly adjusted in phase, is output to the terminal 103 as the color subcarrier signal SC.

In FIG. 6, the second voltage controlled oscillator 2
A case where the second PLL circuit including 12 and the third PLL circuit including the third voltage controlled oscillator 312 are connected in cascade is shown. First, the output from the oscillator 212 oscillated at a frequency of 125.99 kHz is divided into 1/1051 by the frequency divider 213, and the output is further divided by the frequency divider 2.
The frequency is divided into 1/2 at 14, and then the phase comparator 211 compares the phase with the vertical synchronizing signal VS1 from the terminal 201.

The oscillator 212 is voltage-controlled by the output signal from the phase comparator 211, and as a result, the oscillator 2 is controlled.
From 12 onward, the frequency is 4 × fH and the vertical synchronizing signal VS1
A signal in phase with is generated. Accordingly, the frequency divider 213 generates a signal having a frequency of 4 × fH / 1051 = fV, that is, the above-described double speed vertical synchronizing signal VD1. The output signal of the frequency adjuster 215 from the terminal 201 is output. The phase is appropriately adjusted based on the vertical synchronizing signal VS1 and then output to the terminal 202.

On the other hand, the output signal from the oscillator 212 is divided into 1/4 by the frequency divider 216. Therefore,
The frequency divider 216 generates a signal having a frequency fH, that is, the above-described double speed horizontal synchronizing signal HD1.
Based on the double-speed vertical synchronizing signal VD1 from, the phase is adjusted appropriately and then output to the terminal 203.

Subsequently, the output signal from the oscillator 312 oscillated at a frequency of 28.66 MHz is output to 1 by the frequency divider 313.
After the frequency is divided into / 910, the phase is compared with the output signal from the frequency divider 216 by the phase comparator 311. The output signal from the phase comparator 311 controls the voltage of the oscillator 312. As a result, the oscillator 312 generates a read clock signal RCP having a frequency fR = 910 × fH and synchronized with the double speed horizontal synchronization signal HD1. , To the terminal 302.

By the way, in the above-described embodiment, the number N of scanning lines of the double speed signal is set to N = 1051, but the present invention is not limited to this. In the present invention, the scanning line number N of the double speed signal may be any odd number in the vicinity of twice the scanning line number N1 of the standard signal, for example, N1 = 525 in the above embodiment FIG. Of the NTSC signal is set to an odd number N = 1125, which is the same as the number of scanning lines N2 of the high definition television signal, as an odd number in the vicinity of twice, and 112 per frame.
You may make it display, after converting into five double speed signals.

In this case, the number of scan lines is from 1 to 1051
The number of lines is increased to 125, but the 74 lines of the increment may be displayed after being interpolated as a blanking period of no signal (for example, a vertical blanking period). The vertical scanning frequency fV obtained in this case is
Although it is given at fV = 1119.88 Hz as above, the horizontal scanning frequency fH is fH = from the above formula (3).
The frequency can be increased to 33.72 kHz, and the value can be made almost the same as the horizontal scanning frequency fH2 of the high definition television signal = 33.75 kHz, and the compatibility between the two can be further enhanced.

The double speed signal thus converted so that the aspect ratio of the original signal is 4: 3 and the number of scanning lines exceeds twice the original is displayed on the display unit 50 having the aspect ratio of 4: 3. Then, as shown in FIG. 7A, the upper and lower parts of the screen are cut off in accordance with the increment, and the figure is distorted vertically to be displayed.

In order to eliminate this distortion, for example, if the deflection system 42 performs deflection so as to expand vertically from the center of the screen, no graphic distortion will occur as shown in FIG. 7B. You can reproduce a faithful image with. Alternatively, instead of interpolating the 74 lines as a blanking period, by performing a line interpolation process that enlarges in the vertical direction by the signal processing via the memory 12, not only the graphic distortion can be removed. It is also possible to prevent deterioration of the vertical resolution.

Similarly, if this double speed signal is displayed on the display unit 50 having an aspect ratio of 16: 9, this time, as shown in FIG.
As shown in (c), the top and bottom of the screen are cut off, and the figure is displayed with a large horizontal distortion. It goes without saying that the deflection or signal processing for expanding in the vertical direction is effective in order to eliminate the upper and lower non-image areas (blanking areas).

Alternatively, in the deflection system 42, for example,
If the deflection is performed so as to expand in the vertical direction from the center of the screen to the vertical direction and reduce in the horizontal direction to the left and right, the upper and lower non-image areas are eliminated as shown in FIG. Can be reduced.

Alternatively, the graphic distortion can be removed not only by performing the line interpolation processing for expanding in the vertical direction by the signal processing through the memory 12 and simultaneously performing the time axis processing for compressing in the horizontal direction. Also, it is possible to prevent the vertical resolution from decreasing.

As described above, the embodiment of FIG. 1 shows the case where a composite type signal is used to obtain the above-mentioned double speed signal, but the present invention is not limited to this.
A composite format standard signal (NTSC signal) is decoded in advance to obtain a component format signal (luminance signal Y and two color signals C1 and C2), and then the above double speed conversion process is performed for each component signal. It may be displayed later. That is, in one embodiment of the present invention,
The standard NTSC signal is stored in the memory 12 as a composite signal, and after being read from the memory 12,
YC separation is performed, but standard NTSC
It is also possible to adopt a configuration in which the signal is YC separated, then stored in the memory 12, and then read from the memory 12 at double speed.

The standard television signal to which the present invention is applied is not limited to the above-mentioned NTSC signal. For example, the ED system, which is scheduled to be broadcast in Japan in the near future, is currently used in Europe and the like. The present invention can be applied to any standard television signal based on the PAL system (or PAL plus system) being broadcast, the SECAM system, and the digital broadcasting system currently being broadcast in the United States.

The number of scanning lines per frame is N1 =
Although not shown when displaying 625 standard television signals such as PAL and SECAM systems, based on the embodiment of the present invention shown in FIG. 1, for example, these standard television signals are The number N of scanning lines per frame is an odd number in the vicinity of twice N1 (for example, N = 2 ×).
It may be displayed after being converted into a double speed signal such that 625 + 1 = 1251), and the same effect as that of the embodiment of the present invention can be obtained.

Further, when displaying the signals based on the improved standard television system such as the ED system, the PAL plus system and the digital broadcasting system, these signals are decoded in advance and then the decoded signal is displayed. May be displayed after performing the above-described double speed conversion process. In any of these cases, the effects obtained are the same, and all are included in the category of the present invention.

[0085]

Since the present invention is constructed as described above, it has the following effects. For example, NTSC
The number of scanning lines N (=
1051 or 1125) lines are interlaced between fields and the scanning line interval is 1 / N (= 1/1051)
Alternatively, it is converted into a signal of 1/1125) and displayed. Also, the field frequency is doubled (fV ≈ 120H
Since it is converted into z) and displayed, the flicker interference which has been conspicuous in the large area of the image in the related art is removed, and a visually stable image is obtained.

As described above, since the number of scanning lines is converted to approximately double and displayed, the horizontal scanning frequency fH is almost the same as the horizontal scanning frequency fH2 of the high definition television signal (N =
In the case of 1125, fH ≈ 33.72 kHz or a value close to it (in the case of N = 1051, fH ≈ 31.50 kHz)
z), it is possible to provide at low cost an apparatus capable of removing various interferences and significantly improving the image quality when displaying a standard television signal.

Further, like a conventional standard television signal and a next-generation high-definition television signal, two television signals whose horizontal scanning frequencies are nearly doubled are displayed by one device by sharing a deflection system. Since it is configured so that even if the number of scanning lines, the horizontal scanning frequency, the aspect ratio, etc. are different, such as a standard television signal and a high-definition television signal, both can be efficiently displayed by one device. In addition, it is possible to provide an apparatus capable of removing various interferences and significantly improving the image quality at the time of displaying a standard television signal at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a television signal display device according to the present invention.

FIG. 2 is a diagram showing a waveform and timing of a television signal in the example of FIG. 1 and a conventional example.

FIG. 3 is a diagram showing a structure of a scanning line of a television signal in the example of FIG. 1 and a conventional example.

FIG. 4 is a diagram showing a two-dimensional spectrum of a television signal in the example of FIG. 1 and a conventional example.

5 is a first PL in the pulse generation circuit of the example of FIG.
It is a figure which shows an example of an L circuit.

6 is a diagram showing an example of second and third PLL circuits in the pulse generation circuit of the example of FIG.

FIG. 7 is an explanatory diagram for reducing the distortion of the display image in the example of FIG.

[Explanation of symbols]

 11 A / D conversion circuit 12 memory 13 YC separation circuit 14 color decoding circuit 15, 16, 17 D / A conversion circuit 18 signal switching circuit 21, 31 synchronization separation circuit 22, 32 pulse generation circuit 23 write control circuit 24 read control Circuit 41 Deflection switching circuit 42 Deflection system 50 Display

Claims (4)

[Claims] 1. The field frequency is fV1, the number of scanning lines in one frame is N1, and the horizontal scanning frequency is fH1 (= N1).
A signal input means for inputting a television signal of × fV1 / 2) and a television signal from the signal input means have a field frequency fV twice that of the television signal (fV = 2 ×).
fV1), the number of scanning lines N has an odd value in the vicinity of twice the number of the television signal within the period of one frame of the television signal, and the horizontal scanning frequency fH is fH = N × fV /
And a display means for displaying the display signal from the signal conversion means through a deflection system deflected at a field frequency fV and a horizontal scanning frequency fH. A display device for a television signal characterized by. 2. The television signal display device according to claim 1, wherein the signal conversion means writes a composite signal including a color signal and a luminance signal at a first timing, and the memory. A display device for a television signal, comprising: a reading control means for reading the composite signal thus generated at a timing almost twice that of the first timing. 3. The field frequency is fV1, the number of scanning lines in one frame is N1, and the horizontal scanning frequency is fH1 (= N1).
× fV1 / 2) first television signal, the number of scanning lines is larger than that of the first television signal, the field frequency is fV2, the number of scanning lines in one frame is N2, and the horizontal scanning frequency is fH2 ( = N2 × fV2 / 2) second television signal and at least one of the signal input means for inputting the television signal, and when the first television signal is input, from the signal input means Of the first television signal of which the field frequency fV is 2 times that of the first television signal.
(FV = 2 × fV1), the number of scanning lines N has an odd value in the vicinity of twice the number of the first television signal within the period of one frame of the first television signal, and horizontal scanning is performed. A signal converting means for converting the frequency fH into a display signal given by fH = N × fV / 4, and deflecting the display signal from the signal converting means at a field frequency fV and a horizontal scanning frequency fH, or by the second signal And a display means for displaying through a deflection system that selectively switches and deflects whether the television signal is deflected at a field frequency fV2 and a horizontal scanning frequency fH2. apparatus. 4. The television display device according to claim 3, wherein the signal conversion means changes the number of scanning lines N of the first television signal within a period of one frame of the first television signal. A display device for a television signal, wherein the second television signal is converted into a display signal having an odd value (N≈N2) near the number N2 of scanning lines.