JPH01168188A - Television signal decoder - Google Patents

Abstract

PURPOSE:To obtain a picture having a wider aspect ratio than that of the existing picture and to receive the existing television signal without hindrance by providing a means applying synchronizing detection to a television signal and a means applying time base compression and time base expansion. CONSTITUTION:The signal sent from a sender side is received by an antenna, subjected to frequency conversion into an intermediate frequency band by a tuner, band limit by a 1st filter and synchronization detection by a 1st detector by using a carrier I1 and becomes a main signal. Moreover, the output of the tuner is subject to band limit by a 2nd filter, synchronizing detection by a 2nd detector by using the shifted carrier I2 and becomes a multiplex signal. Then the main signal and multiplex signal are given to a signal processing circuit, opposite time base processing and time base adjustment opposite tot eh time base expansion at the sender side, the result is separated into a luminance signal Y1, a color signal C1 by a YC separator circuit 27 and the time base is adjusted to obtain normal time relation. Thus, the existing television broadcast is received without hindrance and the picture with wider aspect ratio can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a television signal decoding device, and in particular, the current television system has an aspect ratio (horizontal to vertical ratio) of 4:
This invention relates to a television signal decoding device that reproduces television signals that are suitable for transmitting scene information having a larger aspect ratio than that of 3, and that is compatible with current television systems. .

Conventional technology Japan's current NTSC [National Television
System Committee (National Te1e-
vision system comm1tee)
] More than 25 years have passed since color television broadcasting began in 1960. In the meantime, various new television systems have been proposed in response to demands for high-definition screens and improvements in the performance of television receivers. Furthermore, the content of the programs provided is changing from simple studio programs and relay programs to programs with higher quality and more realistic images, such as cinema-sized movie broadcasts.

Against this background, the Japan Broadcasting Corporation (NHK) proposed a high-definition television system. (For example, Literature Special Feature on High Definition Television (Television Society Journal Vol. 36,
No. 10, 1982)) The contents are 1125 scanning lines, 2:1 interlaced scanning, and a luminance signal horizontal bandwidth of 20.
MHz, and high definition, and from the viewpoint of visual engineering such as immersion, the aspect ratio (ratio of horizontal to vertical screen) was increased to 5:
3. This system has already been almost completed in the closed system, and with the start of satellite broadcasting, the MUSE system (Reference, Tasuku Ninomiya et al. ) (IEICE Technical Research Report I
E84-72.1984)) and are conducting experiments.

On the other hand, current broadcasting uses 525 scanning lines, 2:1 interlaced scanning,
Luminance signal horizontal bandwidth 4.2MHz, aspect ratio 4:3
It has various specifications. (For example, refer to the literature Broadcasting Technology Library, Color Television, edited by Japan Broadcasting Corporation, Japan Broadcasting Publishing Association, 1961.) When a movie is provided as the above program, the screen size should be adjusted to the aspect ratio of the current television receiver. Either the ends are cut off to make it 4:3, or invalid screens are placed at the top and bottom of the screen, and the aspect ratio of the valid screen is sent out to match the movie value.

Problems to be Solved by the Invention As mentioned above, when transmitting and servicing movie programs and immersive screens in current broadcasting, some parts of the screen are cut or the screen area becomes smaller, so producers have to There was a problem in that the intention was not fully conveyed. Furthermore, if a signal with an aspect ratio larger than 4:3 is simply transmitted, it will not be able to be received by a normal receiver. When the number of scanning lines and frame frequency are the same as those of current broadcasting, in order to obtain the same horizontal resolution, an aspect ratio of m:3 (m is a real number of 4 or more) requires a video bandwidth m/4 times that of the current broadcasting.

However, from the point of view of effective use of radio wave resources, the transmission band cannot be expanded unnecessarily.

Therefore, a device has been invented that transmits a video having an aspect ratio of 4:3 or more, that is, a wide aspect ratio video. This will be explained below. - In general, in order to obtain the same horizontal resolution when the number of scanning lines and frame frequency are the same, a system with an aspect ratio of 5:3 must have an aspect ratio of 4:
:The bandwidth required for transmission is 1.25 times that of 3. By stacking the increased bandwidth in the first and third quadrants of the "time-vertical" two-dimensional frequency, or in the high range of the color signal, the bandwidth of the current television system can be improved while maintaining the horizontal resolution. The idea is to transmit wide-aspect ratio video within the network. (Unexamined Japanese Patent Publication 1986-
(Refer to Publication No. 213185) However, if the video with an aspect ratio of 5:3 was transmitted using this conventional technology, the video would be vertically long when received by a current television receiver. The drawback is that it cannot be compatible with John receivers.

Furthermore, in the case of moving images, the increased bandwidth cannot be multiplexed into the first and third quadrants on the "time-vertical" two-dimensional frequency due to crosstalk, resulting in a decrease in horizontal resolution.

The present invention has been made in view of the above, and an object of the present invention is to provide a television signal decoding device that is compatible with current television systems and that reproduces television signals having a wider aspect ratio. do.

Means for Solving the Problems In order to solve the above-mentioned problems, the television signal decoding device of the present invention includes a frequency-axis multiplexed signal separating means for separating frequency-axis multiplexed signals, and a time-axis multiplexed signal for separating the composite video signal. means for compressing the time axis, means for compressing the time axis multiplexed signal in the time axis, means for compressing the time axis in the frequency axis multiplexed signal, means for expanding the time axis, means for separating the luminance signal and the color signal, and , and includes means for demodulating the color signal.

Effects of the present invention With the above-described configuration, current television broadcasting can be received without any trouble by time axis compression, and by performing synchronous detection, time axis compression, time axis expansion, etc., it is possible to receive a horizontally long screen with a wide aspect ratio. can be obtained.

Embodiment Hereinafter, a television signal decoding apparatus according to an embodiment of the present invention will be described with reference to the drawings. Figure 2(a) is
An example of a display screen of a current television is shown in FIG. 2(b), which shows a composite video signal for one scanning line period near the center of the screen. Since the aspect ratio is 4:3, the second
As shown in the display example in Figure (a), part of the left and right circles among the three circles may be missing. Figure 3(a) shows an example of a display screen with a larger aspect ratio than the current one, for example 5:3, and Figure 3(b) shows an image of one scanning line period near the center of the screen. Figure 3 (C) is a composite signal in which the video signal shown in Figure 3 (b) is rewritten so that the time axis scale is the same as that in Figure 2 (b), and a synchronization signal and color burst signal are added. This shows a video signal. Note that the aspect ratio is not limited to 5:3.

If the aspect ratio is increased as shown in FIG. 3(a), more video information can be obtained than on the screen shown in FIG. 2(a). Here, even when the current television receiver receives a video signal with an aspect ratio of 5:3, it is possible to receive the image without any problems compared to conventional television receivers.In other words, in order to maintain compatibility, the current television receiver The time axis is expanded on the television signal during the period displayed on the screen. This can be seen by comparing Figure 2 (Φ) and Figure 3 (C), when the signal in Figure 3 (C) is received by a current television receiver, the original image is a circle. However, since it becomes a vertically elongated ellipse, it is necessary to expand the time axis of the signal shown in FIG. 3(C). In other words, when an original image is captured with a conventional horizontal aspect ratio of m:3 (m is a real number of 4 or more), the image signal corresponding to the part displayed on the screen of a current television receiver is multiplied by m/4. All you have to do is extend the time axis.

Furthermore, in order to obtain screen information with an aspect ratio of m:3, the remaining signal portions are sent by time axis multiplexing for low frequency components and frequency multiplexing for high frequency components. Furthermore, C
For CD cameras and the like that do not require an image pickup tube during the horizontal retrace period, it is not necessarily necessary to extend the time axis of the image signal corresponding to the portion displayed on the screen of a current television receiver. In other words, this is because the horizontal retrace period is shortened, and there is a margin in the time axis direction.

FIG. 4 is a spectrum diagram showing a frequency axis multiplexing method on the transmitting side according to an embodiment of the present invention. FIG. 4(a) is a spectrum diagram of a television signal subjected to vestigial sideband amplitude modulation in the current television Gibon system. Here, a case is shown in which the lower sideband of the video carrier wave P1 is a residual sideband. 4) is a multiplexed signal in which a carrier wave Pt having the same frequency as the video carrier wave P and having a different phase is subjected to residual sideband amplitude modulation so as to remove the carrier wave P2. FIG. 4(C) shows the signal in FIG. 4(b) multiplexed with the television signal in FIG. 4(a). Note that the band of the signal modulated by the multiplexed signal starts from a frequency 1.25 MHz lower than the carrier wave P2, but it is not limited to this.
, for example, from a frequency as low as 4.25 MHz.

Next, a television signal processing method on the transmitting side in an embodiment of the present invention will be described. Of the electrical signals obtained by capturing an original image with an aspect ratio larger than 4:3, the portion corresponding to the aspect ratio of 4:3 is subjected to residual sideband amplitude modulation of the video carrier wave using a composite video signal in which the time axis is expanded. do. Then, a carrier wave having the same frequency as the video carrier wave but with a different phase is added to the residual sideband amplitude modulated television signal, and a composite signal obtained by time-extending the high frequency components obtained from the remaining part of the electrical signal is used to generate both sides of the television signal. The signals are band-amplitude modulated and band-limited by a Nyquist filter, which has frequency characteristics opposite to those up to the video intermediate frequency amplification stage of the receiver, and then multiplexed. Note that the composite signal obtained by compressing the low frequency components obtained from the remaining part of the electrical signal on the time axis is time-axis multiplexed on at least a part of the video signal period or a part of the retrace period. FIG. 6 shows an example of time axis expansion, compression, and multiplexing on the transmitting side. In the present invention, it is assumed that, for example, a television signal synthesized by the above-described signal processing is received.

Next, a processing method of a television signal decoding apparatus according to an embodiment of the present invention will be described. The video intermediate frequency band signal output from the tuner is band-limited by a filter that removes orthogonal distortion, as shown in FIG. 5(a). If this is expressed as a vector, it will look like Figure 5 (Tsukuda). Since the video baseband signal becomes substantially double-sideband due to the filter, if the upper and lower sidebands are the vector aLIs and the vector aL, their combined vector will be a, and only the component orthogonal to vector 2 will be present. Furthermore, since the multiplexed signal has residual sidebands when considering the carrier wave 2 as the center, the upper and lower sidebands become vector bL+ and vector bL, and when decomposed into orthogonal vectors, they become vector bI and vector b2. That is, when synchronous detection is performed using carrier wave (2), orthogonal distortion due to the vector al and vector b1 components does not occur, and only the multiplexed signal component can be demodulated. Note that the band of the signal modulated by the multiplexed signal starts from a frequency 1.25 MHz lower than the carrier wave 2, but it is not limited to this, and may be multiplexed from a frequency 4.25 MHz lower on the transmitting side. For example, multiplexed signals with a band of 4.25 MHz can be demodulated.

FIG. 1(a) is a block diagram of a television signal decoding apparatus according to an embodiment of the present invention. In FIG. 1(a), 1 is an antenna, 2 is a tuner, 3 is a first filter, and 4
is a first wave detector, 5 is a carrier wave regeneration circuit, 6 is a second filter, 7 is a phase shifter, 8 is a second wave detector, 9 is a main signal output terminal,
10 is a multiplexed signal output terminal, 1 is a signal processing circuit, and 12 is a demodulation circuit. A signal sent from the transmitting side is received by an antenna 1, frequency-converted by a tuner 2 to an intermediate frequency band, and band-limited by a first filter 3. Although an antenna is illustrated, the transmission path is not limited to a wireless system, but may be a wired system.

The band-limited signal is supplied to a first detector 4 and a carrier recovery circuit 5. The carrier wave regeneration circuit 5 regenerates the carrier wave 1 for synchronous detection. The band-limited signal is synchronously detected by the first detector 4 using the carrier wave (2). The output of the first detector 4 is used as the main signal. Further, the output of the tuner 2 is band-limited by a second filter 6 as shown in FIG. 5(a). A band-limited signal is synchronously detected in a second detector 8 using a carrier wave I2 obtained by phase-shifting the carrier wave 1 obtained from the carrier wave regeneration circuit 5 by a phase shifter 7 as shown in FIG. 5(b), for example. . Note that the phase shift direction of the carrier wave I2 is made to match that of the sending side. The detection output becomes a multiplexed signal. The main signal and multiplexed signal are input to the signal processing circuit 11.

Further, as a frequency axis multiplexing method for multiplexed signals, a method of multiplexing the television signal in the first and third quadrants, which are conjugate positions with the color subcarrier in the time-vertical frequency plane, can be considered. (Refer to Japanese Patent Application Laid-open No. 59-171387.) In this case, in the signal demodulated to baseband on the receiving side, the difference between the signals where at least the phase of the color subcarrier is the same between fields, or the phase of the color subcarrier is determined. The main signal and the multiplexed signal can be separated by summing the signals whose phases are opposite to each other.

FIG. 1(Φ) is a block diagram showing an example of the internal configuration of the signal processing circuit 11 of FIG. 1(a). 21 is a main signal input terminal, 25 is a multiplex signal input terminal, 27 is a YC separation circuit,
31 is a color demodulation circuit, 22.23.26 is a time axis compression circuit, 28.32.35 is a time axis expansion circuit, 24 is a switch,
29, 33.36 is an adder, 30 is a luminance signal Y output terminal, and 34 is a color signal! The output terminal 37 is a color signal Q output terminal. Among the main signals input from the main signal input terminal 21, as shown in FIG. The compression circuit 22 compresses the time axis. The other signals that have been time-base compressed on the transmitting side are time-base compressed by the time-base compression circuit 23, and the time base is adjusted so that the signals come during the retrace period. The multiplexed signal input from the multiplexed signal input terminal is subjected to time-base compression by the time-base compression circuit 26. The time axis compression circuits 22 and 26 perform reverse time axis processing and time axis adjustment in contrast to the time axis expansion on the transmitting side, so that the normal time relationship is maintained by integrating the transmission and reception. do. Note that time axis expansion and time axis compression can be performed, for example, by changing the writing and reading clocks to the memory. In the switch 24, the aspect ratio is 4:
During the period corresponding to the screen of the current television receiver shown in No. 3, the output of the time axis compression circuit 22 is used, during the other video signal periods, the output of the time axis compression circuit 26 is used, and during the retrace period, the output of the time axis compression circuit 23 is used. The output is input to the YC separation circuit 27. The YC separation circuit 27 separates the signal into a luminance signal Y1 and a color signal C1. The color signal C1, which is the output of the YC separation circuit 27, is demodulated into a 1 signal and a Q signal by a color demodulation circuit 31. Of the luminance signal Y, which is the output of the YC separation circuit 27, the luminance signal corresponding to the signal compressed in time axis by the time axis compression circuit 23 is expanded in time axis by the time axis expansion circuit 28 to have a normal time relationship. Adjust the time axis accordingly. Then, the other luminance signals and the output of the time axis expansion circuit 28 are added together by an adder 29 to obtain a luminance signal Y. Similarly, among the color signal ■8 which is the output of the color demodulation circuit 31, the color signal ■corresponding to the signal time-axis compressed by the time-axis compression circuit 23 is
A time axis expansion circuit 32 expands the time axis and adjusts the time axis so that a normal time relationship is achieved. Then, the other color signal (2) and the output of the time axis expansion circuit 32 are added by an adder 33 to obtain a color signal I. Similarly, of the color signal Q output from the color demodulation circuit 31, the color signal Q corresponding to the signal compressed in the time axis by the time axis compression circuit 23 is time-axis expanded by the time-axis expansion circuit 35 and converted into a regular time signal. Adjust the time axis so that there is a relationship. Then, the other color signals Q and the output of the time axis expansion circuit 35 are added together by an adder 36 to obtain a color signal Q. The luminance signal Y, color signal (2), and color signal Q may be converted into R-G-B signals by a matrix circuit and displayed on a monitor or the like.

Note that when the color signal is not superimposed on the time-axis multiplexed signal, the time-axis expansion circuits 32 and 35 and the adders 33 and 36
is not necessary, and the output 11, Q of the color demodulation circuit 42.

are the color signal I and the color signal Q, respectively.

Note that the time axis compression circuit 22 restores the television signal by compressing the time axis expanded portion of the television signal having a horizontal aspect ratio so that current television broadcasting can be received without any problems. It is for. In other words, as can be seen by comparing Figure 2 (b) and Figure 3 (C), in order to receive the current broadcasting image without changing its aspect ratio, it is necessary to change the current television signal on the time axis. It needs to be compressed. The compression ratio is determined by the aspect ratio. However, if the display is a liquid crystal display or the like and does not require a CRT during the retrace period, it is not necessarily necessary to compress the time axis. When receiving current television signals, a screen with an aspect ratio of 4:3 is projected near the center, and the remaining area of the receiver screen, which has a horizontal aspect ratio, is darkened by blanking etc. What is necessary is to perform processing such as the following.

Effects of the Invention As is clear from the above description, the present invention includes means for synchronously detecting television signals, and means for time axis compression and time axis expansion, and transmits scene information with a larger aspect ratio than the current one. By reproducing a television signal that is compatible with current televisions and can be received without problems, it is possible to obtain a screen having a horizontally longer aspect ratio than the current television. Furthermore, current television signals can also be received without any problems. In addition, the circuit configuration of the receiver is such that the main signal and multiplexed signal are separated into separate Y
Rather than processing using a C separation circuit and a color demodulation circuit, processing can be performed using the same circuit, resulting in an efficient circuit configuration.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram of a television signal decoding device according to an embodiment of the present invention, and FIG. 1(b) is a block diagram of a television signal decoding device in an embodiment of the present invention.
) is a block diagram showing an example of the internal configuration of the signal processing circuit of
FIG. 2(a) is a front view showing an example of a display screen of a current television, FIG. 2(b) is a waveform diagram showing a composite video signal during one scanning line period near the center of the screen, and FIG. Diagram (a)
is a front view of an example of a display screen when the aspect ratio is set to, for example, 5:3, FIG. 3(b) is a waveform diagram showing a video signal during one scanning line period near the center of the screen, and FIG. C) is a waveform diagram showing a composite video signal in which the video signal shown in Figures 3 and 3) is rewritten so that the scale of the time axis is equal to that in Figure 2(b), and a synchronization signal and a color burst signal are added.
FIG. 4(a) is a spectrum diagram of a television signal subjected to vestigial sideband amplitude modulation in the current television system.
Fig. 4(b) is a spectrum diagram in which the signal shown in Fig. 4(a) is modulated with a band-limited signal, and Fig. 4(C) is a spectrum diagram of the signal shown in Fig. 4(b). Figure 4 (a) is a spectrum diagram multiplexed with the signal, Figures 5 (a) and 5 (b) are spectrum diagrams and vector diagrams at the time of multiplexed signal demodulation, and Figure 6 is a diagram showing time axis compression, time axis expansion, and FIG. 3 is a waveform diagram showing time-axis multiplexed positions. 7... Phase shifter, 3... First filter,
6...Second filter, 4...First detector, 8...Second detector, 22.23.26...
...Time axis compression circuit, 2B, 32.35...
...Time axis expansion circuit, 27...YC separation circuit,
31...Color demodulation circuit. Name of agent: Patent attorney Toshio Nakao Figure 5 gW! la f

Claims (3)

[Claims] (1) Of the electrical signals obtained by capturing an original image with an aspect ratio larger than 4:3, those with an aspect ratio of 4:3
The first signal corresponding to
Frequency domain multiplexing signal separation means for time domain expanding and frequency domain multiplexing of high frequency components of the signal, time domain compression of low frequency components and separating the frequency domain multiplexed signal from the time domain multiplexed television signal. a means for time-axis compressing the composite video signal; a means for time-axis compressing the frequency-axis multiplexed signal; a means for time-axis compressing the frequency-axis multiplexed signal; a means for time-axis expansion; A television signal decoding device comprising means for separating a signal and a color signal, and means for demodulating the color signal. (2) The frequency-axis multiplexed signal separation means includes a filter for removing orthogonal distortion and means for synchronously detecting a carrier wave having the same frequency as the video carrier wave and having a different phase. The television signal decoding device as described. (3) The frequency-axis multiplexed signal separation means includes means for calculating the difference of signals in which at least the color subcarriers have the same phase between fields, or the sum of the signals in which the color subcarriers have opposite phases. A television signal decoding device according to claim 1, characterized in that: