JP2624533B2 - Image signal transmission system with compatibility - Google Patents

Description

The present invention relates to a transmission system compatible with a high-definition television system and a current television system, and particularly relates to an upper and lower screen of a current system receiver screen depending on its aspect ratio. The present invention relates to a high-vision signal transmission system capable of multiplexing the high frequency components.

(Summary of the Invention) The present invention relates to a transmission system compatible with the Hi-Vision system and the current television system, for example, the NTSC system. In doing so, it should be inserted into the signal blanks above and below the current system receiver screen.
The vertical high frequency component of the luminance signal of the HDTV signal and the high frequency component of the chrominance signal are successively inserted into the signal blank between the current field and the next or one previous field at the center of the screen and transmitted. I have.

Thus, the hardware configurations on the transmission side and the reception side are simplified.

(Prior art) For the purpose of compatibility with 16: 9 aspect ratio Hi-Vision signals with the current television system, for example, NTSC system, the number of scanning lines is compressed and converted to be transmitted at the center part of the NTSC receiver screen. For example, there is Japanese Patent Application No. 63-78107 "Television signal scanning conversion system", which is commonly referred to as the upper and lower black system, and is used to convert a high-definition luminance signal separated for compression conversion of the number of scanning lines. Vertical high frequency component,
The method of multiplexing in the signal blank part at the top and bottom of the NTSC receiver screen is described in Japanese Patent Application No. 63-24009 "Image Signal Transmission System", and the high-frequency components of two color difference signals of Hi-Vision signals are also added. The method of multiplexing the signal in the signal blank portion in a field-sequential manner is described in “Compatible color image color difference signal multiplexing transmission method”, filed on the same date as the present invention.

(Problems to be Solved by the Invention) In the example of the transmission system described in the section of the prior art, the multiplexing of signal blank portions above and below the screen of the current system receiver is all performed by multiplexing the vertical high frequency component of the luminance signal of the HDTV. Also, the multiplexing of the high-frequency component of the color signal is also a division of the central portion of the screen into two upper and lower portions corresponding to the field. Thus, there has been a problem that the signal processing requires a complicated configuration of the delay circuit.

An object of the system of the present invention is to eliminate the above-mentioned problems and to provide a high-vision transmission system with a simplified delay circuit.

(Means for Solving the Problems) In order to achieve this object, a compatible image signal transmission system according to the present invention is a high-vision signal having a larger aspect ratio and a larger number of scanning lines than a television signal of a specific system. The effective scanning line of the specific method is compression-scan-converted into a smaller number of effective scanning lines than the effective scanning lines of the television signal of the specific system and transmitted, so that the aspect ratio of the high-definition system is maintained with respect to the receiver of the specific system. In transmitting a high-definition signal, a luminance signal of a high-definition signal corresponding to a central portion of the receiver screen, which cannot be transmitted due to the compression-scan conversion and should be inserted into upper and lower signal blank portions of the receiver screen of the specific method. The vertical high-frequency component of the color signal and the high-frequency component of the color signal in the signal blank portion between the current field and the center of the screen between the next or previous field. It is characterized by insertion and multiplex transmission.

(Operation) As described above, according to the transmission system of the present invention, high-frequency components of HDTV to be multiplexed are continuously multiplexed in units of fields, and
Since it is not necessary to divide the signal into two parts and multiplex the signal, the configuration of the delay circuit is simplified and the object of the present invention can be achieved.

(Example) Hereinafter, the present invention will be described in detail by way of examples with reference to the accompanying drawings.

The high-frequency component of the Hi-Vision signal includes a vertical high-frequency component of a luminance signal and two high-frequency components of two color difference signals I and Q signals. Here, the handling of the I signal among the three high frequency components will be described in detail below, and the processing of the remaining two components will be omitted because they are almost equivalent.

FIG. 1 shows a first example of processing the I signal of the transmission system of the present invention.
3 is a block diagram showing the configuration of the encoder side (a) and decoder side (b) of the embodiment of FIG.

In the circuit of the first embodiment, the writing and reading clocks for the field memories 6 and 15 for high-frequency component processing are set to 1: 2 in the encoder-side memory 6 and 2: 1 in the decoder-side memory 15. This is an example in which the system is set to the NTSC system and the number of effective scanning lines smaller than the effective scanning lines of the television signal of the specific system is set to 320 lines / frame. This is for the purpose of simplifying the explanation. The compression rate / expansion rate naturally differs depending on the setting of the specific method, the high-vision method, and the number of effective scanning lines. In this embodiment, the central portion (320 lines) and the upper and lower portions (160
As a matter of course, the area ratio of the book is 2: 1 and the writing and reading are stopped in the horizontal and vertical blanking periods by the memory control signal.

On the encoder side (a), the low frequency component of the I signal is LPF
(Low-pass filter, 0-3MHz) 1, LPF (0-1.5MHz)
z) Only the central part of the screen is selected by the switching unit 8 via 2 and the multiplier (× 3.58 MHz) 3. On the other hand, high frequency components of 1.5 MHz or more and 3 MHz of the I signal extracted by the LPF 1, LPF 2 and the subtracter 4 are modulated by a multiplier 5 on a 3.58 MHz chrominance signal subcarrier, and then stored in a field memory (time axis compression) 6.
By writing the high-frequency component of the Hi-Vision signal corresponding to the center part of the NTSC system receiver playback screen and continuously reading its contents in the blank part following the center part, a continuous blank part following the center part of the screen, that is, The high frequency component is inserted in the blank space below the field and the blank space above the next field. The signal read from the memory 6 is modulated by a multiplier (× 4.68 MHz), and only the upper and lower blank portions are selected by the switch 8. These time relationships can be understood from FIG. 2 (a) showing the time and signal content on the encoder side.

In FIG. 1 (b) on the decoder side, the low frequency component of the I signal is BP
F (bandpass filter, 2.0-4.0MHz) 9, LPF (0-1.5
MHz) 12 and a multiplier (× 3.58 MHz) 11, and the demodulated signal is delayed by one field in the field delay circuit 10 and input to the adder 18. The high frequency component of the I signal is LPF
(0 to 4.2 MHz) 14, LPF (0 to 3.0MHz) 17, multiplier (× 4.68MHz) 13, and multiplier (× 3.58MHz) 16. During this time, the signals in the upper and lower blank portions are written to the field memory (time-axis expansion) 15 and read out at the timing of the center portion of the screen, so that the phase of the low-frequency component delayed by one field is matched with that of the adder. At 18, it is added to the low frequency component. These time relationships can be understood from FIG. 2 (b) which shows the time and signal contents on the decoder side.

In the first embodiment (see FIG. 1), the method in which the delay circuit (1 field) 10 is inserted in the decoder side and the high frequency component of the I signal is transmitted after the low frequency component of the signal has been described.
As in the second embodiment (see FIG. 3), it is also possible to adopt a configuration in which the delay circuit 10 is provided on the encoder side and the high frequency component of the I signal is transmitted before the low frequency component of the signal.

In the above two embodiments, the processing of the I signal in the transmission system of the present invention has been described. However, the processing of the high frequency component of the Q signal (0.5 to 2.0 MHz) and the processing of the vertical high frequency component of the luminance signal are exactly the same. These are not mentioned here.

As described above, in the embodiment of the present invention, the television signal of the specific system is
NTSC television signal, the number of effective scanning lines after compression scan conversion is 320, and the low and high frequency components of I signal are 0 each.
Although the description has been made as to 1.5 MHz and 1.5 MHz to 3.0 MHz, the present invention is not limited to these, and it is understood by those skilled in the art that changes and modifications can be made within the scope claimed in the claims of the present invention. Would be self-evident.

(Effects of the Invention) As described in detail above, the compatibility between the conventional Hi-Vision system and the current television system is provided, the effective scanning line of the Hi-Vision signal is compression-scan-converted, and the aspect ratio is matched with the Hi-Vision system. In a system in which a high-frequency component of a signal is divided and transmitted above and below a current television receiver, a signal corresponding to the central portion of the receiver and a high-frequency signal both require a delay circuit, and the circuit configuration is complicated. In the method of the present invention, the high frequency component is delayed without being divided, so that the circuit configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the encoder side (a) and the decoder side (b) of the first embodiment of the I signal processing according to the transmission system of the present invention, and FIG. FIG. 3 is a diagram for explaining how to take a timing of a signal by a field memory on the decoder side (b). FIG. 3 shows I-signal processing on the encoder side (a) and the decoder side (b) of the second embodiment. FIG. 2 shows a configuration block diagram. 1,17 LPF (0 to 3 MHz) 2,12 LPF (0 to 1.5 MHz) 3,5,11,16 Multiplier (× 3.58 MHz) 4 Subtractor 6 Field memory ( 7,13: Multiplier (× 4.68 MHz) 8: Switcher 9: BPF (2 to 4 MHz) 10: Delay circuit (1 field) 14: LPF (0 to 4.2 MHz) 15 …… Field memory (expansion of time axis) 18 …… Adder

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuaki Kinji 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Research Institute (72) Ryoichi Yajima 1-10-11 Kinuta, Setagaya-ku, Tokyo No. Japan Broadcasting Corporation Broadcasting Research Institute (72) Inventor Haruo Okuda 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Research Institute (72) Inventor Yutaka Tanaka 1-110, Kinuta, Setagaya-ku, Tokyo No. Japan Broadcasting Corporation Research Institute of Broadcasting Technology (72) Kazumasa Enonami 1-10-11, Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Research Institute (72) Inventor Taiji Nishizawa 1-10 Kinuta, Setagaya-ku, Tokyo No. 11 Inside Japan Broadcasting Corporation Broadcasting Research Institute

Claims (3)

(57) [Claims] An effective scanning line of a high-definition signal having a larger aspect ratio and a larger number of scanning lines than a television signal of a specific system has a smaller number of effective scanning lines than effective scanning lines of a television signal of a specific system. When transmitting a high-definition signal while maintaining the aspect ratio of the high-definition system with respect to the receiver of the specific system, insert it into the signal blank area above and below the screen of the receiver of the specific system, The vertical high-frequency component of the luminance signal and the high-frequency component of the chrominance signal of the Hi-Vision signal, which cannot be transmitted due to the compression scan conversion, and correspond to the current field and the next or one An image signal transmission system having compatibility, characterized in that a multiplex transmission is performed by continuously inserting a signal into a blank portion between the center of the screen and a previous field. 2. A compatible image signal transmission system according to claim 1, wherein said specific system is an NTSC transmission system. 3. The compatible image signal transmission system according to claim 1, wherein said small number of effective scanning lines is 320.