JPH0292082A - Transmission system for television signal - Google Patents

Abstract

PURPOSE:To form a transmission signal compatible with an NTSC signal by separating a picture into a side panel part and a center panel part and transmitting a luminance signal of the side panel part and a luminance high frequency component of the center panel part multiplexedly. CONSTITUTION:A High Vision signal is subject to scanning line number conversion at first, the signal is converted into a signal with a scanning line number of 525 lines, 2:1 interlace and an aspect ratio of 16:9 and the signal is separated into a center panel signal part being the center part whose aspect ratio is 4:3 and into the side panel signal at both side parts. The low and intermediate frequency components of the luminance signal in the side panel signal are subject to time base multiplex respectively in the vertical and horizontal blanking periods. Moreover, the high frequency component and the high frequency component of the center panel signal are subject to frequency multiplex by the subsample system of 4-frame period. A color difference signal high frequency component of the center panel signal is sent by the PAF(Phase-Alternate Field) system. The signal is multiplexed onto the center panel signal whose aspect ratio is 4:3 by the time base and frequency axis.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal transmission system for a high-definition television system that is compatible with the current NTSC system.

More specifically, the present invention uses band compression technology to
This relates to a method for transmitting high-definition images.

It has become.

The luminance signal and the color difference signal are frequency multiplexed by frequency interleaving, and if a frame memory is used, the two signals can be completely separated for images in the still image area.

Further, the discrimination between a moving image area and a still image area is performed by performing motion detection from a low-frequency 2M1lz signal, thereby improving image quality.

[Summary of the Invention] The present invention relates to a transmission system for wideband video signals such as high-definition, and uses a subsampling method and a blanking multiplexing method to maintain compatibility with NTSC signals while transmitting wideband video signals.
This enables narrowband transmission of high wide signals.

[Prior Art] The spectrum of an NTSC signal is shown in FIG. The luminance signal band is 4.2M1lz, the I and Q signals are 1.5M11z and 0.5M)Iz, respectively, and the aspect ratio is 4:3 [Problems to be solved by the invention] Luminance signal that can transmit NTSC signals. The band of the 8-color difference signal is narrower than that of high-definition. Also, the aspect ratio is 4=3, which is different from 16:9 in high-definition.
In this state, it cannot be used to transmit broadband signals such as high-definition.

Therefore, an object of the present invention is to provide a transmission system that makes it possible to transmit a wideband/wide aspect signal while maintaining compatibility with an NTSC signal.

[Means for Solving the Problems] The transmission method according to the present invention extracts the low-frequency components and mid-frequency components of the sight panel section included in the wideband video luminance signal, and vertically converts the low-frequency components and the mid-frequency components. and the horizontal blanking period, and further sub-samples and multiplexes the high-frequency components of the luminance signal.
It transmits multiplexed signals conforming to the C system.

Further, the encoder according to the present invention includes a low-pass means and a band-pass means for respectively extracting the A-range component and the middle-range component of the side panel part included in the wideband video luminance signal, and the low-pass means and the middle-range component. time axis compression/multiplexing means for multiplexing the components into the vertical blanking period and the horizontal blanking period; sampling means for subsampling the high frequency components of the luminance signal; , and PAF means for widebanding the Q signal, and transmits multiplexed signals conforming to the NTSC system.

The decoder according to the present invention extracts low frequency components and mid frequency components of a sight panel section included in a wideband video luminance signal, multiplexes the low frequency components and mid frequency components in vertical and horizontal blanking periods, and further , by subsampling and multiplexing the high-frequency components of the luminance signal, the NTS
A decoder that inputs a video signal related to a transmission system that transmits multiplexed signals based on the C system is equipped with a separation means that separates the video signal on the time axis and frequency axis, and a wideband signal with a predetermined aspect ratio. It demodulates the signal.

[Function] The present invention separates an image into a side panel portion and a center panel portion, and multiplexes the image into the horizontal and vertical blanking periods and multiplexes it using a sub-sampling method, thereby dividing the brightness signal of the side panel portion and the brightness signal of the center panel portion. The high frequency components are multiplexed and transmitted, thereby forming a transmission signal compatible with the NTSC signal, and transmitting a wide band and high wide image.

[Example] Next, an example of the present invention will be described with reference to the drawings.

Embodiments of encoders and decoders according to the transmission system of the present invention that are compatible with the NTSC system are shown in FIGS. 1 to 7.

FIG. 1 is a diagram showing the basic configuration of the transmitting side to which the present invention is applied, that is, the configuration of a scanning line number converter and an encoder.

The input signal is high-definition or equivalent wideband.
This is a high wide television signal. The high-definition signal is first converted to the number of scanning lines (see Japanese Patent Application No. 71225/1983, sequential scanning conversion method), and the number of scanning lines is 525, 2
:L interlaced signal with an aspect ratio of 16:9. This signal is separated into a center panel signal for the center portion and side panel signals for both side portions with an aspect ratio of 4:3.

Since the center panel signal has an aspect ratio of 4:3, it is a part that can be demodulated by a standard type receiver.

On the other hand, the low frequency component and the middle frequency component of the luminance signal in the side panel signal are time-axis multiplexed during the vertical and horizontal blanking periods, respectively.

Further, the high frequency components of the side panel signal and the high frequency component of the center panel signal are frequency multiplexed by a sub-sampling method with a period of 4 frames.

Further, the color difference signal of the side panel signal is multiplexed with the mid-range component of the luminance signal of the side panel signal by frequency interleaving.

The color difference signal high frequency component of the center panel signal is PAF (P
hase-Δ1ternate field) method (Japanese Patent Application No. 7112/1983, color television signal transmission method, see Takashi Fujio).

These signals are multiplexed on the center panel signal with an aspect ratio of 4:3 in the time and frequency axes, and the output signal of the encoder is a signal compatible with the NTSC signal. The functions of the receiver's scanning line number conversion and decoder are the opposite of those of the encoder, so a configuration diagram will be omitted.

FIGS. 2 and 3 show specific embodiments of the encoder shown in FIG. 1. Filter F (1) 8°F (2>9
．． F (3) The center panel signal is time-expanded at a ratio of 5:4 by a time-axis expander 11 and a DO converter 12 that performs sampling frequency conversion. The ideal stretching ratio is 16:12, and when the stretching ratio is 5:4, the circularity deteriorates by 6%.

The mid-range component of the side panel signal is mainly multiplexed during the horizontal blanking period, but the effective scanning portion is also utilized.

For this reason, overscanning (approximately 5% on one side with a general receiver)
) and a deterioration (6%) in the circularity of the center panel signal, it is possible to perform horizontal blanking multiplexing of the side panel signals.

Filter F(9)19. F(12)20. F (10)
21. F (11) 22°F (13) 23 , f (
14) 24 and sine wave oscillator (h) 28° (f3)
29. (f4) 30, π/2 phase shifter 25, π
The part composed of the phase filter 26 and the like is a subcarrier (3
, 58M) 12) (h) and PAF carrier (t3.f
4) is a color difference modulation unit that transmits data.

Filter F (4) 13. F (5) 14. F (
16) 15. F(7) 16°F(8) 17, a sine wave oscillator (f,) 27, a subsample carrier generator (δ,) 31, and a coefficient unit (1-k) 33 are 4-frame subsamples. This is a luminance signal broadband processing unit using the method.

FIG. 3 shows a luminance signal and color difference signal processing section in the side panel section. Moreover, FIG. 14 shows the luminance signal spectrum of the side panel signal. In Figure 14, ■■
■ represents low, middle, and high frequency components, respectively.

FIG. 15 shows the control signal Cλl for controlling the PAF carrier, and FIG. 16 shows the P to F spectrum obtained by modulating the PAF carrier with the high frequency components of I and Q.

The 4-frame sub-sampling method performs frequency interleaving at intervals of 7.5 Hz. Figure 8 shows the spectrum of this method. In this embodiment, the n cape is 72×10'. As shown in Figure 8 (C), the folded component ■
(2) occurs in the regions [1] and [2], respectively, where it coincides with the modulation spectrum of the subcarrier (3, 58 MHz), so this component cannot be used.

FIG. 9 shows an enlarged view of the spectrum. Here, in order to simplify the explanation, n=4.

In the embodiment shown in FIG. 2, in order to avoid overlapping with the color difference signal described above, the area marked ■ is 0 to 2.
Sub-sampling is performed by frequency shifting to the 2 MHz region. FIG. 11(b) shows the result, and the color difference signal is further frequency-multiplexed to become the NTSC signal shown in FIG. FIG. 17 shows filter characteristics related to 4 frame subsamples.

The decoder is a reverse process of the encoder, and expands or compresses one time axis separated on the time and frequency axes, and demodulates a wideband signal with an aspect ratio of 16:9. The configuration is shown in FIGS. 4 to 7. Here 44 is field memory, 4
6 represents a line memory, and 45 represents a 1/2 line memory. 52 is a vertical bypass filter that passes subcarrier frequencies. Also, the number attached to the top of each filter represents the passband.

FIG. 12 shows a subsample pattern.

Interpolation filter 56 for the sub-samples shown in FIG.
The configuration and characteristics of are shown in FIG.

FIG. 18 shows the frequency of the sine wave generator used in the encoder and decoder. The motion detection circuit 18 is known (for example, described in Japanese Patent Application No. 58-205377 or Japanese Patent Application No. 60-51091).
Therefore, the explanation will be omitted.

[Effects of the Invention] Conventionally, in NTSC signals used for broadcasting and the like, horizontal high frequency information is lower than vertical information. Further, the aspect ratio was also limited to 4:3. On the other hand, according to the present invention, it is possible to transmit high-wide-band signals such as high-definition while maintaining compatibility with NTSC signals, and it is also possible to apply it to high-vision broadcasting.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIGS. 2 and 3 are respectively configuration diagrams of an encoder according to an embodiment of the present invention, and FIGS. 4 to 7 are each according to an embodiment of the present invention. A block diagram of the decoder. Figures 8 to 12 are diagrams showing spectra and sampling points to explain the 4-frame sub-sampling method, respectively. Figure 13 shows the configuration and spectrum of an interpolation filter for sub-sampling. Figure 14 shows the spectrum of the side panel luminance signal, Figure 15 shows the phase control signal of the PAF carrier, Figure 16 shows the PAF spectrum, and Figure 17 shows the spectrum used for 4 frame sub-samples. FIG. 18 is a diagram showing the frequency of the sine wave generator.

Claims (1)

[Claims] 1) extracting each of the low-frequency components and mid-range components of the side panel portion included in the wideband video luminance signal, and multiplexing the low-frequency components and mid-range components in vertical and horizontal blanking periods; Furthermore, the television signal transmission system is characterized in that a multiplexed signal compliant with the NTSC system is transmitted by subsampling and multiplexing high frequency components of the luminance signal. 2) low-pass means and band-pass means for respectively extracting low-frequency components and middle-frequency components of the side panel section included in a wideband video luminance signal; A time axis compression/multiplexing means for multiplexing during the blanking period, a sampling means for subsampling the high-frequency components of the luminance signal, and a PAF for widening the I and Q signals of the center panel portion of the image to be transmitted. 1. An encoder comprising means for transmitting multiplexed signals compliant with the NTSC system. 3) Extract the low frequency components and mid frequency components of the sight panel section included in the wideband video luminance signal, multiplex the low frequency components and mid frequency components into the vertical and horizontal blanking periods, and further By subsampling and multiplexing high-frequency components, a decoder that inputs a video signal related to a transmission method that transmits a multiplexed signal compliant with the NTSC system can separate the video signal on the time axis and frequency axis. What is claimed is: 1. A decoder comprising separating means for demodulating a wideband signal having a predetermined aspect ratio.