JPS6036157B2 - High-definition television signal transmission and reception system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-definition television signal transmission and reception system that performs orthogonal transformation on a wideband high-definition television signal and divides it into multiple channels of non-wideband signals for transmission and reception.

In general, high-definition television signals have a number of scan lines approximately an integral multiple, for example approximately twice, of the number of scan lines of standard television in order to increase their vertical resolution. The resolution in the horizontal direction is also approximately an integer multiple, for example twice, that of a standard television signal, so if the multiple is m, the frequency band limit of the signal is The width becomes an extremely wide band of m2 times.

In order to transmit such a wideband high-definition television signal using frequency modulation (FM) having a wideband gain in the same way as a standard television signal, a significantly wideband transmission path is required as described above, and a normal bandpass is required. For example, if a standard television signal is transmitted over a transmission line with the same bandwidth as FM transmission, the signal-to-noise ratio (S/N ratio)
will decrease significantly. Therefore, in order to transmit and receive such wideband high-definition television signals by, for example, a broadcasting satellite, a wideband FM transmission path that combines four FM transmission channels used for satellite relay of standard television signals is required. had to be dedicated.
As mentioned above, when transmitting a broadband high-definition television signal using FM, the S/N ratio decreases because in a high-definition television system in which the number of scanning lines is multiplied by m, the reason is that Since the signal components representing the same fineness are n, compared to n in the standard television system, the frequency deviation in FM transmission is kept constant, and the signal components are transmitted with the same bandwidth and the same power. In this case, the S/N ratio that affects the image, especially the weighted S/N ratio, is 1/m, and the power ratio is 1/m.
/m2.

On the other hand, as mentioned above, for broadband television signals, for example, Madamaru A transmission/reception method is known in which the signal is divided into multiple channels, for example, 4 channels of standard bandwidth signals, by performing orthogonal transformation such as conversion, and the signals are divided and transmitted using multiple channels, for example, 4 channels of standard bandwidth transmission lines. However, for example, when performing divisional transmission by performing such orthogonal transformation on a high-definition television signal with 1051 scanning lines, which is twice the standard system's 525 scanning lines, the conventional As the most theoretical form of orthogonal transformation, for example, as described in Japanese Unexamined Patent Application Publication No. 145432/1989 filed by the applicant, orthogonal transformation is simply performed on a plurality of consecutive pixel signals to obtain the same plurality of pixel signals. By eliminating the conventional conversion method of dividing into narrow band signals, orthogonal transformation is applied to four pixel signals in a rectangular arrangement, two of which are selected on two adjacent scanning lines. A transmission/reception method has been considered in which the signals are divided into 4 channels of narrowband signals with different resolutions in both horizontal directions, and these narrowband signals are divided and transmitted independently from each other over 4 channels of standard band transmission lines. .

However, in such conventional orthogonal transform division transmission systems, broadband high-definition television signals are transmitted over a wideband transmission line with a bandwidth four times that of the standard bandwidth, or over a standard bandwidth transmission route with four consecutive channels. There is no need for dedicated transmission,
Although the advantage of being able to transmit and receive data using four standard band transmission lines arbitrarily spaced apart is obtained, in any case, the transmission line for four channels of standard television signals is still occupied, and therefore, Satellite communications, especially satellite broadcasting, where the number of transmission channels is limited and effective use is desired, reduces the number of occupied transmission channels that are theoretically required to transmit wideband high-definition television signals, as described above. There is a strong need for the development of a transmitting and receiving method that can do this.

An object of the present invention is to solve the above-mentioned conventional problems and efficiently reduce the number of required transmission channels when performing orthogonal transformation on a wideband high-definition television signal and dividing the signal into multiple transmission channels. An object of the present invention is to provide a high-definition television signal receiving system that can transmit wideband television signals.

In other words, the transmission/reception method of the present invention sequentially orthogonally transforms each corresponding pixel signal on two adjacent scanning lines to reduce the number of transmission channels required for divided transmission by half. Regarding a wideband high-definition television signal that has horizontal scanning lines approximately an integral multiple of the horizontal scanning lines of the television system and multiplexes a carrier color signal whose phase is inverted alternately between the scanning lines onto a luminance signal, it is possible to A plurality of time-series pixel signals for each predetermined period each representing a plurality of pixels are sequentially converted into a plurality of simultaneous pixel signals for each predetermined period by applying a required delay to each of the plurality of time-series pixel signals for each predetermined period, By sequentially performing orthogonal transform on the simultaneous pixel signals of , multiple channels of non-wideband television signals are constructed and transmitted, and by receiving these multiple channels of non-wideband television signals and sequentially performing orthogonal inverse transform. In a high-definition television signal transmission/reception system in which a plurality of restored simultaneous pixel signals of the predetermined periods are respectively given a required delay and time-series pixel signals of the predetermined periods are sequentially reproduced, 2 for each predetermined period formed from the two time-series signals each representing each corresponding pixel on two horizontal scanning lines.
The two-channel non-wideband television signal is constructed by sequentially orthogonally transforming the two simultaneous pixel signals, and the two channels of the two-channel non-wideband television signal are
A pre-enhancement system that emphasizes at least one of the high-frequency components of the non-wideband television signal of one channel and the low-frequency components of the non-wideband television signal of the other channels corresponding to the DC component of the two simultaneous pixel signals. By applying the pre-enphasis to the received two-channel non-wideband television signal and transmitting the pre-enphasis corresponding to the pre-enphasis.

A luminance signal component and a carrier color signal respectively formed from a non-wideband television signal corresponding to the DC component and a non-wideband television signal of the other channel, and a horizontal scanning line number halved with respect to the high-definition television. The invention is characterized in that it is possible to form non-wideband television signals having the respective characteristics. The invention will be explained in detail below by way of example embodiments with reference to the drawings.

First, as mentioned above, a wideband high-definition television signal having 11 scanning lines, which is twice the number of scanning lines of a standard television signal, is subjected to orthogonal transformation such as Hadamard transform to create a multiple channel narrowband signal. When dividing into signals, the above-mentioned orthogonal transformation is applied to each corresponding pixel signal on two adjacent scanning lines, that is, the two pixel signals, and the two pixel signals are divided into two independent narrow standard bands. When the image is divided into signals, the orthogonal transformation transforms the signal only with respect to the signal component in the vertical direction of the image.
Since no transformation is performed on the signal components in the horizontal direction, the standard band of the channel representing the DC component corresponding to the sum of the original pair of pixel signals among the two channel standard band signals after orthogonal transformation. The horizontal frequency image component of the castle signal does not change before and after the orthogonal transformation, and although it is in the same frequency band of n, the upper limit frequency of the high-quality television signal before conversion is b' Since the number of scanning lines is almost twice, it is almost twice the upper limit frequency b of the standard band television signal.

Therefore, as mentioned above, compared to the 525 scanning lines of the standard television system, there are 11 scanning lines, which is twice as many as the 525 scanning lines of the standard television system.
Regarding the S/N ratio of a standard band signal after performing orthogonal transformation on a high-definition television signal having 1051 scanning lines, the noise component in the frequency range from frequency na b to frequency na b', that is, na b Since there is no image component, it does not have much effect on the actual S/N ratio, and the signal after conversion of the channel representing the DC component described above is used in a narrow frequency band for standard television signals. Even though the transmission and reception through the transmission path does not cause any change in the horizontal direction of the image, the substantial S/N ratio of the received reproduced image does not decrease that much. In the transmission/reception system of the present invention, as described above, a wideband high-definition television is divided into two by performing orthogonal transformation that changes only the vertical direction of the image, and the above-mentioned properties of the transformed signal components of these two channels are utilized. , FM transmission is performed in an overshifted state in which the low-frequency components of these converted signals are emphasized, so that the substantial S/N ratio of the received reproduced image is improved.

In the transmission and reception system of the present invention, the positional relationship of sampling pixels that perform sampling prior to subjecting the high-quality television signal to the above-described orthogonal transformation is shown in Fig. 1. Configuration examples are shown in Figures 2 and 3.
The process of signal conversion and restoration in the transmission/reception system of the present invention is shown in FIGS. 4a and 4b, respectively.

Regarding the scanning line structure of the high-definition television signal shown in FIG. 1, sequential scanning lines 1, 2,
Let the pixel signals on 3 and 4 be A, B, C, and D, respectively.
The number of scanning lines in such a scanning line structure can be obtained arbitrarily, but in order to maintain compatibility between the high-definition television signal in the system of the present invention and the standard format television signal, when the number of scanning lines in the standard format is n, The number of scanning lines of the high-definition television signal is set to 1 or 1. The horizontal scanning frequency of such a high-definition television signal is assumed to be the band width. "b
Then, the sampling frequency S is a positive integer of 1,
〆S=lfh [1) NaS≧2
Na b [Set so that the relationship becomes 21.

Here, if the high-definition television signal is a composite color television signal in which a carrier color signal is multiplexed on a luminance signal while maintaining a line offset relationship, as in the case of an NTSC color television signal, for example, The standardized frequency Nas is the color subcarrier frequency. ``The method of selecting nearly three times the target is the same as when sampling standard television signals, but at the same time,
The condition of the expression is also satisfied, for example, it is set to 3-na ± back-na h. In the configuration of the transmission system shown in the second diagram, the input high-definition television signal from input terminal 1 and the input terminal 2
A sampling signal with a frequency set as described above is guided to the sampling circuit 1, and a high-definition television signal is sampled as shown in the pixel arrangement shown in Figure 1, and the sampled output signal is , are led directly to the second-order Hadamard transform circuit 3, are delayed by one line via the delay circuit 2, and are also led to the transform circuit 3.

The time relationships of the input sampled image signals to the Hadamard transform circuit 3 are shown at 1 and 2 in FIG. 4a, respectively. That is, each of the image signals A, B, C, and D in the same figure is an image signal in line units, and each corresponds to one sequential pixel on two vertically adjacent lines shown in FIG.
When shown as blocks A and B, Kumo) = Listening Hand - Hand)
(Consistent) The second Hadamard transform signal shown by (1) is converted to day,, day2.

These conversion signals day, day 2 are converted as one block for each pixel in the horizontal direction of the image, and two pixels every two lines for pixels in the vertical direction. Since the converted signal date, , day 2 appears at every other line position surrounded by the frame shown by the dotted line in Figure 4a, the converted signal date,
, day 2 is expressed by expanding the time axis to the length of the two line period, as shown in 3 and 4 in FIG. and the converted signal date of the C and D lines are consecutive to each other, and the converted signal date 2 of the A and B lines and the converted signal date 2 of the C and D lines are consecutive to each other. The time axis expansion operation for the converted signal day, day 2 is performed by the second-order Hadamard transform circuit 3 having the configuration shown in the second figure, but the actual concrete processing is performed by digital processing and the '3' equation. The A+B=day signal and the A−B=day2 signal shown in are written to the memory element at the normal time axis rate, and then,
As mentioned above, the speed is doubled. The converted signals Day, Day 2, whose time axis has been extended by digital processing as described above, are as follows.
The image signal has a bandwidth that is behind the bandwidth b' of a high-definition television signal.

Therefore, the key to the input high-definition television signal in the configuration shown in FIG. In the case of a composite color television signal multiplexed with a luminance signal, the converted signal whose time axis is expanded has a vertical spatial frequency characteristic of 1'2.
It becomes a non-wideband luminance signal that has been degraded to becomes the carrier color signal. The configuration shown in the second diagram is an example of a transmission system assuming a case where the above-mentioned converted signals 1, 2 are transmitted by frequency modulation (FM), and the converted outputs from the conversion circuit 3 whose time axes are expanded are respectively Signal day. and day 2 to the enhancement circuits 4 and 5, respectively; for example, in the enhancement circuit 4,
Alternatively, the ``emphasis method'' described in Japanese Patent Application Laid-Open No. 138212/1982 related to the applicant's application
The gain of the high-frequency components of the converted signal is compared to the gain of the low-frequency components in the horizontal and vertical spatial frequency domains, respectively, using a method such as "Color Television Signal Emphasis Method" described in Publication No. 133026. and take a large amount,
Moreover, by making the modulation degree during frequency modulation, that is, the frequency deviation as large as possible, the signal-to-noise ratio S
/N can be improved as much as possible.

In addition, in the enhancement circuit 5, the gain of the low-frequency component is made larger than the gain of the Takagi component in both the horizontal and vertical spatial frequency regions, and on the receiving side, the converted signal subjected to such enhancement, To increase the overall S/N ratio when a high-definition color television signal is restored by combining and day 2. In the transmission system shown in FIG. , day 2, F
The signals are transmitted via M modulators 6 and 7, respectively, using normal transmission paths having narrow transmission bands for transmitting standard television signals. If the number of scanning lines for a high-definition television signal is set to be approximately twice the number of scanning lines for a standard television signal, the frequency band width of the high-definition television signal will be four times as large as that of the standard television signal, as described above. When a high-definition television signal is converted into converted signals 2, 2 by the process described above, the frequency band width of these converted signals 2, 2 is twice the frequency bandwidth of the standard television signal. reduced by half.

However, the frequency bandwidth of the secondary television signal is designed so that the coefficient that determines the frequency bandwidth, called the Kell factor, is 0.7, and as a result of experiments, high-definition television As for the signal, its Kel coefficient is set to about 0.5. Therefore, the frequency bandwidth of the above-mentioned converted signal is 1.4 times the frequency bandwidth of the standard television signal, and the frequency band width of the converted signal is 1.4 times that of the standard television signal. , Day 2 can be satisfactorily transmitted and received over conventional transmission paths for transmitting standard television signals. Next, the third
The illustrated receiving system receives the converted signals transmitted as described above and restores them to the original high-definition television signal, and each block in the figure has its own block number. Among the numbers shown, the 1-digit number is the block number, and each block performs an operation corresponding to and opposite to the operation of each block in the transmission system shown in the second diagram.
For example, block 13 is a second-order Hadamard restoration circuit that performs orthogonal inverse transform corresponding to the second-order Hadamard transform circuit 3 in the transmission system shown in the second diagram.

That is, in the receiving system shown in Figure 3, the received F
The M signal is amplified by high frequency amplification section 2 and then guided to frequency separation circuits 16 and 17 to have different frequencies.
The converted signals 1 and 2 transmitted through the transmission path of the channel are separated and extracted, respectively, and guided to FM demodulation circuits 14 and 15 for demodulation. The signal-to-noise ratio S/N of the reproduced image is
After improving the above, the second-order Hadamard restoration circuit 13 converts the transmitted converted signal and the image signals A, B, C, 0,
・・・・・・Restores high-definition color television signals.

The process of such signal processing is shown in FIG. 4b. In Fig. 4b, from the transmitted converted signal day and 1 and 2 representing day 2, we get The signals A and B are restored by the conversion process.

Contrary to the time axis of these signals A and B on the transmitting side,
As shown in Figure 4b, 3 and 4, each is shortened to
Of these, only the signal component shown in 4 is delayed by one scanning line period in the high-definition television signal and moved to the time position shown in 5, and the signal shown in 3 is added together so as to be interpolated, as shown in 6. to restore a continuous high-definition television signal. The delay of such signal components is calculated as 1 shown in the third diagram.
The signal components are added by the line delay circuit 12, and the signal components are added by the mixer circuit 11. However, the signal delay described above is actually performed in a memory element having a storage capacity for one line, as shown in FIG. 4b. 1 and 2 are written in sequence, and of the converted signal 1, signal A is read with the phase and seed shown in 3, and signal B is read with the phase and speed shown in 5 and the reduced rate of high-definition television signals. The signal is then restored to the high-definition television signal shown in 6 above. Furthermore, if the number of scanning lines of the high-definition television signal is selected to be 11 or 11 compared to the number of scanning lines n of the standard television signal, the converted signal , corresponds to the luminance signal component of the standard television signal. Then, by directly supplying this converted signal to a standard television receiver, the image content of the high-definition television signal can be reproduced and displayed as a black and white image.

Furthermore, if the carrier color signal is multiplexed in the same frequency region by converting the frequency of the high-frequency component of the converted signal 2 to make it the same color subcarrier frequency as the standard television signal, the NTSC color television signal As a result, color images can be reproduced and displayed on the screen of a standard color television receiver.

Furthermore, in that case, as described above, it is sufficient to perform signal processing to convert the color subcarrier frequency. In addition, when actually transmitting a high-quality television signal using orthogonal transformed signals, if the signal band width is constant, the FM frequency will be larger than when transmitting a standard format television signal.
Transmission power is required.

However, such an increase in FM transmission power requires increasing the size of the receiving antenna in the receiving system for receiving high-definition television signals, and increasing the size of the transmission system for transmitting high-definition television signals using the standard television transmission system. By configuring this, the increase in power can be made unnecessary. As is clear from the above explanation, according to the method of the present invention, by using a memory element whose storage capacity is sufficient for one line, a high-definition television signal is divided into two channels of non-wideband signals, and the divided signals are Since each of the two channels is transmitted and received after being subjected to signal processing that matches the characteristics of those signals, the normal non-wideband transmission path for transmitting standard television signals is used independently for each of the two channels. It is possible to transmit a wideband high-definition television signal, and by appropriately selecting a high-definition television system, the image content of the high-definition television signal can be transmitted in a standard manner on the screen of a standard television receiver. It can be played and displayed as a television image,
Furthermore, regarding the high-definition television signal itself, which has an extremely wide band compared to the standard format television signal, such a wide band signal can be transmitted over a normal standard format signal transmission path by just 2 times.
Only the channels can be used independently of each other for sufficient transmission.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the pixel arrangement of a high-definition television signal, FIG. 2 is a block diagram showing an example of the configuration of a transmission system in the high-definition television signal transmission/reception system of the present invention, and FIG. Similarly, FIGS. 4A and 4B are block diagrams showing an example of the configuration of the receiving system, and FIGS. 4A and 4B are diagrams showing examples of signal processing on the transmitting side and the receiving side, respectively. 1... Sampling circuit, 2... 1 line delay circuit,
3...Second-order Hadamard transform circuit, 4...
・Emphasis circuit, 5...Signal processing circuit, 6
, 7...Modulation circuit, 11...Mixing path,
12...1 line delay circuit, 13...
Secondary Hadamard restoration circuit, 14, 15... demodulation circuit, 16, 17... frequency separation circuit, 20... reception high frequency amplification section. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Regarding a wideband high-definition television signal in which a luminance signal is multiplexed with a carrier color signal having a number of horizontal scanning lines that is approximately an integral multiple of the number of horizontal scanning lines of the standard television system and whose phase is alternately inverted in each scanning line, A plurality of time-series pixel signals for each predetermined period each representing a plurality of pixels on a television screen are sequentially converted into a plurality of simultaneous pixel signals for each predetermined period by applying a necessary delay to each of the plurality of time-series pixel signals for each predetermined period; Multiple channels of non-wideband television signals are constructed and transmitted by sequentially performing orthogonal transformation on multiple simultaneous pixel signals for each pixel signal, and the non-wideband television signals of multiple channels are received and sequentially orthogonally inversely transformed. In a high-definition television signal transmission and reception system, the time-series pixel signals for each predetermined period are sequentially reproduced by applying a required delay to each of the plurality of simultaneous pixel signals for each predetermined period restored by applying , by sequentially performing orthogonal transformation on the two simultaneous pixel signals for each predetermined period formed from the two time series pixel signals representing respective pixels on two adjacent horizontal scanning lines. A high-frequency component of the non-wideband television signal of the channel corresponding to the DC component of the two simultaneous pixel signals among the non-wideband television signals of the two channels, and other non-wideband television signals of the channel. The non-wideband television signals of the two channels are subjected to pre-emphasis that emphasizes at least one of the low frequency components of the non-wideband television signals of the two channels, and the two channels of the received non-wideband television signals are transmitted.
a luminance signal component formed from the non-wideband television signal of the channel corresponding to the DC component and the non-wideband television signal of the other channel by subjecting the non-wideband television signal of the channel to de-emphasis corresponding to the pre-emphasis; A high-definition television signal transmission/reception system, characterized in that it is possible to form a carrier color signal component and a non-wideband television signal each having a horizontal scanning number half that of the high-definition television.