JPS5831793B2 - Kotai Iki TV Jiyoung Shingoden Souhoshiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wideband television signal, particularly a wideband color television signal, for realizing a wideband high-definition television system in which the number of scanning lines is increased compared to that of a standard television system. The present invention relates to a wideband television signal transmission system suitable for narrowband transmission of television signals in satellite communications and the like.

When transmitting a composite color television signal, in which a chromaticity signal is frequency-multiplexed by a color subcarrier set at the upper limit of the luminance signal frequency band, by frequency modulating (FM) the main carrier wave in satellite relay, satellite broadcasting, etc., FM Since the carrier color signal is multiplexed and transmitted in the high frequency band of the modulation sideband where noise increases, in order to avoid deterioration of the signal-to-noise ratio of the reproduced color signal on the receiving side, it is necessary to increase the transmission power of the main carrier wave. needs to be large enough.

In order to avoid such an increase in transmission power in FM transmission of a wideband color television signal, the luminance (7) signal and the chrominance Q signal are separated into separate carrier waves (FML), and appropriate power allocation is performed for each. However, in future satellite broadcasting, especially high-quality color television satellite broadcasting, it is expected that the television signal itself will have a wider band. It is difficult to reduce the transmission power sufficiently by using only the separate transmission method.

An object of the present invention is to solve the above-mentioned problems, and to improve the quality of a wideband television signal such as a color television signal by not only transmitting the luminance signal and color signal separately, but also by appropriately narrowing the band. It is an object of the present invention to provide a wideband television signal transmission system that can transmit high-quality television signals by reducing the transmission power required for high-quality transmission or by effectively utilizing the transmission band.

The present invention separates a wideband color television signal or the like into a luminance signal and a chrominance signal, and further separates these signals into a wideband signal and a narrowband signal that appropriately represent necessary information for each, A wideband signal is made into a narrow band by stretching its time axis. On the other hand, a narrowband signal is compressed in time axis to compensate for this time expansion, so that both the wide and narrow band signals described above can be efficiently converted into a narrowband signal with the same bandwidth. It is designed for narrowband transmission.

That is, the wideband television signal transmission system of the present invention is as follows:
Regarding a wideband high-definition television signal, the brightness signal is separated into a wideband brightness signal including a high frequency component of horizontal spatial frequency and a narrowband brightness signal consisting of a middle to low frequency component of horizontal spatial frequency, and and a wideband signal and a narrowband signal, which collectively refer to the wideband chrominance signal, the narrowband luminance signal, and the narrowband chrominance signal, respectively. By making the sum of the time-axis expanded transmission period and the time-axis compressed transmission period equal to the sum of the transmission periods of each original signal, the time-axis expanded wideband signal and the time-axis compressed The present invention is characterized in that it is possible to transmit a narrowband signal with a substantially average band through a transmission path.

The present invention will be described in detail below with reference to the drawings.

First, with reference to FIG. 1, a conventional signal processing system for separating YC and transmitting color television signals will be described.

In the circuit configuration shown in FIG. 1a, three primary color image signals R, G, and B obtained as the imaging output of a color television camera (not shown) are led to a matrix circuit 1, and a luminance (1) signal and, for example, a color difference Signal (RY) and (B-Y)
Two types of color signals C1 and C2 are formed.

The color signals C1 and C2 are switched line alternately by a line switching pulse from an input terminal 6 in a switcher circuit 2 and converted into a line sequential signal C.
The two types of color signals are made into color signals having the same bandwidth, and separate luminance signals and color signals are obtained at output terminals 4 and 5, respectively.

On the other hand, in the circuit configuration shown in FIG. 1, of the two types of color signals formed in the same manner as in the above configuration,
The wideband chromaticity signal Cw and the narrowband chrominance signal CN are passed through low-pass r wave generators 7 and 8 each having a required bandwidth, and then guided to the switcher circuit 2, in the same manner as in the above configuration. The line sequential color signal C is converted into a line sequential color signal C. In this case, the line sequential color signal C is transmitted through a transmission path having a bandwidth of the wideband color signal cw.

Y of the color television signal formed as described above
When applying the method of the present invention to transmission luminance signals and chrominance signals for C-separated transmission, the frequency band characteristics of each transmission signal to be transmitted separately are determined. 2a and 2b, respectively, and the waveform diagrams of FIGS. 2C and d show aspects of signal processing of such a YC separated transmission signal according to the present invention.

In the transmission method of the present invention, the horizontal resolution of the image information represented by the luminance signal is determined by thinning out the scanning period of the original wideband luminance signal to create an image signal with fewer scanning lines, and then extending the scanning period. On the other hand, the vertical resolution is determined by reproducing a narrowband luminance signal consisting of frequency components below the middle range of the horizontal spatial frequency for each scanning line. As shown in Figure 2a,
For example, wide and narrow band luminance signals Yw and YN having upper limit frequencies fYW and fYN, respectively, are
The broadband luminance signal is transmitted separately to the (odd) line and the second (even) line, and is transmitted to the odd line, as described above, to reproduce the horizontal spatial frequency image resolution, that is, the resolution in the horizontal direction. However, if vertical spatial frequency image information, that is, vertical resolution, is reproduced using narrowband luminance signals transmitted for each scanning line, it is possible to achieve sufficiently high quality and high image quality through narrowband transmission as described above. Images can be transmitted.

Also, regarding image information represented by color signals, wideband color signals Cw are selected to have appropriate hues to match visual sensitivity.
and a narrowband color signal CN selected to have an appropriate hue, such as having a phase substantially perpendicular to this, respectively, as shown in FIG. 2, each having an upper limit frequency f.

The second as a wideband and narrowband chrominance signal with W and fCN.
Similar to the luminance signal shown in Figure a, if the signals are divided into odd and even lines and transmitted line-sequentially, and the signal processing described above is applied, it is possible to obtain sufficiently high-quality and high-quality image information for the color signal as well. can be transmitted.

The second aspect of signal processing is to appropriately expand and compress the time axes of the line-sequential wide- and narrow-band signals of the luminance signal and chrominance signal set as described above, respectively, and to transmit the narrow-band signals.
Shown in Figures C and d, respectively.

In the above signal processing, for the luminance signal Y, the second
As shown in FIG. The luminance signals are transmitted sequentially at alternating periods.

In this case, the time axes are expanded and compressed so that the highest frequencies of both luminance signals whose time axes have been converted are equal, and the band utilization efficiency of the transmission path for transmitting both luminance signals is maximized.

That is, the time-axis expanded and compressed transmission periods of the wide and narrow band luminance signals transmitted line sequentially are tw and tN, respectively.
If the line scanning period of the original signal is τh, then the transmission periods tw and tN after time axis conversion are set as follows.

Therefore, the original luminance signal Y can be transmitted with band efficiency through a signal transmission path with an average narrow band of (fyw+fyN)/2.

That is, for example, the upper limit frequency fYw of the wideband luminance signal
is 4.0 MHz, and the upper limit frequency fYN of the narrowband luminance signal is 1.6 MHz, then the required transmission band of the line sequential luminance signal time-axis converted by the signal processing described above is 2.8 MHz, which is 2.8 MHz. A broadband luminance signal with an upper limit frequency of 4.0 MHz will be transmitted through a transmission path with a MHz bandwidth.

Similarly to the above, for the line-sequential wide and narrow band color signals, if the respective transmission periods after time axis conversion are respectively tw/ and tN/ as shown in FIG. 2d, then Therefore, in the same way as above, the primary color signal C is (
This means that the signal can be transmitted efficiently using a signal transmission path with an average narrow band of fow+foN)/2.

That is, for example, if the upper limit frequency of the wideband color signal is set to 2.0
MHz, and the upper limit frequency of the narrowband color signal is 0.6MHz, the required transmission band of the line sequential color signal is 1.3M.
Hz, and a broadband color signal with an upper limit frequency of 2.0 MHz will be transmitted through a transmission line with a bandwidth of 1.3 MHz.

In short, when transmitting a wideband television signal in YC separation, the Y signal is converted into a line sequential signal with both wide and narrow bands as shown in Figure 2a, and the C signal is converted into a line sequential signal with both wide and narrow bands as shown in Figure 2a. By converting the Y and C signals into band line sequential signals, converting the time axis and transmitting them as shown in Figure 2 C and d, both the Y and C signals can be converted into narrow band signals that are equal to the average bandwidth of the respective wide band and narrow band signals. It can be transmitted via a band transmission path.

As mentioned above, FIG. 3 shows an example of the configuration of a signal conversion device on the transmitting side when a wideband television signal is separated into a Y signal and a C signal, and each of them is converted into a line sequential signal of both wide and narrow bands and transmitted. The signal waveforms of each part are shown in FIG.

In the signal conversion device shown in Fig. 3a, the Y signal or C signal, which is formed by separating a wideband television signal in advance and converted into a line sequential signal of both wide and narrow bands, is sampled at an appropriate repetition frequency. With the pulse,
The sampled signal is applied to the input terminal 9, and is switched every two horizontal scanning periods (2H) by the changeover switches S1 and S2.
Data is written to memories 10 and 11 alternately for 2H periods.

2H memories 10 and 11 have shift pulses P1 and P.
2 and 2 are alternately switched and supplied by changeover switches S1 and S2 every <2H period in synchronization with the switching of the sampling signal, and these shift pulses have a repetition period as shown in Fig. 3. , and the shift pulse P1
has the same repetition frequency as the sampling pulse and includes the same number of N pulses for each horizontal scanning period, whereas the shift pulse P2 has the same repetition frequency as the sampling pulse, while the shift pulse P2 has the same repetition frequency as the sampling pulse
Of the above 2H switching period, the repetition frequency is reduced for N pulses included in the first half IH period corresponding to the wideband signal transmission period, and the repetition frequency is reduced for the N pulses included in the first half IH period corresponding to the narrowband signal transmission period. The repetition frequency is increased for the N pulses that include the pulses, so that the total period corresponding to 2N pulses including the first and second half periods is the same 2H period as the shift pulse P1.

When writing into the 2H memory a sampling signal using a sampling pulse with a repetition frequency sufficient to sample the information contained in the wideband signal described above, the shift pulse P described above is used.
1, 2N sample values are written in a 2H period at a uniform speed common to both wide and narrow band signals.

Therefore, during the 2H period in which the sampling signal is written to one of the 2H memories 10 and 11, the data is written from the other 2H memory.
The sampling signal written in the immediately preceding 2H period is read out by controlling the time axes of both the wide and narrow band signals to be expanded and shortened, respectively, to average the signal bandwidths of both the wide and narrow band signals using the shift pulse P2. The sampled signal whose axis has been transformed is
The changeover switch S3 is used to switch at a 2H cycle, and the 2H memories 10 and 11 are read out alternately, converted into a continuous signal via the low-pass P-wave device 12, and then output to the output terminal 13.
Send it out.

Note that each switch S1. S2. The switching of S3 is performed by driving with a switching pulse of 2H period as shown in FIG.

The line-sequential wide- and narrow-band signals whose signal bands are averaged as described above are efficiently transmitted through a transmission path having an average transmission band. An example of the configuration of a receiving side signal conversion device for restoring the signal is shown in FIG. 4, and an example of the transmission signal waveform before and after such conversion is shown in FIG.

In the configuration example of the receiving side signal conversion device shown in FIG. 4a, the above-mentioned transmission signal having the waveform shown in the figure is converted into a sample signal with an unequal period, which is exactly the same as that in the shift pulse P2 shown in FIG. 3. That is, in the first and second half of the 2H period, the receiving side sampling signal which is input by forming sampling pulses with different repetition periods is switched to the switches S4 and S.
5 is switched in a 2H cycle, and 2H is input from the input terminal 14.
Write to memories 15 and 16 alternately.

That is, when writing to the memory on the receiving side, contrary to the case on the transmitting side, in addition to the above-mentioned sample signal, the shift pulse P2 of unequal period shown in FIG. 3 formed as described later is used. In the first half of the 2H period of the signal switching period corresponding to the wideband signal, N sample values are written in the memory at a slow repetition period.
The second half, which corresponds to narrowband signals, has a fast repetition period and the remaining N
Write sample values to memory.

Furthermore, 2H memories 15 and 16 are installed in the same way as on the sending side.
When reading sampled signals alternately from 1 to 2, if the memory is controlled by a shift pulse P1 with a uniform period and 2N sample values are read out at a uniform speed, the samples written and read in the first half of 2H of the switching period The time axis of the sampled signal is compressed to restore a wideband signal, and the time axis of the sampled signal written and read in the latter half is expanded to restore a narrowband signal.

In this way, the sampled signals read out alternately while converting the time axis are transferred to the low-pass r waver 1 via the switch S6.
7 and in the form of a continuous signal, it is possible to extract from the output terminal 18 a reconstructed line-sequential television signal with wide and narrow sides.

Note that the above-mentioned receiving side signal conversion device also converts the Y signal and C
Similar signal conversion is performed for each signal.

Further, FIG. 4 shows the correspondence between the unequal period transmission signals before and after the receiving side signal conversion as described above and the restored line-sequential wide and narrow band signals.

As described above, in the wideband television signal transmission system of the present invention, in separating the wideband television signal into the luminance signal Y and the color signal C and transmitting the same,
The Y signal and C signal are separated into wideband yw times signal and Cw signal, and narrowband YN signal and CN signal, respectively, and each wideband signal component is expanded on the time axis to form Yw/Cw signal having approximately average band. The narrow band signal components are compressed in time axis and converted into YN/signals and CN/signals having approximately average bands, for example during even line periods. In this way, the transmission path band is used extremely efficiently to transmit a wideband television signal, and on the receiving side, the Yv signal and CW/signal in the received signal are compressed on the time axis and are respectively yw times the wideband. Signal and Cw
Restore to signal, YN/signal and ON! The signals are expanded on the time axis and restored to narrowband YN and CN signals, respectively.

Of the above-mentioned restored signals, for the luminance signal, a wideband yw times signal is regenerated during the odd line period, and a narrowband YN signal is delayed by the yw times signal IH period during the even line period, and the YN signal is reproduced. The high band (Yw
) H signal is added to reproduce the wideband luminance signal, and as for the color signal, the line-sequential wideband and narrowband color signals are each delayed by the LH period and combined with the original signal, for example, SEC
Continuous color signals are formed in the same manner as in the AM system, and a wideband television signal identical to the original signal is formed by these luminance signals and color signals.

Therefore, it is possible to transmit a wideband television signal using a transmission path with a band much narrower than the original signal band, with image quality equivalent to that of transmission through a wideband transmission path required to directly transmit the original signal band.

Although the transmission method of the present invention has been described above for the case of transmitting a color television signal, the transmission method of the present invention is not limited to the above-mentioned example. Regardless of the format of multiplexing with color signals, these signals can be separated and the present invention can be implemented in the same manner as in the above example, and when monochrome television signals are transmitted in a television telephone or the like. Of course, the present invention can also be implemented in exactly the same way as the transmission of the luminance signal component in the above example.

Furthermore, when separating a wideband original signal into a wideband component and a narrowband component, the mode of wideband and narrowband separation, such as at which point in the original signal band the upper limit of the band of the narrowband component is set, depends on the transmission used. It can be set appropriately by taking into account the bandwidth of the road, etc.

Therefore, the transmission method of the present invention not only transmits a so-called television signal, but also has a signal format similar to a television signal, that is, has appropriate periodicity and has an appropriate correlation between signal components in adjacent periods. The present invention can be similarly applied to the transmission of other types of signals, such as facsimile signals and character signals, or CATV.

As explained above, in the transmission system of the present invention, a signal, such as a television signal, which is composed of an information signal divided at a fixed period and a periodic signal indicating the period, is divided into wide and narrow band signal components. In order to expand and compress the time axis of each signal before transmitting it, by converting the above constant period into alternating unequal periods, the synchronous signal with a uniform period in the original signal is transmitted to the receiving side as is. The received signal contains only the synchronization signals of unequal periods as described above.

Examples of means for regenerating switching pulses, sampling pulses, shift pulses, etc. necessary for restoring the time axis of the original synchronization signal of uniform period and the information signal from the received synchronization signal of unequal period are shown in FIGS. 5 and 6. show.

In the configuration example of the horizontal synchronizing signal reproducing circuit shown in FIG. 6, a received signal having a waveform as shown in FIG. Take out the periodic signal with unequal periods as shown in a,
This is added to the flip-flop 21 to form switching pulses with unequal periods as shown in FIG. 5a.

If this unequal period switching pulse is applied to the differentiating circuit 22 and a differentiated pulse corresponding to the falling edge of the pulse waveform is extracted, a periodic signal with a 2H period corresponding to one alternate period of the time-axis converted wide and narrow band signal can be obtained. is obtained.

On the other hand, the IH same-period output from the synchronous frequency oscillator 25, which has the same frequency as the original synchronization signal with a uniform period, is added to the 1 counter 26 to convert it into an oscillation output with a 2H period, and this is added to the phase comparator 23, By comparing the phase with the reproduced synchronization signal of the period, feeding back the phase comparison output to the oscillator 25 via the loop filter 24, and controlling the phase of the oscillation output, it is possible to obtain a signal with the same period as the original synchronization signal as the oscillation output. A phase-synchronized signal can be obtained.

This oscillation output is sent to the output terminal 2 via the pulse shaping circuit 27.
8, it is possible to reproduce the original synchronization signal with a uniform period.

Furthermore, in order to restore the wide and narrow band signals from the time-axis converted information transmission signal, the periods of these pulses are adjusted in advance for the reproduction of shift pulses P1 and P2 used in the receiving side signal converter shown in FIG. Also, the average period of the synchronization signal and the mutual interval are, respectively,
Preferably, set it so that it has an integer relationship,
The above-mentioned pulses can be regenerated by providing oscillators having respective periods on the receiving side and controlling the frequency and phase of the oscillation output by the regeneration synchronization signal.

Among them, regarding the shift pulse P2 having unequal periods, continuous pulse Pa having a slower repetition frequency and continuous pulse Pb having a faster repetition frequency are
As shown in the figure, reproduction can be performed by driving the changeover switch S7 with the unequal cycle switching pulses shown in FIG. 5a to alternately switch and take out the data.

As is clear from the above explanation, in the transmission system of the present invention, both the luminance signal and the color signal that make up the wideband television signal are divided into a wideband signal and a narrowband signal that are appropriately configured to suit visual perception. Furthermore, among the wide and narrow band signals with the same period, the wide band signal is transmitted over a longer period of time, and the narrow band signal is transmitted over a longer period of time. (1) Wideband color TV It is possible to transmit a video signal using much less transmission power than when transmitting a standard composite color television signal in the form of a standard composite color television signal. As a result, a remarkable effect can be obtained in that a high-quality wideband color television signal can be efficiently transmitted with even less transmission power.

[Brief explanation of the drawing]

Fig. 1 avb is a block diagram showing the configuration of a conventional signal processing circuit for YC separation transmission when transmitting a color television signal by separating it into a luminance (1) signal and a color (Q signal), and Fig. 2 a+b, c, and d are signal waveform diagrams respectively showing a transmission signal and a transmission signal processing method in the transmission system of the present invention, and Fig. 3 a and b are configuration examples and signals of each part of the transmitting side signal conversion device in the transmission system of the present invention. FIGS. 4a and 4b are block diagrams and waveform diagrams showing the waveforms, respectively, and FIGS. b is a signal waveform diagram showing the mode of regeneration of switching pulses and shift pulses in the receiving side signal conversion device of the transmission system of the present invention, No. 6;
The figure is a block diagram showing an example of the configuration of a horizontal synchronizing signal reproducing circuit on the receiving side in the transmission system of the present invention. 1...Matrix circuit, 2...Switcher circuit, 3...Low pass r wave generator, 4...
...Brightness signal output terminal, 5...Color signal output terminal, 6...Line switching pulse input terminal, 7,
8...Low pass P wave device, 9...Sampling signal input terminal, io, ii...2H memory,
12...Low pass P wave device, 13...Transmission signal output terminal, 14...Sampling signal input terminal, 15.16...2H memory , 17...
...Low-pass r-wave device, 18...Restored signal output terminal, 19...Received signal input terminal, 20...
...Synchronization separation circuit, 21...Flip-flop,
22...Differentiating circuit, 23...Phase comparator, 24...Loop filter, 25...
... Synchronous frequency oscillator, 26 ... Temple counter, 27 ... Pulse shaping circuit, 28 ...
Reproduction synchronization signal output terminal, S1 to S7...changeover switch.

Claims (1)

[Claims] 1 Regarding a wideband high-definition television signal, the luminance signal is separated into a wideband luminance signal containing a high-frequency component of horizontal spatial frequency and a narrow-band luminance signal consisting of a middle-low frequency component of horizontal spatial frequency, and With respect to a wideband signal and a narrowband signal, which collectively refer to a wideband chrominance signal, a narrowband luminance signal, and a narrowband chrominance signal, respectively, the wideband signal is expanded in time axis, and the narrowband signal is compressed in time axis, and alternately By making the sum of the time axis expanded transmission period and the time axis compressed transmission period equal to the sum of the transmission periods of each original signal, the time axis expanded wideband signal and the time axis A wideband television signal transmission system characterized in that a compressed narrowband signal can be transmitted through a transmission path having a substantially average band.