JPS63123289A - High definition television signal transmitter and receiver - Google Patents

Abstract

PURPOSE:To prevent the leaking into chrominance signal in a current receiver while high definition information can be separated and transmitted at horizontal vertical spatial frequency areas by removing the inclined high frequency area component of a luminance signal including a fine signal and further, executing the sub-sampling. CONSTITUTION:A luminance signal Y including high definition information is added to a horizontal vertical pre-filter 108 and an inclined high frequency area component is removed. The signal is processed by a sub-sampling circuit 109 and the above- mentioned high definition information is housed into an NTSC system limit area. The signal is added to an adder 115, and a chrominance modulating signal C and the above-mentioned converting luminance signal are multiplexed and transmitted separatably in horizontal vertical spatial frequency areas. At the receiving side, the luminance signal Y is separated by a Y/C separating circuit, a non-inter converting circuit is passed through, thereafter, the signal is sub-sampled by a sub-sampling circuit, next, interpolated by a horizontal vertical interpolating filter, the high definition information is separated, this is added to a low frequency area luminance signal and a wide band television signal is restored.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is a high-definition television that handles a television signal in which high-definition information is multiplexed within the limited band of the NTSC standard television system. tion signal transmitter and receiver.

(Prior Art) The standard television system currently adopted in Japan is the NTSC system. In the NTSC system, the horizontal frequency band of the luminance signal is limited to 4.2 MHz, and the theoretical limit value of the horizontal resolution is 320 to 350 TV lines. The theoretical limit value of the other vertical resolution is 450 lines, and the fineness of the image quality is determined by the lower of the horizontal or vertical resolution. Therefore, in order to increase the sense of definition, it is necessary to improve the horizontal resolution.

Therefore, on the transmitting side, high-definition information, which is a high-frequency luminance signal exceeding the limited band (4.2 MHz), is converted to NTSC.
A method has been proposed in which the high-definition information is inserted into a gap in the frequency band of the method and the high-definition information is reproduced on the receiving side, thereby improving the horizontal resolution. - Examples include IEEE
TRANSANCTIONS ON COMMUN
ICATIONS, VOL, C0M-32, No. 8.
AUGUST 1984. There is a high-definition television system described in P, 948-P, 953.

The configuration of an NTSC television signal is determined by the vertical spatial frequency ν [cphl and the temporal spatial frequency f [Hz].
Let's look at it in two dimensions. At this time, the color signal C is as shown in FIG. 9(a).
As shown in
．． 15) It can be seen that the areas (shi, f)-(525/4.15) and (-525/4.-15) are free areas.

The above-mentioned high-definition television system focuses on this point and multiplexes the high-definition information HD into the above-mentioned free area, as shown in FIG. 9(b).

On the receiving side, horizontal resolution can be improved by separating and demodulating the multiplexed high-definition information HD.

(Problems to be Solved by the Invention) The high-definition television system described above uses a dedicated receiver that can separate the high-definition information. Horizontal resolution can be improved.

However, since high-definition information is multiplexed in a temporal frequency region of 15 Hz, high-definition information cannot be multiplexed with respect to moving images having temporal frequency components close to this region. Therefore, according to the above method, the horizontal resolution is improved only for substantially still images whose temporal spatial frequency is 7.5 Hz or less.

In addition, since multiplexed high-definition information must be separated in the vertical, temporal, and spatial frequency domains, the dedicated receiver described above must have a large capacity frame memory (at least 1.5 frame memories) to perform processing in the time direction. )Is required. Therefore, this type of receiver has to be expensive.

Furthermore, when a high-definition television signal based on the above system is received by a current receiver, the added high-definition information becomes an interference, and the image quality deteriorates.

That is, regarding color signals, cross-color phenomena occur because current receivers cannot separate color signals and high-definition information. In addition, high-definition information also leaks into the luminance signal. Since high-definition information is multiplexed as a 15 Hz movement in the time direction, 15 Hz flicker appears. As described above, the conventional high-definition television system described above is unsatisfactory in its compatibility with the current NTSC system.

The present invention has been made in view of the various problems mentioned above.
It is a high-definition system that can expand the range of improvement in horizontal resolution not only for still images but also for videos, improves compatibility with current receivers, and can be manufactured at low cost even when obtaining a dedicated receiver. The present invention aims to realize a high-definition television system, and presents a high-definition television signal transmitter and receiver that can achieve this goal.

[Configuration of the Invention (Means for Solving Problems) A high-definition television signal transmitter according to the present invention removes diagonal high-frequency components of a wideband television signal (luminance signal) containing high-definition information. By further subsampling, the high-definition information is contained within the limited band of the NTSC system, and a color modulation signal is separably multiplexed with the high-definition information in the horizontal and vertical spatial frequency regions to achieve high definition. The main purpose is to construct and transmit television signals.

Furthermore, the high-definition television signal receiver according to the present invention receives the high-definition television signal transmitted from the transmitting side, subsamples and then interpolates a luminance signal obtained by separating the received high-definition television signal. Or, frequency filtering the luminance signal to separate it into high-definition information and a low-band luminance signal, detecting the high-definition information, and then adding it to the low-band luminance signal to restore a wideband television signal. That is the main point.

(Function) According to the high-definition television signal transmitter according to the present invention, high-definition information can be transmitted while being separable in the horizontal and vertical spatial frequency regions.

In addition, since the high-definition information in the transmitted high-definition television signal is multiplexed in an area with no time variation, flicker interference does not occur, and compatibility with current receivers has been improved. becomes.

Further, the high-definition television signal receiver according to the present invention can easily separate high-definition information without using a large-capacity memory, and can be manufactured at low cost.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of a transmitter according to the present invention. Non-interlaced R, C, and B signals are input to input terminals 101, 102, and 103. The inputted R signal, C signal, and B signal are input to the matrix circuit 104 and converted into the Y signal, ■ signal, and C signal. The Y signal is input to the A/D converter 105 and converted into a digital signal.

The converted Y signal has the oblique component band limited by a low-pass filter 108 in the horizontal and vertical spatial frequency domains.

Meanwhile, the input signal is simultaneously input to the odd/even field determining circuit 120 and the burst generating circuit 121. Strange,
The even field determination circuit 120 determines whether the television signal currently being processed is an odd field or an even field, and outputs a control signal indicated by a broken line to the sub-sample circuit 109 and interlace conversion circuits 111 and 113. do.

Further, the burst generation circuit 121 generates a sampling clock frequency division waveform 801 which is a basic clock signal. This frequency-divided waveform 801 is multiplexed by an adder 122 onto a gold edge portion 802 within the horizontal blanking period of the transmitted television signal.

Now, the output signal of the low-pass filter 108 is input to an offset command sub-sampling circuit 109. Based on the control signal output from the odd/even field determining circuit 120, the offset sub-sampling circuit 109 sets the sub-sampling circuit so that, for example, the even field has the same phase as the burst signal, and the odd field has the opposite phase of the burst signal. Determine the subsample phase and perform offset subsampling.

The output of the sub-sampling circuit 109 is band-limited by a horizontal Nike low-pass filter 110.

Thereafter, in accordance with the control signal of the odd/even field determination circuit 120, the interlace conversion circuit 111 converts the signal into an interlaced signal having an inter-field offset subsampling structure.

On the other hand, the I signal and C signal outputted from the matrix circuit 104 are band-limited by a low-pass filter 112 in the horizontal and vertical frequency domains, and then converted into an interlace signal by an interlace conversion circuit 113. The converted ■ and C signals are converted to quadrature 2 by the balanced modulator 114.
It is phase modulated and converted into a C signal. This C signal is multiplexed onto the luminance signal by an adder 115. The high-definition television signal thus obtained is converted into an analog signal by the D/A converter 116, outputted from the output terminal 117, and transmitted.

Next, based on FIG. 2, the principle of multiplexing high-definition information by the above-described operation will be described.

The A/D converter 105 of the transmitter has a horizontal scanning frequency of 2 to −fH (k is an integer), where fH[H2] is the horizontal scanning frequency.
With this clock, grid sampling is performed as shown in FIG. 2(b). Below, as an example, the sub-sampling frequency is selected around 8MHz, and the high-definition information is set to 4.2MHz.
A case where the frequency is MHz to 6MH2 will be explained.

First, as shown in FIG. 2(a), the low-pass filter 108 shown in FIG. Each is limited to

In the band-limited signal 301, as shown in FIG. 2(d), high-definition information 303 of 4.2 MHz or higher is folded back to a horizontal low frequency band. A point 302 in the figure indicates a turning point.

Further, the sampled signal is filtered by a horizontal Nike low-pass filter 110 having the characteristics shown in FIG.
．． Components of 2MH2 or more are removed. Thereafter, the color signals are multiplexed to obtain the spectrum shown in FIG. 2(e). In FIG. 2(e), the high-definition information 304 is multiplexed in the vertical high range of the color signal 305. , there is little leakage into the color signal. Note that if the vertical band limitation of the high-definition information is strictly performed by the low-pass filter 108, the amount of leakage can be further reduced as shown in FIG. 2(f).

Multiplexing of high-definition information according to the present invention is performed at a vertical frequency of 525/
2 cph, time frequency OHz. As with the current system, transmission is performed using signals after interlace conversion. In interlaced structure, time frequency 3
It has a turning point at 0 Hz s vertical frequency 525/2 c ph. Therefore, the multiplexing of high-definition information according to the present invention can be said to be effective for still images with a temporal spatial frequency of 15 Hz or less and moving images with very slow movement. However, since the resolution of a television camera decreases when capturing a moving image, the present invention can actually be used for normal speed moving images without any problem.

Next, FIG. 4 shows an embodiment of a receiver according to the present invention.

A high-definition television signal on which the above-described high-definition information is multiplexed is input to an input terminal 401 . The input signal is Y
/C separation circuit 402 separates the signal into a Y signal and a C signal. The separated Y signal is converted to a non-interlaced signal and input to the sub-sampling circuit 405.

On the other hand, the input signal is also input to a burst reproduction circuit 420 and an odd/even field determination circuit 421. The burst reproducing circuit 420 reproduces a sampling clock phase synchronized with the burst signal 801 multiplexed on the leading edge portion 802 of the horizontal blanking period shown in FIG. 8, and outputs it to the sub-sampling circuit 405.

Further, the odd/uneven field determining circuit 421 determines whether the field currently being processed is an odd field or an even field, and outputs a determination signal to the sub-sampling circuit 405. The sub-sampling circuit 405 controls the burst reproducing circuit 42 based on the signal for determining odd and even fields output from the odd and odd field determining circuit 421.
The sampling phase of the sampling clock output from 0 is switched for each field, and the input signal is
) to a signal with the sample structure shown in . In this case, the sampling phase is determined in advance on the transmitting side, for example, in-phase with the burst phase 801 for even-numbered fields, and opposite to the burst phase 801 for odd-numbered fields.

Next, the output signal of the sub-sampling circuit 405 is processed by a horizontal/vertical frequency domain interpolation filter 4 having the same characteristics as the low-pass filter 108 that performs band-limiting on the transmitting side.
06, the sample structure is converted into the sample structure shown in FIG. 6(b). At this time, the spectrum of the signal is a wideband television signal with a horizontal frequency band of 6 MHz, as shown in FIG. 3(a), which makes it possible to restore a high-definition image.

On the other hand, the C signal separated by the Y/C separation circuit 402 is input to the IQ demodulation circuit 403, and a ■ signal and a Q signal are output. The matrix circuit 407 converts the Y, I%Q signals into R, G, B signals, and outputs the output terminals 40g, 409.4.
Output to 10.

Next, FIG. 5 shows a second embodiment of the receiver according to the present invention.

The Y signal separated by the Y/C separation circuit 402 is input to the field memory 504. A non-interlaced signal is equivalently obtained from the Y signal output from the memory 504 and information for two fields of the original Y signal, and this is horizontally and
By guiding the signal to a horizontal/vertical frequency domain bypass filter 505 that passes only high-frequency diagonal components in the vertical spatial frequency domain, only high-definition information can be separated.

The separated high-definition information HD is multiplexed in a region with a vertical frequency Oc p h s and a temporal frequency of 30 Hz as shown in FIG. 6, so if it is detected using a carrier with a temporal frequency of 30 Hz and a vertical frequency of 0 cph, It is possible to shift and demodulate to a region where the temporal frequency is OHz and the vertical frequency is 0 cph.

The carrier is generated by a carrier generation circuit 510. The carrier generation circuit 510 is the burst regeneration circuit 42
It is phase-synchronized with the burst signal output from the odd/even field determination circuit 421 and generates a carrier of m f II±39 Hz.

The high-definition information HD separated by the bypass filter 505 is detected by a multiplier 507 using the carrier. As a result of the above detection, the high-definition information HD is shifted by 30 Hz in the time direction, as shown in FIG. 6(a).
Further, as shown in FIG. 6(C), mfl(+
Shifted by 30Hz.

The detected high-definition information is sent to a low-pass filter 508
is input. The output of the low-pass filter 508 is added in an adder 509 to a signal obtained by subtracting the high-definition information HD from the Y signal using an adder 506, thereby restoring a wideband television signal.

Next, FIG. 7 shows a third embodiment of a receiver according to the present invention.

The non-interlaced Y signal is passed through a horizontal/vertical spatial frequency domain low-pass filter 601 and an adder 602.
The high-definition information HD is separated. The separated high-definition information is detected by a multiplier 603 using the carrier output from the carrier generation circuit 105. The output of the multiplier 603 is passed through a low-pass filter 606,
The signal is input to an adder 604 and added to the output of the low-pass filter 601. As a result, a wideband television signal can be obtained at the output of the adder 604.

In this example, the vertical frequency is 525/2 cp
By performing detection using the h carrier, high-definition information is vertically shifted by 525/2 c p h,
demodulated. Since such a carrier has been converted to non-interlace, it has a frequency of 2fH x odd number/2, that is, an odd number multiple of fH, using the burst signal output from the burst generation circuit 121, and also has a frequency that is an odd number multiple of fH. In order to align the phases with each other, a signal that can be switched for each field is selected based on a signal for determining odd and even fields obtained from an odd and even field determination circuit 421.

Now, in the embodiment described above, when obtaining the sample clock or carrier, as shown in FIG.
A newly inserted burst signal is used at the leading edge 802 of the horizontal synchronization signal 803.

The reason for using the burst signal 801 will be explained below.

In order to demodulate signals multiplexed in the horizontal and vertical spatial frequency domains on the receiving side, it is necessary to use a sample clock or a carrier that is phase-synchronized with the sample clock used for signal processing on the transmitting side.

The most stable signal available with current receivers is the color subcarrier fsc. However, in order to minimize interference to current receivers and obtain maximum effect on high-definition receivers, it is desirable to be able to set the multiplexing position of high-definition information without being constrained by the color subcarrier frequency.

For example, set the sample clock on the transmitting side to the horizontal periodic frequency f
A conceivable method is to set the value to m times +1 and use m f H on the receiver side as well. At this time, on the receiver side, if the horizontal synchronization signal 803 of FIG. 8 is input and horizontal AFC is used, a clock with a stable frequency nfH can be obtained. However, in reality, it is not possible to accurately define the signal phase of m f H due to the slope of the edge of the horizontal synchronizing signal 803 and ghost interference. Therefore, as shown in FIG. 8, by newly inserting a burst signal 801 having a frequency component of m f H/n into the leading edge part 802 within the horizontal retrace period, m f is set using this burst signal 801 as a phase reference. A continuous H signal can be easily reproduced.

Note that the frequency component of m f 11 / n to be inserted into the front edge portion 802 can be selected to be a high frequency component of about 4 MHz, so there is little possibility that it will have an adverse effect on the synchronous reproduction of the current receiver.

[Effects of the Invention] As described above, according to the high-definition television signal transmitter of the present invention, high-definition information can be transmitted so as to be easily separated in the horizontal and vertical spatial frequency regions, and when received by a current receiver. Since the high-definition information is multiplexed at a position where the time frequency is OHz, flicker interference does not occur. The transmitter of the invention is thus able to transmit high definition television signals with very good compatibility with current receivers.

Furthermore, the high-definition television signal receiver according to the present invention includes:
The high-definition information to be transmitted can be separated using two-dimensional filters in the horizontal and vertical spatial frequency domains, reducing the circuit size and
Both the price can be reduced compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a transmitter according to the present invention,
FIG. 2 is a frequency characteristic diagram for explaining the structure of a high-definition television signal according to the present invention, FIG. 3 is a characteristic diagram of a horizontal Nike low-pass filter used in the transmitter of the present invention, and FIG. 5 and 7 are block diagrams showing one embodiment of the receiver according to the present invention, and FIG. 6 is a frequency characteristic diagram for explaining the method of detecting high-definition information performed in the receiver of the present invention. FIG. 8 is a waveform diagram showing a burst signal transmitted by the transmitter of the present invention, and FIG. 9 is a frequency characteristic diagram for explaining a conventional high-definition television system. 108...Horizontal, vertical low pass filter, 109...
・Subsample circuit, 110... Nike low pass filter, 111.1
13... Interlace conversion circuit, 112... Horizontal/vertical filter, 115.122... Adder, 120... Odd, even field determination circuit, 121...
Burst generation circuit, 402... Y/C separation circuit, 404... Non-inter conversion circuit, 405... Sub sample circuit, 406... Horizontal/vertical interpolation filter, 407... Matrix circuit, 420. ...Burst reproduction circuit, 421...Odd/even field determination circuit, 505...
・Horizontal ◆ Vertical bypass filter, 506.507.50
9... Adder, 510... Carrier generation circuit, 601... Horizontal vertical low pass filter, 602.6
03.604... Adder, 505... Carrier generation circuit, 801... Burst signal, HD... High definition information.

Claims (4)

[Claims] (1) Input a wideband television signal that has a horizontal frequency band wider than the limited band limited by the NTSC standard television system and includes high-definition information, and from this signal, select its horizontal frequency component μ and vertical frequency component ν. μν0+μ0ν>μ0ν0 μ0: highest horizontal frequency of the wideband television signal ν0: remove at least a diagonal high-frequency component signal that satisfies the highest vertical frequency of the wideband television signal and output it as a first band-limited signal. a first band-limiting means; and limiting the first band-limited signal by offsetting and subsampling the first band-limiting signal with a sampling signal having a high sampling frequency equal to or higher than the highest horizontal frequency μ0. sub-sampling means for multiplexing the high-definition information in a horizontal frequency domain above the band into a frequency domain from which the diagonal high-frequency components have been removed, and multiplexing it on the first band-limited signal; and output of the sub-sampling means. a second band limiting means for limiting the horizontal frequency band of the multiplexed signal to the limited band and outputting a second band limiting signal; a modulating means for obtaining a color modulation signal by vertically band-limiting the signal to be a signal in a low frequency region and then modulating it with a color subcarrier; and multiplexing the color modulation signal onto the second band-limiting signal; multiplexing means for obtaining a subsampled high-definition television signal containing the high-definition information within the limited band, and transmitting the high-definition television signal. transmitter. (2) The first band limiting means is driven by a clock signal having a frequency of 2k·fH, which is the horizontal frequency fH multiplied by an integer 2, and the sampling frequency in the sub-sampling means is k·fH. A high-definition television signal transmitter according to claim 1. (3) The high-definition information is obtained by removing diagonal high-frequency components of a wideband television signal that has a horizontal frequency band wider than the limited band limited by the NTSC standard television system and contains high-definition information, and subsampling the signal. is included in the limited band, and a color modulation signal is separably multiplexed with the high-definition information in the horizontal-vertical spatial frequency domain.
Y/C separation means for separating and outputting the luminance signal and the color modulation signal; subsampling means for subsampling the luminance signal and converting and arranging the high-definition information within a horizontal frequency band equal to or higher than the limited band; The apparatus further comprises interpolation means for interpolating the output signal of the sub-sampling means, converting the sampling form into a grid pattern, restoring the signal to a wideband television signal from which the diagonal high-frequency components have been removed, and outputting the signal. High-definition television signal receiver. (4) The high-definition information is obtained by removing diagonal high-frequency components of a wideband television signal that has a horizontal frequency band wider than the limited band limited by the NTSC standard television system and contains high-definition information, and subsampling the signal. is included in the limited band, and a color modulation signal is separably multiplexed with the high-definition information in the horizontal-vertical spatial frequency domain.
Y/C separation means for separating and outputting the luminance signal and the color modulation signal; frequency separation means for separating and outputting the high-definition information and the low-band luminance signal by frequency filtering the luminance signal; a detection means for inputting high-definition information and performing frequency conversion so that its vertical frequency and temporal frequency become 0; A high-definition television signal receiver comprising: addition means for restoring and outputting a television signal.