JPS61126885A - Tv signal generation system - Google Patents

Abstract

PURPOSE:To enable the titled system to generate TV signal with high resolution at a present broadcast equipments by compressing the regular band of a luminous signal to 1/2, forming 1 frame by 4 fields, and inserting or not inserting an equalizing pulse every 2 field periods. CONSTITUTION:A luminous signal ya is sampled and held by a sampling pulse fsy of frequency 512 fH in a sample and hold circuit 1, and a luminous signal ya' outputted through a filter 4 is folded at 256fH. And a color difference signal is the same,too. (B-Y)a, (R-Y)a are outputted as color degree signals. Insertion or non-insertion of the equalizing pulse is repeated very two field periods because one frame is composed of four fields. It is the addition of the equalizing pulse E discriminates 4n fields and 4n+1 fields, non-application of the equalized pulse discriminates 4n+2 and 4n+3 field, odd and even inclusively. Thus, an image of high resolution can be obtained by the use of a present broadcast equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a high-definition television signal generation system (background of the invention) A signal system for realizing high-definition television has been proposed.

However, is it possible to perform koji delivery with current broadcasting equipment (excluding studio equipment)? There was no television signal generation system that could receive high-resolution images.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a high resolution television signal generation system that can be transmitted using current broadcasting equipment.

(Example of the invention) The present invention will be explained below with reference to Examples.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In this embodiment, the number of scanning lines is doubled from the current number, and the frame is composed of four fields.
In the SC method, the number of scanning lines is doubled (1050), the frame frequency is 14.985Hz, and the field frequency is 5.
The frequency shall be 9.94Hz.

The luminance signal ya is sampled and held in the sample and hold circuit 1, the color difference signal (B-Y) a is sampled and held in the sample and hold circuit 2, and the color difference signal (R-
Y)a is sampled and held in the sample and hold circuit 3.

In the NTSC system, color signals are multiplexed by frequency interleaving and sent out, so in order not to disturb this relationship, the horizontal synchronization signal frequency rH (15.75 kHz)
Sample at a frequency that is an integer multiple of z). The frequency of the sampling pulse rsy of the sample and hold circuit 1 is set to a frequency approximately twice the luminance signal bandwidth, for example, 512 f.
H (8,056 MHz), and a filter 4 having a pass frequency range of the luminance signal bandwidth is connected to the output side of the sample and hold circuit 1. Sample hold circuit 2.3
For example, the frequency is 64fH (1,007MHz)
A sampling pulse fSC is supplied. The outputs of the sample and hold circuits 2.3 are each limited to a band below IMHz via filters 5.6.

Color difference signal (B-Y
) a, (RY) Based on a! Generate a signal, a Q signal! The subcarrier with a frequency of 227.5 fH is orthogonally modulated by the signal and the Q signal in the quadrature modulation circuit 7, and the output of the filter 4 and the output of the quadrature modulation circuit 7 are transmitted to the adder 8.
It is added at .

On the other hand, the phases of the sampling pulses fsy and fsc are shifted by 180 degrees every two field periods in the phase control circuits 9 and 10, respectively.

An adder 11 adds a vertical synchronizing signal, a horizontal synchronizing signal, and a color burst to the output of the adder 8 .

Here, one frame consists of four fields.Equivalent pulses are inserted every two field periods in the ninth vertical synchronization signal.
Four fields are identified by repeating non-insertion.

Furthermore, the sampling pulse fsY is supplied to a divider 12 that divides the frequency by two, and the output of the divider 12 is supplied to the gate circuit 13, and the monostable multivibrator 14 is triggered by the horizontal synchronization signal to generate a monostable multivibrator. The gate of the gate circuit 13 is opened by the output of the waveform shaping circuit 15 which shapes the output of the multivibrator 14, and the 512 fa signal is superimposed on the front porch for several cycles.

The output of the gate circuit 13 is sent to the adder 11 together with the synchronization signal etc.
It is added to the output of the adder 8 at the modulator 16 for transmission.
It is supplied to

The operation of one embodiment of the present invention configured as described above will be explained.

The frequency band of the brightness signal ya is twice that of the conventional band, that is, the frequency spectrum distribution of the brightness signal ya is shown in Fig. 2 (a
) as shown in <512fl("!), and a part of it is shown in FIG. 2(b) when enlarged.

The luminance signal ya is 512 in the sample hold circuit 1.
The luminance signal y a / sampled and held by the sampling pulse fsY of frequency fH and output through the filter 4 is as shown in FIG. 2(C) (256
f) Folded back at I, the frequency spectrum distribution is 25
It is distributed up to 6 fH (4,028 MHz), which is the same as the luminance signal band in the conventional NTSC system. If a part of the frequency spectrum distribution of the nine luminance signals ya′ shown in FIG. 2(C) is extracted and shown, FIG.
) as shown below. 9 For example, if n=200, 20
0fH (=3.147MHz) (7) component is 3.14
The original component of 7MHz (shown as a solid line) and (
512-2,00) f H = 4.909MHz component is folded back by sampling and becomes 3.
This is a combination with the component (indicated by a broken line) that has a frequency of 147 MHz.

The same applies to color difference signals. Color difference signal (B-Y
)a, (R-Y)a are converted into color difference signals (B-Y)a', (R-
Y)a', and the subcarrier is orthogonally modulated by the ■ signal and the Q signal based on this signal, and is output as a carrier color signal (hereinafter referred to as a chromaticity signal).

An adder 8 adds the luminance signal from the filter 4 and a chromaticity signal from the orthogonal modulation circuit 7, and an adder 11 adds the synchronization signal and color burst.

However, as mentioned above, one frame consists of four fields, so it is necessary to identify them, but as mentioned above, the insertion and non-insertion of equalization pulses are repeated every two field periods, and as shown in FIG. a) As shown, by not adding the equalization pulse E, the field is 4n+2.4n+3, and the field is distinguished from odd and even fields.

Note that the luminance signal and the color signal maintain a frequency interleaving relationship as in the conventional case, and are frequency interleaved by the adder 8.

Also, the passband width of filter 5.6 is I MHz
is limited to. ■The signal is 1, 5 in the case of NTSC system.
Although it has a MHz band, there is no problem because it only demodulates up to about 500 KHz except for special monitor television receiver aircraft.

The 180 degree phase is switched by the phase control circuit 9.10 by the sampling pulse fsY, signal V which switches every two field periods. Therefore, the aliasing noise caused by sampling is averaged out by the afterimage effect, and there is no problem even if the appearance is not good.

On the other hand, the frequency of the sampling pulse fSY is divided by half by the frequency divider 12 and supplied to the gate circuit 13. The monostable multivibrator 14 is triggered by the horizontal synchronization signal, and the monostable multivibrator 14
The horizontal synchronizing signal is delayed and waveform shaped by the waveform shaping circuit 15. The output of this waveform shaping circuit 15 is applied to the front porch of the composite video signal for several cycles, 256
The gate of the gate circuit 13 is opened during the period in which the fH signal is superimposed. As a result, as shown in FIG. 4, the 256fH signal S is superimposed on the front porch of the composite video signal for several cycles. This signal can be used as an index signal during demodulation during image reception, and if the superimposition period and level are appropriately selected, it will not become a signal that interferes with image reception by a conventional receiver. In addition, in FIG. 4, C indicates a color burst.

In the above embodiment of the present invention, the case of the NTSC system will be explained as an example, but the same applies to the case of the PAL system and the SBCAM system.

(Effects of the Invention) As explained above, according to the present invention, it is possible to transmit twice as much information both horizontally and vertically by a method compatible with conventional methods, and it is possible to use current broadcasting equipment. , high resolution images can be obtained. Furthermore, even if the image is received by a conventional receiver, the same image as the conventional one can be obtained due to the afterimage effect.

In addition, by changing the phase of the sampling pulse by 180 degrees every t-2 field, the aliasing noise caused by sampling is averaged out by the afterimage effect and can be considered to have no apparent appearance.y') By inserting it into the pouch It can be used as an index signal for demodulation during image reception.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing a frequency spectrum distribution for explaining the operation of an embodiment of the present invention. FIGS. 3 and 4 are waveform diagrams showing part of the waveform of a synthesized television signal in one embodiment of the present invention. 1.2 and 3...sample hold circuit, 4.5 and 6... Filter, 7... Quadrature modulation circuit, 8 and 11... Adder, 12... Frequency divider, 13... Gate circuit, 14... Monostable multivibrator, 15
...Waveform shaping circuit, 9 and 10...Phase control circuit,
16...Modulator. Fig. 2 wfH (Ksu2infH js+2fo-(513-chofH1 ("2fH-(s+21fH) (s+2f+-(sn鴫)tHJ 40th □ in Fig. 3

Claims (3)

[Claims] (1) Sample the luminance signal, compress the bandwidth of the luminance signal to 1/2, form one frame with 4 fields, and insert equalization pulses every 2 field periods to identify each field. , a television signal generation system that does not require insertion. (2) The luminance signal and color difference signal are sampled with a sampling pulse whose frequency is an integral multiple of the horizontal synchronization signal and whose phase changes by 180 degrees every two fields, compressing the bandwidth of the luminance signal and converting one frame into four A television signal generation system in which an equalization pulse is inserted or not inserted every two field periods to identify each field. (3) Sampling the luminance signal and compressing the bandwidth of the luminance signal to 1/2, forming one frame with 4 fields and inserting equalization pulses every 2 field periods to identify each field. , a television signal generation method in which a signal related to a sampling pulse for sampling a luminance signal is inserted into the front porch over a predetermined cycle.