JPS6192084A - Data transmission system - Google Patents

Abstract

PURPOSE:To use a television transmission system and to set a medium speed class transmission line to two channels independently by giving, as a chromaticity signal component, the signal which amplitude-modulates, by a base band binary digital signal, a chrominance subcarrier signal having an orthogonally intersected phase. CONSTITUTION:At a transmission side 21, a Y signal of black-and-white animation information is supplied to a terminal 22Y and to terminals 22I and 22Q, respective separate base band binary signals are supplied instead of an I signal and a Q signal. In this case, a chrominance carrier signal, in which the phase is different by 90 deg. mutually, is amplitude-modulated by respective different base band binary digital signals, given as a chromaticity signal component, and a chromaticity signal component 46 by the digital signal is overlapped and transmitted to a luminance signal 45 of a black-and-white animation. At output terminals 35I and 35Q of a receiving side 33, a base band binary digital signal given to the input terminals 22I and 22Q of the transmitting side are respectively obtained. Thus, two channel digital transmission systems are formed between the input terminal 22I and the output terminal 35I and between the input terminal 22Q and the output terminal 35Q.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a data transmission system for transmitting data using an NTSC color television signal transmission system, such as teletext broadcasting.

``Prior art'' Conventionally, in teletext broadcasting, etc., a channel for transmitting a luminance signal (hereinafter referred to as Y signal) is used in the NTSC color television signal transmission system, and in particular, on the horizontal scanning line within the vertical retrace interval. Transmission was performed by giving a 2-segment code signal.

That is, in the NTSC color television signal, as shown in FIG. 3A, a vertical retrace interval 11 is inserted every vertical cycle, and the blank interval is defined as a video interval 12. In the 1-image period 12, a horizontal synchronous pulse 13 and an 1-image signal 14 are inserted. The vertical retrace section 11 is provided with a vertical synchronizing pulse 16 sandwiched between equalizing pulses 15, as shown in FIG.
Each of these has three horizontal periods, and the horizontal synchronization pulse 13 is inserted for the remainder. Between the horizontal synchronizing pulses 130 within the vertical retrace section 11, that is, the horizontal running f line 17
A binary digital signal was applied to the top. That is, as shown in FIG. 3C, a binary digital signal 18 is applied between each horizontal pulse 13 in the vertical blanking section 11. A color burst signal 19 is inserted into the back porch of the horizontal synchronization pulse 13.

``Problems to be Solved by the Invention'' As described above, conventionally, binary digital signals are inserted only in the vertical retrace section 11, so the transmission details are approximately 24 horizontal scanning lines//frames at maximum. It was only 200 kb/s.

"Means for Solving the Problem" According to the present invention, in a transmission system for an NTSC color television signal, color subcarrier signals having nine phases that are orthogonal to each other are transmitted to two separate baseband digital signals. The amplitude modulated signal is given as the chromaticity signal component.

The chromaticity signal component of such a digital signal may be provided only on the horizontal scanning line in the vertical blanking interval, or on all horizontal scanning lines, that is, on all horizontal scanning lines including the vertical blanking interval and the video-signal interval. may be given to In the former case, color moving image information, black and white moving image information, or a baseband binary digital signal is given to the video signal section, and in the latter case, black and white moving image information or a baseband 2-level digital signal is given to the video signal section.

In this way, in this invention, since a binary digital signal is transmitted using the chromaticity signal component, a medium-speed data transmission line can be set up as two independent channels using a television transmission system. .

"Embodiments" Examples of the present invention will be described below with reference to the drawings). 1st
The figure shows a conventional NTSC color television transmission system to which this invention is applied. show.

In transmission @21, the Y signal is given to the terminal 22Y,
The signal is amplified by the Y signal amplifier 23Y and supplied to the synthesis circuit 24. The I signal is applied to a terminal 221, and a low-pass T-wave generator 251 cuts off components of 1.5 MHz or higher, and the signal is supplied to an amplitude modulator 261. The Q signal is applied to a terminal 22Q, and a low-pass P wave generator 25Q cuts off components of 500 KHz or more, and the Q signal is supplied to an amplitude modulator 26Q. The 3.58 MH2 chrominance subcarrier signal from the chrominance subcarrier oscillator 27 is supplied to the amplitude modulator 261 through the phase shifter 28, and is amplitude modulated by the (2) signal.

The color subcarrier signal is branched from the phase shifter 28 and the phase of the color subcarrier signal is shifted by 5.
The signal is supplied to the amplitude modulator 26Q through 29, and is amplitude-modulated by the Q signal. Amplitude modulator 26I.

The phases of the color subcarrier signals supplied to the 26Q channels are different from each other by 90 degrees. The color subcarrier signal from the oscillator 27 is supplied to a color burst modulator 31 and then supplied as a color burst signal 19 to a combining circuit 24 . In the synthesis circuit 24, a luminance signal and an amplitude modulator 261 + 26c
The color signal components from 2 and the color burst signal are combined and sent to the transmission line 32 as a color television signal.

On the receiving side 33, a Y signal from the color television signal transmitted from the transmission path 32 is amplified by a Y signal amplifier 347 and output to a terminal 35Y. In addition, the color signal components from the transmitted color television signal are separated by an IQ separation waveform filter 36 and supplied to an industrial signal synchronous detection circuit 37, an I%Q signal synchronous detection circuit 37q, and a color burst sampling circuit 38. Ru. A color burst sampling circuit 38 extracts the color burst signal l) and supplies it to a phase@wave circuit 39. 3.58 from color subcarrier oscillator 41
The MHz color subcarrier signal is supplied to a phase detection circuit 39, where the phase is compared with the color burst signal, and the color printing carrier wave oscillator 41 is controlled by its output to perform phase synchronization. The color subcarrier signal of the color subcarrier oscillator 41 is transmitted to the phase shifter 4.
2 to the mechanical signal synchronous detection circuit 371, and
The signal is synchronously detected. The engineering signal is a low-pass F wave filter 4
31, jo 1. The component on SMH2H is blocked and output to terminal 35I. Phase shifter 420 color sub-color carrier signals are received, phase shifted by 90 degrees in phase shifter 44, and supplied to Q signal synchronous detection circuit 1M137Q, where the Q signal is synchronously detected. The Q signal is outputted to a terminal 35Q after its components of 500 KH2 or more are cut off by a low-pass F wave filter 43Q.

In such a color television signal transmission system,
For example, on the transmitting side 21, a Y signal of black and white video information is supplied to the terminal 22Y, and the terminal 22. , 22Q are respectively supplied with separate baseband binary digital signals 'ThI signal and Q signal for all horizontal scanning lines. In this case, color carrier wave signals having a phase difference of 90 degrees from each other are amplitude-changed by different baseband binary digital signals, and are intertwined on all horizontal scanning lines as chromaticity signal components, resulting in black and white signals as shown in Figure 2. A chromaticity signal component 46 based on the digital signal is superimposed on the luminance signal 45 of the moving image and transmitted. Receiving side 3
The paceband binary digital signals applied to the transmitting side input terminals 221 and 22Q are obtained at the output terminals 351* and 35Q, respectively. In this way, input terminal 2
A two-channel digital transmission system is constructed between the input terminal 21 and the output terminal 351 and between the input terminal 22Q and the output terminal 35Q.

Note that the baseband binary digital signals may be supplied to the input terminals 221 and 22Q only in the vertical retrace interval. At this time, the video section can be transmitted as a color telepicture/signal "lr: (.In either case, the baseband 2@digital signal may also be applied to the input terminal 22Y, and this may be transmitted as a ty signal. .

The transmission speed of the baseband 21 direct digital signal applied to the terminal 221 is below 1.5 MHzJa, and
The transmission speed of the baseband binary digital signal applied to the terminal shall be 500 KH2 or less.

``Effect of the invention'' The data (
Transmission capacity Icy, CQ (Mb/binary digital signal)
s') are given by the following equations.

Here, cY is the data transmission capacity (M
b/s), Wl# WQr Wy are I signals, respectively.
Each transmission band (MH2) of the Q signal and Y signal, ('') is the S/N ratio of the YY signal transmission system, and α and β are the ratios of the S/N ratio of the engineering signal and Q signal transmission system to (dan), respectively. .

Therefore, compared to the conventional character multiplex transmission in which digital signals are transmitted only on the horizontal scanning line in the vertical retrace interval, the present invention allows the digital signal to be transmitted only on the horizontal scanning line in the vertical retrace interval. When transmitting digital signals, the transmission cost increases by about 40%. In addition, in contrast to the conventional teletext service that transmits two digital signals using all the horizontal scanning lines of the Y signal transmission system, the present invention allows two digital signals to be transmitted on all the horizontal scanning lines of the Y signal transmission system.
When transmitting value digital signals, the transmission capacity is approximately 40
can rise.

In addition, by sending constant video information (black and white image rkl) as the Y signal and transmitting digital information using the ■ signal and Q signal transmission system, it is possible to monitor each part of the dam in industrial television, for example when monitoring a dam. Video in black and white, water level,
Data such as divergence can be transmitted as digital data. In such cases, unlike broadcasting where transmission is carried out over a wide area with different propagation conditions, transmission between specific points is generally performed using original fibers, so high S
The N ratio can be obtained, and the engineering signal, for all horizontal scanning lines,
Even if a digital signal is transmitted to the Q signal transmission system, it is possible to demodulate the Y signal and the chromaticity signal component of the digital signal with almost no influence on each other.

As explained above, with this invention, existing color television circuits can be used to easily and economically set up two medium-speed data transmission lines independently, and can be used for purposes other than Y signal transmission data lines. It has the advantage that it can be used and its capacity can be increased, and that the video band can be used effectively.

[Brief explanation of the drawing]

FIG. 3 is a diagram showing an example in which chromaticity components based on digital signals are superimposed, and FIG. 3 is a diagram showing a television signal.

Claims (1)

[Claims] (1) In a system capable of transmitting an NTSC color television signal, a signal obtained by amplitude modulating chrominance subcarriers with mutually orthogonal phases using a baseband binary digital signal is provided as a chromaticity signal component. Characteristic data transmission method.