JPH03159477A - Device and method for transmitting video signal - Google Patents

Abstract

PURPOSE:To simplify circuit configuration by making an H synchronizing signal into the alternating pattern of a line number, and establishing synchronism in a vertical direction by detecting a part not to become the alternating pattern when frame synchronization is established by detecting the H synchronizing signal. CONSTITUTION:At a transmission system, an inputted analog video signal is converted into a digital signal by an A/D converting part 1, and simultaneously, the horizontal and a vertical synchronizing signals are detected by a video synchronizing signal detecting part 2. On the reception of this detection signal from the video synchronizing signal detecting part 2, an H synchronizing signal generating part 3 generates the H synchronizing signal for an odd line and the H synchronizing signal for an even line. At a receiving side, on the reception of this transmission signal, an H synchronizing signal detecting part 5 detects the H synchronizing signal. Here, the H synchronizing signal detecting part 5 detects successively the synchronizing signals of the odd line and the even line alternately. Thus, the partition of the frame of the video signal can be known, and therefore, the synchronism in the vertical direction can be established.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a transmission device and a transmission method for digitally transmitting a video signal.

(Prior Art) Digital transmission is ideal for transmitting high-definition video because it is less susceptible to attenuation and noise during transmission, and is particularly effective for wired television broadcasting (cable vision).

On the other hand, when transmitting a video signal such as a television image by digital transmission, it is necessary to transmit an audio signal as well.

Therefore, in conventional methods of this type, a digital pattern (frame synchronization signal) is added instead of the synchronization signal waveform of the analog video signal in order to compress the time axis of the video signal and multiplex other information such as audio signals. A frame for transmission is constructed by adding an 11 synchronization signal, which is a synchronization signal for the horizontal direction of the video signal, and a V synchronization signal, which is a synchronization signal for the vertical direction of the video signal. It was structured like this.

According to this conventional method, in order to correctly reproduce the signal on the receiving side, there are two steps: Therefore, two synchronization detection circuits are required.

That is, as shown in FIG. 2, in the conventional system, an input analog video signal is converted into a digital signal by an A/D converter 1 in a transmitting system, and a horizontal synchronizing signal is converted by a video synchronizing signal detector 2. and a vertical synchronization signal is detected. Then, the detection outputs of these horizontal synchronization signals and vertical synchronization signals are received from the video synchronization signal detection section 2, and
1 synchronization signal generation section 3 generates 11 synchronization signals (digital patterns) corresponding to horizontal scanning lines, and (1) synchronization signal generation section 10 generates V synchronization signals corresponding to vertical synchronization signals of video signals.

This H synchronization signal (digital pattern), the V synchronization signal corresponding to vertical synchronization, and the output signal of the A/D conversion section 1 are sent to the multiplexing section 4, where they are multiplexed to form a frame and sent out for transmission. .

On the other hand, the receiving side receives this transmission signal, detects the II synchronization signal in the synchronization signal detection section 11, detects the II synchronization signal in the synchronization signal detection section 1l, and detects the digital video signal in the separation section 6. Separate one signal.

The video synchronization signal generating section 7 generates a horizontal synchronization signal by receiving the detection signal of the I synchronization signal, and generates a vertical synchronization signal by receiving the detection signal of the synchronization signal. Then, these synchronization signals and the digital video signal from the separation unit 6 are selected by the switching unit 8 to reproduce the digital video signal including the synchronization signal waveform, and the digital video signal containing the synchronization signal waveform is converted into an analog signal by the D/A conversion unit 9 and converted to the original. Obtain video signal.

According to the conventional method, in order to correctly reproduce the signal on the receiving side, it is necessary to detect the H synchronization signal to establish frame synchronization, and then to detect the V synchronization signal to establish vertical synchronization. Therefore, two synchronization detection circuits are required.

(Problems to be Solved by the Invention) As mentioned above, the analog video signal is digitized and multiplexed with the audio signal for transmission, and on the receiving side, these are separated and the digital video signal is demodulated into the analog video signal. In the conventional video signal transmission system of digital transmission type, which detects both the 11 synchronization signal and the V synchronization signal of the video signal, two synchronization detection circuits are required, and the circuit configuration is However, the disadvantage is that it becomes more complicated.

When considering cable vision, etc., there are a large number of user terminals on the receiving side, so in order to reduce the cost of the system, reduce the burden on users, and spread it widely, it is necessary to improve the circuit configuration as much as possible. It is about simplification.

Therefore, the purpose of this project is to enable a single synchronization detection circuit to correctly reproduce video signals in both the horizontal and vertical directions, thereby simplifying the circuit configuration. An object of the present invention is to provide a video signal transmission device and a video signal transmission method.

[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, the present invention is configured as follows.

In other words, in a system that digitally transmits a video signal constituting one frame using an odd number of scanning lines, the video signal to be transmitted is received, vertical and horizontal synchronization signals in this video signal are detected, and the odd numbered scanning lines and horizontal synchronization signals of the video signal are detected. synchronization signal generation means for generating different predetermined digital patterns in synchronization with even-numbered scanning lines and outputting them as digital signals in place of the synchronization signal; and A/D conversion for receiving and digitally converting the transmitted video signal. and a transmitting system comprising a multiplexing means for receiving, multiplexing and transmitting each of these digital signals, and detecting a digital signal in place of the synchronization signal from the received multiplexed signal to generate even and odd scanning lines. synchronization signal detection means for generating different synchronization detection signals, and receiving the synchronization detection signals of the synchronization signal detection means to generate horizontal synchronization signals of analog video signals and continuously receiving synchronization detection signals of odd-numbered scanning lines. In this case, a video synchronization signal generation means for generating a vertical synchronization signal of an analog video signal, a separation means for separating the received multiplexed signal into each digital signal, and a video signal component of the separated digital signal is converted into an analog signal. and a receiving system that includes a D/A converting means for converting into a video signal, and a means for synthesizing the output of the video synchronizing signal generating means and the output of the D/A converting means, restoring it to a video signal, and outputting the video signal. .

(Function) The present invention is a transmission method for digitally transmitting a video signal that constitutes one frame using an odd number of scanning lines,
The transmission system detects the vertical and horizontal synchronization signals in the video signal to be transmitted, and also generates different predetermined digital patterns in synchronization with the odd and even scan lines of the video signal. A digital signal is used as a substitute for the signal, and the digital conversion output of the video signal to be transmitted is multiplexed onto this digital signal and transmitted.

On the other hand, the receiving system detects a digital signal in place of the synchronization signal from the received multiplexed signal, generates different synchronization detection signals for even and odd scanning lines, and uses these synchronization detection signals to detect the horizontal synchronization signal of the analog video signal. When a synchronization detection signal of an odd numbered scanning line is received continuously, a vertical synchronization signal of an analog video signal is generated, and the video signal component obtained by separating the received multiplexed signal is converted into an analog signal. Combine it with the output and send it back to the image fm (K).

That is, the present invention applies to the NTSC system, PAL system, SEC
In standard TV video signals such as AM and ItD TV, the number of horizontal scanning lines per frame is an odd number. (a digital signal substituted for a synchronization signal) is made into an alternating pattern of the number of lines, and when detecting the I1 synchronization signal and establishing frame synchronization, detecting parts that do not become an alternation pattern and establishing vertical synchronization. In the present invention, on the transmitting side, a predetermined pattern of digital synchronization information is added instead of the horizontal synchronization signal waveform, and one transmission frame is configured with a signal of one line (one horizontal scanning line). , the digital synchronization information is made different between odd and even lines in the video signal, and on the receiving side, the digital synchronization information on the odd lines and the digital synchronization information on the even lines are alternately detected to establish frame synchronization. However, since the number of lines is odd, there is only one place where the digital synchronization information of the odd numbered lines is continuous, so vertical synchronization is established and horizontal and vertical synchronization signal waveforms are reproduced. Restore the original video signal.Since it is like this,
Video signals can now be transmitted and received correctly with one synchronization signal, simplifying the circuit configuration.

(Example) An embodiment of the present invention will be described below with reference to FIG.

In the figure, reference numeral 1 denotes an A/D conversion section, which converts a manually input analog video signal into a digital signal. Reference numeral 2 denotes a video synchronization signal detection section, which detects a horizontal synchronization signal and a vertical synchronization signal from the manually inputted analog video signal. Reference numeral 3 denotes an 11 synchronization signal generating section, which generates 11 synchronization signals (digital patterns) for odd lines of the video signal and 11 synchronization signals for even lines based on the detected outputs of the horizontal synchronization signal and direct synchronization signal. be. Reference numeral 4 denotes a multiplexing section, which multiplexes the II synchronization 1= signal and the output signal of the A/D conversion section 1 and outputs the multiplexed signal. The above is the configuration of the transmission system.

Next, the configuration of the receiving system will be explained. The reception system includes 11 synchronization signal detection section 5, separation section 6, video synchronization signal generation section 7, switching section 8,
It consists of a D/A converter 9.

Of these, the II synchronization signal detection section 5 detects the 11 synchronization signal from the received multiplexed signal, and the separation section 6 separates the digital video signal from the received multiplexed signal. Here, the II synchronization signal protruding section 5 alternately detects the 11 synchronization signals on the odd lines and the 11 synchronization signals on the even lines to generate a horizontal synchronization signal detection output. In the case of signals, the number of lines per frame is odd, so the last line of one frame and the first line of the next frame are the II of the odd line.
A synchronization signal follows, and this is used to detect the frame break of the video signal and generate a vertical synchronization signal detection output to synchronize in the vertical direction.

The video synchronization signal generation section 7 receives these horizontal synchronization signal detection output and vertical synchronization signal detection output and generates a horizontal synchronization signal and a vertical synchronization signal for the video signal, and the switching section 8 receives the horizontal synchronization signal detection output and the vertical synchronization signal detection output. While receiving the horizontal synchronization signal detection output and the vertical synchronization signal detection output output from the video synchronization signal generation section 7,
During this period, the separation unit 6 side is selected and these horizontal synchronization signals, vertical synchronization signals, and digital video signals are
/A converter 9 selectively. The D/A converter 9 converts these horizontal synchronizing signals, vertical synchronizing signals, and digital video signals into analog signals, converts them into analog video signals, and outputs the analog video signals.

In such a configuration, in the transmission system, an analog video signal input manually is converted into a digital signal by an A/D converter, and a horizontal synchronization signal and a vertical synchronization signal are detected by a video synchronization signal detection unit 2. Ru. Then, upon receiving the detection outputs of these horizontal synchronization signals and vertical synchronization signals from the video synchronization signal detection section 2, the I1 synchronization signal generation section 3 generates 11 synchronization signals (digital patterns) for the odd lines.
and 11 synchronization signals (digital patterns) for even-numbered lines.

These 11 synchronization signals, the 11 synchronization signals for even lines, and the output signal of the A/D converter 1 are sent to a multiplexer 4, where they are multiplexed, and the frames are divided and transmitted.

On the other hand, on the receiving side, the transmission signal is received and the 11 synchronization signal detection unit detects the 11 synchronization signal, and the separation unit 6
to separate the digital video signals.

Here, the 11 synchronization signal detection section alternately detects the 11 synchronization signals on the odd lines and the I{sync signals on the even lines, but since the number of lines per frame of the video signal is an odd number, The last line of a frame and the first line of the next frame are followed by 11 synchronization f3 of odd lines, which makes it possible to know the frame division of the video signal and therefore establish vertical synchronization. can.

Therefore, using this, the video synchronization signal generating section 7 generates a horizontal synchronization signal and a vertical synchronization signal, and this signal and the digital video signal are selected by the switching section 8 to generate a digital video signal including the synchronization signal waveform. The D/A converter performs analog conversion to obtain the original video signal.

In this way, this device supports NTSC, PAL, and SE
Focusing on the fact that standard TV video signals such as CAM and IIDTV have an odd number of horizontal scanning lines per frame,
The synchronization signal has an alternating pattern of the number of lines, and when 11 synchronization signals are detected and frame synchronization is established, vertical synchronization is established by detecting areas where the alternating pattern does not occur.

Therefore, on the transmitting side, a digital pattern It synchronization signal is added in place of the horizontal synchronization signal waveform, and one transmission frame is configured with one line of signals. At this time, the 11 synchronization signals are made different between odd and even lines so that odd lines and even lines can be distinguished.

Then, on the receiving side, the 11 synchronization signals of the odd lines and the 11 synchronization signals of the even lines are detected alternately, thereby establishing frame synchronization. is an odd number, there is only one place where the 11 synchronization signals of the odd numbered lines are continuous, so this establishes vertical synchronization, creates both horizontal and vertical synchronization signal waveforms, and restores the original image. Restore the signal.

In this way, in this device, the video signal can be correctly reproduced with one synchronization detection circuit, and the circuit configuration can be simplified.

Note that the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope of the gist thereof. For example, the synchronization signal waveform may be a signal with a fixed pattern. Therefore, this pattern can be easily reproduced by storing it in a memory or the like and reading it out.

Further, in the above example, the synchronizing signal waveform was added in the digital section, but it is also possible to add it in the analog section. Also,
Video signals include NTSC, PAL, and SECA
In addition to the M method and IIDT'/, this method can be applied regardless of whether it is wireless or wired, as long as the number of lines per frame is an odd number.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to compress the time axis by using the synchronization signal waveform part in digital transmission of a video signal, and to multiplex other information such as an audio signal. In this case, synchronization can be established on the receiving side only by detecting the II synchronization signal, and the circuit configuration can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. 1... A/D conversion section, 2... Video synchronization signal detection section,
3... H synchronization signal generation section, 4... Multiplexing section, 5...
- II synchronization signal detection section, 6... Separation section, 7... Video synchronization signal generation section, 8... Switching section, 9... D/A conversion section.

Claims (2)

[Claims] (1) In a system that digitally transmits a video signal that constitutes one frame using an odd number of scanning lines, it receives the video signal to be transmitted, detects the vertical and horizontal synchronization signals in this video signal, and and synchronization signal generation means for generating different predetermined digital patterns in synchronization with the even-numbered scanning lines and outputting them as digital signals in place of the synchronization signal;
a transmitting system comprising a D conversion means, a multiplexing means for receiving, multiplexing, and transmitting each of these digital signals; and detecting a digital signal in place of the synchronization signal from the received multiplexed signal and converting it into an even number and an odd number. a synchronization signal detection means for generating a different synchronization detection signal for each scanning line; and a synchronization signal detection means for generating a horizontal synchronization signal of an analog video signal in response to the synchronization detection signal of the synchronization signal detection means, and continuously generating a synchronization detection signal of odd-numbered scanning lines. video synchronization signal generation means for generating a vertical synchronization signal of an analog video signal when received; separation means for separating the received multiplexed signal into each digital signal; A reception system comprising: D/A conversion means for converting into an analog signal; and means for synthesizing the output of the video synchronization signal generation means and the output of the D/A conversion means, restoring it to a video signal, and outputting the resultant signal; What is claimed is: 1. A video signal transmission device comprising: a video signal transmission device configured to establish horizontal synchronization and vertical synchronization of video signals by transmitting and receiving only horizontal synchronization components. (2) As a transmission system for digitally transmitting a video signal that constitutes one frame using an odd number of scanning lines, the transmission system detects vertical and horizontal synchronization signals in the video signal to be transmitted, and Different predetermined digital patterns are generated in synchronization with the odd-numbered scanning lines and even-numbered scanning lines of the signal, and are used as a digital signal in place of the synchronization signal, and the digital conversion output of the video signal to be transmitted is multiplexed with this and transmitted. At the same time,
The receiving system detects a digital signal in place of the synchronization signal from the received multiplexed signal, generates different synchronization detection signals for even and odd scanning lines, and generates a horizontal synchronization signal for the analog video signal from this synchronization detection signal. When synchronization detection signals of odd-numbered scanning lines are received continuously, a vertical synchronization signal of an analog video signal is generated, and these signals are converted into an analog signal conversion output of the video signal component obtained by separating the received multiplexed signal. A video signal transmission method characterized by combining and restoring a video signal.