Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Signal transmission system

Signal transmission system description/claims

This application is a continuation application of U.S. patent application Ser. No. 10/088,468, (U.S. Patent Publication No. US2002163970) filed Jun. 11, 2002 entitled, “Signal Transmission System,” incorporated herein by reference, which is a national stage application under 35 U.S.C. §371 of PCT/JP01/06340 filed Jul. 23, 2001 entitled, “Signal Transmission System,” incorporated herein by reference, which claims priority to Japanese Patent Application No. 2000-220751 filed Jul. 21, 2000 entitled, “Signal Transmission System.” Priority of each of the above applications is claimed.

The present invention relates to a signal transmission system for transmitting picture signals and, more particularly, to a signal transmission system in which hardware configurations of the video signal transmitting end and receiving end can be simplified.

A prior art example will be described with reference to FIG. 17. FIG. 17 is a block diagram illustrating the configuration of a conventional signal transmission system.

In FIG. 17, reference numeral 1701 denotes a video signal output unit (transmitting end) such as a STB (Set-top box), which outputs a video signal. Numeral 1702 denotes an MPEG decoder, which receives digital broadcasting and outputs baseband Y color-difference signals. Numeral 1703 denotes a signal conversion circuit, which converts the Y color-difference signals into RGB signals. Numeral 1704 denotes a transmission path encoding circuit, which encodes the signals converted by the signal conversion circuit 1703 into signals in formats suited to the transmission path. Numeral 1705 denotes a display unit (receiving end) such as a TV monitor. Numeral 1706 denotes a transmission path decoding circuit, which decodes the signals encoded by the transmission path encoding circuit 1704. Numeral 1707 denotes a signal conversion circuit, which converts the RGB signals outputted from the transmission path decoding circuit 1706 into YPBPR signals. Numeral 1708 denotes a Y processing circuit, which processes luminance signals Y out of the output from the signal conversion circuit 1707. Numeral 1709 denotes a chrominance processing circuit, which processes chrominance signals out of the output from the signal conversion circuit 1707. Numeral 1710 denotes a signal conversion circuit, which receives the outputs from the Y processing circuit 1708 and the chrominance processing circuit 1709 and converts the Y color-difference signals into the RGB signals. Numeral 1711 denotes a display device, which receives the output from the signal conversion circuit 1710 and outputs it to a LCD or CRT.

An operation of the so-configured signal transmission system will be described.

The MPEG decoder 1702 receives digital broadcasting and outputs baseband video signals. As the data format of the MPEG is based on Y color-difference signals, the output here is YPBPR, or YUV, or YCbCr. Further, this signal must be converted into RGB signals to encode it adaptively to a transmission path, and thus the Y color-difference signals are converted into RGB signals by the signal conversion circuit 1703. The converted RGB signals are encoded into signal forms suited to the transmission path by the transmission path encoding circuit 1704.

On the other hand, on the TV monitor 1705 side, the transmission path decoding circuit 1706 receives the signals encoded by the transmission path encoding circuit 1704 and generates the original RGB signals. The RGB signals are converted into the YPBPR of the Y color-difference signals by the signal conversion circuit 1707. Here, to perform independent processing on the TV monitor 1705 side, the Y signals are processed by the Y processing circuit 1708, and the chrominance signals PBPR are enhanced by the chrominance processing circuit 1709, respectively, and these signals are outputted. The enhanced and outputted Y color-difference signals are converted into the RGB signals by the signal conversion circuit 1710 so as to be outputted to the final display device 1711. The display device 1711 outputs the RGB signals which have been outputted from the signal conversion circuit 1710, thereby to perform display.

However, in the above-described conventional signal transmission system, since the transmission path encoding is performed on the RGB signals, the output from the MPEG decoder is once converted into the RGB signals, encoded, and transmitted through the transmission path and, thereafter, the RGB signals must be converted into the YPBPR to perform signal processing again on the monitor side and, further, the Y color-difference signals must be converted into the RGB signals once again to output the RGB signals to the final display device, resulting in a drawback of requiring a lot of hardware.

The present invention is made to solve the above-mentioned problems and has for its object to provide a signal transmission system in which hardware configurations of the video signal transmitting end and receiving end can be simplified.

According to one embodiment of the present invention, there is provided a signal transmission system for transmitting a video signal, comprising: a signal transmission unit including; a decoder which receives digital broadcasting and outputs a luminance signal and two color difference signals, and an encoding circuit which encodes the luminance signal and the respective color difference signals into signal forms suited to a transmission path, and transmits the encoded signals; and a signal reception unit including; a decoding circuit which receives the encoded luminance signal and respective color difference signals, and decodes these signals, a luminance signal processing circuit which processes the decoded luminance signal, a color difference signal processing circuit which processes the respective decoded color difference signals, and a signal conversion circuit which converts the luminance signal outputted from the luminance signal processing circuit and the respective color difference signals outputted from the color difference signal processing circuit into RGB signals.

Therefore, it is possible to realize a signal transmission system in which hardware configurations at the video signal transmitting end and receiving end can be simplified.

According to a second embodiment of the present invention, there is provided a signal transmission system for transmitting a video signal through a transmission path, comprising: a signal transmission unit including; a decoder which receives digital broadcasting and outputs a luminance signal and two color difference signals, a time division multiplexing circuit which sub-samples the two color difference signals to signals with half pixel rates, subjects the signals to time division multiplexing, and outputs a multiplexed signal, and an encoding circuit which encodes the luminance signal and the multiplexed signal into signal forms suited to a transmission path, and transmits the encoded signals; and a signal reception unit including; a decoding circuit which receives the encoded luminance signal and multiplexed signal, and decodes these signals, a demultiplexing circuit which demultiplexes the decoded multiplexed signal into the original two color difference signals, a luminance signal processing circuit which processes the decoded luminance signal, a color difference signal processing circuit which processes the respective color difference signals demultiplexed, and a signal conversion circuit which converts the luminance signal outputted from the luminance signal processing circuit and the respective color difference signals outputted from the color difference signal processing circuit into RGB signals.

Since two color difference signals are multiplexed and transmitted, only two transmission paths are required while three transmission paths are required in the conventional system, resulting in a signal transmission system in which hardware configurations at the video signal transmitting end and receiving end can be simplified.

According to a third embodiment of the present invention, there is provided a signal transmission system for transmitting a video signal and an audio signal, comprising: a signal transmission unit including; an MPEG decoder which receives digital broadcasting and outputs the video/audio signal, an output interface which outputs the video/sound signal that has been outputted from the MPEG decoder, an 12C controller which outputs an 12C (Inter IC control) signal, a CPU which controls the whole unit, and a program ROM which stores an operation program of the CPU; and a signal reception unit including; an input interface which receives the video/audio signal from the signal transmission unit, a device interface which converts the video/audio signal into a video image and a sound, a video/audio output device which outputs the video image and the sound outputted from the device interface, to the outside, and an 12C controller which has a ROM table in which information relating to performance of the signal reception unit is stored, receives an 12C signal from the signal transmission unit, and outputs the information stored in the ROM table to the signal transmission unit according to a request from the signal transmission unit.

Therefore, the signal transmission unit can be previously informed of the performance of the signal reception unit, and signal transmission can be performed on the basis of the performance of the signal reception unit without transmitting a signal at a rate which cannot be scanned on the signal reception unit side as in the conventional system, thereby avoiding such a problem that no video image is displayed or no sound is outputted at the signal reception side.

According to a fourth embodiment of the present invention, in the signal transmission system as defined in embodiment 3, the ROM table stores information relating to resolution of a video image that can be outputted from the video/audio output device.

Therefore, the signal transmission unit can be previously informed of the resolution of a video image that can be outputted from the signal reception unit, thereby realizing a signal transmission system which can avoid such a problem that no video image is displayed.

• Provisional Patent
• Utility Patent

• What Is a Patent?
• What Is a Trademark or Servicemark?
• What Is a Copyright?
• Patent Laws