Abstract:
A transmission device having optical fiber high definition digital audio-video data interface (HDMI/DVI/UDI), in which optical fiber is utilized as the physical connection for the logical channels of the transmission device, and is used to carry images, voices and auxiliary data of the logic channels. For the half-duplex transmission mode utilized by the display data channel, the reverse unit, the serial unit, and the multi-serial unit are properly arranged, thus fulfilling the DC balance requirement of optical fiber transmission, and resolving the lower tolerance rate shortcomings of the I2C bus specification of display data channel (DDC) and the customer electronics control (CEC) channel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 095124522 filed in Taiwan, R.O.C. on Jul. 5, 2006, the entire contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to a high definition digital audio-video data interface, and in particular, to a high definition digital audio-video data transmission device utilizing optical fiber as the transmission medium. 
   2. Related Art 
   In general, the high definition digital audio-video data interface includes a High Definition Multimedia Interface (HDMI), a Digital Visual Interface (DVI), and a forthcoming Unified Display Interface (UDI). Among them, the High Definition Multimedia Interface (HDMI) is utilized to integrate and standardize the transmission specification of the signals coming from the audio and video sources, so that in the design of a high definition digital audio-video system, the DVI is used as a basis in providing wider transmission bandwidth and a much more miniaturized connector. As such, only one single cable is required to transmit the uncompressed audio signal and high definition video signal, thus simplifying the installation of the audio-video system, and further raising the audio and video signals transmission quality. In this respect, the UDI is used as a PC digital display interface standard in compatible with the standard of HDTV signals. It is now replacing the gradually out-dated and phasing-out Video Graphic Array (VGA) analog standard, and thus in compatible with the DVI and the HDMI. 
   In this respect, the HDMI is taken as an example. To improve the performance of the transmission specification, a Transmission Minimized Differential Signaling (TMDS) coding is utilized by the HDMI. In general, TMDS is provided with a color data of three original colors (RGB)/intensity aberration (YPbPr) and a serial transmission loop of four channels (a connection) including a clock pulse channel. The respective channel utilizes the low amplitude differential transmission having 50 Ω terminal impedance and 0.15V voltage difference. The maximum transmission speed of the respective channel is 1.65 Gbps, thus ensuring the connection having transmission speed of 5 Gbps. 
   In addition, the HDMI is further provided with a support for the High Bandwidth Digital Content Protection (HDCP) mechanism, which is a kind of agreement reached and agreed upon jointly by the movie and program producers and the TV program transmission provider for protecting the intellectual property rights of the movie and TV programs, hereby preventing the illegal duplication of digital signal and image data. Meanwhile, the HDMI is used to provide better Display Data Channel (DDC) that is utilized to read the Extended Display Identification Data (EDID) indicating the displaying capability such as the resolution of the reception device. As such, password verification is performed between the transmission and reception device of the HDCP mechanism for the signals by making use of DDC, so that the transmission device and the reception device may verify each other at a predetermined time interval. In case that the verification fails, then the audio-video signals transmission is terminated immediately to protect the contents of the signals. In the signal transmission making used of HDMI, the transmission of Consumer Electronics Control (CEC) may optionally be utilized. Presently, in Europe, the audio-video equipment of communication habitually utilizes a cross-system remote-control transmission protocol called AV.Link, and in this connection, HDMI may be utilized in support of this standard protocol, thus achieving the control of a plurality of audio-video devices through a single remote controller. 
   For a more detailed description of the above-mentioned system, refer to  FIG. 1 .  FIG. 1  is a schematic diagram of a framework of a transmission/reception system having a HDMI according to the prior art. As shown in  FIG. 1 , the transmission/reception system includes a transmission device  10  and a reception device  11  both having HDMI, with the former having a transmission unit  101 , and the latter having a reception unit  111 . In the transmission device  10  having HDMI, the audio-video data  601  to  603  are transmitted to the reception device  11  having HDMI through the transmission unit  101 , and is received by the reception unit  111 . The logic channels carrying these data are the first data channel  901 , the second data channel  902 , and the third data channel  903 . In addition, a clock pulse channel  904  is responsible for transmitting a video pixel clock  604  to the reception unit  111 , the frequency of which is utilized as a reference frequency for the return data. The above-mentioned four logic channels are operated in a simplex transmission mode, namely, they are used to carry only the data transmitted from the transmission unit  101 , and received by the reception unit  111 . 
   Moreover, the system is further provided with a DDC  905  and a Consumer Electronics Control (CEC) channel  906 , that are used to read the Extended Display Identification Data (EDID) indicating the display capability such as the resolution of the reception device  11 . In general, the DDC  905  is a logic channel, with its transmission specification in compatible with that of I2C Bus, and is usually utilized as a system management bus, including a Serial Data Line (SDA) and a Serial Clock Line (SCL), and are used to transmit the identification data of the reception device  11  and the reference clock pulses between the devices. Usually, the DDC  905  is operated in a half-duplex transmission mode, namely, both the transmission device  10  and the reception device  11  having HDMI may proceed with data transmission in both directions. However, at any one particular time interval, data may only be transmitted from the device on one side and received by the device on the other side. 
   In the conventional transmission/reception system having HDMI, the above-mentioned channels are realized by copper wires to achieve physical connection. However, for the application of this kind of copper wire, the major drawback is that it is susceptible to electromagnetic interference, mainly due to the limited bandwidth of the copper wire, and this kind of drawback constitutes an obstacle in the development of wider bandwidth transmission interface. Furthermore, usually, the signals transmitted in the copper wire are susceptible to power loss, so that the length of the transmission wire used for high definition multimedia interface may only reach 15 m at most. In the invention, optical fiber is used to replace copper wire to achieve physical connection in the framework of conventional transmission/reception system having HDMI, DVI, and UDI, thus overcoming and improving the shortcomings of the prior art utilizing copper wire. 
   SUMMARY OF THE INVENTION 
   In order to overcome the problems and shortcomings of the prior art, the present invention discloses a transmission device having optical fiber high definition digital audio-video data interface (including HDMI/DVI/UDI), wherein optical fiber is used to replace the conventional copper wire, thus serving as a transmission medium of a high definition digital audio-video data interface, by making use of its characteristics of no electromagnetic interference, high transmission speed, and low transmission power loss. 
   In the transmission and reception device having optical fiber high definition digital audio-video data interface as disclosed by the present invention, optical fiber is utilized as the physical connection wire for the logic channels of the high definition digital audio-video data interface. Wherein, the logic channels include a first data channel, a second data channel, a third data channel, a clock pulse channel, a display data channel, and a customer electronics control channel. In the present invention, more than one logic channels are arranged into at least an optical fiber, so that the data of the display data channel and the customer electronics control channel are optical-coupled to other logic channels. Moreover, for the half-duplex transmission mode utilized by the display data channel, a reverse unit, a serial unit, and a multi-serial unit are properly arranged, thus fulfilling the DC balance requirement of optical fiber transmission, and resolving the lower tolerance rate shortcomings of the I2C bus specification of DDC and the CEC channel. 
   Further scope of applicability of the invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will become more fully understood from the detailed description given hereinbelow for illustration only, and thus is not limitative of the invention, and wherein: 
       FIG. 1  is a schematic diagram of a framework of a transmission/reception system having High Definition Multimedia Interface (HDMI) according to the prior art; 
       FIG. 2  is a schematic diagram of a framework for a transmission/reception system having optical fiber high definition digital audio-video data interface according an embodiment of the invention; 
       FIG. 3A  is a schematic diagram of the structure of a dual transmitter optical sub-assembly according to one embodiment of the invention; 
       FIG. 3B  is a schematic diagram of the structure of a dual transmitter optical sub-assembly according to another embodiment of the invention; 
       FIG. 4A  is a schematic diagram of the framework of the transmission module of the first display data channel according to one embodiment of the invention; and 
       FIG. 4B  is a schematic diagram of the framework of the transmission module of the second display data channel according to another embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The purpose, construction, features, and functions of the invention can be appreciated and understood more thoroughly through the following detailed description with reference to the attached drawings. 
   As shown in  FIG. 2 , it is a schematic diagram of a framework for a transmission/reception system having optical fiber high definition digital audio-video data interface (including HDMI/DVI/UDI) according an embodiment of the present invention. As shown in  FIG. 2 , the transmission/reception system includes a first transmission device  100  having high definition digital audio-video data interface, and a second transmission device  110  having high definition digital audio-video data interface, with the former having a transmission unit  101 , and the latter having a reception unit  111 . Wherein, a light emitting unit  201  and a light reception unit  211  are also provided. The light emitting unit  201  is arranged in the first transmission device  100  having high definition digital audio-video data interface, and is used to transmit data on the logic channels of a first data channel  901 , a second data channel  902 , a third data channel  903 , and a clock pulse channel  904 , in a form of light to a second transmission device  110  having high definition digital audio-video data interface through optical fiber  20 . Wherein, the light reception unit  211  is used to receive these data. In such a structure, the light emitting unit  201  is connected to the light reception unit  211  through the optical fiber  20 , hereby realizing data transmission. 
   In a real embodiment of the present invention, the light emitting unit  201  is composed of a plurality of Transmitter Optical Sub-Assembly (TOSA), with one logic channel corresponding to a TOSA; or, alternatively, it is composed of a plurality of Dual Transmitter Optical Sub-Assembly (DTOSA), with two logic channels corresponding to a DTOSA. Furthermore, the wavelengths of the two lights emitted by the a DTOSA are different, that may be selected from any two of the following: 650 nm, 855 nm, 1310 nm, and 1550 nm etc., so that the light signals converted from signals on different logic channels can be transmitted on an optical fiber without interfering each other. 
   Next, refer to  FIG. 3A  for a schematic diagram of the structure of the DTOSA according to an embodiment of the present invention. As shown in  FIG. 3A , the DTOSA according to an embodiment of the present invention is composed of: two light emitters  250 ,  251 , and a light filter  252 . Wherein, the wavelengths of the lights emitted by the two light emitters  250  and  251  are 1310 nm and 1550 nm respectively, which are taken as an example for explanation purpose. In this respect, the light emitter can be a laser or light-emitting-diode (LED). The film coated on the surface of light filter  252  is used to allow the passage of light of wavelength 1310 nm, however, reflect the light of wavelength 1550 nm. As such, when the two light emitters  250 , 251  emit lights, the signals carried by the light can be transmitted synchronously into the optical fiber  20 , thus achieving the purpose of the real embodiment of converting the signals on the logic channel into light signals. Alternatively, another way of achieving a real embodiment is to make a transmitter optical sub-assembly (TOSA) correspond to a logic channel, then convert the signals on the respective logic channels into light signals, and finally couple the light signals into an optical fiber by making use of an optical coupler/splitter. Naturally, the light signals transmitted in the same optical fiber can be of different wavelengths. 
   Furthermore, the light reception unit  211  can be composed of a plurality of Receiver Optical Sub-Assembly (ROSA), with a logic channel corresponding to a ROSA. Or, alternatively, the light reception unit  211  can be composed of a plurality of Dual Receiver Optical Sub-Assembly (DROSA), with two logic channels corresponding to a DROSA. As shown in  FIG. 3B , the DROSA is composed of two light receivers  260 ,  261  and a light filter  262 . Its principle of operation is the same as that of the DTOSA, thus it will not be repeated here for brevity. 
   Moreover, in the above description, the data on the various logic channels are transmitted/received in a Wavelength Division Multiplexing (WDM) manner, or Dense Wavelength Division Multiplexing (DWDM) manner. The optical fiber  20  utilized can be the Single-Mode Fiber (SMF) of wavelength 1310 nm or 1550 nm, or the Multi-Mode Fiber (MMF) of wavelength 850 nm or 1300 nm. 
   In the real embodiment of the present invention, the data on a display data channel  905  and on a consumer electronics control channel  906  can be physically linked through a conventional copper wire or an optical fiber. As shown in  FIG. 2 , in a first transmission device  100  having high definition digital audio-video data interface, a transmission module  202  of the first display data channel is utilized to transmit the data of a display data channel  905  and a consumer electronics control  906  in a form of light signals through an optical fiber  20 , and a first light coupler/splitter unit  203  is used to optical-couple data of the light emitting unit  201  and data of the transmission module  202  of the first display data channel, and then the optical-coupled data are transmitted to the second transmission device  110  having high definition digital audio-video data interface. 
   In the second transmission device  110  having high definition digital audio-video data interface, a second light coupler/splitter unit  213  is used to receive the data transmitted to the light reception unit  211  and a transmission module  212  of the second display data channel. 
   In addition, the transmission module  212  of the second display data channel is utilized to receive in an optical manner the data of a display data channel  905  and a consumer electronics control channel  906  through the optical fiber  20 . In the process of data transmission, all the logic channels except the display data channel  905  are operated in a simplex transmission mode. As such, only the transmission module  212  of the second display data channel is utilized to transmit the data of a display data channel  905  through the optical fiber  20  to the first transmission device  100  having high definition digital audio-video data interface by making use of the second light coupler/splitter unit  213 . 
   In the first transmission device  100  having high definition digital audio-video data interface, the first light coupler/splitter unit  203  is used to receive the data transmitted to the transmission module  202  of the first display data channel from the transmission module  212  of the second display data channel. 
   Subsequently, refer to  FIGS. 4A and 4B  for a schematic diagram of the framework of the transmission module  202  of the first display data channel according to an embodiment of the present invention, and a schematic diagram of the framework of the transmission module  212  of the second display data channel according to an embodiment of the present invention respectively. 
   As shown in  FIG. 4A , in the transmission module  202  of the first display data channel, the data on Serial Data Line (SDA) and Serial Clock Line (SCL) of the display data channel  905  and on Customer Electronics Control (CEC) channel  906  are reverse processed into the first reverse data by making use of a first reverse unit  301 , namely, the binary bits “1” and “0” are exchanged with each other, then the reversed data are input into the first serial unit  302  together with the un-reversed first un-reversed data, so that in the same data, there exist the un-reversed bits and the corresponding reversed bits, as such the numbers of bits “0” and “1” are the same in the data contents, thus in compatible with the requirement of DC balance in optical fiber data transmission. Therefore, in decoding the received data in a second transmission device  110  having high definition digital audio-video data interface, the received data can be read and correctly obtained by fetching only the reversed data or the un-reversed data. In the real embodiment of the present invention, for the proper operations of the SDA, SCL and CEC channel  906 , a plurality of fist reverse units  301  are utilized. 
   Next, the first serial unit  302  is used to process the input first reverse data and the first un-reversed data into the first serial data and output them to the first light transmission/reception unit  304 . Then, the first light transmission/reception unit  304  is used to transmit and output the input first serial data in a form of light to the first optical coupler/splitter  203  for coupling the light emitting unit  201 . 
   Subsequently, the first serial unit  302  receives the data input from the first optical coupler/splitter  203 , and outputs the received data to a first de-serialized unit  303 . The first de-serialized unit  303  is then utilized to perform de-serialization processing of the data on the display data channel  905  and the customer electronics control channel  906  received from the second transmission device  110  having high definition digital audio-video data interface, thus obtaining the SDA and SCL of the display data channel  905  and on CEC channel  906  respectively. 
   In addition, as shown in  FIG. 4B , in the transmission module  212  of the second display data channel, the data on SDA and SCL of the display data channel  905  and on CEC channel  906  are reverse processed into the second reverse data by making use of a second reverse unit  311 , then the reversed data are input into the second serial unit  312  together with the un-reversed second un-reversed data. In the real embodiment of the present invention, for the proper operations of the SDA, SCL and CEC channel  906 , a plurality of second reverse units  311  are utilized. 
   Moreover, the second serial unit  312  is used to process the input second reverse data and the second un-reversed data into a second serial data and output them to the second light transmission/reception unit  314 . Then, the second light transmission/reception unit  314  is used to transmit and output the input second serial data in a form of light to the second optical coupler/splitter  213 . 
   Finally, the second serial unit  312  may receive the data input from the second optical coupler/splitter  213 , and outputs the received data to a second de-serialized unit  313 . The second de-serialized unit  313  is then utilized to perform de-serialization processing of the data on the display data channel  905  and the customer electronics control channel  906  received from the first transmission device  100  having high definition digital audio-video data interface, thus obtaining the data on SDA and SCL of the display data channel  905  and on CEC channel  906 . 
   In the real embodiment of the present invention, the first light transmission/reception unit  304 , and the second light transmission/reception unit  314  are bi-directional optical sub-assemblies (BOSA) respectively. 
   The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.