Abstract:
A method and device for transmitting non-broadband signals using power lines as media is provided, whereby frequencies of numerous kinds of signals (including sounds, images, data information, etc.) are divided firstly, and then such signals are mixed by applying linear algebra to form a mixed transformed signal that is then coupled to an ordinary power line (such as an AC power line) or any of the transmission media, characterized in that time periods are used for dividing frequencies of signals, such that all frequencies of signals chosen fall into the scope of low bandwidths required and are linearly independent.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a method and device for signal transmission, and more particularly, the present invention pertains to a method and device for transmitting non-broadband signals using power lines as media, with the technology of mixing and separating a plurality of signals being the basis thereof.  
         [0003]     2. Description of the Related Art  
         [0004]     The technology of coupling carrier signals to power lines as signal transmission means between devices has already been applied to control systems of home appliances, yet since factors of high noise rate and signals susceptible to decay that are caused by the nature of power lines seriously affect the quality of communication. Therefore, the difficulties as to how to prevent signals from being interfered by other signals during signal transmission, and how to increase the capacity of signal transmission and efficiency for signal transmission are constantly required to be overcome.  
         [0005]     Based upon the prior art, WO 99/48218, which disclosed a power line carrier communication device, whereby a high-speed data processor is assembled with or engaged in the base unit of the power line carrier communication device, so as to speed up the transmission rate while signals become weak. The power line carrier communication device incorporates the power line carrier extension unit, so that as such device transmits data to an electronic equipment of an end user, the power line carrier extension unit enables such electronic equipment to receive or transmit data via standard telephone lines and AC power lines. However, it is highly complicated using means of power line carrier communication to transmit a plurality of signals simultaneously. Thus, a method and device for signal transmission using power lines as media can only be realized by using algorithm capable of mixing and separating a plurality of signals as the basis thereof.  
       SUMMARY OF THE INVENTION  
       [0006]     The object of the present invention is to provide a method for simultaneously transmitting a plurality of signals using power lines as media under non-broadband circumstance.  
         [0007]     The object of the present invention is to provide a device for simultaneously transmitting a plurality of signals using power lines as media under non-broadband circumstance.  
         [0008]     The object of the present invention is to provide a method for simultaneously transmitting a plurality of signals using power lines as media capable of increasing the speed of signal transmission and avoiding overload.  
         [0009]     The object of the present invention is to provide a device for simultaneously transmitting a plurality of signals using power lines as media capable of increasing the speed of signal transmission and avoiding overload.  
         [0010]     The object of the present invention is to provide a signal transmission method for avoiding signal interference.  
         [0011]     The object of the present invention is to provide a signal transmission device for avoiding signal interference.  
         [0012]     The object of the present invention is to provide a signal transmission method that is wire-free and thus saves costs.  
         [0013]     The object of the present invention is to provide a signal transmission device that is wire-free and thus saves costs.  
         [0014]     According to one preferred embodiment of the present invention, a method employs the art disclosed in U.S. Pat. No. 6,442,224, entitled “MIXING AND SEPARATING METHOD FOR A PLURALITY SIGNALS” (Taiwan Invention Patent No. 117048) as a basis, whereby frequencies of numerous kinds of signals (including sounds, images, data information, etc.) are divided firstly, then such signals are mixed by applying linear algebra to form a mixed transformed signal that is then coupled to an ordinary power line (such as AC power lines) or any of the transmission media, characterized in that time periods are used to divide frequencies of signals and all frequencies of signals chosen fall into the scope of low bandwidths required and are linearly independent. Thus, common media for transmitting signals can be used for transmitting summed mixing signals with low bandwidths. This kind of design not only increases the quantity of signals transmitted and the efficiency for transmission, but also can avoid network congestion.  
         [0015]     Further, the problem of signal interference can be avoided while large quantity of signals being transmitted via a single channel with an ordinary power line due to low bandwidth. As for inherent factors of high noise rate and signals susceptible to decay that are caused by the power lines, the present invention also employs the means of carriers to carry mixed transformed signals with single and low bandwidths, and then filters are used for extracting carriers, so as to separate and restore the plurality of signals. Therefore, the method and device of the present invention enabling the simultaneous transmission of the plurality of signals with power lines as media shall meet the requirements of industrial utility, novelty and inventive step. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings that are provided only for further elaboration without limiting or restricting the present invention, where:  
         [0017]      FIG. 1  shows a schematic architecture of an embodiment of the present invention with regarding to sound signal transmission;  
         [0018]      FIG. 2  shows a block diagram for a transmitting end with signal mixing and separating devices in one of the embodiments of the present invention; and  
         [0019]      FIG. 3  shows a block diagram for a receiving end with signal mixing and separating devices in one of the embodiments of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     The following is a detailed description of the best presently known modes of carrying out the inventions. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the inventions.  
         [0021]     According to the preferred embodiment of the present invention, a device for transmitting non-broadband signals using power lines as media based upon the technology of mixing and separating signals, employs a power line disposed between a transmitting end and a receiving end for transmitting and receiving a plurality of source signals, which can be sound signals, image signals, data signals and so forth, and those source signals are then mixed to be a mixed transformed signal with a low bandwidth, and then said mixed transformed signal is coupled, under the non-broadband condition, to a ordinary power line (such as an AC power line) or any other transmission medium for simultaneous transmission.  
         [0022]     The transmitting end comprises a transmitted signal processor and an interface circuit, wherein the transmitted signal processor is to couple with a power line via the interface circuit, such that the mixed transformed signal with the low bandwidth of the transmitted signal processor is coupled to the power line. The transmitted signal processor receives and transmits a plurality of source signals, and the transmission and reception of each source signal is processed by a signal transformation device and a signal separation device, such that a mixed transformed signal with a low bandwidth is formed by mixing and summing up a plurality of transformed signals according to the characteristics of linear independent coefficients and functions.  
         [0023]     Each receiving end thereof comprises a received signal processor and an interface circuit, wherein the received signal processor is to couple with a power line via the interface circuit, such that the mixed transformed signals with low bandwidths are coupled on the power line by the received signal processor. The received signal processor comprises multiple sets of signal transformation devices and signal separation devices and a selector. The received signal processor couples mixed transformed signals from the power line, and chooses, according to the selector, a set of the signal transformation device and the signal separation device so as to receive and correspond to one of the plurality of source signals. The signal transformation device and the signal separation device chosen are to form an independent equation according to linearly independent functions, with a plurality of transformed signals as unknown variables for solving simultaneous equations, so as to restore the corresponding source signals, thus enabling the receiving end and the transmitting end to receive and transmit signals mutually. It is further elaborated next regarding the method for mixing and separating a plurality of source signals between the transmitted signal processor and the received signal processor by using the art disclosed in Taiwan Invention Patent No. 117048 or U.S. Pat. No. 6,442,224 as a basis.  
         [0024]     The signal mixing method employed by the signal transformation device comprises the following steps: 
        firstly obtain n samples S i (t j ) (i=1, 2, . . . m; j=1, 2, . . . n) from m (m is a positive integer) source signals S i (t) (tε[T 0 ,T 1 ]; T 0 , T 1 εR in [T 0 ,T 1 ], where t is a time variable);        
 
         [0026]     Next a collection of coefficient functions { i a j (t), i=1, 2, . . . m; j=1, 2, . . . n} is chosen, and the coefficient functions  i a j (t) are rendered to be linearly independent in [T 0 ,T 1 ], and finally the transformed function  
           S   i   0     ⁡     (   t   )       =       ∑     j   =   1     n     ⁢     [         a   j           i         ⁡     (   t   )       ⁢       S   i     ⁡     (     t   j     )         ]           
 
 of S i (t) is obtained. Subsequently all the transformed functions S i   0 (t) are summed up to obtain  
         SM   ⁡     (   t   )       =       ∑     i   =   1     m     ⁢         S   i   0     ⁡     (   t   )       .           
 
 Therefore, after being mixed, SM(t) is then the mixed transformed signal suitable for a specific bandwidth. 
 
         [0029]     The method for separating signals by the signal separation device comprising the following steps: 
        m×n samples S i (t j ) (i=1, 2 , . . . m; j=1, 2, . . . n) are obtained from the mixed transformed signals SM(t), with each sample S i (t j ) being corresponding to the coefficient function  i a j (t);     m×n independent equations are obtained with S i (t j ) being the unknown variable by relied upon the characteristic of  i a j (t) mutually causing to be linearly independent in [T 0 ,T 1 ]; and     The S i (t j ) is obtained by solving the m×n independent equations via the means of solving simultaneous equations so as to restore each source signal S i (t).        
 
         [0033]     According to the present invention of a device or method for transmitting non-broadband signals using power lines as media, m source signals S i (t), wherein i=1,2, . . . , m, are transmitted between the transmitting end and the receiving end. Said method comprises the following steps: 
        m source signals S i (t) are dealt with at said transmitting end so as to generate a mixed transformed signal SM(t);     said mixed transformed signal SM(t) is coupled to a power line with a specific bandwidth;     said mixed transformed signal SM(t) is received from said power line; and     said mixed transformed signal SM(t) is sampled at the receiving end so as to selectively restore each said source signal S i (t). The signal transmission between the transmitting end and the receiving end is characterized in that:     n samples S i (t j ) (i=1, 2, . . . m; j=1, 2, . . . n) from m source signals S i (t) (tε[T 0 ,T 1 ]; T 0 , T 1 εR; t is a time variable) in [T 0 ,T 1 ] are obtained at said transmitting end; a collection of coefficient functions { i a j (t), i=1, 2 , . . . m; j=1, 2, . . . n} is chosen, and said coefficient functions  i a j (t) are rendered to be linearly independent in [T 0 ,T 1 ], and finally the transformed function  
           S   i   0     ⁡     (   t   )       =       ∑     j   =   1     n     ⁢     [         a   j           i         ⁡     (   t   )       ⁢       S   i     ⁡     (     t   j     )         ]           
 
 of S i (t) is obtained. Subsequently all the transformed functions S i   0 (t) are summed up to obtain  
           SM   ⁡     (   t   )       =       ∑     i   =   1     m     ⁢       S   i   0     ⁡     (   t   )           ;       
    said mixed transformed signals SM(t) are transmitted on said power line with a specific bandwidth; and     at said receiving end, m×n samples S i (t j ) are obtained from the mixed transformed signals SM(t), with each sample S i (t j ) being corresponding to the coefficient function  i a j (t); m×n independent equations are obtained with S i (t j ) being the unknown variable by relied upon the characteristic of  i a j (t) being linearly independent; S i (t j ) is obtained by solving the m×n independent equations via the means of solving simultaneous equations so as to restore each source signal S i (t).        
 
         [0042]      FIG. 1  is a schematic architecture of one embodiment of the present invention with regarding to sound signal transmission. Said embodiment of the present invention is a device for transmitting non-broad signals using power lines as media. Based upon said various signal mixing and separating techniques, a plurality of sound signals are transmitted and received between one transmitting end and a plurality of receiving ends. Signals transmitted between said transmitting end and receiving ends are formed into mixed transformed signals of low bandwidths, and then said signals are coupled to ordinary power lines, such as AC power lines, or any transmission media via an interface circuit with a specific low bandwidth, preferably with 4 KHz.  
         [0043]     In this embodiment, said transmitting end includes a signal mixing and separating device  11  for receiving and sending m sound signals, and an interface circuit  12  which serves to couple the mixed transformed signals generated by said signal mixing and separating device to a power line  16  with a specific low bandwidth, wherein various signal mixing and separating techniques are employed by said signal mixing and separating device  11  to treat the m sound signals; whereas said receiving end includes a signal mixing and separating device  13  for selectly receiving and sending one of the m sound signals, a telephone  15  for receiving and sending one of the m sound signals selected and treated by said signal mixing and separating device  13 , and an interface circuit  14  which serves to couple the mixed transformed signals generated by said signal mixing and separating device to the power line  16  with a specific low bandwidth, wherein various signal mixing and separating techniques are employed by said signal mixing and separating device  13  to select and treat one of the m sound signals.  
         [0044]      FIG. 2  shows a block diagram for the transmitting end with the signal mixing and separating devices in one of the embodiments of the present invention. Said transmitting end with the signal mixing and separating device  11  includes m sets of signal transformation devices  17  and signal separation devices  18  which serve to receive and send m sound signals respectively, and a signal mixing circuit  19  for mixing and summing up m transformed signals to form a mixed transformed signal. Said transmitting end with the signal mixing and separating device  11  realizes said various signal mixing and separating techniques by use of an integrator, differentiator, multiplier, adder and subtractor, A/D converter, D/A converter, operational amplifier and buffer.  
         [0045]      FIG. 3  shows a block diagram for the receiving end with the signal mixing and separating devices in one of the embodiments of the present invention. Said receiving end with the signal mixing and separating device  13  includes m sets of signal transformation devices  17  and signal separation devices  18  which serve to restore m sound signals respectively, a selector  20  to select one device from said m sets of signal transformation devices  17  and signal separation devices  18 , and a signal mixing circuit  19  to mix transformed signals to form a mixed transformed signal. Said receiving end with the signal mixing and separating device  13  realizes said various signal mixing and separating techniques by use of an integrator, differentiator, multiplier, adder and subtractor, A/D converter, D/A converter, operational amplifier and buffer.  
         [0046]     Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, those skilled in the art can easily understand that all kinds of alterations and changes can be made within the spirit and scope of the appended claims. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein.