Abstract:
A digital wireless transmitter is disclosed. The digital wireless transmitter includes an interface, used to receive an audio signal and/or a video signal, the digital wireless transmitter is pluggable into an electronic device via the interface; a digital modulator, coupled to the interface, the digital modulator is used to modulate the audio signal and/or the video signal into a digital television signal; and a RF front end circuit, coupled to the digital modulator, the RF front end circuit is used to transform the digital television signal to a RF signal on a predetermined band.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefit of Taiwan application serial no. 100204232, filed on Mar. 10, 2011. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a wireless transmitter and the system thereof, and more particularly to a wireless transmitter used to remotely display audio and/or video and the system thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    If someone wants to wirelessly transmit a screen from one device to another, such as from a laptop to a mobile phone or a remote television set, he/she may choose WiFi or UWB transmitter which is available for sale now. However, if the screen is chosen to be displayed on a home television set, it can&#39;t be because a home television set usually does not equip a WiFi or UWB receiver. As such, not only the WiFi or UWB transmitter but also the receiver should be bought together. That is really a big cost. 
         [0004]    As WiFi transmission technology is widely used on many electronic devices, the channels are too busy to transmit data quickly, so video and/or audio may not be displayed smoothly on the home television set. 
         [0005]    Moreover, UWB transmitter and receiver are very expensive because super high frequency element is used. The transmission distance is another issue for UWB transmitter. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Thus, the invention discloses a digital wireless transmitter and the system thereof. Users may receive audios and/or videos transmitted from the digital wireless transmitter by just using their own home television sets or set top boxes. 
         [0007]    One object of the invention is to provide a digital wireless transmitter, including an interface, used to receive an audio signal and/or a video signal, the digital wireless transmitter is pluggable into an electronic device via the interface; a digital modulator, coupled to the interface, the digital modulator is used to modulate the audio signal and/or the video signal into a digital television signal; and a RF front end circuit, coupled to the digital modulator, the RF front end circuit is used to transform the digital television signal to a RF signal on a predetermined band. 
         [0008]    Another object of the invention is to provide a digital wireless transmitter pluggable into an electronic device, including an audio interface, used to receive an audio signal; a video interface, used to receive a video signal; an audio encoder, coupled to the audio interface, the audio encoder is used to encode the audio signal and generate a encoded audio signal; a video encoder, coupled to the video interface, the video encoder is used to encode the video signal and generate a encoded video signal; a multiplexer, coupled to the audio encoder and the video encoder, the multiplexer is used to merge the encoded audio signal and the encoded video signal and generate a multiplexed signal; a digital modulator, coupled to the multiplexer, the digital modulator is used to modulate the multiplexed signal into a digital television signal; a RF front end circuit, coupled to the digital modulator, the RF front end circuit is used to transform the digital television signal to a RF signal on a predetermined band; and an antenna, coupled to the RF front end circuit, the antenna is used to radiate the RF signal on the predetermined band. 
         [0009]    Still another object of the invention is to provide a digital wireless system, including: an audio/video source, used to provide an audio signal and a video signal; a digital wireless transmitter, including: an interface, used to receive the audio signal and the video signal, the digital wireless transmitter is pluggable into an electronic device via the interface; a digital modulator, coupled to the interface, the digital modulator is used to modulate the audio signal and the video signal into a digital television signal; and a RF front end circuit, coupled to the digital modulator, the RF front end circuit is used to transform the digital television signal to a RF signal on a predetermined band; and a digital television set, used to receive the RF signal on the predetermined band. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1  is the first embodiment of the digital wireless system. 
           [0011]      FIG. 2  is the second embodiment of the digital wireless system. 
           [0012]      FIG. 3  is the third embodiment of the digital wireless system. 
           [0013]      FIG. 4  is the fourth embodiment of the digital wireless system. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The digital television system prevails over the traditional analog television system because of anti-noise ability. Many countries put much effort to develop their own digital television system recently, such as Advanced Television System Committee (ATSC) standard for pan-American; Digital Video Broadcasting-Terrestrial (DVB-T) standard for Euros; Integrated Service Digital Broadcasting-Terrestrial (ISDB-T) standard for Japan; and Digital Multimedia Broadcast-Terrestrial/Handheld (DMB-TH) standard for China. 
         [0015]    The invention focuses on a digital wireless transmitter and the system thereof. An audio and/or video signal can be transmitted to home televisions or set top boxes and displayed remotely. 
         [0016]      FIG. 1  illustrates a first embodiment of the invention. Please refer to  FIG. 1  which depicts a digital wireless system  1000 . The digital wireless system  1000  includes a computer  10 , a digital television set  20  and a digital wireless transmitter  30 . The digital wireless transmitter  30  is a peripheral device which includes an interface  310 , a digital modulator  312 , a RF front end circuit  314  and an antenna  316 . 
         [0017]    The computer  10  may be desktop PC, laptop, netbook, tablet PC, digital camera (DC) or digital video (DV). The digital wireless transmitter  30  couples to the computer  10  via the interface  310  and receives an audio signal and/or a video signal from the computer  10 . For example, if the computer  10  is equipped with an USB port (not shown in the  FIG. 1 ), the interface  310  may be designed to have a USB connector and a USB control chip; if the computer  10  is equipped with an 1394 port (not shown in the  FIG. 1 ), the interface  310  may be designed to have a 1394 connector and a 1394 control chip; if the computer  10  is equipped with an SDIO port (not shown in the  FIG. 1 ), the interface  310  may be designed to have a SDIO connector and a SDIO control chip; if the computer  10  is equipped with an PCI/PCI-e port (not shown in the  FIG. 1 ), the interface  310  may be designed to have a PCI/PCI-e connector and a PCI/PCI-e control chip; and if the computer  10  is equipped with an CardBus/ExpressCard port (not shown in the  FIG. 1 ), the interface  310  may be designed to have a CardBus/ExpressCard connector and a CardBus/ExpressCard control chip. After the digital wireless transmitter  30  is plugged into the port of the computer  10 , the computer  10  provides a transport stream (TS) signal containing the audio signal and/or the video signal to the digital modulator  312 . The digital modulator  312  modulates the audio signal and/or video signal into a digital television signal. The RF front end circuit  314  transforms the digital television signal to a RF signal on a predetermined band. And then, the RF signal is radiated via the antenna  316 . One skilled in the art would know the audio signal and the video signal can be recovered by a tuner, demodulator and decoder though these are not shown in the  FIG. 1 . 
         [0018]    As the description above, the digital modulator  312  modulates the audio signal and/or the video signal into a digital television signal. For example, if the digital television set  20  adopts ATSC standard, the digital modulator  312  modulates the audio signal and/or the video signal into a 8 Vestigial Side Band (8VSB) signal whose bandwidth is 6 MHz; if the digital television set  20  adopts DVB-T standard, the digital modulator  312  modulates the audio signal and/or the video signal into a Orthogonal Frequency Division Multiplexing (OFDM) signal whose bandwidth is 6, 7 or 8 MHz; if the digital television set  20  adopts ISDB-T standard, the digital modulator  312  modulates the audio signal and/or the video signal into a OFDM signal whose bandwidth is 6 MHz; and if the digital television set  20  adopts DMB-T/H standard, the digital modulator  312  modulates the audio signal and/or the video signal into a Time Domain Synchronous Orthogonal Frequency Division Multiplexing (TDS-OFDM) signal whose bandwidth is 8 MHz. 
         [0019]    It should be noted that the first embodiment omits the descriptions about converting the audio signal and/or video signal to the transport stream (TS) signal by the computer  10 . However, one skilled in the art would know the audio signal and/or video signal must be converted to a MPEG2 or H.264 stream signal before being modulated. 
         [0020]    Moreover, it should be noted that though the first embodiment is illustrated based on a digital television set  20 , it can be applied to an analog television set or a project with a set top box as well. 
         [0021]    Next,  FIG. 2  illustrates a second embodiment of the invention. Please refer to  FIG. 2  which depicts a digital wireless system  2000 . The digital wireless system  2000  includes an audio/video source  40  and a digital wireless transmitter  50 . The audio/video source  40  includes an audio source  352  and a video source  354 . The digital wireless transmitter  50  includes an audio interface  356 , a video interface  358 , an audio encoder  360 , a video encoder  362 , an information-adding element  364 , a multiplexer  366 , a digital modulator  312 , a RF front end circuit  314  and an antenna  316 . 
         [0022]    The audio/video source  40  is a blue ray DVD player, a surveillance device, a fixed camera, a handheld camera, a nanny camera, a digital camera, a desktop PC, a laptop, a netbook, a multimedia player, a gamer, a smart phone, a tablet PC or an e-book reader. The audio source and the video source output raw data containing an audio signal and a video signal. The digital wireless transmitter  50  couples to the audio/video source and receives the audio signal and the video signal via the audio interface  352  and the video interface  354 . For example, if the audio/video source  40  is equipped with a VGA port and an audio-out port (not shown in the  FIG. 2 ), the audio interface  352  and the video interface  354  may be designed to have a VGA connector, an audio connector, and a corresponding audio/video control chip; if the audio/video source  40  is equipped with a CCIR-601/CCIR-656/DVI/HDMI port and an audio-out port (not shown in the  FIG. 2 ), the audio interface  352  and the video interface  354  may be designed to have a CCIR-601/CCIR-656/DVI/HDMI connector, an audio connector, and a corresponding audio/video control chip; and if the audio/video source  40  is equipped with a composite/S-video/component port and an audio-out port (not shown in the  FIG. 2 ), the audio interface  352  and the video interface  354  may be designed to have a composite/S-video/component connector, an audio connector, and a corresponding audio/video control chip. 
         [0023]    After the digital wireless transmitter  50  is plugged into the audio/video source  40 , an audio signal sent from the audio/video source  40  is encoded by the audio encoder  360  and a video signal sent from the audio/video source  40  is encoded by the video encoder  362 , and then both of them are transferred to the multiplexer  366 . The information-adding element may also input a service information (SI) and a program specific information (PSI) to the multiplexer  366 . 
         [0024]    It should be noted that the second embodiment omits the descriptions about analog-digital converting issue. However, one skilled in the art would know an audio signal and/or a video signal should be converted to be digital before being encoded if the audio and/or the video signal is analog. 
         [0025]    The multiplexer  366  merges the encoded audio signal, the encoded video signal and the information wanted to be added. The merged signal, i.e. a transport stream (TS) signal, is transferred to the digital modulator  312 . The digital modulator  312  modulates the merged signal into a digital television signal. The RF front end circuit  314  transforms the digital television signal to a RF signal on a predetermined band. And then, the RF signal is radiated via the antenna  316 . 
         [0026]      FIG. 3  illustrates a third embodiment of the invention. Please refer to  FIG. 3  which depicts a digital wireless system  3000 . The digital wireless system  3000  includes a digital wireless transmitter  100  and a digital television set  20 . The digital wireless transmitter  100  includes an audio/video source  80  and a digital wireless transmission element  90 . The digital wireless transmission element  90  includes a digital modulator  312 , a RF front end circuit  314  and an antenna  316 . 
         [0027]    The digital wireless transmitter  100  may be a desktop PC, laptop, netbook, tablet PC, digital camera (DC), digital video (DV), blue ray DVD player, multimedia player, gamer, feature phone, smart phone, e-book reader or digital television repeater. A transport stream (TS) signal containing an audio signal and/or a video signal sent from the audio/video source  80  is transferred to the digital modulator  312 . The digital modulator  312  modulates the transport stream (TS) signal into a digital television signal. The RF front end circuit  314  transforms the digital television signal to a RF signal on a predetermined band. And then, the RF signal is radiated via the antenna  316 . The digital television set  20  receives the RF signal radiated from the digital wireless transmitter  90 , and then the audio signal and the video signal can be recovered by a tuner, demodulator and decoder though these are not shown in the  FIG. 3 . 
         [0028]    It should be noted that the third embodiment omits the descriptions about converting the audio signal and/or video signal to the transport stream (TS) signal by the computer  10 . However, one skilled in the art would know the audio signal and/or video signal must be converted to a MPEG2 or H.264 stream signal before being modulated. 
         [0029]    Moreover, it should be noted that though the third embodiment is illustrated based on a digital television set  20 , it can be applied to an analog television set or a project with a set top box as well. 
         [0030]      FIG. 4  illustrates a fourth embodiment of the invention. Please refer to  FIG. 4  which depicts a digital wireless system  4000 . The digital wireless system  4000  includes a digital wireless transmitter  200  and a digital television set  20 . The digital wireless transmitter  200  includes an audio/video source  120  and a digital wireless transmission element  110 . The digital wireless transmission element  110  includes an audio/video encoder  332 , a digital modulator  312 , a RF front end circuit  314  and an antenna  316 . 
         [0031]    The digital wireless transmitter  200  may be a desktop PC, laptop, netbook, tablet PC, digital camera (DC), digital video (DV), blue ray DVD player, multimedia player, gamer, feature phone, smart phone or e-book reader. An audio signal and/or a video signal sent from the audio/video source  120  are transferred to the audio/video encoder  332 . The audio/video encoder  332  encodes the audio signal and/or video signal into a MPEG2 or H.264 format and generates a transport stream (TS) signal. The transport stream (TS) signal is then transferred to the digital modulator  312 . The digital modulator  312  modulates the transport stream (TS) signal into an ATSC, DVB-T, ISDB-T or DMB-TH television signal. The RF front end circuit  314  transforms the ATSC, DVB-T, ISDB-T or DMB-TH television signal to a RF signal on a predetermined band. And then, the RF signal is radiated via the antenna  316 . The digital television set  20  receives the RF signal radiated from the digital wireless transmitter  110 , and then the audio signal and the video signal can be recovered by a tuner, demodulator and decoder though these are not shown in the  FIG. 4 . 
         [0032]    The details of the audio/video encoder  332  can be found in the second embodiment and is omitted here. 
         [0033]    Besides, it should be noted that though the fourth embodiment is illustrated based on a digital television set  20 , it can be applied to an analog television set or a project with a set top box as well. 
         [0034]    Based on the descriptions above, the embodiments may have a lot of applications, such as audio/video sharing, brief reports meeting, surveillance monitoring, babies monitoring, elders monitoring, wireless doorbell, and so on. 
         [0035]    Although the present invention has been described with reference to the above embodiments, it will be apparent to one of the ordinary skill in the art that modifications to the described embodiment may be made without departing from the spirit of the invention. Accordingly, the scope of the invention will be defined by the attached claims not by the above detailed descriptions.