WO2008048051A1

WO2008048051A1 - Dmb receiver for changing service frequency

Info

Publication number: WO2008048051A1
Application number: PCT/KR2007/005100
Authority: WO
Inventors: Jong-Boo Kim; Keun-Do Kim
Original assignee: Park, Yong-Woon
Priority date: 2006-10-18
Filing date: 2007-10-18
Publication date: 2008-04-24
Also published as: KR100845523B1; KR20080035196A

Abstract

The present invention relates to a digital multimedia broadcasting receiver, and more particularly, a digital multimedia broadcasting receiver having a service frequency changing function that can automatically or manually change a service frequency by automatically or manually searching a service frequency when a service frequency band region is changed while moving and changing the service frequency into broadcasting or a channel serviced in the current service region.

Description

DMB RECEIVER FOR CHANGING SERVICE FREQUENCY

Technical Field

[1] The present invention relates to a digital multimedia broadcasting receiver, and more particularly, a digital multimedia broadcasting receiver having a service frequency changing function that can automatically or manually change a service frequency by automatically or manually searching a service frequency when a service frequency band region is changed while moving and changing the service frequency into broadcasting or a channel serviced in the current service region.

[2]

Background Art

[3] Digital multimedia broadcasting (DMB) is mobile multimedia broadcasting enabling a user to enjoy high quality of audio (i.e., radio) and picture services (i.e., TV) while moving around. The DMB has been developed for the digitalization of radio, and it can process audio signal at a speed of 380 Kbps. However, it can process additional data higher than the speed, and thus it can provide moving image services.

[4] A TV receiver has been provided in some conventional cars. However, there is a problem that the TV receiver generates some noises or its connection is cut off because of a low reception rate of radio wave. Recently, in order to solve the problem, the DMB, i.e., a sort of mobile TV, has been commercially developed. The currently broadcasted DMB provides a user with high definition broadcasting without disconnection, and enables the user to watch DMB through a mobile phone according to development of slimming technology.

[5] The DMB is generally classified into satellite digital multimedia broadcasting

(S-DMB) and terrestrial digital multimedia broadcasting (T-DMB). The T-DMB by catching radio waves transmitted from a transmitting station like a general TV, and the S-DMB enables a use to watch broadcasting by scattering radio waves all over the country through a satellite.

[6] The T-DMB transmits various contents such as music, short messages, moving images, etc. through portable terminals such as a small-sized TV, a PDA, etc., due to an excellent characteristic of mobile reception, and can create great demand through services combined with a mobile communication terminal by constructing a complementary connection with the terrestrial digital TV broadcasting.

[7] The S-DMB provides multimedia broadcasting services including audios, additional data or moving images to a fixed receiver, a mobile receiver or a portable receiver through a satellite, and can supply audio broadcasting services in various qualities at a low cost and greatly expand a service range of the conventional broadcasting by covering wide regions due to use of a satellite.

[8] The difference between the T-DMB and S-DMB is the same as that of general TV broadcasting and satellite TV broadcasting. In other words, the T-DMB provides a user with free broadcasting. However, the user should pay some fee for watching the S- DMB because of a charge for satellite usage. In addition, the number of channels of the T-DMB is currently smaller than that of channels of the S-DMB. However it is predicted that the number of channels of the T-DMB will be gradually increased.

[9] According to current technological progress, a user will enjoy high definition broadcasting on a HD TV at home and watch digital multimedia broadcasting while moving around, in other words, driving a car or watching broadcasting through a mobile phone or a PDA.

[10] FIG. 1 shows a conceptual view of general digital broadcasting.

[11] Referring to FIG. 1, in satellite broadcasting, picture and voice signals produced in a broadcasting station transmitted via a transmitting earth station, and then transmitted to a remote receiving earth station by using an artificial satellite (a geostationary satellite) as a repeater. The signals are transmitted from a ground digital broadcasting station to the satellite for the digital broadcasting, and the transmitted signals are received at the satellite and downstreamed via a S-band with 2GHz to 4GHz. On the other hand, in ground wave broadcasting, the picture and voice signals produced in the broadcasting station transmitted to the repeater, and the transmitted picture and voice signals are downstreamed through UHF or VHF or a L-band. The digital broadcasting signal is received by a mobile or fixed digital broadcasting receiver and thus the user can watch various videos.

[12] At the present time or in the future in Korea, the DMB broadcasting is disposed with different frequencies according to the regions. The frequency of the ground wave DMB serviced in Korea is classified into the frequency of capital area and non-capital area. A frequency disposition plan of the capital area and the non-capital area is shown in Fig. 2, and will be serviced according to the plan.

[13] Accordingly, the frequency for a received signal is changed when the user moves to other region having a different frequency while moving, and thus the service is not available with a current frequency in other region having the different frequency.

[14] When the user moves to the other region having the different frequency while moving, the ground wave DMB receiver should be formed so as to be automatically or manually connected to broadcasting or a channel serviced in a current region. However, there has been no idea to solve the problem described above.

[15] Disclosure of Invention

Technical Problem

[16] An object of the present invention is to provide a digital multimedia broadcasting receiver having a service frequency changing function that can automatically or manually change a service frequency by automatically or manually searching a service frequency when a service frequency band region is changed while moving and changing the service frequency into broadcasting or a channel serviced in the current service region.

[17]

Technical Solution

[18] According to one aspect of the present invention, there is provided a digital multimedia broadcasting receiver having a service frequency changing function, which includes: an antenna receiving a digital multimedia broadcasting signal; a tuner selecting a specific channel frequency band for the digital multimedia broadcasting signal inputted from the antenna and filtering and receiving the digital multimedia broadcasting signal; a decoder extracting video data and audio signals included in the channel selection frequency and decoding the video data and the audio signal according to a predetermined format and outputting the decoded video data and the audio signal; an audio processing unit converting the audio signal decoded by the decoder into an analog audio signal and outputting the analog audio signal; a video processing/graphic processor converting the video data decoded by the decoder into the analog signal and outputting the analog signal; a display unit outputting the video signal outputted from the video processing/graphic processor to a screen; a received signal sensor sensing a size of a digital multimedia broadcasting signal received from the antenna in real time and outputting data out-of-service in a current frequency band; and a main controller controlling all components so as to provide the digital multimedia broadcasting to a user through the display unit and receiving the out- of-service data outputted from the received signal sensor and searching a service frequency stored in a storage unit and changing a channel selection frequency band of the tuner.

[19] The received signal sensor may output the out-of-service data to the main controller when a size of the received signal is smaller than predetermined size.

[20] The main controller may output a message of separation from the service region through the display unit after receiving the out-of-service data.

[21] The main controller may automatically or manually search a service frequency stored in the storage unit and change the channel selection frequency band of the tuner.

[22] According to another aspect of the present invention, there is provided a digital multimedia broadcasting receiver having a service frequency changing function, which includes: an antenna receiving a digital multimedia broadcasting signal; a tuner selecting a specific channel frequency band for the digital multimedia broadcasting signal inputted from the antenna and filtering and receiving the digital multimedia broadcasting signal; a decoder extracting video data and audio signals included in the channel selection frequency and decoding the video data and the audio signal according to a predetermined format and outputting the decoded video data and the audio signal; an audio processing unit converting the audio signal decoded by the decoder into an analog audio signal and outputting the analog audio signal; a video processing/graphic processor converting the video data decoded by the decoder into the analog signal and outputting the analog signal; a display unit outputting the video signal outputted from the video processing/graphic processor to a screen; a GPS processor calculating a current position value of the digital multimedia broadcasting receiver and outputting the calculated position value; and a main controller controlling all components so as to provide the digital multimedia broadcasting to a user through the display unit and determining whether the position of the receiver outputted from the GPS processor is in a current service frequency region and searching a service frequency stored in a storage unit when the position of the receiver is not in the current service frequency band and changing a channel selection frequency band of the tuner.

[23] The main controller may determine whether the position of the receiver outputted from the GPS processor is in the current service frequency region, and output the message of separation from the service frequency region through the display unit when the position of the receiver is not in the current service frequency region.

[24] The main controller may determine whether the position of the receiver outputted from the GPS processor is in the current service frequency region, and, when the position of the receiver is not in the current service frequency region, the main controller may automatically or manually search a service frequency stored in the storage unit, and change the channel selection frequency band of the tuner.

[25] The display unit may display a map and digital multimedia broadcasting simultaneously by using a PIP (Picture In Picture) function.

[26]

Advantageous Effects

[27] According to the digital multimedia broadcasting receiver having service frequency changing function of the present invention, there is an advantage that the receiver can automatically or manually change the service frequency to a channel or broadcasting serviced into the current region by automatically or manually searching and changing the service frequency into a frequency band of the current region when the service frequency band region is changed while moving. [28]

Brief Description of the Drawings

[29] The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[30] FIG. 1 is a schematic view illustrating general digital broadcasting;

[31] FIG. 2 is a view illustrating a frequency arrangement for ground wave digital multimedia broadcasting in the whole country;

[32] FIG. 3 is a construction view of a digital multimedia broadcasting receiver having service frequency changing function according to one exemplary embodiment of the present invention; and

[33] FIG. 4 is a construction view of a digital multimedia broadcasting receiver having service frequency changing function according to another exemplary embodiment of the present invention.

[34]

Best Mode for Carrying Out the Invention

[35] FIG. 3 shows a entire construction view of a digital multimedia broadcasting receiver having a service frequency changing function according to a first exemplary embodiment of the present invention.

[36] The digital multimedia broadcasting receiver having the service frequency changing function according to the present invention receives and decodes digital multimedia broadcasting signals in response to demand of user, and outputs it through a speaker or a display device equipped in the inside or outer devices connected to the digital multimedia broadcasting receiver, thereby allowing the user to be able to hear or watch contents provided through internet.

[37] Referring to FIG. 3, the digital multimedia broadcasting receiver having a service frequency changing function includes a first storage unit 10 storing an operation program for enabling a main controller 60 to operate an entire system of the digital multimedia broadcasting receiver, an antenna 5 receiving digital multimedia broadcasting signals, a tuner 20 receiving a channel selection frequency in response to a frequency channel selection signal inputted from the main controller 60, a decoder 30 extracting video data and audio data included in the channel selection frequency in response to a control signal inputted from the main controller 60 and decoding and outputting the video data and the audio data according to predetermined format, an audio processing unit 40 for converting the audio signal decoded by the decoder 30 into an analog audio signal and outputting the analog audio signal, a video processing/ graphic processor 50 for converting the video data decoded by the decoder 30 to an analog signal and outputting the analog signal, a display unit 70 outputting the video signal outputted from the video processing/graphic processor 50 to a screen according to control of the main controller 60, a second storage unit 80 storing the video data processed by the video processing/graphic processor 50, a received signal sensor 90 sensing a size of a digital multimedia broadcasting signal received from the antenna in real time and outputting out-of-service data in a current frequency band, a main controller 60 outputting the frequency channel selection signal to the tuner 20 and controlling the entire system according to an operation program stored in the first storage unit 10 so as to provide video data and audio signals included in the channel selection frequency selected by the tuner 20 and receiving the out-of-service data outputted from the received signal sensor 90 and searching a service frequency stored in the storage unit(the first storage unit 10) and changing the channel selection frequency band of the tuner 20.

[38]

Mode for the Invention

[39] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawing. The aspects and features of the present invention and methods for achieving the aspects and features will be apparent by referring to the embodiments to be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed hereinafter, but can be implemented in diverse forms. The matters defined in the description, such as the detailed construction and elements, are nothing but specific details provided to assist those of ordinary skill in the art in a comprehensive understanding of the invention, and the present invention is only defined within the scope of the appended claims. In the entire description of the present invention, the same drawing reference numerals are used for the same elements across various figures.

[40] FIG. 3 shows an entire construction of the digital multimedia broadcasting receiver having the service frequency changing function.

[41] The digital multimedia broadcasting receiver having a service frequency changing function receives and decodes digital multimedia broadcasting signals and outputs the digital multimedia broadcasting signals through a speaker or a display device equipped in inner or outer devices connected to the digital multimedia broadcasting receiver in response to demand of the user, thereby allowing the user to listen or watch contents provided through an internet.

[42] Referring to FIG. 3, the digital multimedia broadcasting receiver having a service frequency changing function includes a first storage unit 10 storing an operation program for enabling a main controller 60 to operate an entire system of the digital multimedia broadcasting receiver, an antenna 5 receiving digital multimedia broadcasting signals, a tuner 20 receiving a channel selection frequency in response to a frequency channel selection signal inputted from the main controller 60, a decoder 30 extracting video data and audio data included in the channel selection frequency in response to a control signal inputted from the main controller 60 and decoding and outputting the video data and the audio data according to predetermined format, an audio processing unit 40 for converting the audio signal decoded by the decoder 30 into an analog audio signal and outputting the analog audio signal, a video processing/ graphic processor 50 for converting the video data decoded by the decoder 30 to an analog signal and outputting the analog signal, a display unit 70 outputting the video signal outputted from the video processing/graphic processor 50 to a screen according to control of the main controller 60, a second storage unit 80 storing the video data processed by the video processing/graphic processor 50, a received signal sensor 90 sensing a size of a digital multimedia broadcasting signal received from the antenna in real time and outputting out-of-service data in a current frequency band, a main controller 60 outputting the frequency channel selection signal to the tuner 20 and controlling the entire system according to an operation program stored in the first storage unit 10 so as to provide video data and audio signals included in the channel selection frequency selected by the tuner 20 and receiving the out-of-service data outputted from the received signal sensor 90 and searching a service frequency stored in the storage unit(the first storage unit 10) and changing the channel selection frequency band of the tuner 20.

[43] The digital multimedia broadcasting receiver includes a first port outputting the video data processed by the video processing/graphic processor 50. The first port is a USB port, and the DMB receiver transmits the video data received through the antenna to a computer system connected through the USB port.

[44] The digital multimedia broadcasting receiver further includes a second port outputting the video data for high-speed digital video processing in addition to the first port and in this time, the second port is a RS 1394 port.

[45] The second storage unit 80 includes a hard disk, a flash memory, an external storage medium and various storage mediums, and includes both of built-in or external storage device.

[46] The user having the digital multimedia broadcasting receiver set a desired frequency band or a desired channel, and can be provided with digital multimedia broadcasting received through the frequency band.

[47] The main controller 60 of the digital multimedia broadcasting receiver receives a key signal corresponding to a channel selected by the user, and outputs the frequency channel selection signal corresponding to the key signal to the tuner 20. The frequency channel selection signal is a signal for selecting a channel of the frequency band. The signal is formed by synthesizing and processing a digital audio signal processed by a DAB method and a video data encoded into MPEG4 by a predetermined method.

[48] The tuner 20 receives only a channel signal corresponding to the frequency channel selection signal of the main controller 60 among signals received through the antenna 5 and outputs the signal to the decoder 30. On the other hand, the received signal sensor 90a senses a size of the digital multimedia broadcasting signal inputted to the tuner 20 through the antenna 5.

[49] The received signal sensor 90 senses the size of the digital multimedia broadcasting signal received through the antenna 5 in real time. This is the reason that it should be checked whether a current service frequency band firstly selected by a user is applied in a region where the current digital multimedia broadcasting receiver is located.

[50] In other words, because the service frequency band is different according to region and, in many cases, the digital multimedia broadcasting receiver is moving, the frequency band firstly selected by the user may be not serviced in the region where the digital multimedia broadcasting receiver is currently located. Accordingly, it is necessary to check if the digital multimedia broadcasting receiver is separated from a region where the service is possible with the firstly selected frequency band by sensing the size of the digital multimedia broadcasting signal in real time.

[51] When the digital multimedia broadcasting is not serviced in the firstly selected current frequency band in a region where the digital multimedia broadcasting receiver is located, the received signal sensor 90 outputs out-of-service data in a current frequency band to the main controller 60. In determining the service unavailability in the current frequency, the received signal sensor 90 determines that the region cannot service when the size of received digital multimedia broadcasting is smaller than the previously set size, and determines that the region can service otherwise. The previously set size is data that can be decided by checking attenuation trend of a received signal according to region movement by an experiment.

[52] The decoder 30 decodes the received signal to a channel, video data and audio data according to a predetermined format, and then outputs the audio data to the audio processing unit 40, and the video data to the video processing/graphic processor 50.

[53] The audio data decoded by the decoder 30 is basically encoded by MPEG 1 Layer

2 or MPEG 2 Layer 2 or AC(Advanced Audio coding) and WMA(Window Media Audio), and the encoded audio data is decoded by the decoder 30.

[54] The decoder 30 converts a signal inputted from the tuner 20 into a digital signal and divides the converted signal into the audio signal and the video signal and outputs the audio signal to the audio processing unit 40 and the video signal to the video processing/graphic processor 50. Especially, the decoder 30 divides muxed signals in accordance with a DAB specification into a digital audio signal, a digital video signal and a digital additional data signal, etc. and outputs the digital audio signal, the digital video signal and the digital additional signal, etc. to a respective processing block. Then, the audio processing unit 40 converts the audio data into an analog signal and respectively outputs the analog signals to L, R ports of a speaker.

[55] The video processing/graphic processor 50 processes the decoded video data for outputting the decoded video data through a display unit 70, that is, a LCD unit. The video processing/graphic processor 50 outputs the video signal to a USB port or a RS 1394 port included in the digital multimedia broadcasting receiver 100.

[56] The USB port is connected to a computer system and stores received videos received in the computer system, thereby allowing the user to watch the videos later. The video processing/graphic processor 50 performs an audio processing separately from the audio processing unit 40, thereby outputting the video data and the audio data to the USB port, the RS 1394 port and the second storage unit 80.

[57] When performing high speed digital video processing that is not supported by the

USB port, the RS 1394 port is connected to a processing system corresponding to the port.

[58] The main controller 60 controls the video processing/graphic processor 50 in response to a storage key signal inputted according to purpose of user and the video processing/graphic processor 50 stores the video data and the audio data decoded by the decoder 30 in the storage unit 80.

[59] The decoder 30 and the video processing/graphic processor 50 process video data compressed by MEPG-4, but may process different kinds of videos in addition to the MEPG-4. The audio data are encoded by AAC(Advanced Audio Coding) engaged with MEPG-4 videos or by BSAC(Bk Slice Arithmetic Coding). The AAC and the BSAC have the best compression rate and sound quality in current audio coding.

[60] When out-of-service data are received from the received signal sensor 90, the main controller 60 outputs a message of separation from service region to the display unit(LCD) through the video processing/graphic processor 50, thereby notifying the user of out-of-service in the first channel selection frequency band at a current position. The user can check the message while receiving digital multimedia broadcasting.

[61] When the user checks the message and a frequency search mode is set manually, the user enables the main controller 60 to search a frequency stored in a storage unit(a first storage unit 10) and to find a service frequency in current position region and control the tuner 20 by key input. [62] The main controller 60 automatically or manually searches the frequency stored in the storage unit(the first storage unit 10) and changes the channel selection frequency band of the tuner 20. The automatic or manual search may be performed by key input previously provided in the digital multimedia broadcasting receiver.

[63] In other words, when the automatic search mode is previously set by the previous key input and the main controller 60 receives the out-of-service data from the received signal sensor 90, the main controller automatically searches the frequency stored in the storage unit(the first storage unit 10) without waiting additional key input and changes the channel selection frequency band of the tuner 20. On the other hand, when a manual search mode is previously set by the key input and the main controller 60 receives the out-of-service data from the received signal sensor 90, the main controller automatically searches the frequency stored in the storage unit(the first storage unit 10) only when an additional key input is performed and changes the channel selection frequency band of the tuner 20.

[64] According to the operation of the main controller 60 as described above, the user can use the broadcasting and other services provided from a channel of a frequency band serviced in current position region of the digital multimedia broadcasting receiver.

[65] A construction of the digital multimedia broadcasting receiver having service frequency changing function according to another exemplary embodiment of the present invention is shown in FIG. 4.

[66] The construction of the digital multimedia broadcasting receiver having the service frequency changing function shown in FIG. 4 is similar to the construction shown in FIG. 3 except that the digital multimedia broadcasting receiver does not includes the received signal sensor 90 but includes a GPS processor 95. Thus, an operation of a main controller 60 is also different.

[67] The construction shown in FIG. 4 includes a case where the digital multimedia broadcasting receiver has a navigation function. Accordingly, the GPS processor 95 is included in the entire construction. Other components except for the GPS processor 95 are similar to the components shown in FIG. 3 and thus the explanation will be omitted.

[68] Referring to FIG. 4, the digital multimedia broadcasting receiver having a service frequency changing function includes a first storage unit 10 storing an operation program for enabling a main controller 60 to operate an entire system of the digital multimedia broadcasting receiver, an antenna 5 receiving digital multimedia broadcasting signals, a tuner 20 receiving a channel selection frequency in response to a frequency channel selection signal inputted from the main controller 60, a decoder 30 extracting video data and audio data included in the channel selection frequency in response to a control signal inputted from the main controller 60 and decoding and outputting the video data and the audio data according to predetermined format, an audio processing unit 40 for converting the audio signal decoded by the decoder 30 into an analog audio signal and outputting the analog audio signal, a video processing/ graphic processor 50 for converting the video data decoded by the decoder 30 to an analog signal and outputting the analog signal, a display unit 70 outputting the video signal outputted from the video processing/graphic processor 50 to a screen according to control of a main controller 60, a second storage unit 80 storing the video data processed by the video processing/graphic processor 50, a GPS processor 95 calculating a current position value of the digital multimedia broadcasting receiver and outputting the current position value to the main controller 60, and the main controller 60 outputting a frequency selection signal to the tuner 20 and controlling all components according to an operation program stored in the first storage unit 10 so as to provide video, data and audio signal included in the frequency selected by the tuner 20 to a user and determining whether the position of the digital multimedia broadcasting receiver outputted from the GPS processor 95 is in a firstly set current service frequency region and searching a service frequency stored in a storage unit (the first storage unit 10) when the position of the receiver is not in the current service frequency band and changing a channel selection frequency band of the tuner 20.

[69] The antenna, the tuner, the decoded unit, the audio processing unit and the video processing/graphic processor, etc. are the same as the components shown in FIG. 3 and thus only the GPS processor 95 and the main controller 60 will be explained.

[70] The GPS processor 95 analyzes GPS data inputted from a GPS receiving antenna

(not shown) and calculates the current position value of the digital multimedia broadcasting receiver and outputs the current position value to the main controller 60.

[71] After the main controller 60 receives the current position value of the digital multimedia broadcasting receiver from the GPS processor 95, the main controller determines whether a current receiver position is included in the current service frequency region by using map data stored in the first storage unit 10 and the received position value.

[72] As a result of the determination, when the receiver position is located in the current service frequency region, the main controller 60 maintains the service. However, when the receiver position is not located in the current service frequency region, the main controller 60 outputs a message of separation from the current service frequency region to the display unit (LCD) 70 through the video processing/graphic processor 50, thereby notifying the user of out-of-service in the first channel selection frequency band at a current position. The user can identify the message while receiving digital multimedia broadcasting. [73] When the user checks the message and a frequency search mode is set manually, the user enables the main controller 60 to search a frequency stored in a storage unit (a first storage unit 10) and to find a service frequency in current position region and control the tuner 20 by key input.

[74] The main controller 60 automatically or manually searches the frequency stored in the storage unit (the first storage unit 10) and changes the channel selection frequency band of the tuner 20. The automatic or manual search may be performed by key input previously provided in the digital multimedia broadcasting receiver.

[75] In other words, when the automatic search mode is previously set by the previous key input and the main controller 60 receives the out-of-service data from the received signal sensor 90, the main controller automatically searches the frequency stored in the storage unit (the first storage unit 10) without waiting additional key input and changes the channel selection frequency band of the tuner 20. On the other hand, when a manual search mode is previously set by the key input and the main controller 60 receives the out-of-service data from the received signal sensor 90, the main controller automatically searches the frequency stored in the storage unit (the first storage unit 10) only when an additional key input is performed and changes the channel selection frequency band of the tuner 20.

[76] According to the operation of the main controller 60 as described above, the user can use the broadcasting and other services provided from a channel of a frequency band serviced in current position region of the digital multimedia broadcasting receiver.

[77]

Industrial Applicability

[78] The present invention relates to a digital multimedia broadcasting receiver, and more particularly, a digital multimedia broadcasting receiver having a service frequency changing function that can automatically or manually change a service frequency by automatically or manually searching a service frequency when a service frequency band region is changed while moving and changing the service frequency into broadcasting or a channel serviced in the current service region, and very useful in the field of digital broadcasting.

[79] It should be understood by those of ordinary skill in the art that various replacements, modifications and changes in the form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. Therefore, it is to be appreciated that the above described embodiments are for purposes of illustration only and are not to be construed as limitations of the invention.

Claims

[1] A digital multimedia broadcasting receiver having a service frequency changing function, comprising: an antenna receiving digital multimedia broadcasting signals; a tuner selecting a specific channel frequency band for the digital multimedia broadcasting signals inputted from the antenna and filtering and receiving the digital multimedia broadcasting signals; a decoder extracting video data and audio signals included in the channel selection frequency and decoding the extracted video data and the audio signals according to a predetermined format and outputting the decoded video data and the audio signals; an audio processing unit converting the audio signals decoded by the decoder into an analog audio signals and outputting the analog audio signals; a video processing/graphic processor converting the video data decoded by the decoder into a video analog signals and outputting the video analog signals; a display unit outputting the video analog signal outputted from the video processing/graphic processor to a screen; a received signal sensor sensing the size of digital multimedia broadcasting signals received from the antenna in real time and outputting out-of-service data in a current frequency band; and a main controller controlling all the components so as to provide the digital multimedia broadcasting to user through the display unit and receiving the out- of-service data outputted from the received signal sensor and searching a service frequency stored in a storage unit and changing a channel selection frequency band of the tuner.

[2] A digital multimedia broadcasting receiver having a service frequency changing function comprising: an antenna receiving digital multimedia broadcasting signals; a tuner selecting a specific channel frequency band for the digital multimedia broadcasting signals inputted from the antenna and filtering and receiving the digital multimedia broadcasting signals; a decoder extracting video data and audio signals included in the channel selection frequency and decoding the extracted video data and the audio signals according to a predetermined format and outputting the decoded video data and the audio signals; an audio processing unit converting the audio signals decoded by the decoder into an analog audio signal and outputting the analog audio signals; a video processing/graphic processor converting the video data decoded by the decoder into a video analog signal and outputting the video analog signal; a display unit outputting the video analog signal outputted from the video processing/graphic processor to a screen; a GPS processor calculating a current position value of the digital multimedia broadcasting receiver and outputting the calculated position value; and a main controller controlling all the components so as to provide the digital multimedia broadcasting to user through the display unit and determining whether the position of the receiver outputted from the GPS processor is in a current service frequency region and searching a service frequency stored in a storage unit when the position of the receiver is not in the current service frequency region and changing a channel selection frequency band of the tuner.

[3] The digital multimedia broadcasting receiver of claim 1, wherein the received signal sensor outputs the out-of-service data to the main controller when the size of the received signal is smaller than a predetermined set size.

[4] The digital multimedia broadcasting receiver of claim 3, wherein the main controller outputs a message of separation from the service region through the display unit after receiving the out-of-service data.

[5] The digital multimedia broadcasting receiver of claim 1, wherein the main controller automatically or manually searches the service frequency stored in the storage unit and changes the channel selection frequency band of the tuner.

[6] The digital multimedia broadcasting receiver of claim 2, wherein the main controller determines whether the position of the receiver outputted from the GPS processor is in the current service frequency region and outputs the message of separation from the service frequency region through the display unit when the receiver is not in the current service frequency region.

[7] The digital multimedia broadcasting receiver of claim 2, wherein the main controller determines whether the position of the receiver outputted from the GPS processor is in the current service frequency region, and automatically or manually searches the service frequency stored in the storage unit and changes the channel selection frequency band of the tuner when the receiver is not in the current service frequency region.

[8] The digital multimedia broadcasting receiver of claim 6 or 7, wherein the display unit displays a map and digital multimedia broadcasting simultaneously by using a PIP (Picture In Picture) function.