JP2010283531A - Receiving device and broadcasting channel detection method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically perform a channel search, even if there is no country designation from a user. <P>SOLUTION: A DTV (digital television) receiver has a plurality of branches for receiving a broadcast signal transmitted from a broadcast station which fundamentally forms a diversity with four branches in the case of reproducing the broadcast signal; whereas such a diversity configuration is separated and channel search is executed with a bandwidth different in each branch, when channel search is to be carried out. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a receiving apparatus having a function of detecting a receivable broadcast channel and a broadcast channel detecting method thereof.

  Conventionally, a DTV (digital television) receiver performs a channel search for searching for a carrier frequency (hereinafter referred to as “broadcast channel”) of a broadcast station that can be received by the device itself, and broadcast obtained by the channel search. It has an auto preset function that registers and registers channels in storage devices such as memory.

  In the DTV receiver having the auto-preset function, when a broadcast channel is selected by the user, it is not necessary to search the selected broadcast channel each time, and the user selects from the broadcast channels stored in the memory. Since the selected broadcast channel can be immediately selected and received, the broadcast channel can be switched quickly.

  As such a DTV receiver, for example, Patent Literature 1 discloses a broadcast channel detection apparatus that performs a channel search for each branch in a digital broadcast receiver having a plurality of branches. A broadcast receiving apparatus that sequentially searches channels of each country based on the frequency bandwidth of a set country where the digital broadcast is set to be received and its neighboring countries is disclosed.

JP 2006-13689 A JP 2008-245169 A

  However, both Patent Document 1 and Patent Document 2 described above are based on the premise that the designation of the country is accepted from the user itself. Without this country designation, the frequency bandwidth to be searched is not determined, and the channel search is performed. There was a problem that it could not execute itself.

  Accordingly, the present invention has been made to solve the above-described problems caused by the prior art, and provides a receiving apparatus and a broadcast channel detection method thereof capable of automatically performing a channel search without a country designation from a user. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a receiving apparatus according to the present invention is a receiving apparatus having a function of detecting a receivable broadcast channel, and receives a broadcast signal transmitted from a broadcast station. A plurality of branches, grouping means for grouping the plurality of branches into a plurality of branch groups, and search control for searching for the broadcast channel with different frequency bandwidths in each branch group grouped by the grouping means Means.

  According to the present invention, the channel search is executed in parallel with all the bandwidths that can be assumed for each branch group. As a result, the channel search can be executed including the bandwidth of the country where the digital television receiver is located. The channel search can be automatically performed even if the user does not specify the country.

FIG. 1 is a functional block diagram illustrating the configuration of the DTV receiver according to the present embodiment. FIG. 2 is an explanatory diagram for explaining branch grouping. FIG. 3 is an explanatory diagram for explaining a difference in bandwidth of channel search for each group. FIG. 4 is a diagram illustrating an example of grouping. FIG. 5 is a diagram illustrating an example of grouping. FIG. 6 is a diagram illustrating an example of a channel display screen. FIG. 7 is a diagram illustrating an example of a channel display screen. FIG. 8 is a flowchart illustrating the procedure of the channel search control process according to the present embodiment. FIG. 9 is a flowchart illustrating the procedure of the channel search process according to the present embodiment.

  Exemplary embodiments of a receiving apparatus and a broadcast channel detecting method thereof according to the present invention will be explained below in detail with reference to the accompanying drawings. In the following, a case where the present invention is applied to an in-vehicle DTV receiver digital television) will be exemplified, but the present invention can be similarly applied regardless of whether it is in-vehicle.

  First, an outline of the DTV receiver according to the present embodiment will be described. FIG. 1 is a functional block diagram illustrating the configuration of the DTV receiver according to the present embodiment. As shown in the figure, the DTV receiver 1 is an in-vehicle digital television receiver connected to an audio integrated car navigation system (AVN) 3.

  The AVN 3 has various devices such as an audio output unit such as a speaker and a display such as a touch panel. The AVN 3 outputs a broadcast signal decoded by the DTV receiver 1 and outputs a video, and a user views it. A channel change operation is received and a channel change instruction is transferred to the DTV receiver 1.

  The DTV receiver 1 employs a diversity system and receives four digital television signals (hereinafter referred to as “broadcast signals”) transmitted from a broadcasting station, namely, branch 10, branch 20, branch 30, and branch 40. Has a receiving system.

  In the present embodiment, the DTV receiver 1 is provided with four reception systems. However, the number of reception systems provided in the DTV receiver 1 is not limited to four. Any number of receiving systems may be provided.

  The detailed configuration of the DTV receiver 1 will be described later. The branch 10 of the DTV receiver 1 includes an RF / IF unit 11 that detects and amplifies a received signal from the antenna shown in FIG. 2, and a predetermined modulation method. And a demodulator 12 that demodulates the broadcast signal modulated by.

  Similarly, the branch 20 includes an RF / IF unit 21 and a demodulation unit 22, the branch 30 also includes an RF / IF unit 31 and a demodulation unit 32, and the branch 40 includes an RF / IF unit 41 and a demodulation unit. 42.

  As described above, in the DTV receiver 1, when receiving a broadcast signal on the broadcast channel selected by the user, the plurality of reception systems receive the broadcast signal of the same broadcast channel and are received by each reception system. A diversity system that removes noise contained in the broadcast signal by synthesizing the broadcast signal is employed.

  Here, the present embodiment is characterized in that a plurality of branches 10 to 40 are grouped into a plurality of branch groups, and each of the grouped branch groups is searched for a broadcast channel with a different frequency bandwidth.

  In other words, the above-mentioned conventional techniques entrust the user to the country designation based on the idea that it is inefficient to perform a channel search in a bandwidth other than the set country. Even if there is no country designation, there is no idea of performing channel search autonomously.

  For this reason, in the above-described prior art, when the DTV receiver is mounted on a mobile body such as a vehicle, if the receivable broadcast channel changes, the user must specify the country again. Furthermore, not only does the user need to specify a country, but depending on the position where the DTV receiver 1 is located, even if it is possible to receive broadcast channels in a plurality of countries, only a channel search for a set country can be performed. It is also impossible to present all receivable broadcast channels to the user.

  Therefore, in this embodiment, paying attention to the fact that the bandwidth of the broadcasting in each country is different, in the case of reproducing a broadcast signal, on the other hand, while the diversity is basically composed of four branches 10 to 40, the channel search is performed. When performing, the diversity configuration is separated, and each branch 10 to 40 is caused to execute a channel search with a different bandwidth.

  Specifically, as shown in FIG. 2, the DTV receiver 1 divides the four reception systems into four branch groups when performing a channel search. For example, in the example of FIG. 2, a receiving system having four systems of grouping processing units 130 to be described later includes a group A configured by the branch 10, a group B configured by the branch 20, and a group configured by the branch 30. The group is divided into four branch groups, which are C and a group D composed of branches 40.

  In addition, the DTV receiver 1 causes the group A to group D to search for broadcast channels with different frequency bandwidths.

  For example, the example shown in FIG. 3 illustrates a case where a broadcast channel in the UHF (Ultra-High Frequency) band is searched. In the case of this UHF, four types of bandwidths of 5 MHz, 6 MHz, 7 MHz, and 8 MHz are defined as standards when the broadcasting station transmits.

  In the example of FIG. 3, the DTV receiver 1 uses a common frequency for starting a search (hereinafter referred to as a search start frequency) in any of group A to group D at 470 MHz, and group A has a bandwidth of 8 MHz. The search frequency is increased by 8 MHz from 470 MHz, and the channel search is repeatedly executed until the search of 862 MHz, which is the search end frequency, is completed. For group B, the channel search is similarly executed with a bandwidth of 7 MHz. Then, the group C is caused to perform a channel search in the same manner with a bandwidth of 6 MHz, and the group D is similarly caused to perform a channel search with a bandwidth of 5 MHz. In the following description, a search with a bandwidth of 8 MHz is referred to as search A, and similarly, search B, search C, and search D.

  As described above, in this embodiment, since channel search is performed in parallel with all the bandwidths that can be assumed for each branch group (in this case, each branch), the channel search is performed in the country where the DTV receiver 1 is located. The channel search including the bandwidth can be executed, and the channel search can be automatically performed even if the user does not specify the country. In addition, since search A to search D are executed in parallel in each branch group, channel search is performed at the same speed as the case where diversity is configured in all branches and channel search of one type of bandwidth of the set country is performed. Can be executed.

  Further, in this connection, when not only the broadcast channel of the country where the DTV receiver 1 is located but also the broadcast channels of a plurality of countries can be received, the search can be performed without leaking the broadcast channels that the DTV receiver 1 can receive. it can.

  Further, in this embodiment, the DTV receiver 1 can independently perform channel search without acquiring the position information where the DTV receiver 1 is located from the GPS or the like mounted on the AVN 3.

  Next, the configuration of the DTV receiver according to the present embodiment will be described. In FIG. 1, only the components necessary for explaining the characteristics of the DTV receiver according to the present embodiment are shown, and descriptions of general components are omitted.

  As shown in FIG. 1, the DTV receiver 1 includes branches 10 to 40, a diver switching unit 50, a decoder 60, and a DTV control microcomputer 100.

  The branch 10 constitutes one receiving system capable of receiving a broadcast signal by itself, and includes an RF / IF unit 11, a demodulator 12, and a program information acquisition unit 13. Note that the term “branch” here refers to a received signal processing circuit or processing unit provided corresponding to each antenna.

  The branch 20, branch 30, and branch 40 are also reception systems configured in the same manner as the branch 10 described above. The RF / IF units 21, 31, and 41 and the demodulation unit 22 are included in each branch 20 to 40, respectively. , 32 and 42 and program information acquisition sections 23, 33 and 43, respectively.

  Since all of these branches 10 to 40 have the same configuration, only the configuration of the branch 10 will be described here.

  The RF / IF unit 11 is a tuning circuit that causes an antenna to receive a broadcast signal of a broadcast channel specified by a control signal input from a search control unit 140 described later. In this embodiment, the RF / IF unit 11 receives a broadcast signal that has been modulated by OFDM (Orthogonal Frequency Division Multiplexing), and outputs the broadcast signal to the demodulation unit 12.

  The demodulator 12 is a processor that returns the TS (Transport Stream) packet to the program information acquisition unit 13 by OFDM demodulation of the broadcast signal input from the RF / IF unit 11. Since OFDM demodulation is a known technique, its description is omitted here.

  The program information acquisition unit 13 is a processing unit that performs processing such as determination of presence / absence of a broadcasting station and acquisition of program information including country information based on the broadcast signal input by the demodulation unit 12.

  Specifically, the program information acquisition unit 13 acquires TMCC (Transmission and Multiplexing Configuration and Control: transmission control information) from the broadcast signal input by the demodulation unit 12, and based on the acquisition result, the RF information It is determined whether or not a broadcast station exists in the broadcast channel being scanned set in the / IF unit 11. When diversity is configured with other branches, this process and subsequent processes are performed with phase synchronization with broadcast signals received at other branches that configure diversity. .

  The TMCC is composed of a group of information including transmission parameter information and the like necessary for combining broadcast signals, and is information transmitted from each broadcast station at a relatively short time interval of about 300 ms.

  When the program information acquisition unit 13 succeeds in acquiring this TMCC in the broadcast channel being scanned set in the RF / IF unit 11, the program information acquisition unit 13 determines that a broadcast station exists in the broadcast channel, and determines a predetermined time (for example, , 300 ms), if TMCC cannot be acquired, it is determined that there is no broadcast station in the broadcast channel being scanned.

  When it is determined that a broadcast station exists, the program information acquisition unit 13 acquires PSI (Program Specific Information) / SI (Service Information) or the like as program information from the broadcast signal of the broadcast channel. The PSI includes a network information table (NIT), a program association table (PAT), and a program map table (PMT).

  PSI (program specific information) or SI (program arrangement information) includes country information. The NIT includes information about the network such as frequency information of a broadcast channel that receives a broadcast signal, a modulation method, a guard interval, and the like. Further, the PMT includes a PID (packet ID) for identifying each packet constituting the audio and video of the program being broadcast. The PAT stores a list of programs included in a certain TS as a PID list of PMTs.

  The program information acquisition unit 13 associates the information such as PSI / SI and the broadcast channel corresponding to the broadcast signal from which the information is obtained, and the reception intensity of the broadcast signal of the broadcast channel together with the associated information. The search result is output to the preset control unit 150. If it is determined that there is no broadcasting station, a search result indicating that there is no corresponding broadcasting station is output to the preset control unit 150.

  The diver switching unit 50 is a switching unit that divides the branches 10 to 40 into a plurality of branch groups based on an instruction from the grouping processing unit 130 described later. The configuration and separation of diversity is a known technique and will be described here briefly.

  That is, the diver switching unit 50 conducts the conductive wire connected from the demodulation unit of one branch A to the demodulation unit of the other branch B when any two of the branches 10 to 40 are branches A and B. A post-stage connection switch that conducts or cuts off the conducting wire connected from the demodulating unit of branch B to the subsequent processing unit (program information obtaining unit) by conducting ON control of the inter-demodulating unit switch to be cut off By cutting off the connection to the subsequent stage by performing OFF control, diversity is configured between a plurality of branches, or by switching control in the opposite manner, diversity is separated.

  In the following, a case where an inter-demodulation unit switch is provided between the demodulation unit 12 and the demodulation unit 22, the demodulation unit 22 and the demodulation unit 32, and the demodulation unit 32 and the demodulation unit 42 will be described. Arbitrary combinations between demodulating units can be installed as targets.

  For example, when a grouping instruction is given in which branch 10 is group A, branch 20 is group B, branch 30 is group C, and branch 40 is group D (see FIG. 2), all inter-demodulator switches are controlled to be OFF. At the same time, all the branch connection switches are ON-controlled to operate each of the branches 10 to 40 independently.

  Further, when a grouping instruction is given in which the branch 10 and the branch 20 are group A and the branch 30 and the branch 40 are group B (see FIG. 4), the switch between the demodulation unit 12 and the demodulation unit 22 is controlled to be ON. At the same time, the switch between the demodulator 22 and the demodulator 32 is controlled to be OFF, and further, the subsequent stage connection switch of either the branch 10 or the branch 20 is controlled to be ON, thereby configuring the diversity of the group A including the branch 10 and the branch 20 To do. Further, similarly, the diversity of the group B composed of the branch 30 and the branch 40 is configured.

  When a grouping instruction for all branches 10 to 40 as group A is made (see FIG. 5), all the inter-demodulator switches are controlled to be ON and any one of the subsequent connection switches of the branches 10 to 40 Only one of them is ON-controlled so that all branches constitute one diversity.

  The decoder 60 includes a decoder that composites the broadcast signal (TS packet) input from the program information acquisition unit 13 and a D / A converter that performs D / A (digital / analog) conversion on the composite broadcast signal. Have.

  The audio broadcast signal D / A converted by the D / A converter of the decoder 60 is output to the AVN3 speaker and output, and the video broadcast signal is output to the AVN3 display and displayed as a television image.

  The DTV control microcomputer 100 is a microcomputer that performs overall control of the DTV receiver 1, and includes a preset information storage unit 110, a schedule information storage unit 120, a grouping processing unit 130, a search control unit 140, and a preset control unit 150. And have.

  The preset information storage unit 110 is a storage device such as a nonvolatile memory that stores preset information. Specifically, information such as PSI / SI and the broadcast channel corresponding to the broadcast signal from which the information is acquired are associated and stored as preset information. The preset information 110 is written, read or erased by the preset control unit 150.

  The schedule information storage unit 120 is a storage device such as a nonvolatile memory that stores preset schedule information by the preset control unit 150. Specifically, the frequency at which the search has been completed in each of search A, search B, search C, and search D (search progress frequency) is stored as progress information, or assigned to search A to search D. A branch group is stored as allocation information.

  The grouping processing unit 130 is a processing unit that groups a plurality of branches 10 to 40 into a plurality of branch groups. Specifically, when performing a channel search, the branches 10 to 40 are grouped, and whether or not the grouping needs to be changed is monitored until the channel search is completed. If it is determined that the grouping needs to be changed, the branches 10 to 40 are monitored. Change the grouping.

  For example, when the channel search is activated, as shown in FIG. 2, it is composed of group A composed of branch 10, group B composed of branch 20, group C composed of branch 30, and branch 40. Group D into four branch groups. In this example, the channel search is grouped into four branch groups when the channel search is started. However, the grouping may be performed according to the reception strength of the branches 10 to 40.

  In addition, when the search is completed in any branch group, the grouping processing unit 130 performs grouping in which the branch group for which the search has been completed is incorporated into the branch group for which no other search has been completed.

  That is, for example, when searching for the UHF band, since the search A to search B commands having different bandwidths of 5 MHz, 6 MHz, 7 MHz, and 8 MHz are executed, each group starts a search from the search start frequency at the same timing. Even so, there is a time difference until the search end frequency is reached.

  In such a case, the grouping processing unit 130 incorporates a branch group that has been searched earlier than other branch groups into a branch group that has not been searched and has the smallest bandwidth.

  In addition, the grouping processing unit 130 changes the number of constituent branches of the branch group according to the reception strength notified as a search result from the branch group.

  For example, the grouping processing unit 130 determines the reception strength of the broadcast signal in three stages of “high”, “medium”, and “low”, and performs grouping that assigns the number of branches according to the determination result to each branch group. .

  When the grouping processing unit 130 determines that the broadcast signal reception strength is “high”, the grouping processing unit 130 sets the number of branches in each branch group to “1” and configures the diversity in each branch 10 to 40 as shown in FIG. Each group independently.

  Specifically, when the grouping processing unit 130 determines that the reception intensity of the broadcast signal notified from the branch group as a search result is “high”, the group 10 is configured by the branch 10, and the group B is configured by the branch 20. The group 30 is configured by the branch 30, and the group D is configured by the branch 40.

  As a result, when all the broadcast signals of all the broadcast channels are determined to have a high reception strength, the four channels are compared with the case where the channel search is performed by receiving each broadcast signal by all four reception systems. Searches A to D, which are bandwidth search commands, can be searched in 1/4 time.

  If the grouping processing unit 130 determines that the broadcast signal reception intensity is “medium”, the number of branches in each branch group is set to “2” as shown in FIG. Configure to have two branch groups.

  Specifically, when the grouping processing unit 130 determines that the reception intensity of the broadcast signal notified as a search result from the branch group is “medium”, the group 10 includes the branch 10 and the branch 20, and the branch A 30 and the branch 40 constitute a group B.

  As a result, when all the broadcast signals of all the broadcast channels are determined to have a medium reception strength, the four channels are compared with the case where each broadcast signal is received by all four reception systems and channel search is performed. The channel search can be completed in half the time for search A to search D, which are bandwidth search commands.

  Furthermore, for broadcast signals for which the reception strength is determined to be “medium”, the same broadcast signal is diversity-received by two reception systems, and channel search is performed. Therefore, compared with a broadcast signal for which the reception strength is determined to be “high”. Thus, channel search can be performed by removing noise by a diversity method from a broadcast signal having a medium reception strength expected to be affected by noise.

  If the grouping processing unit 130 determines that the reception intensity of the received broadcast signal is “low”, the number of branches in the branch group is set to “4” as shown in FIG. Thus, one branch group is set.

  Specifically, when the grouping processing unit 130 determines that the reception intensity of the broadcast signal notified as a search result from the branch group is “low”, the group 10 is processed by the branch 10, the branch 20, the branch 30, and the branch 40. A is configured.

  For this reason, noise is removed by a diversity method using all branches from a broadcast signal with a low reception strength that is difficult to receive normally due to the influence of noise compared to a broadcast signal with a reception strength determined to be high. Since the search can be performed, the channel search can be accurately performed even in a place where it is relatively difficult to receive the broadcast.

  The search control unit 140 is a processing unit that causes each branch group grouped by the grouping processing unit 130 to search for broadcast channels with different frequency bandwidths.

  For example, when the channel search is started, the grouping processing unit 130 is grouped into four groups, group A to group D. Therefore, the search start frequency 470 MHz is distributed to each of the groups A to D. A bandwidth of 8 MHz is notified, the frequency to be searched is increased by 8 MHz from 470 MHz, and the channel search is repeatedly executed until the search frequency reaches the search end frequency of 862 MHz. The group B is notified of the bandwidth 7 MHz, the group C is notified of the bandwidth 6 MHz, and the group D is notified of the bandwidth 5 MHz, and the channel search is similarly executed.

  In addition, when the group change is performed by the grouping processing unit 130, the search control unit 140 re-instructs the frequency and bandwidth to be searched for each branch group.

  For example, when branch A and branch 20 constitute group A and branch 30 and branch 40 constitute group B (see FIG. 4), search A, search B, and search stored in schedule information 120 storage unit With reference to the progress information of C and search D, two search commands are selected from search commands that have not been searched, and the search progress frequency and bandwidth of the selected search command are assigned to each of branch groups A and B. Instruct. At this time, a bandwidth having a high probability of being the DTV receiver 1 in the search A to the search D may be estimated from the past country determination results, and the search command may be preferentially allocated.

  When group A is configured by all branches 10 to 40 (see FIG. 5), the progress information of search A, search B, search C, and search D stored in the schedule information 120 storage unit is referred to. Then, one search command is selected from the search commands for which the search is incomplete, and the search progress frequency and bandwidth of the selected search command are instructed to each branch group A.

  The preset control unit 150 is a processing unit that registers preset information obtained as a search result by a branch group in the preset information storage unit 110. Specifically, when the search result is notified from the branch group, the search progress frequency of the search command corresponding to the branch group among the search progress frequencies stored as progress information in the schedule information storage unit 120 is searched this time. When the preset information is obtained as a search result, the preset information is registered in the preset information storage unit 110.

  When the preset control unit 150 receives a channel information call request from the AVN 3, the preset control unit 150 displays the preset information stored in the preset information storage unit 110 on a display device such as a touch panel included in the AVN 3.

  At this time, if the country information of one country is included in the preset information, as shown in FIG. 6, if the channel number is displayed and the language of two or more countries is included in one channel, the language is displayed. A selection button is also displayed. Also, if country information for more than two countries is included in the preset information, as shown in FIG. 7, if channel numbers are displayed by country and languages for more than two countries are included in one channel, For example, a language selection button is also displayed.

  In this way, when multiple country information is obtained as a search result for each branch group, channel information is displayed by country to prevent channel information from different countries from being displayed together, and at least two countries. It can be clearly stated that the broadcast channel is receivable.

  Next, the process flow of the DTV receiver according to the present embodiment will be described. Here, after (1) channel search control processing performed by the DTV control microcomputer 100 is described, (2) channel search processing performed by each branch group will be described.

(1) Channel Search Control Process As described above, here, the channel search control process according to the present embodiment will be described. This process is performed when the DTV receiver 1 is activated, that is, when the accessory is turned on, and is then repeatedly performed in a predetermined cycle in the background of the AVN 3 until a viewing request is received by the AVN 3.

  FIG. 8 is a flowchart illustrating the procedure of the channel search control process according to the present embodiment. As shown in FIG. 8, first, the grouping processing unit 130 includes a group A configured by the branch 10, a group B configured by the branch 20, a group C configured by the branch 30, and the branch 40. The diver switching unit 50 is instructed to perform grouping into four branch groups called group D and to perform switching control corresponding to the grouping (step S101).

  Subsequently, the search control unit 140 notifies each of the groups A to D of the search start frequency 470 MHz, the group A has a bandwidth of 8 MHz, the group B has a bandwidth of 7 MHz, the group C has a bandwidth of 6 MHz, and the group D. Is instructed to perform a channel search with a bandwidth of 5 MHz (step S102), and the channel search is started (step S103).

  Thereafter, when a search result is received from any branch group (step S104), the preset control unit 150 searches for the search command corresponding to the branch group among the search progress frequencies stored as progress information in the schedule information storage unit 120. The search progress frequency is updated to the frequency searched this time (step S105).

  At this time, if the preset information is obtained as a search result (Yes at Step S106), the preset control unit 150 registers the preset information in the preset information storage unit 110 (Step S107). If preset information has not been obtained as a search result (No at step S106), the process directly proceeds to step S108.

  When the search command corresponding to the branch group is completed, that is, when the search progression frequency stored in the schedule information storage unit 120 reaches 862 MHz (Yes in step S108), all of the searches A to D are performed. As long as the search command does not end (No at Step S109), the branch group for which the search has been completed is incorporated into a group for which no other search has been completed (Step S110).

  Here, when the reception intensity obtained as a search result changes from reception intensity “high”, “medium”, or “low” corresponding to the current grouping (Yes in step S111), the grouping processing unit 130 changes the reception intensity. If the received intensity is “high”, the groups A to D are grouped. If “medium”, the groups A and B are grouped. If the group is “low”, the groups A and D are grouped. The diver switching unit 50 is again instructed to do so (step S112).

  Then, the search control unit 140 refers to the progress information of search A, search B, search C, and search D stored in the schedule information storage unit 120, and determines the number of branch groups in the search command that has not been completed. A corresponding search command is selected, the search progress frequency and bandwidth of the selected search command are instructed to each branch group (step S113), and a transition to a search result standby state is made (step S104).

  If the reception strength obtained as a search result has not changed from “high”, “medium”, or “low” corresponding to the current grouping (No in step S111), the search result standby state is entered. The process proceeds (step S104), and the above steps S105 to 108 are repeated.

  When all the search commands of search A to search D are completed (Yes at step S109), the preset control unit 150 displays the preset information stored in the preset information storage unit 110, such as a touch panel provided in the AVN3. It is displayed on the device (step S114), enters the viewing channel standby state, and ends the process.

(2) Channel Search Processing Next, channel search processing according to the present embodiment will be described. This process is started when the search start frequency and bandwidth are set by the search control unit 140 or when the search progression frequency and bandwidth are reset. Note that, here, the branch 10 is illustrated as an example, and the processing content of a branch to which a demodulated broadcast signal is input among the branch groups constituting the diversity will be described.

  FIG. 9 is a flowchart illustrating the procedure of the channel search process according to the present embodiment. As shown in the figure, upon receiving an instruction from the search control unit 140, the branch 10 sets the search start frequency 470 MHz and the bandwidth (8 MHz, 7 MHz, 6 MHz, or 5 MHz) to the RF / IF unit 11 (step S201). A channel search is started, and the RF / IF unit 11 detects and amplifies the received signal, and the demodulator 12 demodulates the broadcast signal (step S202).

  Here, the program information acquisition unit 13 acquires TMCC from the broadcast signal input by the demodulation unit 11, and broadcasts to the broadcast channel being scanned set in the RF / IF unit 11 based on the acquisition result. Is determined (step S203).

  As a result, when acquisition of this TMCC is successful in the broadcast channel being scanned set in the RF / IF unit 11, that is, when there is a broadcast station (Yes in step S203), the program information acquisition unit 13 Program information such as PSI / SI is acquired from the broadcast signal of the broadcast channel (step S204).

  Then, the program information acquisition unit 13 associates the information such as PSI / SI and the broadcast channel corresponding to the broadcast signal from which the information is obtained, and receives the associated information in the broadcast signal of the broadcast channel. The preset is notified to the preset control unit 150 as a search result (step S205). If there is no broadcast station (No at Step S203), the preset control unit 150 is notified of a search result indicating that there is no corresponding broadcast station.

  Thereafter, until the search frequency reaches the search end frequency 862 MHz (No in step S206), the value obtained by adding the set bandwidth to the current search frequency is set as the next search frequency (step S207), and the above-described steps S202 to S206 are performed. The process is repeated, and the process ends when the search frequency reaches the search end frequency of 862 MHz (Yes at step S206).

  As described above, according to the present embodiment, the plurality of branches 10 to 40 are grouped into a plurality of branch groups, and the grouped branch groups are searched for broadcast channels with different frequency bandwidths. Therefore, as a result of performing the channel search in all the bandwidths that can be assumed for each branch group in parallel, the channel search can be performed including the bandwidth of the country where the digital television receiver is located, Channel search can be performed automatically without country designation.

  In the above embodiment, the case where the search commands A to D are executed without interruption from the search start frequency to the search end frequency has been described. However, it is necessary to perform channel search for all search commands. There is no.

  For example, a country-specific bandwidth storage unit that stores bandwidths by country is provided in the DTV control microcomputer 100 in advance, and the country information is obtained when the program information acquisition unit 13 acquires country information from PSI or SI. Bandwidth is acquired from the country-specific bandwidth storage unit, and subsequent channel searches can be performed by configuring diversity with multiple branches for only the bandwidth acquired from the country-specific bandwidth storage unit. .

  That is, by using the bandwidth of the country that cannot be received at the location where the DTV receiver 1 is located, the channel search is not performed wastefully, and only the bandwidth of the country that can be received at the location where the DTV receiver 1 is located is used. A channel search can be performed, and the efficiency of the channel search can be improved.

  Further, since the bandwidth used for the channel search can be carefully selected, the number of branches constituting the branch group can be increased as compared with the case where the channel search is executed for every type of bandwidth.

  In the above embodiment, the case where the frequency band from the search start frequency of 470 MHz to the search end frequency of 862 MHz is described has been described. However, it is not always necessary to perform a channel search for this frequency band.

  For example, a country-specific search range storage unit that stores a frequency search range for each country is provided in the DTV control microcomputer 100 and corresponds to the country when the program information acquisition unit 13 acquires the country information from PSI or SI. The search range to be acquired is acquired from the country-specific search range storage unit, and the subsequent channel search can be performed only for the frequency band of the search range acquired from the country-specific search range storage unit.

  That is, it is possible to perform a channel search only for the frequency band where the broadcasting station exists without performing a channel search for the frequency band where the broadcasting station does not exist, and the frequency from the search start frequency 470 MHz to the search end frequency 862 MHz. As a result of being able to shorten the search range as compared with the band search, it is possible to improve the efficiency of channel search.

  In the above embodiment, the grouping performed by the grouping processing unit 130 has been described as being grouped into four, two, or one branch group. However, it is naturally possible to group into three branch groups. Needless to say, the number of branches and the number of constituent branches constituting the branch group are arbitrary.

  In the above-described embodiment, the case where the UHF band broadcast channel is searched has been described. However, the present invention is not limited to this, and the present invention is similarly applied to the case of searching for a broadcast channel in another frequency band. it can.

  In the above embodiment, the case where the present invention is applied to a DTV receiver has been described. However, the present invention is not limited to this, and a digital radio receiver, a mobile phone, a radio, a wireless LAN (Local It can be applied to receivers such as (Area Network) devices.

  As described above, the receiving apparatus and the broadcast channel detection method thereof according to the present invention are suitable for automatically performing a channel search without a country designation from the user.

DESCRIPTION OF SYMBOLS 1 DTV receiver 10, 20, 30, 40 Branch 11, 21, 31, 41 RF / IF part 12, 22, 32, 42 Demodulator 13, 23, 33, 43 Program information acquisition part 50 Diver switching part 60 Decoder 100 DTV control microcomputer 110 Preset information storage unit 120 Schedule information storage unit 130 Grouping processing unit 140 Search control unit 150 Preset control unit 3 AVN

Claims (4)

A receiving device having a function of detecting a receivable broadcast channel,
A plurality of branches for receiving broadcast signals transmitted from a broadcasting station;
Grouping means for grouping the plurality of branches into a plurality of branch groups;
And a search control means for causing the branch groups grouped by the grouping means to search the broadcast channel with different frequency bandwidths. Receiving intensity acquisition means for acquiring the receiving intensity from each branch group grouped by the grouping means,
The grouping means performs grouping so that the number of branches constituting the branch group used for searching the broadcast channel increases as the reception strength acquired by the reception strength acquisition means decreases. Item 4. The receiving device according to Item 1.   3. The receiving apparatus according to claim 1, further comprising display control means for displaying channel information for each country when a plurality of country information is obtained as a search result for each branch group. A broadcast channel detection method of a receiving apparatus having a function of detecting a receivable broadcast channel,
A grouping step of grouping a plurality of branches that receive broadcast signals transmitted from a broadcasting station into a plurality of branch groups;
And a search control step of causing the branch groups grouped by the grouping step to search for the broadcast channel with different frequency bandwidths.

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