JP2001251229A - Broadcast receiver for mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcast receiver for mobile body that can prevent errors in switching timing and undesirable switching to a channel, whose signal quality is deteriorated due to multi-path possibly caused in an automatic channel switching system at a border of broadcast areas. SOLUTION: When a 1st reception system 3 detects entry to a broadcast area border, on the basis of navigation information (a) obtained during reception, a 2nd reception system 3' selects a channel of the same sequence as that of a received channel. A microcomputer 4 receives signal quality data c, c' from Viterbi decoders 34, 34' of the 1st and 2nd reception systems 3, 3' and compares the signal quality of both the reception systems, to switch the active reception signal system from the 1st reception system 3 into the 2nd reception system 3', when the signal quality of the channel in a succeeding broadcast area is higher than the signal quality of the channel in the current broadcast area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terrestrial digital television receiving technology with an automatic channel switching function for mounting on a moving object. More specifically, when a vehicle or the like is moved, reception is performed while automatically switching to a channel (broadcasting station) of the same series, thereby enabling the same program to be continuously viewed without operation by a viewer. The present invention relates to a body broadcast receiver.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a configuration example of a conventional terrestrial analog television receiver. In FIG. 6, a channel selection button 69 is used to select a channel desired by a viewer, and a remote control circuit 70 selects channel information from a remote control (remote control device) independent of the television (television receiver) main body. And transmits it to the channel selection position detection circuit 67.

A tuning position detecting circuit 67 which has received a tuning signal from the receiving channel tuning button 69 or the remote control circuit 70 outputs a voltage corresponding to the tuning channel stored in the receiving channel storage circuit 62 in advance. . This voltage is applied to the band switching circuit 63 and the tuning signal generation circuit 6
4 to generate a voltage necessary for band switching and tuning of the tuner to control the tuner 61.

[0004] Similarly to a home terrestrial television, an on-vehicle TV tuner unit selects a channel by a channel selection button 69 as shown in FIG. 6 or remote-controls a channel selection signal from a remote controller independent of the TV body. Circuit 7
It was sent through 0 and tuned in.

[0005] Even with the above-described method, a home television can continuously enjoy clear images and sounds once a desired channel is set. However, if you leave the original broadcasting area (for example, the Kanto area, the Osaka area, each prefecture, etc.) at the time of departure due to the movement of the car, the on-board TV will show the program you have been watching on the same channel. It was necessary to switch channels in order to keep watching programs from the same affiliated station.

More specifically, when a terrestrial television set is received by a mobile unit, as a specific example, if the user moves to the Kinki area while watching the NHK general television broadcast of 3 channels (channels) in the Chukyo area, 2 channels will be used in the Kinki area. If the channel is left as it is because it is an allocated channel for television broadcasting, the program that has been viewed until now becomes unreceivable.

[0007] Therefore, in order to continuously watch the same program, it is necessary for the driver or passenger to switch channels. In the case of the NHK comprehensive TV channel, the number of channels is only one difference between the Chukyo area and the Kinki area (3 channels in the Chukyo area, 2 channels in the Kinki area), so when switching channels, it takes much time to find the channel to switch to. Although it does not take long, private broadcasts, for example, in the case of ○○○ TV station series, ○○ △ TV broadcast (35c
In order to change the channel from h) to ○ △ ○ TV broadcasting (10 ch) in the Kinki region, it will be difficult and time-consuming to search for a target channel unless the TV channel selector knows the channel of the affiliated station in advance. Further, there is a problem that performing such a channel selection operation while driving while the driver is driving alone is dangerous.

[0008] In order to solve such a problem, when a broadcast area is changed, a tuner unit of a television broadcast receiver for reselecting and displaying a channel on which a target program is broadcast is positioned from a navigation device. A device 60 'for automatically re-selecting a channel by judging a change between the vehicle position and the broadcast area based on the information has also been devised. FIG. 7 shows a typical example of such an apparatus. Further, in some cases, the tuner unit 60 'shown in FIG. 7 is improved or developed so that the electric field level of the broadcast wave is used as a criterion for switching channels and determining whether or not the program is the same, in addition to the information from the navigation device 100. Such a device 60 "
8 is shown in FIG.

[0009]

However, based on the position information from the navigation device 100 as described above, a tuner unit for judging a transition between the vehicle position and the broadcast area and automatically reselecting a channel, for example, as shown in FIG. In the tuner unit 60 ″ of the configuration example shown in FIG. 7, a CD-ROM or DV
If D does not include data for judging the structure at the boundary of the broadcast area or the surrounding terrain, the distance from the position of the vehicle may be increased even though the propagation path of the broadcast wave is blocked by a building or the like. There is a problem that the closest transmitting station is determined as a result, and as a result, the channel may be switched to a channel having worse radio wave quality.

[0010] Further, even if channel switching is determined in consideration of a building at the boundary of a broadcasting area and surrounding terrain, a commercially available navigation device updates map data and building information in real time. Not updated, but updated after a certain period of time,
Because it is practically impossible to respond to a newly built building in real time, even though the propagation path of the broadcast wave is blocked by a building that is not registered in the database, There is a case where the position of the transmitting station closest in distance to the position is determined, and as a result, the channel is switched to a channel having a worse radio wave quality.

The tuner unit 60 ″ of the configuration example shown in FIG. 8 solves the problem of switching to a channel in which video and audio are degraded at the boundary of the broadcast area. In addition to the electric field strength of the broadcast wave
It is possible to exclude a case where the electric field strength is reduced due to an obstacle even though the transmitting station is closest to the own vehicle position. Therefore, there is an advantage that errors are reduced as compared with a case where channel switching is performed based on only the navigation information, and the possibility of selecting a channel with further degraded image quality and audio during automatic channel switching is reduced. However, in a multipath environment at the boundary of a broadcast area as shown in FIG. 9, there are the following problems.

In FIG. 9, reference numerals A and B denote broadcast stations, C denotes an on-vehicle receiver, D denotes a building capable of reflecting radio waves, and on-vehicle receiver C extends from a broadcast area α of the broadcast station A to a boundary area between the broadcast stations. It is assumed that the vehicle is passing through γ to the broadcast area β of the broadcast station B. Symbols a and b are propagation paths of direct waves, c is a propagation path of reflected waves, and the in-vehicle receiver C is located at a position closer to the broadcasting station B (that is, a> b) within the boundary area γ. If the routes a and b have a relationship of a> b in terms of distance, the superposition of the radio waves from the routes a and b causes the superposition of the radio waves from the broadcast station A received by the in-vehicle receiver C. The electric field level may be higher than the electric field level of the radio wave from the broadcasting station B received from the propagation path b (however, in this case, when the video and audio actually received and output are compared, the broadcasting station B Better results are obtained with radio waves from).

That is, in a multipath environment as shown in FIG. 9, when a channel is switched by a tuner unit having a configuration as shown in FIG. 8 based on the position information from the navigation device and the electric field strength, Problems such as selecting the channel of broadcasting station A where the video and audio are deteriorated (automatic channel selection, which would save the driver and passengers the trouble of selecting a channel, would cause the driver or passenger to select However, there is a problem that the station needs to be re-tuned, and a problem that deviates from the original purpose of the automatic tuning may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is intended for a channel in which switching error due to multipath or signal quality is deteriorated, which can occur in an automatic channel switching system at a boundary of a broadcast area. It is an object of the present invention to provide a mobile broadcast receiver capable of preventing the switching of the broadcast.

[0015]

According to the present invention, when a channel is switched, reception position information ("own vehicle position information", "broadcast station position information, broadcast area, etc.") detected by reception position detecting means such as a navigation device is provided. Information "),
Next, a channel predicted to be switched (selected) is received by a second receiving system provided separately, and the reception state (quality of a received signal) of the channel received by the second receiving system is determined by: The reception state (quality of the received signal) of the channel currently being received (outputting) is compared with the reception state, and the reception of the channel whose signal quality is determined to be good based on the comparison result is performed.

More specifically, in order to solve the above-mentioned problems, a mobile broadcast receiver according to a first invention receives a first broadcast and a second broadcast. Second
Receiving means, a receiving position detecting means for detecting a receiving position, a receiving position detected by the receiving position detecting means, and receiving by the second receiving means based on broadcast area information corresponding to the receiving position. Receiving control means for controlling the first and second receiving means,
And a broadcast selecting means for selectively outputting a broadcast having a good reception state based on a result of the comparison by the comparison means. Features.

Further, a mobile broadcast receiver according to a second aspect of the present invention includes a first receiving means for receiving a first broadcast;
Broadcast output means for outputting only the broadcast received by the receiving means, and second receiving means for receiving the second broadcast;
Receiving position detecting means for detecting a receiving position; receiving position detected by the receiving position detecting means; and receiving control means for controlling reception by the second receiving means based on broadcast area information corresponding to the receiving position. Comparing means for comparing the reception state of the first broadcast received by the first receiving means with the reception state of the second broadcast received by the second receiving means; Receiving broadcast selecting means for causing the first receiving means to receive a broadcast having a good state as a first broadcast and receiving a broadcast having a poor receiving state as a second broadcast.

According to a third aspect of the present invention, in the mobile broadcast receiver according to the first or second aspect, the second broadcast is a broadcast based on information about a network station that broadcasts the same program. And

According to a fourth aspect of the present invention, there is provided the mobile broadcast receiver according to the second aspect of the present invention, wherein the most receiving is performed based on a plurality of antennas and a reception state of the second broadcast received by the second receiving means. Antenna selection means for selecting an antenna in a good state.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment (1)] FIG. 1 is a block diagram showing a configuration of an embodiment of a terrestrial digital television receiver mounted on a mobile object according to the present invention. The device 2 includes a first reception system 3 including a reception circuit 31, an IF circuit 32, a demodulation circuit 33, and a Viterbi decoding unit 34.
Receiving circuit 31 ', IF circuit 32', demodulating circuit 33 '
And a second receiving system 3 'comprising a Viterbi decoding unit 34'
And a microcomputer (microcomputer) 4 and a system switching unit 5 (note that components after the system switching unit 5 are not shown because they are not directly related to the description of the basic elements of the present invention). ). The terrestrial digital television receiver 2 is configured to be connectable to the navigation device 100, and inputs navigation information a from the navigation device 100. The navigation device 1 connected to the terrestrial digital television receiver 2 of the present invention
00, the broadcast station position, broadcast area boundary information, and the like are registered. The navigation information a sent from the navigation device 100 to the terrestrial digital television receiver 2 includes the own vehicle position, a broadcast station near the own vehicle position, Location (plural), broadcast area boundary information with these broadcasting stations, etc.
Information necessary for automatic channel selection control by the microcomputer 4 (described later (see FIGS. 2 and 4)) is included.

Radio wave received by antenna 1 (received signal)
Is received in the first signal system 3 in the initial state,
The output signal b (data of video, audio, EPC, etc.) passes through the system switching unit 5 and continues to the hierarchical division / TS (transport stream) playback unit. The Viterbi decoding unit 3
4 outputs data relating to signal quality to the microcomputer 4.

When the moving object approaches the broadcasting area, the radio wave received by the antenna 1 is also received and processed by the second signal system 3 'under the control of the microcomputer 4.
A signal b ′ (data such as video, audio, EPC, etc.) is output (when the output signal b ′ is switched from the first reception system to the second reception system by the system switching unit 5,
It is provided to the hierarchical division / TS reproduction unit through the system switching unit 5). Further, the Viterbi decoding unit 34 ′ outputs data relating to signal quality to the microcomputer 4.

The microcomputer 4 is composed of a microcomputer incorporating a CPU, a RAM, a program and peripheral circuits, and executes an automatic channel selection control operation as described later.
The channel switching operation is controlled by the CPU based on a program (automatic channel selection control program) incorporated in the microcomputer 4. The automatic tuning control program can be configured as firmware. In the embodiment, the program is stored in a program storage memory (ROM or the like) provided in the microcomputer 4, and is read into the RAM and executed when the apparatus is started. Is done.

The system switching unit 5 switches the receiving system in response to a switching control signal e output from the microcomputer 4 (this switching causes the hierarchical division / TS reproducing unit to output signals (video, video, Voice, E
PC).

(Example of Automatic Tuning Control Operation) FIG. 2 is a flowchart showing one embodiment of the automatic tuning control operation by the microcomputer of the terrestrial digital television receiver mounted on the mobile unit in FIG. Step S0: (Initial Setting Operation) In FIG. 1, the microcomputer 4 includes the receiving circuit 31 of the first receiving system 3.
Control signal d to start the reception processing of the radio wave received from the antenna 1 for the channel selected by the user, and the system switching unit 5, the switching control signal e
To switch the reception system so that the output signal b from the first signal system 3 is sent to the hierarchical division / TS reproduction unit.

Step S1: (Reception Processing) The radio wave received by the antenna 1 is switched by the reception system switched by the system switching unit 5 (the first reception system 3 in the initial state, and switched when the reception system is switched in step S8). Reception processing is performed in a subsequent reception system (that is, either the second reception system 3 ′ or the first reception system 3), and the output signal b or b ′ is hierarchically divided by the system switching unit 5.
The signal is supplied to the S reproduction unit (that is, the reception processing signal by the switched reception system is reproduced and viewed).

Step S2: (Acquisition of Navigation Information and Judgment of Approach to Boundary Area) The microcomputer 4 acquires the navigation information a sent from the navigation device 100 and determines whether or not the own vehicle is within the boundary of the broadcast area. It is determined, and if the vehicle is approaching the boundary of the broadcast area, the process proceeds to S3. If not, the process returns to S1 to repeat the reception processing operation.

Step S3: (Acquisition of Channel of Broadcasting Area to Enter) The microcomputer 4 acquires information of the broadcasting area to enter based on the current position of the own vehicle, and the same series as the broadcasting station (channel) of the program currently being received. Is selected from the broadcasting stations in the broadcasting area to enter.

Step S4: (Start of Reception Processing by Both Reception Systems) The microcomputer 4 operates a reception circuit of a reception system different from the reception system currently performing reception processing (if the current reception system is the first reception system 3, The receiving circuit 31 'of the second receiving system 3', or the receiving circuit 31 of the first receiving system 3 when the current receiving system is the second receiving system 3 ', the channel number (step S4). Alternatively, a control signal d '(d) including the center frequency of the selected channel is transmitted to select a channel in the same series as the currently received channel.
As a result, the reception processing of the two channels by the first and second reception systems 3, 3 'is started.

Step S5: (Reception processing and output of signal quality by both reception systems) The first and second reception systems 3, 3 'are respectively connected to the antenna 1
The reception processing is performed on the channel selected from the received radio wave from the receiver (however, the output signal from the receiving system that has been switched by the system switching unit 5 is given to the hierarchical division / TS reproduction unit). Also, the Viterbi decoding units 34 and 34 '
Sends data on signal quality to the microcomputer 4.

Step S6: (Comparison of signal quality) The microcomputer 4 transmits the data relating to the signal quality transmitted from the Viterbi decoding unit 34 of the first receiving system 3 and the Viterbi decoding unit 34 'of the second receiving system 3'. c and c ′ are taken in, and the signal quality of the receiving system is compared and determined based on them.
If the signal quality of the channel in the next broadcast area is better than the signal quality of the channel in the current broadcast area,
The process transits to S7 for switching the signal system. If the signal quality of the channel in the current broadcast area is better than the signal quality of the channel in the next broadcast area, the process returns to S5. The data relating to the signal quality refers to a signal correlated with the signal quality output from the Viterbi decoding unit. Examples of such a signal include a difference between a maximum value and a minimum value of a path metric, and a maximum path value. The difference between the metric and each other metric, the rate of increase of the maximum metric, the correlation data between the decoded data re-encoded sequence and the received data sequence, etc.
One known one may be used (in the embodiment, the Viterbi decoding unit 3
The difference between the maximum value and the minimum value of the path metric sent from 4,4 ′, Δ, Δ ′ is divided for each bit or for each block, and the average value is compared for each block. Is determined).

Step S7: (Transmission of switching signal) If it is determined in step S6 that the signal quality of the channel in the next broadcast area is better than the signal quality of the channel in the current broadcast area, the microcomputer 4 sends a switching control signal e to the system switching unit 5.

Step S8: (Switching of Reception System) Upon receiving the switching control signal e from the microcomputer 4, the system switching unit 5 switches the input destination of the output signal subjected to the reception processing to a reception system different from the current reception system ( That is,
When the output signal b from the current receiving system 3 is being input, switching is performed so as to input the output signal b 'from the receiving system 3').

Step S9: (Tuning determination based on transition of reception quality after switching of reception system) The microcomputer 4 checks the transition of reception quality by the reception system even after switching at step S8, and when the transition is stable. A receiving circuit of a receiving system different from the receiving system to which the input destination of the output signal is switched in the above step S8 (the first receiving system in the case of switching to the second receiving system 3 ′ in step S8). 3 receiving circuit 31, first receiving system 3
Is switched to the receiving circuit 31 ') of the second receiving system 3') to stop the receiving process of the receiving system and then return to S1. As a result, when the transition of the reception quality is not stable, that is, when the broadcast area is complicated, the superiority of the reception quality may be reversed in a short time as the vehicle moves. In such a case, the receiving system can be switched again. The determination of the transition of the reception quality is performed, for example, by storing the determination results of the signal quality of both systems in a memory in a time-series manner (the determination results may be sampled and stored). (For example, 30 minutes) can be determined based on whether all the determination results match.

When the vehicle enters the next broadcast area in step S9, the same program can be continuously received in the broadcast area in steps S1 and S2, and after traveling for a while, the vehicle approaches the third broadcast area. If the deterioration of the output signal in the receiving system after the switching becomes remarkable, the judgment of step S2 determines in steps S3 to S6 the signal reception and signal quality comparison of both receiving systems and steps S7 and S8.
, The switching operation of the receiving system is performed. That is, by repeating the series of operations in FIG. 2, automatic channel switching (automatic channel selection) at the boundary of the broadcast area is smoothly performed.

[Embodiment (2)] FIG. 3 is a block diagram showing a configuration of another embodiment of a terrestrial digital television receiver for mounting on a mobile object according to the present invention, and is a terrestrial digital television receiver 2 '. Has a configuration in which the system switching unit 5 is omitted from the configuration of the terrestrial digital television receiver 2 in FIG. In FIG. 3, only data relating to signal quality is taken out from the second receiving system 3 ', and the channel switching control operation of the microcomputer 4' (see FIG. 4) is performed by the microcomputer 4 'of FIG.
(FIG. 2). That is, the radio wave (received signal) received by the antenna 1 is subjected to reception processing by the first signal system 3 and its output signal b (data such as video, audio, EPC, etc.)
Is sent to a hierarchical division / TS (transport stream) reproducing unit (the Viterbi decoding unit 34 outputs data relating to signal quality to the microcomputer 4). On the other hand, when the moving object approaches the broadcast area, the radio wave received by the antenna 1 is received and processed by the second signal system 3 'based on the control of the microcomputer 4', and the Viterbi decoding unit 34 'relates to the signal quality. Output data.

The microcomputer 4 'has the same configuration as the microcomputer 4 of FIG. 1, but performs an automatic channel selection control operation different from that of the microcomputer 4 shown in FIG. 2 as described later (FIG. 4). The automatic tuning control operation is controlled by the CPU based on a program (automatic tuning control program) incorporated in the microcomputer 4 '.

(Example of Automatic Tuning Control Operation) FIG. 4 is a flowchart showing one embodiment of the automatic tuning control operation by the microcomputer of the terrestrial digital television receiver mounted on the mobile unit in FIG. Step T1: (Reception processing by the first reception system) The radio wave received by the antenna 1 is subjected to reception processing by the first reception system 3, and the output signal b is provided to the hierarchical division / TS reproduction unit (that is, the first reception). The reception processing signal by the system 3 is reproduced and viewed).

Step T2: (Acquisition of Navigation Information and Judgment of Approach to Boundary Area) The microcomputer 4 'acquires the navigation information a sent from the navigation device 100 and determines whether or not the own vehicle is approaching the boundary of the broadcast area. Is determined, and if the vehicle is approaching the boundary of the broadcast area, the process transits to T3. If not, the process returns to T1 and repeats the reception processing operation.

Step T3: (Acquisition of Channel of Incoming Broadcasting Area) The microcomputer 4 'acquires information of the entering broadcasting area based on the current position of the car, and obtains the same series as the broadcasting station (channel) of the program currently being received. From the broadcast stations in the broadcast area where the broadcast station enters.

Step T4: (Tuning by the second receiving system) The microcomputer 4 'sends the channel number (or the channel number) acquired in step T3 to the receiving circuit 31' of the second receiving system 3 '.
A channel switching control signal d 'including the center frequency of the selected channel) is sent to select the same channel. As a result, the receiving circuit 31 'of the second receiving system 3' selects a channel that is the same as the channel that has been received so far.

Step T5: (Reception processing and signal quality output by both receiving systems) The first and second receiving systems 3, 3 '
The reception processing of the channel selected from the received radio wave from the receiver is performed (however, an output signal is output only to the first reception to the hierarchical division / TS reproduction unit). Also, the Viterbi decoding unit 34,
34 'sends data c and c' relating to signal quality to the microcomputer 4 '.

Step T 6: (Comparison of signal quality) The microcomputer 4 ′ sets the Viterbi decoding unit 34 of the first reception system 3.
And the data c and c 'relating to the signal quality sent from the Viterbi decoding unit 34' of the second receiving system 3 ', and comparing them to determine the signal quality of the receiving system. If the signal quality of the received signal from the previous broadcast area being received is less than the signal quality of the received signal from the next broadcast area, the process goes to T7. Also,
If the signal quality of the signal received from the previous broadcast area being received by the second receiving system 3 'is good in the current broadcast area, the process returns to T5.

Step T7: (Reversal of the channels of both receiving systems) The microcomputer 4 'sends the channel number (or the center frequency of the selected channel) obtained in step T3 to the receiving circuit 31 of the first receiving system 3. ) Is sent to select a channel of the same series. Further, it transmits a channel switching control signal d 'including the channel number (or the center frequency of the channel) selected by the first receiving system 3 to the receiving circuit 31' of the second receiving system 3 '. Thereby, the first receiving system 3
Causes the same channel as that of the broadcasting station that has been received to be selected, and the second reception system 3 ′ to select a channel that has been selected by the first reception system 3.

Step T8: (Determining whether or not the reception quality of the second reception system has progressed) The microcomputer 4 'checks the transition of the reception quality of the second reception system, and the transition continues to deteriorate, and as a result, the deterioration has been remarkably deteriorated. In this case, the control signal is sent to the receiving circuit 31 'of the second receiving system 3' to stop the receiving process of the receiving system, and then the control is returned to T1. If the degree of deterioration is within the threshold, the process returns to T5.

By operating as described above, the terrestrial digital television receiver 2 'shown in FIG. 3 can smoothly perform automatic channel switching at the boundary of the broadcast area, similarly to the terrestrial digital television receiver 2 shown in FIG. Can be done.

(Application Example) FIG. 5 is a block diagram showing an application example of the automatic channel selection method of the terrestrial digital television receiver shown in FIG. 3, and shows an example in which the method is combined with antenna diversity. The configuration and operation of the terrestrial analog television receiver 2 ″ relating to automatic channel selection (that is, the automatic channel selection control operation by the microcomputer 4 ″ is the same as the configuration and operation of the terrestrial analog television receiver 2 ′ in FIG. 3 (FIG. 4). ) Is the same.

In this example, a plurality of data (four in the embodiment, but not limited to this number) are used by using data relating to the signal quality from the second receiving system 3 'and the switches 7, 8 and the microcomputer 4 ". An antenna diversity system can be configured by selecting an antenna having the best signal quality from the antennas 1 'and sequentially switching the first receiving system 3 to an antenna having a good signal quality.

It should be noted that whether to give priority to antenna switching or channel switching is determined by the navigation device 10.
The determination must be made in consideration of the navigation information a and the like obtained from 0, and the same antenna must be used for comparison at the time of channel switching determination.

When the same program is broadcasted by the same series of broadcasting stations at the time of channel switching, it is determined whether a terrestrial television broadcast is digitized by an EPG (EPG) transmitted by the same broadcast in addition to the television program. (Electric program guide) Information is added with information about a network that broadcasts the same program, and the information is broadcasted. The receiver takes out the information and makes a determination, whereby technically the same number can be easily determined.

In each of the above embodiments, the navigation device is connected to the terrestrial digital television receiver. However, the navigation device is configured to share the screen of the terrestrial digital television receiver and the monitor screen of the navigation device. Alternatively, the terrestrial digital television receiver and the navigation device may be integrally configured.

In each of the above-described embodiments, the reception position detecting means includes a navigation device including a mobile terminal mounted on a terrestrial digital receiver, which includes position information of a mobile unit, broadcast station position information, broadcast area information, and the like. An example in which information is provided is shown, but the present invention is not limited to this. For example, navigation information including position information is acquired from a navigation device, and a terrestrial digital receiver is provided with a database storing broadcast station position information and broadcast area information, etc., based on the navigation information of the navigation device. The microcomputer may be configured to determine the broadcast station position and the broadcast area boundary.

The position information is not limited to acquisition from the navigation device. For example, it may be obtained using a map database based on speed information from a vehicle speed sensor and direction information from a direction sensor. As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, It cannot be overemphasized that various deformation | transformation implementation is possible.

[0054]

As described above, according to the mobile broadcast receivers of the first to third aspects of the invention, the advantages of the automatic channel selection system proposed in the conventional analog television, that is, when the user gets on the vehicle, This eliminates the need for a person to tune in directly, so it is convenient because the driver is automatically selected even if the driver or passenger enters an area that does not know the channel correspondence with the broadcast station, such as when driving a long distance. In addition, it is possible to reduce the risk of harmful actions such as selecting a channel while driving when the driver is alone, and enjoy the digital television receiver as it is. it can.

In addition, since the channel is switched by comparing the reception state (signal quality), in a multipath environment that may occur at the boundary of the reception area, it is more effective than the conventionally proposed electric field level comparison method. Channel switching (automatic channel selection) in accordance with the target and signal quality can be performed.

In particular, with the digitization of terrestrial television,
Since the quality of television video and audio in mobile communication is better than analog, it is expected that discomfort to viewers will increase if a channel with a deteriorated signal quality is selected by mistake when switching channels. While this may hinder the spread of television receivers,
The use of the digital television receiver to which the automatic channel selection system of the present invention is applied can prevent such a problem from occurring.

According to the mobile broadcast receiver of the fourth invention, the antenna having the best reception state is selected according to the reception state of the second receiving means (second reception system).
When the moving object enters the boundary of the broadcast area, the channel can be automatically selected when the reception state of the next broadcast is improved. That is, a plurality of roles are imposed on the second receiving means, and the second receiving means can be effectively used, and the receiving quality can be further improved. In addition, the conventional method (Japanese Patent No. 276503)
7, the cost can be reduced when there are three or more antennas. In addition, compared with the conventional one-reception system diversity system, the waste of switching the antenna (that is, the deterioration of the signal quality due to the sequential comparison of the signal levels in the reception system that sends the signal including the video and audio information to the back end) is minimized. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of a terrestrial digital television receiver mounted on a mobile object according to the present invention.

FIG. 2 is a flowchart showing an embodiment of an automatic tuning control operation by a microcomputer.

FIG. 3 is a block diagram showing a configuration of an embodiment of a terrestrial digital television receiver mounted on a mobile object according to the present invention.

FIG. 4 is a flowchart showing one embodiment of an automatic tuning control operation by the microcomputer.

FIG. 5 is a block diagram illustrating an application example of the automatic channel selection method of the terrestrial digital television receiver in FIG. 3;

FIG. 6 is a block diagram of a configuration example of a conventional terrestrial analog television receiver.

FIG. 7 is a block diagram of a configuration example of a conventional terrestrial analog television receiver.

FIG. 8 is a block diagram of a configuration example of a conventional terrestrial analog television receiver.

FIG. 9 is an explanatory diagram illustrating an example of a multipath environment at a broadcast area boundary.

[Explanation of symbols]

1 'Plural antennas 2, 2', 2 "Terrestrial digital television receiver (mobile broadcasting receiver) 3 First receiving system (first receiving means) 3 'Second receiving system (second Receiving means) 4,4 ', 4 "microcomputer (receiving control means, comparing means,
Receiving broadcast selecting means, antenna selecting means) 100 Navigation device (receiving position detecting means)

Claims (4)

[Claims] 1. A first receiving means for receiving a first broadcast, a second receiving means for receiving a second broadcast, a receiving position detecting means for detecting a receiving position, and a receiving position detecting means A reception control unit that controls reception by the second reception unit based on the detected reception position and broadcast area information corresponding to the reception position; and a first reception unit that is received by the first and second reception units. Comparing means for comparing the reception state of the broadcast with the reception state of the second broadcast, and broadcast selection means for selectively outputting a broadcast having a good reception state based on the comparison result by the comparison means. Characteristic broadcast receiver for mobile. 2. A first receiving means for receiving a first broadcast, a broadcast output means for outputting only a broadcast received by the first receiving means, and a second receiving means for receiving a second broadcast Means, a receiving position detecting means for detecting a receiving position, and controlling the receiving by the second receiving means based on the receiving position detected by the receiving position detecting means and broadcast area information corresponding to the receiving position. Reception control means; comparison means for comparing the reception state of the first broadcast received by the first reception means with the reception status of the second broadcast received by the second reception means; comparison by the comparison means Receiving broadcast selecting means for causing the first receiving means to receive a broadcast having a good reception state as a first broadcast and receiving a broadcast having a poor reception state as a second broadcast based on the result. Especially Moving object broadcast receiver to be. 3. The mobile broadcast receiver according to claim 1, wherein the second broadcast is a broadcast based on information on a network station that broadcasts the same program. 4. An apparatus comprising: a plurality of antennas; and antenna selection means for selecting an antenna having the best reception state based on a reception state of a second broadcast received by the second reception means. The broadcast receiver for a mobile object according to claim 2, wherein