JP2006013945A - Ground digital broadcasting receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground digital broadcasting receiver capable of updating a receivable channel to the latest state by corresponding to a change in a receiving area by the movement of the receiver and a change in the receivable channel by a change in the number of broadcasting stations. <P>SOLUTION: This ground digital broadcasting receiver receives a broadcast signal of ground digital broadcasting and is mounted on a portable information terminal or on-vehicle television receiving apparatus. The ground digital broadcasting receiver is provided with a first receiving means for receiving the broadcast signal, a signal processing means for processing the broadcast signal received by the first receiving means and outputting the broadcast signal to a display part, a second receiving means for receiving the broadcast signal, and a control means for scanning the broadcast signal in the entire frequencies, controlling the second receiving means so as to detect the receiving intensity of each frequency, comparing whether the receiving intensity is equal to or greater than a threshold, preparing a list of receivable channels, using the list to make the first receiving means scan the broadcast signal, and using a changed list to make the first receiving means scan the channels again when the contents of the list are changed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a terrestrial digital broadcast receiver, and more particularly to a terrestrial digital broadcast receiver that automatically scans the frequency of a receivable channel when the receivable channel is changed.

  When the television receiver is mounted on a portable information terminal or the like, when the user moves, the reception area of the television broadcast is changed, and the receivable channel is changed. Therefore, the user needs to scan the channel again and change the channel setting in order to cope with such a change in the receivable channel. Conventionally, such channel rescanning has been performed manually by the user and has been very cumbersome. In order to solve this problem, a television receiver that automatically performs channel rescanning or a device equipped with the television receiver has been proposed.

  For example, Patent Document 1 describes a portable terminal device equipped with a television receiver. This mobile terminal device stores a region code and a receivable channel for each region, and when the reception region is changed due to the movement of the user, the mobile terminal device can be located at the current position based on the position information transmitted from the base station Display receivable channels on the screen.

  Patent Document 2 describes a portable terminal device equipped with a broadcast receiving device. This mobile terminal device receives region identification information every predetermined time, receives the region identification information from the base station when the service area of the broadcasting station is changed as the user moves, and stores the information in advance Compared with the identification information, the area identification information before and after the movement is compared. If the two information are the same, the channel setting information before the movement is retained. If the information is not the same, the area identification information after the movement is stored, and the channel information corresponding to the area identification information stored in the memory in advance is read. Change the channel settings.

  Patent Document 3 describes an in-vehicle television device. In this vehicle-mounted device, when the power is initially turned on, channel assignments in all television broadcast frequency bands are read from the ROM, and it is determined whether or not each channel has a tuning frequency assignment. Then, the channel to which the tuning frequency is assigned is extracted and written as a channel plan in the RAM. When the self-check mode for receiving broadcast signals at the tuning frequency corresponding to the channel number order is set for the channel to which the tuning frequency is assigned at the time of subsequent power-on, tuning is performed for three or more channels. If no frequency is assigned, channel assignments in all television broadcast frequency bands are read from the ROM, broadcast signals are received at the tuning frequencies corresponding to the respective channels, the channels to which the tuning frequencies are assigned are extracted and stored in the RAM. Overwrite memorized channel plan.

Patent Document 4 describes an information processing apparatus with a built-in television broadcast receiver. This information processing apparatus includes a television receiving unit that directly receives a television broadcast radio wave and a communication unit that uses a wireless mobile phone or the like. It is possible to receive broadcasts.
JP 2003-309774 A JP 2003-174376 A Japanese Patent Laid-Open No. 2002-176591 JP 2003-69910 A

  As described above, in the mobile terminal device described in Patent Document 1, the channel setting is changed based on the area code and the receivable channel for each area stored in advance, so the stored information must be updated. In this case, there is a problem that the latest receivable channel cannot be supported. Also with respect to the portable terminal device described in Patent Document 2, since channel setting is performed based on channel information stored in advance, it is not possible to correspond to the latest receivable channel unless channel information is updated. There is. Further, in the in-vehicle television device described in Patent Document 3, the list of receivable channels can be rewritten in accordance with the change of the reception area, but the change of the reception area can be recognized when the apparatus is turned on. However, when mounted on a mobile terminal or the like that moves in a reception area with the power turned on, it is impossible to rewrite the channel list. In the information processing apparatus described in Patent Document 4, a reception unit that directly receives broadcast radio waves and a reception unit that receives broadcast waves can be switched according to the reception state. It does not address how to respond to possible broadcast station changes.

  Accordingly, an object of the present invention is to provide a terrestrial network capable of updating a receivable channel to the latest state in response to a change in reception area due to movement of a receiver or a change in receivable channel due to a change in the number of broadcasting stations. It is to provide a digital broadcast receiver.

A terrestrial digital broadcast receiver according to a first aspect of the present invention is a terrestrial digital broadcast receiver that receives a terrestrial digital broadcast signal and is mounted on a portable information terminal or an in-vehicle television receiver,
First receiving means for receiving a broadcast signal, signal processing means for processing the broadcast signal received by the first receiving means and outputting it to the display unit, second receiving means for receiving the broadcast signal, and all the broadcast signals Scan by frequency, control the second receiving means to detect the reception strength of each frequency, compare whether the reception strength is above the threshold, create a receivable channel list, and use this list Control means for causing the first receiving means to scan the channel again using the changed list when the broadcast signal is scanned by the first receiving means and the contents of the list change. It is characterized by.

  This terrestrial digital broadcast receiver has two receiving means, a first receiving means and a second receiving means, and is received separately from the first receiving means for outputting the broadcast signal to the display unit via the signal processing means. The second receiving means for detecting the intensity is provided. Then, the control unit controls the second reception unit to scan the broadcast signal at all frequencies and detect the reception intensity of each frequency, and the first reception unit receives a signal that is equal to or higher than a threshold value from the detected reception intensity. Controlled to scan only possible channels. Accordingly, two receiving means having different roles can be operated simultaneously in parallel, and only the broadcast signal having a reception intensity equal to or higher than the threshold can be scanned by the first receiving means. Channel scanning can be performed more efficiently than a terrestrial digital broadcast receiver. Further, since the second receiving means performs only the processing for detecting the reception intensity, the circuit configuration is simple and high-speed processing is possible. Therefore, as a result, a series of channel scans can be performed at high speed.

  In addition, when the contents of the receivable channel list change due to the movement of the user during the reception of the terrestrial digital broadcast, the receivable channels are automatically scanned and the list is always updated to the latest state. I can do it. Further, the control unit creates a channel list based on the reception intensity detected by the second receiving means and monitors the change in the list contents, but the second receiving means detects only the reception intensity. It is possible to monitor a receivable channel without performing complicated signal processing.

  A terrestrial digital broadcast receiver according to a second aspect of the present invention is a terrestrial digital broadcast receiver that receives a broadcast signal of a terrestrial digital broadcast, the first receiving means for receiving the broadcast signal, and the broadcast received by the first receiving means. Signal processing means for processing the signal and outputting it to the display unit, second receiving means for receiving the broadcast signal, and second receiving means for scanning the broadcast signal at all frequencies and detecting the reception intensity of each frequency Control means for determining whether or not the reception intensity is equal to or higher than a threshold, creating a receivable channel list, and causing the first receiving means to scan the broadcast signal using the list. Features.

  This terrestrial digital broadcast receiver has two receiving means, a first receiving means and a second receiving means, and is received separately from the first receiving means for outputting the broadcast signal to the display unit via the signal processing means. The second receiving means for detecting the intensity is provided. Then, the control unit controls the second reception unit to scan the broadcast signal at all frequencies and detect the reception intensity of each frequency, and the first reception unit receives a signal that is equal to or higher than a threshold value from the detected reception intensity. Controlled to scan only possible channels. Accordingly, two receiving means having different roles can be operated simultaneously in parallel, and only the broadcast signal having a reception intensity equal to or higher than the threshold can be scanned by the first receiving means. Channel scanning can be performed more efficiently than a terrestrial digital broadcast receiver. Further, since the second receiving means performs only the processing for detecting the reception intensity, the circuit configuration is simple and high-speed processing is possible. Therefore, as a result, a series of channel scans can be performed at high speed.

  A terrestrial digital broadcast receiver according to a third aspect of the present invention is the terrestrial digital broadcast receiver according to the second aspect of the present invention, wherein when the contents of the received intensity list change, the control means uses the changed list, One reception unit is caused to execute channel scanning.

  According to this digital terrestrial broadcasting receiver, for example, when the location of the receiver is changed due to the moving of the user, or when the location of the receiver is not changed, but the broadcasting station is newly opened, it can be received. Corresponding to the change of the channel, the receivable channel list can be always updated to the latest state, and the receivable channel can be automatically scanned. In addition, according to this configuration, the control unit creates a channel list based on the reception intensity detected by the second reception unit and monitors the change of the list, but the second reception unit detects only the reception intensity. Therefore, it is possible to monitor a receivable channel without performing complicated signal processing.

  A terrestrial digital broadcast receiver according to a fourth aspect of the present invention is the terrestrial digital broadcast receiver according to any of the second to third aspects, wherein the terrestrial digital broadcast receiver is mounted on a portable information terminal or an in-vehicle television receiver.

  According to this terrestrial digital broadcast receiver, the broadcast receiver can be used as a portable information terminal device such as a mobile phone, a PHS (Personal Handyphone System), a notebook computer, a PDA (Personal Digital Assistants), or an in-vehicle television receiver. When installed, even if the contents of the receivable channel list change due to the movement of the user during reception of terrestrial digital broadcasting, the receivable channels can be automatically scanned to update the list. It becomes possible.

  A terrestrial digital broadcast receiver according to a fifth invention is the terrestrial digital broadcast receiver according to any of the second to fourth inventions, wherein the control means stops the second receiving means and the terrestrial digital broadcast receiver is omitted. When operating in the power mode and the second receiving means is stopped, the CN ratio or bit error rate detected by the signal processing means is obtained from the first receiving means, and when these values fall below the threshold value, (2) The reception means is operated to scan the broadcast signal at all frequencies.

Although it is necessary for portable information terminals to operate in a power saving mode that reduces power consumption,
According to this terrestrial digital broadcast receiver, even when the second receiving means is stopped by switching to the power saving mode, the CN ratio or bit error rate detected by the signal processing means by the control unit is detected from the first receiving means. If these values fall below the threshold, the second receiving means can be operated again to scan all frequencies and update the receivable channel list. Therefore, not only can the power consumption be suppressed by the power saving mode, but also the situation where the channel that can be received in the power saving mode has changed can be dealt with.

  According to the present invention, a receivable channel can be updated to the latest state in response to a change in reception area due to movement of the receiver or a change in receivable channel due to a change in the number of broadcasting stations.

(1) First embodiment
[Constitution]
FIG. 1 is a schematic configuration diagram of a terrestrial digital broadcast receiver according to an embodiment of the present invention. The terrestrial digital broadcast receiver 1 includes an antenna 2, an amplifier 3, a main tuner unit 18, a sub tuner unit 19, a control unit 13, a signal processing unit 20, and an operation unit 17.

  The antenna 2 receives a broadcast wave of digital terrestrial television broadcasting and converts it into a broadcast signal that is an electrical signal. The amplifier 3 amplifies this electric signal and outputs it to the main tuner unit 18.

  The main tuner unit 18 includes a filter 4, a mixer 5, a PLL 6, an amplifier 7, and a filter 8. In the main tuner unit 18, the filter 4 passes the broadcast signal having the frequency of the selected channel set by the control unit 13 and outputs it to the mixer 5. The PLL 6 receives a frequency division ratio corresponding to the selected channel from the control unit 13 and outputs a local oscillation signal corresponding to the selected channel to the mixer 5. The mixer 5 mixes the broadcast signal from the filter 4 and the local oscillation signal from the PLL 6, and outputs an intermediate frequency to the amplifier 7. The amplifier 7 amplifies the intermediate frequency signal corresponding to the selected channel among the intermediate frequency signals from the mixer 5 and outputs the amplified signal to the filter 8. The filter 8 removes an extra signal component of the intermediate frequency signal from the mixer 5 and outputs it to the signal processing unit 20.

  The signal processing unit 20 includes a demodulation IC 14, an MPEG decoder 15, and a D / A converter 16. The demodulation IC 14 demodulates the signal from the main tuner unit 18 and outputs it to the MPEG decoder 15. The MPEG decoder 15 decodes the signal from the demodulation IC 14 and outputs it to the D / A converter 16. The D / A converter 16 converts the digital signal into an analog signal and outputs it to the display unit.

  The sub tuner unit 19 includes a mixer 9, a PLL 10, an amplifier 11, and a level detection unit 12. In the sub-tuner unit 19, the PLL 10 receives the frequency division ratio corresponding to the selected channel from the control unit 13 and outputs a local oscillation signal corresponding to the selected channel to the mixer 9. The mixer 9 mixes the broadcast signal output from the amplifier 3 and the local oscillation signal from the PLL 10, and outputs an intermediate frequency to the amplifier 11. The amplifier 11 amplifies the intermediate frequency signal corresponding to the selected channel among the intermediate frequency signals from the mixer 9 and outputs the amplified signal to the level detection unit 12. The level detector 12 detects the reception intensity of the intermediate frequency signal from the mixer 9 and outputs it to the controller 13.

  The operation unit 17 receives an input from the user and outputs an input result to the control unit 13.

The control unit 13 receives a signal from the operation unit 17 and controls the main tuner unit 18 and the sub tuner unit 19. In addition, the control unit 13 processes a signal from the sub tuner unit 19 and controls the main tuner unit 18 based on the result.

[Channel scan of terrestrial digital broadcasting]
FIG. 3 is a flowchart of channel scanning executed by the terrestrial digital broadcast receiver 1 according to the first embodiment of the present invention, and the processing of FIG.

  The terrestrial digital broadcast receiver according to the present embodiment is a terrestrial digital broadcast receiver mounted on an in-vehicle television receiver. In the terrestrial digital broadcast receiver, the antenna 2 receives a terrestrial television broadcast signal. When receiving, the control unit 13 controls the sub-tuner unit 19 to scan the broadcast signal at all frequencies and detect the reception intensity of each frequency (S20). Among the detected reception strengths, a channel list having a reception strength equal to or higher than a threshold value is created (S21). As for the threshold value of the reception strength, a specific value obtained by experiment is used, and a list of channels that can be received is equivalent to the content listed in FIG. Then, it is determined whether or not this receivable channel list is already stored in the storage unit (not shown) of the control unit 13 (S22). If the channel list is created for the first time this time, the channel list is stored. And the main tuner unit 18 is controlled to scan only the channels corresponding to the channel list (S23). On the other hand, if a receivable channel list has already been stored, it is determined whether or not the existing channel list and the newly created channel list have the same contents (S24). Specifically, when the combination of receivable channels changes or when the combination of receivable channels is the same, but the reception level changes beyond a preset range, the contents of the channel list are changed. Can be assumed. If the contents of both channel lists are the same, the process returns to step 20 (S20) shown in FIG. If the contents of both channel lists are not the same, the contents of the channel list are updated by storing the newly created channel list in the storage unit, and the channel is sent to the main tuner unit 18 based on the contents of the channel list. The scan is executed (S25). And it returns to step 20 (S20) illustrated in FIG.

[Effect]
The terrestrial digital broadcast receiver according to the present embodiment includes two tuners, a main tuner unit 18 and a sub tuner unit 19, and the main tuner 18 that outputs a broadcast signal to the display unit via the signal processing unit 20. Separately, a sub-tuner unit 19 that detects reception intensity is provided. The control unit 13 controls the sub-tuner unit 19 to scan the broadcast signal at all frequencies, detect the reception intensity of each frequency and output it to the control unit 13. The main tuner unit 18 is controlled so as to scan only receivable channels. Accordingly, two tuner units having different roles can be operated simultaneously in parallel, and only the broadcast signal having a reception intensity equal to or higher than the threshold can be scanned by the main tuner unit 18. Compared to a single digital broadcast receiver, channel scanning can be performed more efficiently. Further, since the sub tuner unit only detects the reception intensity, high-speed processing is possible with a simple circuit configuration. This therefore helps to perform a series of channel scans at high speed.

Furthermore, in the terrestrial digital broadcast receiver according to the present embodiment, the control unit 13 creates a channel list based on the reception intensity detected by the second receiving means, and monitors changes in the list contents. When the user moves while receiving a broadcast and the contents of the receivable channel list change, the receivable channels can be automatically scanned to update the list to the latest state. Further, since the sub-tuner unit 19 detects only the reception intensity, the control unit can monitor a receivable channel without performing complicated signal processing.
(2) Second embodiment
[Constitution]
Regarding the configuration of the second embodiment, the configuration other than the operation unit 17 is the same as the configuration of the first embodiment described above, and thus the description of the same parts is omitted. In the second embodiment, when the operation unit 17 receives an input of the power saving mode, the operation unit 17 controls the control unit 13 to activate the power saving mode.

[Channel scan in power saving mode]
FIG. 4 is a flowchart of channel scanning in the power saving mode executed by the terrestrial digital broadcast receiver 1 of the second embodiment, and the processing of FIG. 4 is executed in accordance with instructions of the control unit 13. Also, the processing in steps 20 to 25 in FIG. 4 has the same processing contents as the channel scan described in FIG. Therefore, hereinafter, the description will be made from the step (S26) regarding the switching of the power saving mode.

  In the present embodiment, the user inputs to the operation unit 17 to execute switching to the power saving mode (S26). If the user has not switched to the power saving mode, the process returns to START in FIG. On the other hand, when the user switches to the power saving mode by input to the operation unit 17, the control unit receives the output from the operation unit 17 and stops the operation of the sub tuner unit 19 (S26). ). The control unit 13 controls the main tuner unit 18 to detect the CN ratio or the bit error rate of each broadcast signal (S28). Then, the control unit determines whether or not the CN ratio or the bit error rate is equal to or less than the threshold value (S29). If the CN ratio or the bit error rate is equal to or greater than the threshold value, the control unit returns to the START of FIG. The operation of 19 is restored (S30). Then, the channel scan shown in FIG. 3 is executed by re-activating the sub tuner unit 19. In addition, since the said method is only an example, it is good also as a structure which performs operation | movement stop (S26) of the sub tuner part 19 by the action | operation of a power saving mode not based on selection by a user but based on a fixed condition automatically.

[Effect]
In the present embodiment, the operation of the sub-tuner unit 19 can be stopped and switched to the power saving mode as required by the user. Even when the sub tuner unit 19 is stopped by switching to the power saving mode, the control unit can acquire the CN ratio or the bit error rate detected by the signal processing unit 20 from the main tuner unit, When these values are lower than the threshold value, the subtuner unit 19 in the stopped state is operated again to scan all frequencies, and the receivable channel list can be updated. Therefore, not only can the power consumption be suppressed by the power saving mode, but also the situation where the channel that can be received in the power saving mode has changed can be dealt with.

1 is a schematic configuration diagram of a terrestrial digital broadcast receiver. List of channels with received strength above the threshold The flowchart regarding the channel scan which concerns on 1st Embodiment. The flowchart regarding the channel scan at the time of the power saving mode which concerns on 2nd Embodiment.

Explanation of symbols

1 Terrestrial digital broadcast receiver
2 Antenna
3 Amplifier 4 Filter 5 Mixer 6 PLL
7 Amplifier 8 Filter 9 Mixer 10 PLL
11 Amplifier 12 Level detection unit 13 Control unit 14 Demodulation IC
15 MPEG decoder 16 D / A converter
17 Operation unit 18 Main tuner unit 19 Sub-tuner unit 20 Signal processing unit

Claims (5)

A terrestrial digital broadcast receiver that receives a terrestrial digital broadcast broadcast signal and is mounted on a portable information terminal or an in-vehicle television receiver,
First receiving means for receiving the broadcast signal;
Signal processing means for processing the broadcast signal received by the first receiving means and outputting the processed signal to the display unit;
Second receiving means for receiving the broadcast signal;
The broadcast signal is scanned at all frequencies, the second receiving means is controlled to detect the reception intensity of each frequency, a comparison is made as to whether or not the reception intensity is equal to or greater than a threshold, and a receivable channel list is obtained. When the contents of the list are changed by using the list, the first receiving means scans the broadcast signal, and when the contents of the list change, the list is used again to the first receiving means. A terrestrial digital broadcast receiver, comprising: A terrestrial digital broadcast receiver for receiving a terrestrial digital broadcast signal,
First receiving means for receiving the broadcast signal;
Signal processing means for processing the broadcast signal received by the first receiving means and outputting the processed signal to the display unit;
Second receiving means for receiving the broadcast signal;
The broadcast signal is scanned at all frequencies, the second receiving means is controlled to detect the reception intensity of each frequency, it is determined whether or not the reception intensity is greater than or equal to a threshold, and a receivable channel list is obtained. A terrestrial digital broadcast receiver comprising: control means for creating and causing the first reception means to scan the broadcast signal using the list.   The ground according to claim 2, wherein when the content of the list changes, the control means causes the first receiving means to perform channel scanning using the list after the change. Digital broadcast receiver.   The terrestrial digital broadcast receiver according to any one of claims 2 to 3, wherein the terrestrial digital broadcast receiver is mounted on a portable information terminal or an in-vehicle television receiver.   The control means stops the second receiving means, causes the terrestrial digital broadcast receiver to operate in a power saving mode, and detects the CN ratio detected by the signal processing means while the second receiving means is stopped. A bit error rate is obtained from the first receiving means, and when the received CN ratio or bit error rate falls below a threshold value, the second receiving means is operated to scan the broadcast signal at all frequencies. The terrestrial digital broadcast receiver according to any one of claims 2 to 4, wherein the terrestrial digital broadcast receiver is executed.

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