JP2007096760A - Vehicle mounted receiving device, and receive control method of vehicle mounted receiving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change a broadcast reception channel to the optimum reception channel adequately in an automatic way without using an exterior device. <P>SOLUTION: A vehicle mounted receiving device 1 has a tuner 13 for receiving a reception channel that a broadcast station and a relay station thereof are used for broadcast. A one-segment tuner 14 is provided for receiving the reception channel. If the reception level of the tuner 13 is less than a predetermined threshold value Kth, the one segment tuner 14 is caused to receive a reception channel by specifying the reception channel of a broadcast station (relay station) adjoining to the broadcast station (relay statio), which the tuner 13 receives. Then, the optimum reception channel is specified and thereby the reception channel of the tuner 13 is switched to the optimum reception channel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle-mounted receiving device that is mounted on a vehicle and receives a reception channel of a broadcasting station, and a reception control method for the vehicle-mounted receiving device.

2. Description of the Related Art Conventionally, a digital broadcast receiver that receives digital television broadcasts and digital radio broadcasts (hereinafter simply referred to as “broadcast”) is known (see, for example, Patent Literature 1). It has been proposed that digital broadcasts can be viewed indoors. By the way, in general, in broadcasting, in addition to the main broadcasting station (key station), a relay station (affiliation station) is provided for each prefecture and region, and these relay stations relay the broadcast, so that the same broadcasting The program can be received nationwide.
JP 2005-26914 A

However, the reception channel (reception frequency) used for broadcasting is generally different between the key station and the relay station and between the relay stations. Therefore, when the vehicle moves across prefectures and regions and the reception channel of the broadcast that has been viewed up to now is changed, the broadcast cannot be received.
Therefore, for example, when an in-vehicle navigation device is provided separately, and the vehicle moves across prefectures or regions, it detects the switching of the broadcast reception channel based on the current position information acquired by the in-vehicle navigation device, and automatically Although it is possible to configure the receiver so as to change the reception channel, in this configuration, there is a problem in that an in-vehicle navigation device is essential and the device cost is increased.

  The present invention has been made in view of the above-described circumstances, and includes an in-vehicle receiver and an in-vehicle receiver that can automatically and appropriately switch a broadcast reception channel to an optimal reception channel without using an external device. An object is to provide a reception control method.

  In order to solve the above-described problems, the present invention provides a sub-reception for receiving a reception channel in an in-vehicle receiver having a reception means for receiving a reception channel used for broadcasting by a broadcast station and a relay station of the broadcast station. Means for detecting the reception level of each of the receiving means and the sub-receiving means, and storing station information indicating a receiving channel and an adjacent broadcasting station or relay station for each of the broadcasting station and the relay station Storage means, and when the reception level of the reception means falls below a predetermined threshold, the reception channel of the broadcast station or relay station adjacent to the broadcast station or relay station that is received by the reception means. Based on the station information, the sub reception unit receives the signal, and the optimum reception is performed based on the reception level of each reception channel of the sub reception unit. Identify Yan'neru, characterized in that switching the reception channel for said received reception means to the optimum reception channel.

  In the present invention, the reception channel of the reception unit is switched to the reception channel received by the sub reception unit when the reception level of the sub reception unit exceeds the reception level of the reception unit. It is characterized by that.

  Further, the present invention is the above invention, wherein, when a period in which the reception level of the sub reception unit exceeds the reception level of the reception unit continues for a certain period, the reception channel is receiving the reception channel received by the sub reception unit. The receiving channel of the means is switched.

  Further, the present invention is the digital broadcast according to the above invention, wherein the broadcast includes a plurality of segments in the reception channel, and each segment is used to perform a broadcast for a fixed terminal and a broadcast for a mobile terminal. The receiving means is constituted by a receiving means for receiving a broadcast for the portable terminal.

  Further, the present invention is the above invention, wherein the digital broadcast is multiplexed and modulated by a predetermined frequency multiplexing method, and each of the receiving means and the sub-receiving means includes a demodulating means for demodulating and outputting the broadcast. The reception level detection means detects the reception level based on the level of a signal output from each demodulation means of the reception means and the sub reception means.

  In order to achieve the above object, the present invention provides a receiving control method for a vehicle-mounted receiving device comprising a receiving means for receiving a broadcast station and a reception channel used by the relay station of the broadcast station for broadcasting. When the reception level of the reception means falls below a predetermined threshold value, the broadcast means or the relay station receiving the reception means is detected. The reception channel of the adjacent broadcasting station or relay station is received by the sub reception unit provided separately from the reception unit, and the optimum reception channel is specified based on the reception level of each reception channel of the sub reception unit. The receiving channel received by the receiving means is switched to the optimum receiving channel.

  According to the present invention, when the reception level of the receiving means falls below a predetermined threshold, the receiving channel of the broadcasting station or relay station adjacent to the broadcasting station or relay station that is received by the receiving means is Reception based on the information is specified and received by the sub-reception unit, the optimum reception channel is identified based on the reception level of each reception channel of the sub-reception unit, and the reception unit receives the reception on the optimum reception channel. Since the channel is switched, the broadcast reception channel can be automatically and appropriately switched to the optimum reception channel without using an external device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, a case where the in-vehicle receiving apparatus receives digital television broadcast is exemplified, but the present invention is not limited to this, and may be digital radio broadcast, for example.

  FIG. 1 is a block diagram showing a functional configuration of an in-vehicle receiving device 1 according to the present embodiment. In this figure, the microcomputer 10 functions as a control means for controlling each part of the in-vehicle receiver 1, and the ROM 11 stores a control program executed by the microcomputer 10 and various data. . The antenna input unit 12 receives a reception signal (RF signal) received by a digital broadcast reception antenna and outputs the reception signal to each of the tuner 13 and the one-segment tuner 14.

  The tuner 13 generates an IF signal by down-converting the reception signal (RF signal) of the reception channel (reception frequency) designated by the microcomputer 10 and outputs the IF signal to the OFDM decoder 15. The tuner 13 and the OFDM decoder 15 This constitutes the main receiving means. The reception channel is configured so that the user can select from among a plurality of reception channels by operating an operation unit (not shown), and the reception channel is instructed to the tuner 13 by the microcomputer 10.

The OFDM decoder 15 demodulates the IF signal and outputs it to the MPEG decoder 16. More specifically, digital television broadcasting is broadcast with OFDM (Orthogonal Frequency Division Multiplexing) modulation, and the OFDM decoder 15 generates a TS (Transport Stream) signal by OFDM demodulation of the IF signal. And output to the MPEG decoder 16. This TS signal includes a video signal (Video signal) and an audio signal (Audio signal) encoded by the MPEG system, and the MPEG decoder 16 decodes the TS signal to generate a video signal and an audio signal. The video signal is output to the video output unit 17 and the audio signal is output to the audio output unit 18.
These video signals and audio signals are input to an in-vehicle device such as an in-vehicle audio device, and the video and audio can be viewed in the passenger compartment.
The tuner 13 outputs an AGC (Auto Gain Control) signal indicating received radio wave intensity to the microcomputer 10 in addition to the IF signal, and the microcomputer 10 executes amplification factor control of the received signal based on the AGC signal. It is configured as follows.

  Here, in the present embodiment, when the vehicle moves across prefectures and regions, as shown in FIG. 1 above, it is possible to detect that the broadcast receiving channel that has been viewed so far has changed. The in-vehicle receiving apparatus 1 includes a 1-segment tuner 14 and a 1-segment OFDM decoder 19 as sub-reception means separately from the tuner 13.

  More specifically, in general, in digital broadcasting, a single reception channel (frequency band) is provided with a plurality of segments obtained by dividing a frequency band, and high-definition video using 12 segments. Broadcasting is performed using each segment, such as broadcasting four different segments or broadcasting images of different standard image quality.

In addition, in digital broadcasting, in addition to broadcasting for fixed terminals (for example, home TV) using a plurality of segments as described above, one segment for mobile terminals such as mobile phones and PDAs, for example. In this embodiment, the one-segment tuner 14 receives a broadcast using this one segment (one-segment broadcast), and the one-segment OFDM decoder 19 It is configured to perform OFDM demodulation.
The one-segment tuner 14 and the one-segment OFDM decoder 19 are sometimes used for portable terminals, and are small and inexpensive. By using the one-segment tuner 14 and the one-segment OFDM decoder 19, the apparatus can be downsized and the cost can be reduced. Is achieved.

  The reception channel of the 1-segment broadcast received by the 1-segment tuner 14 is configured to be instructed by the microcomputer 10, and each of the 1-segment OFDM decoder 19 and the OFDM decoder 15 determines the degree of reception status. The level of the TS signal is output to the microcomputer 10 as a reception level indicating (level), and the microcomputer 10 determines the reception status of the reception channel received by each tuner 13, 14 based on these reception levels. It can be determined.

  The microcomputer 10 monitors the reception status based on the reception level while receiving the reception channel of the broadcasting station selected by the user by the tuner 13 and receives the vehicle by moving across prefectures and regions. When the level falls below a predetermined threshold, the optimum reception channel is identified by sequentially receiving each reception channel of the relay station or broadcast station adjacent to the broadcast station or relay station of the currently received reception channel. The specified reception channel is received by the tuner 13.

  The adjacency relationship between the broadcasting station and the relay station is stored in the ROM 11 as station information data 30. FIG. 2 is a diagram schematically showing the station information data 30. As shown in this figure, the station information data 30 includes, for each broadcast station (key station) or relay station, an identification ID, a reception channel, and an identification ID of an adjacent broadcast station and relay station. The microcomputer 10 searches the station information data 30 to identify a broadcast station or relay station adjacent to the broadcast station or relay station that uses the currently received reception channel.

Next, the operation of the in-vehicle receiver 1 configured as described above will be described in detail with reference to FIG.
FIG. 3 is a flowchart showing a receiving channel switching process during the broadcast receiving operation of the in-vehicle receiving device 1. As shown in this figure, when the in-vehicle receiving apparatus 1 is currently receiving the reception channel of the relay station A (step S1), the microcomputer 10 uses an OFDM decoder 15 to monitor the reception status of this broadcast. The reception level Ka is acquired from (Step S2), and it is determined whether or not the reception level Ka is smaller than a predetermined threshold value K (Step S3). The predetermined threshold value Kth is based on the reception level when the broadcast wave is a weak electric field.

If the reception level Ka is greater than the threshold value Kth (step S3: N), the microcomputer 10 returns the processing step to step S2 to indicate that the current reception status is good, and Continue monitoring the reception status.
On the other hand, when the reception level ka is smaller than the threshold value Kth (step S3: Y), as shown in FIG. 4, the relay station A receives another relay station from the reception area Ra of the relay station A that is currently receiving. It moves to the reception areas Rb and Rc of B and C, or approaches, and the reception channel of the broadcast that has been viewed so far changes from the reception channel CH-A to the other reception channels CH-B and CH-C. As a result, the switching timing of the reception channel is detected. When the reception channel switching timing is detected, the microcomputer 10 starts processing for specifying an optimal reception channel.

That is, the microcomputer 10 searches for a relay station (or broadcast station) adjacent to the currently receiving relay station A based on the sequence channel data 30 (step S4), and then receives the corresponding relay station. The 1-segment tuner 14 receives the channel.
Specifically, the microcomputer 10 stores the number of relay stations corresponding to the search in step S4 in the hit count L and initializes the counter variable N to “1” (step S5).

  Then, the microcomputer 10 causes the one-segment tuner 14 to receive the reception channel of the Nth relay station among the corresponding relay stations (step S6), and obtains the reception level Kb from the one-segment OFDM decoder 19 (step S7). . Next, the microcomputer 10 determines whether or not the reception level Kb is higher than the reception level Ka of the reception channel currently received by the tuner 13 (step S8). If the reception level Kb is smaller than the reception level Ka as a result of this determination (step S8: N), the reception channel received by the one-segment tuner 14 is located far from the vehicle (for example, FIG. 4). It is estimated that the relay station C) shown in FIG.

  Therefore, the microcomputer 10 increments the counter variable N by “1” (step S9), and then determines whether or not the counter variable N is equal to or less than the hit count L (step S10). If it is below (step S10: Y), the processing procedure returns to step S7 to receive the reception channel of the next relay station. If the counter variable N exceeds the number of hits L (step S10: N), the microcomputer indicates that there is no reception channel with better reception than the reception channel currently received by the tuner 13. 10 returns the processing procedure to step S2. As described above, when a reception channel having a reception level exceeding the reception level Ka is not found, the reception channel of the tuner 13 is not changed, so that switching to a reception channel having a reception condition worse than that at present is prevented.

  If the reception level Kb is smaller than the reception level Ka as a result of the determination in step S8 (step S8: N), the microcomputer 10 continues to receive the reception level Ka for a certain period T. In order to determine whether or not the value exceeds the predetermined time T, the processes in steps S7 and S8 are repeated until the duration exceeds a certain period T (that is, while step S11 is “N”). If the reception level Kb continues to exceed the reception level Ka for a certain period T (step S11: Y), the reception channel received by the one-segment tuner 14 is the optimum reception channel. Therefore, the reception channel received by the tuner 13 is switched to this optimum reception channel. Thereafter, the process is repeated again from step S1.

  As described above, according to the present embodiment, the in-vehicle receiving apparatus 1 stores the station information data 30 indicating the reception channel and the adjacent broadcasting station or relay station for each broadcasting station and relay station, and the tuner 13 When the reception level falls below the threshold value Kth, the reception channel of the broadcast station or relay station adjacent to the broadcast station or relay station that the tuner 13 is receiving is specified based on the station information data 30, and the one-segment tuner 14, the optimum reception channel is specified based on the reception level of each reception channel of the one-segment tuner 14, and the reception channel of the tuner 13 is switched to the optimum reception channel.

As a result, when the vehicle moves to the reception area of another relay station (broadcast station), the reception level of the tuner 13 is lower than the threshold value Kth, so that reception is possible without using an external device such as a navigation device. The movement of the area will be detected. Further, since the reception level of each reception channel is detected by sequentially receiving the reception channel of the broadcasting station or relay station adjacent to the broadcasting station or relay station that the tuner 13 is receiving, the one-segment tuner 14 receives the reception level. It becomes possible to detect an optimal reception channel with a high level.
Then, since the reception channel of the tuner 13 is switched to this optimal reception channel, a complicated operation in which the user reselects the reception channel every time the reception area changes is unnecessary. In particular, even when only the driver is on board the vehicle, it is not necessary for the driver to reselect the receiving channel, so traffic safety can be achieved.

  Further, according to the present embodiment, when the reception level of the one-segment tuner 14 exceeds the reception level of the tuner 13, the reception channel of the tuner 13 is switched to the reception channel received by the one-segment tuner 14. Therefore, the tuner 13 is surely switched to a reception channel having a better reception condition than the reception channel currently being received.

  Further, according to the present embodiment, the reception channel of the tuner 13 is switched when the period during which the reception level of the one-segment tuner 14 exceeds the reception level of the tuner 13 continues for a certain period. This prevents a situation in which the reception channel of the tuner 13 is changed even though the reception situation temporarily deteriorates due to traveling in a tunnel or mountains.

  Further, according to the present embodiment, the tuner provided separately from the tuner 13 is the one-segment tuner 14 that receives the broadcast for the portable terminal, so that the cost of the apparatus can be reduced.

  Further, according to the present embodiment, the reception level of the reception channel received by each of the tuner 13 and the one segment tuner 14 is set based on the level of the signal output from each of the OFDM decoder 15 and the one segment OFDM decoder 19. It was set as the structure to detect. As a result, since the demodulated data state is used as an indicator of the reception level, it is possible to switch the reception channel as described above only when valid data is not demodulated.

The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.
For example, in the embodiment described above, the output of the one-segment OFDM decoder 19 is used only for detection of the reception level. However, the present invention is not limited to this, and the output of the one-segment OFDM decoder 19 is input to the MPEG decoder 16. A broadcast video signal and audio signal received by the one-segment tuner 14 may be output.

  For example, in the above-described embodiment, the output signal levels of the OFDM decoder 15 and the one-segment OFDM tuner 19 are used as reception levels. However, the present invention is not limited to this. For example, the error rate (bits at decoding) Error rate), the S / N ratio of the received signal, the AGC signals of the tuners 13 and 14, and the like can also be used.

  Further, for example, in the above-described embodiment, the vehicle-mounted receiving device 1 has been described as a device that receives a broadcast wave of terrestrial digital broadcasting that is broadcast by the OFDM modulation method, but the present invention is not limited to this. The present invention can also be applied to an apparatus that receives a digital broadcast using another modulation method, and can also be applied to an apparatus that receives an analog broadcast.

  Further, for example, in the above-described embodiment, the station information data 30 may be separately received from the outside, and the station information data 30 stored in the ROM 11 may be dynamically changed.

  Further, in the in-vehicle receiving device 1, since the optimum receiving channel, that is, the broadcasting station or the relay station and the respective receiving area can be specified according to the current position of the vehicle, the broadcasting station or the relay station, Based on this reception area, a rough current position of the vehicle may be specified and notified by display or the like.

It is a block diagram which shows the functional structure of the vehicle-mounted receiving apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows an example of station information data. It is a flowchart of a receiving channel switching process. It is a figure for demonstrating the switching operation of a receiving channel.

Explanation of symbols

1 In-vehicle receiver 10 Microcomputer 11 ROM
13 tuner 14 1 segment tuner 15 OFDM decoder 19 1 segment OFDM tuner CH-A to CH-C reception channel Ka, Kb reception level Ra to Rc reception area

Claims (6)

In a vehicle-mounted receiving device having a receiving means for receiving a receiving channel used for broadcasting by a broadcasting station and a relay station of the broadcasting station
Sub-receiving means for receiving the receiving channel;
Reception level detection means for detecting the reception level of each of the reception means and the sub reception means;
For each broadcast station and relay station, storage means for storing station information indicating a reception channel and an adjacent broadcast station or relay station, and
When the reception level of the receiving means falls below a predetermined threshold, the receiving channel of the broadcasting station or relay station adjacent to the broadcasting station or relay station that the receiving means is receiving is specified based on the station information The sub-reception unit receives the signal, specifies the optimum reception channel based on the reception level of each reception channel of the sub-reception unit, and switches the reception channel received by the reception unit to the optimum reception channel. A vehicle-mounted receiving device. 2. The reception channel of the reception unit is switched to the reception channel received by the sub reception unit when the reception level of the sub reception unit exceeds the reception level of the reception unit. The vehicle-mounted receiving device described. When the period during which the reception level of the sub reception unit exceeds the reception level of the reception unit continues for a certain period, the reception channel of the reception unit is switched to the reception channel received by the sub reception unit. The in-vehicle receiving device according to claim 1 or 2. The broadcast includes a plurality of segments in the reception channel, and is a digital broadcast that performs broadcasting for a fixed terminal and broadcasting for a mobile terminal using each segment,
The in-vehicle receiving device according to any one of claims 1 to 3, wherein the sub-receiving unit is configured by a receiving unit that receives a broadcast for the mobile terminal. The digital broadcast is multiplexed and modulated by a predetermined frequency multiplexing method,
Each of the receiving means and the sub-receiving means comprises demodulation means for demodulating and outputting the broadcast,
The in-vehicle receiving device according to claim 4, wherein the reception level detection means detects the reception level based on a level of a signal output from each demodulation means of the reception means and the sub reception means. In a reception control method for a vehicle-mounted receiving device comprising a receiving means for receiving a receiving channel used for broadcasting by a broadcasting station and a relay station of the broadcasting station,
While the receiving means is receiving, the reception level of the receiving means is detected,
When the reception level of the receiving means is below a predetermined threshold,
The receiving channel of the broadcasting station or relay station adjacent to the broadcasting station or relay station that is received by the receiving unit is received by a sub-receiving unit provided separately from the receiving unit, and each reception of the sub-receiving unit is received. A reception control method comprising: identifying an optimum reception channel based on a reception level of the channel, and switching the reception channel received by the reception unit to the optimum reception channel.

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