JP2015130588A - Digital broadcast receiver and its reception mode switching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital broadcast receiver in which frequent switching of full-segment broadcast reception and one-segment broadcast reception and frequent generation of block noise can be prevented while increasing the opportunity of full-segment broadcast reception, and to provide its reception mode switching method.SOLUTION: A digital terrestrial broadcasting receiver 100 includes a full-segment/one-segment switching section 53 for mutually switching the reception of one-segment digital broadcasting and the reception of full-segment digital broadcasting according to changeable switching conditions, and a reception mode switching section 54 for changing the reception to a first reception mode of one-segment priority, when the reception of full-segment digital broadcasting and the reception of one-segment digital broadcasting are switched a first predetermined number of times within a predetermined time, in a state where the reception mode is set to a second reception mode of full-segment priority.

Description

  The present invention relates to a digital broadcast receiver that is used in a vehicle or the like, and in which a broadcast signal reception environment changes over time, and a reception mode switching method thereof.

  Conventionally, there are operation modes of 1Seg mode for playing 1Seg broadcast and Full Seg mode for playing full Seg broadcast. Full Seg broadcast is received when reception quality is good, and 1Seg broadcast is received when reception quality deteriorates. There is known a portable terminal for receiving (see, for example, Patent Document 1). In this portable terminal, switching from reception of one-segment broadcasting to reception of full-segment broadcasting is performed when the one-segment C / N (carrier power to noise power ratio) exceeds the threshold over a predetermined time and the full-segment BER (bit error rate) falls below the threshold. If done. As a result, even if the one-segment CNR and the full-segment BER do not have a linear correlation due to the influence of fading due to multipath, the reception quality is poor and the one-segment broadcast reception is not switched to the full-segment broadcast reception. It has become.

JP 2011-103539 A

  By the way, in the portable terminal disclosed in Patent Document 1, it is possible to set whether to receive full-seg broadcasting preferentially or receive one-seg broadcasting preferentially by changing a threshold value compared with full-seg BER. It becomes.

  For example, when the threshold value is increased, full-segment broadcasting can be preferentially received because switching from full-segment broadcasting reception to one-segment broadcasting reception is not performed until reception quality is considerably deteriorated. As shown in FIG. 3 (B), when full-seg broadcasting is preferentially received, if the reception of full-seg broadcasting is continued even when the reception quality deteriorates, it is frequently switched to one-seg broadcasting reception, and the program contents are temporarily There has been a problem that the video quality is deteriorated due to discontinuity or frequent occurrence of block noise.

  On the other hand, when the one-segment broadcasting is preferentially received with a small threshold, if the reception quality deteriorates even a little, the full-segment broadcasting reception is switched to the one-segment broadcasting reception. Therefore, as shown in FIG. However, it is possible to avoid frequent switching and block noise when maintaining the video, but there is a problem that the video quality of the one-segment broadcasting itself with many opportunities to receive cannot be said to be good.

  The present invention was created in view of these points, and its purpose is to increase the chances of receiving full-segment broadcasts, and frequently switching between full-segment broadcast reception and one-segment broadcast reception and frequent occurrence of block noise. It is an object of the present invention to provide a digital broadcast receiver and a reception mode switching method thereof that can prevent this.

  In order to solve the above-described problems, a digital broadcast receiver according to the present invention includes a receiving unit that receives a first broadcast and a second broadcast having better video quality than the first broadcast, and the first broadcast. The first reception mode for preferentially receiving the first broadcast and the second reception mode for preferentially receiving the second broadcast by changing the switching conditions for switching between the first broadcast and the second broadcast A reception mode setting means for setting each reception mode, a switching means for switching between reception of the first broadcast and reception of the second broadcast according to the switching condition, and the reception mode is set to the second reception mode. Reception mode switching means for changing the reception mode to the first reception mode when the reception of the second broadcast and the reception of the first broadcast are switched for the first predetermined number of times within a predetermined time in a state of being performed. ing.

  Further, the reception mode switching method of the digital broadcast receiver according to the present invention includes a step of receiving the first broadcast and the second broadcast having better video quality than the first broadcast by the receiving means; The first reception mode for preferentially receiving the first broadcast and the second reception mode for preferentially receiving the second broadcast by changing the switching conditions for switching between the first broadcast and the second broadcast Each of the reception mode is set by the reception mode setting means, the step of switching the reception of the first broadcast and the reception of the second broadcast by the switching means according to the switching condition, and the reception mode is the second The reception mode is changed to the first reception mode when the reception of the second broadcast and the reception of the first broadcast are switched for the first predetermined number of times within a predetermined time in the state set to the reception mode. Yo And a step of changing Te.

  In particular, it is desirable that the first broadcast described above is a one-segment digital broadcast of terrestrial digital broadcast, and the second broadcast is a full-segment digital broadcast of terrestrial digital broadcast.

  If the reception quality deteriorates during reception of a second broadcast (full segment digital broadcast) with good video quality set in the second reception mode, the second broadcast and the first broadcast (one segment digital broadcast) However, in the present invention, when the number of times of switching reaches the first predetermined number of times, the mode is changed to the first reception mode, and thereafter the first broadcast is preferentially received. For this reason, switching between the second broadcast and the first broadcast can be stopped halfway, so that frequent switching can be prevented and block noise can be prevented from occurring frequently. be able to. Further, since the second broadcast can be received in the second reception mode until the second reception mode is changed to the first reception mode, reception of the second broadcast (full segment digital broadcast) is possible. Can increase opportunities.

  In addition, the reception mode switching means described above has switched between reception of the first broadcast and reception of the second broadcast within a predetermined time period for the second predetermined number of times while the reception mode is set to the first reception mode. Sometimes it is desirable to change the reception mode to the second reception mode. Thereby, the reception of the second broadcast can be resumed after confirming that the reception quality has improved during the reception of the first broadcast.

  The first predetermined number of times described above is preferably a plurality of times. Thereby, after confirming that the reception quality has deteriorated, the second reception mode can be changed to the first reception mode.

  The second predetermined number of times described above is preferably one time. Thereby, when the reception quality is improved, the reception of the second broadcast can be started promptly, and further the opportunities for receiving the second broadcast can be increased.

  The switching condition in the first reception mode described above has a threshold set corresponding to the high reception quality of the broadcast signal, and the switching condition in the second reception mode corresponds to the low reception quality of the broadcast signal. It is desirable to have a threshold value set as described above. Accordingly, the first broadcast can be preferentially received by switching from the second broadcast to the first broadcast with high reception quality in the first reception mode. In addition, the second broadcast can be preferentially received while maintaining the reception state of the second broadcast until the reception quality is low in the second reception mode.

  Moreover, it is desirable that the switching condition described above uses a threshold value that is compared with any of the bit error rate, the carrier power to noise power ratio, and the electric field strength of the broadcast signal corresponding to the first and second broadcasts. Thereby, it is possible to reliably switch between the first broadcast and the second broadcast according to the reception quality.

  The digital broadcast receiver according to the present invention is preferably mounted on a vehicle. Thereby, even when the reception quality changes as the vehicle travels, the second broadcast is preferentially received and the frequent switching to the first broadcast and the occurrence of block noise can be prevented. It becomes possible.

  Alternatively, the digital broadcast receiver according to the present invention is preferably provided in a portable terminal. As a result, the user's mobile terminal moves and the reception quality changes as the user moves (including not only walking, but also moving on a vehicle such as a vehicle). Even in such a case, it is possible to prevent frequent switching to the first broadcast and occurrence of block noise while receiving the second broadcast with priority.

It is a figure which shows the structure of the terrestrial digital broadcast receiver of one Embodiment. It is a flowchart which shows the operation | movement procedure which switches reception mode and full segment digital broadcast / one segment digital broadcast, when BER corresponding to the broadcast wave under reception changes. It is explanatory drawing which shows the mode of switching between full segment digital broadcasting and one segment digital broadcasting.

  Hereinafter, a digital terrestrial broadcast receiver according to an embodiment to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a terrestrial digital broadcast receiver according to an embodiment. As shown in FIG. 1, the terrestrial digital broadcast receiver 100 according to the present embodiment includes four tuner units 10, 12, 14, 16, two OFDM (Orthogonal Frequency Division Multiplex) demodulation units 30, 32, an MPEG decoder 40, A digital-analog converter (D / A) 42, a speaker 44, a display processing unit 46, a display device 48, and a control unit 50 are included. This terrestrial digital broadcast receiver 100 is mounted on a vehicle.

  Each of the tuner units 10, 12, 14, and 16 receives a broadcast wave having a reception frequency corresponding to a designated broadcast station via an antenna. Each of the OFDM demodulation units 30 and 32 performs OFDM demodulation processing on broadcast signals (IF signals) input from a plurality of tuner units, and outputs a TS (transport stream) signal. In the present embodiment, a combined diversity configuration is employed in which broadcast signals input from a plurality of tuner units are used, and the phases of these broadcast signals are adjusted and then combined and received. As the number of tuner units used increases, C / N can be improved and BER can be reduced.

  For example, in this embodiment, the OFDM demodulator 30 performs the operation of a four-combining diver that performs OFDM demodulation processing by combining four IF signals output from the four tuner units 10, 12, 14, and 16. Further, when performing the operation of the 4-combining diver, the output signal of the other OFDM demodulator 32 is input to one OFDM demodulator 30, and the OFDM demodulator 30 performs IF signal synthesis and OFDM demodulation processing. Done.

  The MPEG decoder 40 decodes the received program audio and video MPEG signals included in the TS signals output from the OFDM demodulation units 30 and 32, and outputs audio data and video data. In practice, the TS signals output from the OFDM demodulating units 30 and 32 are input to the demultiplexer, and the audio and video MPEG signals corresponding to the program that the user desires to watch are separated. The program receiving operation itself is the same as that of the conventional method, and only a schematic configuration is shown in FIG.

  The digital-analog converter 42 converts the audio data output from the MPEG decoder 40 into an analog audio signal and outputs it from the speaker 44. The display processing unit 46 converts the video data output from the MPEG decoder 40 into a video signal in a format suitable for display (for example, NTSC format) and displays the video signal on the display device 48.

  The control unit 50 controls the entire terrestrial digital broadcast receiver 100 and performs an operation of switching the reception mode according to the radio wave state. For this purpose, the control unit 50 includes a BER measurement unit 51, a reception mode setting unit 52, a full segment / one segment switching unit 53, and a reception mode switching unit 54.

  The BER measuring unit 51 measures the BER based on the demodulated TS signal output from the OFDM demodulating unit 30 in response to the 4-synthesis diver operation using the four tuner units 10 to 16.

  The reception mode setting unit 52 changes a switching condition when switching between the one-segment digital broadcast and the full-segment digital broadcast, so that the one-segment digital broadcast is preferentially received, and the full-segment digital Each reception mode of the second reception mode for receiving broadcasts preferentially is set. The full segment / one segment switching unit 53 switches between the reception of the one segment digital broadcast and the reception of the full segment digital broadcast according to the switching condition.

  For example, the switching condition in the first reception mode has a threshold value (threshold value S1 corresponding to a small BER value) set corresponding to the high reception quality of the broadcast signal. In the first reception mode, when the BER measured by the BER measuring unit 51 is larger than the threshold value S1 corresponding to the small BER value, switching to one-segment digital broadcasting is performed, and the measured BER is larger than the threshold value S1. If it is small, it can be switched to full segment digital broadcasting. That is, since the reception quality of the broadcast signal is high (the BER is low), the full segment digital broadcast can be switched to the one segment digital broadcast. Therefore, in the first reception mode, the one segment digital broadcast is preferentially received. Can do.

  On the other hand, the switching condition in the second reception mode has a threshold value (threshold value S2 corresponding to a large BER value) set corresponding to the low reception quality of the broadcast signal. In the second reception mode, when the BER measured by the BER measuring unit 51 is larger than the threshold value S2 corresponding to the large BER value, switching to one-segment digital broadcasting is performed, and the measured BER is larger than the threshold value S2. If it is small, it can be switched to full segment digital broadcasting. That is, since the reception quality of the broadcast signal is low (the BER is high), the full segment digital broadcast can be switched from the full segment digital broadcast to the one segment digital broadcast. Can do.

  The reception mode switching unit 54 performs a first predetermined number of times N (for example, N) within a predetermined time between reception of a full segment digital broadcast and reception of a one segment digital broadcast in a state where the reception mode is set to the second reception mode. = 5) When switched, the reception mode is changed to the first reception mode. In addition, the reception mode switching unit 54 receives the one-segment digital broadcast and the full-segment digital broadcast in a second predetermined number of times M (in a predetermined time while the reception mode is set to the first reception mode. For example, when M = 1), the reception mode is changed to the second reception mode.

  The one-segment digital broadcasting described above corresponds to the first broadcasting, the full-segment digital broadcasting corresponds to the second broadcasting, the tuner units 10 to 16, the OFDM demodulating units 30 and 32, and the MPEG decoder 40 correspond to the receiving unit. The reception mode setting unit 52 corresponds to the reception mode setting unit, the one-segment / full-segment switching unit 53 corresponds to the switching unit, and the reception mode switching unit 54 corresponds to the reception mode switching unit.

  The terrestrial digital broadcast receiver 100 according to the present embodiment has such a configuration. Next, an operation for switching the reception mode when the BER corresponding to the received broadcast wave changes will be described.

  In terrestrial digital broadcasting, broadcast waves having a structure conforming to the MPEG2-TS (Transport Stream) standard are distributed. MPEG2-TS has a TS header part and a payload part (data body). The TS header part and the payload part constitute a 188-byte transport packet. The data transmitted by the MPEG2-TS includes PAT (Program Association Table), PMT, NIT, BIT, and the like.

  PAT: PID (Packet Identification, packet identification information) of a transport packet transmitting a table (PMT) describing the program configuration is described for each program (program) number. The PAT itself has a fixed value (0x0000). This PAT is received once within a predetermined time.

  PMT: The transport packet PID list and associated information (service identification, etc.) are described in the payload portion of this transport packet in which individual streams such as video and audio constituting one program are transmitted. Yes.

  NIT: The network identification of the broadcasting station is described in the payload portion of this transport packet.

  BIT: affiliated station information is included in the payload portion of this transport packet. The PID of BIT has a fixed value (0x0024). The extended broadcaster descriptor of this BIT includes affiliation_id (affiliation station identification).

  FIG. 2 is a flowchart showing an operation procedure for switching the reception mode and full segment digital broadcast / one segment digital broadcast when the BER corresponding to the broadcast wave being received changes.

  First, the reception mode switching unit 54 sets the reception mode to a second reception mode that prioritizes reception of full segment digital broadcasting (step 100). Thereafter, full-segment digital broadcasting is received using the four tuners 10 to 16 (step 102). When the BER is measured by the BER measuring unit 51 in parallel with the reception operation, the full segment / one segment switching unit 53 determines whether the measured BER is larger than a threshold S2 corresponding to a large BER value. (Step 104). If the BER is less than or equal to the threshold value S2, a negative determination is made, and the process returns to step 102 to continue receiving full segment digital broadcasting.

  On the other hand, if the BER is larger than the threshold value S2, an affirmative determination is made in step 104. In this case, the full segment / one segment switching unit 53 switches to one segment digital broadcast reception using the four tuners 10 to 16 (step 106). Further, the reception mode switching unit 54 determines whether or not the number of times of mutual switching within a predetermined time between full segment digital broadcast reception and one segment digital broadcast reception has reached N (= 5) (step 108). If not, a negative determination is made, and the full-segment / one-segment switching unit 53 determines whether or not the BER measured at this time is smaller than a threshold value S2 corresponding to a large BER value (step 110). If the BER is greater than or equal to the threshold value S2, a negative determination is made, and the process returns to step 106 to continue receiving the one-segment digital broadcast.

  Note that the BER used in step 110 described above is a BER measured when receiving a one-segment broadcast, and the BER used in step 104 is a BER measured when receiving a full segment digital broadcast, which is originally different. Therefore, it is necessary to use a different threshold value S2 to be compared with these BERs. However, in the above description, the same symbol S2 is used for convenience. This also applies to the threshold value S1 used in steps 118 and 124 described later.

  If the BER is smaller than the threshold value S2, an affirmative determination is made in the determination of step 110. In this case, the process returns to step 102 to switch to full segment digital broadcast reception.

  When the number of times of switching reaches N, an affirmative determination is made in the determination of step 108. Next, the reception mode switching unit 54 resets the number of times of switching so far (step 112).

  Next, the reception mode switching unit 54 sets the reception mode to a first reception mode that prioritizes reception of one-segment digital broadcasting (step 114). Thereafter, the one-segment digital broadcast is received using the four tuners 10 to 16 (step 116). Further, when the BER is measured by the BER measuring unit 51 in parallel with this reception operation, the full segment / one segment switching unit 53 determines whether or not the measured BER is smaller than a threshold S1 corresponding to a small BER value. (Step 118). If the BER is greater than or equal to the threshold value S1, a negative determination is made, and the process returns to step 116 to continue receiving the one-segment digital broadcast.

  If the BER is smaller than the threshold value S1, an affirmative determination is made in the determination in step 118. In this case, the full segment / one segment switching unit 53 switches to full segment digital broadcast reception using the four tuners 10 to 16 (step 120). In addition, the reception mode switching unit 54 determines whether or not the number of mutual switching within a predetermined time between the one-segment digital broadcast reception and the full-segment digital broadcast reception has reached M (= 1) (step 122). If not, a negative determination is made, and the full segment / one segment switching unit 53 determines whether or not the BER measured at this time is larger than a threshold S1 corresponding to a small BER value (step 124). If the BER is less than or equal to the threshold S1, a negative determination is made, and the process returns to step 120 to continue receiving full-segment digital broadcasting.

  If the BER is greater than the threshold value S1, an affirmative determination is made in the determination in step 124. In this case, it returns to step 116 and is switched to the one-segment digital broadcast reception.

  When the number of switching times reaches M, an affirmative determination is made in the determination at step 122. Next, the reception mode switching unit 54 resets the number of times of switching so far (step 126). Thereafter, the process returns to step 100, and the operations after the second reception mode setting process are repeated.

  FIG. 3 is an explanatory diagram showing a state of switching between full segment digital broadcasting and one segment digital broadcasting. For comparison with the switching state of the present invention shown in FIG. 3 (A), the switching state in the case of prioritizing the reception of the conventional full segment digital broadcasting gives priority to the reception of the one segment digital broadcasting in FIG. 3 (B). The switching state in this case is shown in FIG.

  As shown in FIG. 3 (A), in the present invention (this embodiment), when reception quality deteriorates during reception of a full segment digital broadcast in the second reception mode (full segment priority), it is shown in FIG. 3 (B). As in the case of conventional full segment priority, switching between block noise and one-segment digital broadcasting frequently occurs. However, in this embodiment, when the number of switching between full segment digital broadcast and one segment digital broadcast reaches N (= 5), the reception mode is changed from the second reception mode to the first reception mode (one-segment priority). Since the change is made, subsequent generation of block noise and switching between one-segment digital broadcasting and full-segment digital broadcasting are suppressed.

  On the other hand, when the reception quality is improved during the reception of the one-segment digital in the first reception mode and the full-segment digital broadcasting is switched, the reception mode returns from the first reception mode to the second reception mode. Therefore, after that, it becomes possible to preferentially receive full segment digital broadcasting having good video quality.

  As described above, in the terrestrial digital broadcast receiver 100 according to the present embodiment, if the reception quality deteriorates during reception of a full segment digital broadcast in which the second reception mode (full segment priority) is set and the video quality is good, the full segment Digital broadcasting and one-segment digital broadcasting are frequently switched. When the number of times of switching reaches the first predetermined number N, the first reception mode (one-segment priority) is changed. Receive digital broadcasting preferentially. For this reason, switching between full-segment digital broadcasting and one-segment digital broadcasting can be canceled halfway, so that frequent switching can be prevented and block noise is prevented from occurring frequently. be able to. Further, since the full segment digital broadcast can be received in the second reception mode until the second reception mode is changed to the first reception mode, the chance of receiving the full segment digital broadcast can be increased. it can.

  Further, when the reception mode is set to the first reception mode, the reception mode is changed to the second reception mode when the reception of the one-segment digital broadcast and the reception of the full-segment digital broadcast is switched M for the second predetermined number of times within a predetermined time. The reception mode has been changed. As a result, it is possible to resume the reception of the full segment digital broadcast after confirming that the reception quality has improved during the reception of the one segment digital broadcast.

  In addition, by setting the first predetermined number N described above to a plurality of times, it is possible to change from the second reception mode to the first reception mode after confirming that the reception quality has deteriorated. On the other hand, by setting the above-mentioned second predetermined number of times M to one, when the reception quality is improved, it is possible to start receiving full-segment digital broadcasts promptly, and to provide opportunities for receiving full-segment digital broadcasts. Can be increased.

  The switching condition in the first reception mode has a threshold S1 (small) set corresponding to the high reception quality of the broadcast signal, and the switching condition in the second reception mode is a low reception quality of the broadcast signal. Has a threshold value S2 (large) set corresponding to. Thereby, the full segment digital broadcast can be preferentially received by switching from the full segment digital broadcast to the one segment digital broadcast with high reception quality in the first reception mode. Further, the full segment digital broadcast can be preferentially received while maintaining the reception state of the full segment digital broadcast until the reception quality is low in the second reception mode.

  Moreover, threshold value S2 and S1 compared with BER corresponding to full segment digital broadcasting and one segment digital broadcasting are used for the switching conditions mentioned above. Thereby, it is possible to reliably switch between full segment digital broadcast and full segment digital broadcast according to the reception quality.

  In addition, the digital broadcast receiver 100 is mounted on a vehicle, and even when the reception quality changes as the vehicle travels, the full-segment digital broadcast is preferentially received, and the frequency between the one-segment digital broadcast is frequently received. Switching and block noise can be prevented.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the present invention is applied to the terrestrial digital broadcast receiver 100 having the diversity configuration using the four tuner units 10 to 16, but the number of tuner units may be other than this. A single tuner may also be used.

  In the above-described embodiment, the present invention is applied to the terrestrial digital broadcast receiver 100. However, the present invention is also applied to a receiver that receives a broadcast wave having a structure compliant with the MPEG2-TS standard and other types of receivers. Can be applied. In addition, we considered one-segment digital broadcast as the first broadcast and full-segment digital broadcast as the second broadcast. The present invention can be applied to selective reception.

  In the above-described embodiment, BER is used as the characteristic value indicating the reception quality. However, C / N or the electric field strength of the broadcast signal may be used. Even when these are used, it is possible to reliably switch between the one-segment digital broadcast and the full-segment digital broadcast according to the reception quality.

  In the above-described embodiment, the terrestrial digital broadcast receiver 100 mounted on the vehicle has been described. However, the present invention can also be applied to a terrestrial digital broadcast receiver provided in a mobile terminal. In this case, the reception quality changes due to movement of the mobile terminal held by the user as well as movement of the user (including not only movement on foot but also movement on a vehicle such as a vehicle). Even so, it is possible to prevent frequent switching to one-segment digital broadcasting and occurrence of block noise while receiving full-segment digital broadcasting with priority.

  In the above-described embodiment, the first predetermined number N is set to 5 and the second predetermined number M is set to 1. However, other values may be used. In addition, the first reception mode and the second reception mode are alternately switched, but a plurality of values are prepared as the threshold value S2 and the threshold value S1, and the threshold values S2 and S1 are set according to the number of switching times within a predetermined time. The value may be changed. In this case, the values of the threshold values S2 and S1 may be changed in a plurality of steps or continuously.

  As described above, according to the present invention, if the reception quality deteriorates during reception of the second broadcast (full segment digital broadcast) with good video quality set to the second reception mode, The first broadcast (one-segment digital broadcast) is frequently switched. When the number of times of switching becomes the first predetermined number of times, the first broadcast mode is changed to the first broadcast. Is preferentially received. For this reason, switching between the second broadcast and the first broadcast can be stopped halfway, so that frequent switching can be prevented and block noise can be prevented from occurring frequently. be able to. Further, since the second broadcast can be received in the second reception mode until the second reception mode is changed to the first reception mode, reception of the second broadcast (full segment digital broadcast) is possible. Can increase opportunities.

100 Digital Terrestrial Broadcasting Receiver 10, 12, 14, 16 Tuner Unit 30, 32 OFDM Demodulator 40 MPEG Decoder 42 Digital-Analog Converter (D / A)
44 Speaker 46 Display Processing Unit 48 Display Device 50 Control Unit 51 BER Measuring Unit 52 Reception Mode Setting Unit 53 Full Seg / One Seg Switching Unit 53 Reception Mode Switching Unit

Claims (10)

Receiving means for receiving a first broadcast and a second broadcast having better video quality than the first broadcast;
A first reception mode for preferentially receiving the first broadcast and a priority for the second broadcast by changing a switching condition for switching between the first broadcast and the second broadcast. Receiving mode setting means for setting each receiving mode of the second receiving mode to be received automatically,
Switching means for switching between reception of the first broadcast and reception of the second broadcast according to the switching condition;
When the reception mode is set to the second reception mode, the reception mode is changed when the reception of the second broadcast and the reception of the first broadcast are switched a first predetermined number of times within a predetermined time. Receiving mode switching means for changing to the first receiving mode;
A digital broadcast receiver comprising: In claim 1,
The digital broadcast receiver characterized in that the first broadcast is a one-segment digital broadcast of a terrestrial digital broadcast, and the second broadcast is a full-segment digital broadcast of a terrestrial digital broadcast. In claim 1 or 2,
The reception mode switching means switches the reception of the first broadcast and the reception of the second broadcast to a second predetermined number of times within a predetermined time in a state where the reception mode is set to the first reception mode. And changing the reception mode to the second reception mode. In any one of Claims 1-3,
The digital broadcast receiver characterized in that the first predetermined number of times is a plurality of times. In any one of Claims 1-4,
The digital broadcast receiver characterized in that the second predetermined number of times is one. In any one of Claims 1-5,
The switching condition in the first reception mode has a threshold set corresponding to a high reception quality of the broadcast signal, and the switching condition in the second reception mode corresponds to a low reception quality of the broadcast signal A digital broadcast receiver having a threshold value set as described above. In any one of Claims 1-6,
Digital broadcast reception characterized in that the switching condition uses a threshold value that is compared with any of a bit error rate, a carrier power to noise power ratio, and a field intensity of a broadcast signal corresponding to the first and second broadcasts. Machine. In any one of Claims 1-7,
A digital broadcast receiver which is mounted on a vehicle. In any one of Claims 1-7,
A digital broadcast receiver characterized by being provided in a portable terminal. Receiving a first broadcast and a second broadcast having better video quality than the first broadcast by receiving means;
A first reception mode for preferentially receiving the first broadcast and a priority for the second broadcast by changing a switching condition for switching between the first broadcast and the second broadcast. Setting each reception mode of the second reception mode to be received automatically by the reception mode setting means;
Switching the reception of the first broadcast and the reception of the second broadcast by the switching means according to the switching condition;
When the reception mode is set to the second reception mode, the reception mode is changed when the reception of the second broadcast and the reception of the first broadcast are switched a first predetermined number of times within a predetermined time. Changing to the first reception mode by reception mode switching means;
A receiving mode switching method for a digital broadcast receiver, comprising:

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