JP2013172332A - On-vehicle receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide "an on-vehicle receiver" capable of performing background processing such as channel search while eliminating waste of time and reducing influence on reception and reproduction of an original broadcast signal as much as possible.SOLUTION: An on-vehicle receiver includes: reproduction form switching means for, when reception quality declines to a prescribed quality level, switching from a first reproduction form using a first broadcast signal in a weak hierarchy for reproduction of information to a second reproduction form using a second broadcast signal in a strong hierarchy for the reproduction of the information, and when the state in which the reception quality exceeds the prescribed quality level continues for a certain period, returning from the second reproduction form to the first reproduction form; and background processing timing control means (113, 114) for, while using one or more reception units for the reception of the broadcast signal, allowing execution of prescribed background processing using the remaining one or more reception units, from the timing of switching from the first reproduction form to the second reproduction form.

Description

  The present invention relates to a vehicle-mounted receiving apparatus that performs background processing such as channel search while receiving weak-layer broadcast signals and strong-layer broadcast signals that are digitally broadcast by hierarchical transmission, such as terrestrial digital broadcasting.

  In terrestrial digital broadcasting currently being performed, hierarchical transmission in which the modulation method of carrier waves and the strength of error correction can be changed for each segment in one channel is performed. With this hierarchical transmission, for example, among 13 segments (segment: basic unit of frequency bandwidth) included in one channel, a broadcast signal such as a high-definition high-definition broadcast signal using 12 segments and a high information rate, A broadcast signal including a broadcast signal modulated by a method resistant to fluctuations in radio waves using the remaining one segment is provided for broadcasting. In hierarchical transmission, a high-quality broadcast signal with a high information rate that is broadcast using 12 segments is a weak-layer broadcast signal that is vulnerable to radio wave fluctuations. On the other hand, a broadcast signal modulated using a method resistant to fluctuations of the radio wave broadcast using one segment, that is, a broadcast signal in a strong hierarchy, has a low information rate and a low quality.

  As a vehicle-mounted receiving device that receives a broadcast signal used for broadcasting by hierarchical transmission as described above, a device described in Patent Document 1 is known. In this in-vehicle receiving apparatus, since the reception quality of the broadcast signal varies variously while the vehicle is traveling, reproduction of information (broadcast program audio and video) using the broadcast signal of the weak hierarchy according to the reception quality. (Video display and sound output) and information generation using the broadcast signal of the higher hierarchy are switched. That is, when the reception quality is good, high-quality information (sound, high-definition video, etc.) is reproduced using the broadcast signal of the weak hierarchy (12-segment broadcasting), and when the reception quality is reduced, Information (audio, television video) is reproduced using the broadcast signal of the strong hierarchy (one-segment broadcasting).

  Moreover, in the vehicle-mounted receiving device described in Patent Document 1, broadcast signals received by four receiving units (antenna unit and channel selection / demodulation unit) are diversity-combined (four-diversity combining) to obtain a combined received signal. ing. Then, based on the reception quality parameter C (carrier power) / N (noise power) obtained from the combined received signal, the portion of the weak hierarchy broadcast signal (12-segment broadcast) included in the combined received signal and the strong hierarchy One of the parts of the broadcast signal (one-segment broadcasting) is used for information reproduction.

  Furthermore, in terrestrial digital broadcasting, broadcast programs having the same content as broadcast programs from each broadcast station are broadcast from relay stations on different channels. In addition, different broadcast stations (broadcast stations of the same series) may broadcast broadcast programs with the same content on different channels. In a conventional in-vehicle receiving device (see Patent Document 1) that can receive broadcast signals of various channels (broadcast stations, relay stations), the reception quality of the broadcast signals of the selected channels (broadcast stations) decreases. When it comes, it is used for diversity synthesis after a lapse of a predetermined time t1 from the timing of switching from information reproduction using a weak-layer broadcast signal (12-segment broadcast) to information reproduction using a strong-layer broadcast signal (one-segment broadcast). Receiving (broadcasting program audio and video) reproduction (video display and audio) by receiving a broadcast signal of the selected channel at one or a plurality of receiving units out of four received units. In the background process, a channel search for a channel such as a relay station broadcasting the same broadcast program is performed using the remaining receiving units. As described above, the channel search is performed after the elapse of the predetermined time t1 from the switching timing from the reproduction of the information using the broadcast signal of the weak hierarchy (12-segment broadcasting) to the reproduction of the information using the broadcast signal of the strong hierarchy (one-segment broadcasting). This makes it possible to prevent useless channel search (background processing) when the reception quality is temporarily lowered (within a predetermined time t1) and recovered.

JP 2011-87051 A

  However, the reception quality, which has deteriorated enough to switch from the reproduction of information using the weak broadcast signal (12-segment broadcasting) to the reproduction of information using the strong broadcast signal (one-segment broadcasting), does not immediately recover. In this case, the channel search start timing is delayed by waiting for the predetermined time t1. That is, the waiting time of the predetermined time t1 is a useless time.

  In addition, in order to prevent frequent switching between information reproduction using weak hierarchy broadcast signals (12-segment broadcasting) and information reproduction using strong hierarchy broadcast signals (one-segment broadcasting), weak hierarchy broadcast signals After switching from information reproduction (12-segment broadcasting) used to information reproduction (one-segment broadcasting) using a strong hierarchy broadcast signal, information reproduction using a broadcast signal with a weak reception quality (12-segment broadcasting) If a state exceeding a predetermined quality level suitable for the period is maintained for a period of time, the information is restored to information reproduction (12-segment broadcasting) using a broadcast signal of a weak hierarchy. In such a case, even if the reception quality recovers immediately after switching to the reproduction of information (one-segment broadcasting) using the broadcast signal of the strong hierarchy due to a temporary decrease in the reception quality, the strong quality is maintained for a certain period of time. Since the reproduction of information using the broadcast signal of the hierarchy (one-segment broadcasting) is maintained, the waiting time of the predetermined time t1 set in expectation that the reception quality is immediately recovered becomes a useless time. End up.

  The present invention has been made in view of such circumstances, and performs background processing such as channel search without wasting time and minimizing the influence on reception and reproduction of the original broadcast signal as much as possible. A vehicle-mounted receiving device that can be used is provided.

  An in-vehicle receiving apparatus according to the present invention receives a broadcast signal including a first broadcast signal in a weak hierarchy and a second broadcast signal in a strong hierarchy, which is digitally broadcast by hierarchical transmission, in a reception unit having a predetermined number of reception units. A vehicle-mounted receiving device that receives and reproduces information based on either the first broadcast signal or the second broadcast signal received by the receiving unit, and receiving the broadcast signal at the receiving unit When the quality is reduced to a predetermined quality level, the first reproduction form using the first broadcast signal for information reproduction is switched to the second reproduction form using the second broadcast signal for information reproduction, and the reception quality is the predetermined quality. When the state exceeding the quality level is continued for a certain period, the playback mode switching means for returning from the second playback mode to the first playback mode, and the second playback from the first playback mode by the playback mode switching unit. Form The predetermined background processing is executed using the remaining one or more receiving units while using one or more receiving units of the predetermined number of receiving units for receiving the broadcast signal. The background processing timing control means is permitted.

  With such a configuration, when the reception quality of the broadcast signal is lowered to a predetermined quality level, the second reproduction mode using the strong hierarchy broadcast signal for information reproduction from the first reproduction form using the weak hierarchy broadcast signal for information reproduction. When the mode is switched to the playback mode and the reception quality exceeds the predetermined quality level for a certain period, the mode is restored from the second playback mode to the first playback mode. In the process of switching between the first playback mode and the second playback mode, the reception quality of the broadcast signal is lowered to the predetermined quality level and switched from the first playback mode to the second playback mode. From this timing, one or a plurality of receiving units of a predetermined number of receiving units are used for receiving the broadcast signal, while the background process using the remaining one or more receiving units is allowed to be performed. As a result, the background processing can be started immediately after the reception quality is lowered to a predetermined quality level and the first playback mode is switched to the second playback mode, and the second playback mode is started from the second playback mode. After the switching to the playback mode, even if the reception quality returns to a state exceeding the predetermined quality level, the background processing is performed in at least a period during which the second playback mode is maintained without switching to the first playback mode. Can be made.

  The certain period during which the reception level, which is a condition for returning from the second playback mode to the first playback mode, is maintained above the predetermined level is an arbitrary time, even if it is a predetermined time period. It may be, as long as some time has passed.

  In the in-vehicle receiving apparatus according to the present invention, the background processing timing control means is configured to perform the first reproduction form switching means by the reproduction form switching means from the switching timing from the first reproduction form to the second reproduction form by the reproduction form switching means. It is possible to allow the background process to be executed during the period from the 2 playback mode to the return to the first playback mode.

  With such a configuration, the reception quality of the broadcast signal is reduced to a predetermined quality level, and the first reproduction form (reproduction of information using a weak hierarchy broadcast signal) to the second reproduction form (a strong hierarchy broadcast signal is used). After switching to (information reproduction), until the reception quality exceeds the predetermined quality level for a period of time and returns to the first reproduction form from the second reproduction form. Background processing may be performed during the second reproduction mode in which information is reproduced using a signal.

  In the in-vehicle receiving device according to the present invention, the reproduction mode switching means may change the reproduction mode from the second reproduction mode when the state where the reception quality exceeds the predetermined quality level is continued for a predetermined time. The background processing timing control means can be configured to allow the predetermined time from the switching timing from the first reproduction form to the second reproduction form by the reproduction form switching means.

  With such a configuration, after switching from the first playback mode to the second playback mode, even if the reception quality returns to a state exceeding the predetermined quality level, the second playback mode does not switch to the first playback mode. The background processing may be performed at least for a certain time during which the form is maintained.

  Furthermore, in the in-vehicle receiver according to the present invention, the background processing timing control means starts the background processing from the switching timing from the first reproduction form to the second reproduction form by the reproduction form switching means. It can be configured.

  With such a configuration, the background processing is started from the timing when the reception quality is lowered to the predetermined quality level and switched from the first reproduction form to the second reproduction form. Therefore, the second reproduction is performed from the first reproduction form. After the switching to the mode, the background processing is executed at least during a period in which the second playback mode is maintained without switching to the first playback mode even if the reception quality returns to the state exceeding the predetermined quality level. Is done.

  The in-vehicle receiving device according to the present invention includes a receiving unit having a predetermined number of receiving units for broadcast signals including first broadcast signals of weak layers and second broadcast signals of strong layers, which are digitally broadcast by hierarchical transmission. And receiving the information on the basis of either the first broadcast signal or the second broadcast signal received by the receiving unit, wherein the receiving unit receives the broadcast signal. Switching from the first reproduction mode using the first broadcast signal for reproduction of information to the second reproduction mode using the second broadcast signal for reproduction of information when the reception quality of the video signal falls to a predetermined quality level. A playback mode for returning from the second playback mode to the first playback mode after maintaining the second playback mode regardless of the reception quality at the receiving unit for a certain time from the switching timing from the mode to the second playback mode switching And at a certain time during which the second playback mode is maintained from the switching timing from the first playback mode to the second playback mode by the playback mode switching means, a part of the predetermined number of receiving units. A background processing timing control unit that allows execution of predetermined background processing using the remaining one or a plurality of receiving units while using one or a plurality of receiving units for receiving the broadcast signal.

  With such a configuration, when the reception quality of the broadcast signal is lowered to a predetermined quality level, the second reproduction mode using the strong hierarchy broadcast signal for information reproduction from the first reproduction form using the weak hierarchy broadcast signal for information reproduction. After switching to the playback mode and maintaining the second playback mode for a certain period of time regardless of the reception quality from the switching timing, if the received quality exceeds the predetermined quality level, the first playback mode is switched from the second playback mode to the first playback mode. Return to form. In the process of switching between the first playback mode and the second playback mode, in a certain time during which the second playback mode is maintained from the timing when the first playback mode is switched to the second playback mode. While one or a plurality of receiving units of a predetermined number of receiving units are used for receiving the broadcast signal, execution of background processing using the remaining one or more receiving units is allowed. Thereby, it is possible to start the background processing immediately after the reception quality is reduced to the predetermined quality level and switched from the first reproduction form to the second reproduction form, and regardless of the reception quality of the broadcast signal, That is, the background process can be performed during the period in which the second reproduction mode is maintained regardless of whether or not the information can be reproduced in the first reproduction mode.

  According to the vehicle-mounted receiving device according to the present invention, the background processing can be started immediately after the reception quality is lowered to a predetermined quality level and the first playback mode is switched to the second playback mode. After switching from the first playback mode to the second playback mode, at least the second playback mode is maintained without switching to the first playback mode even if the reception quality returns to a state exceeding the predetermined quality level. Since the background processing can be performed in a certain period, it is possible to perform the background processing without wasting time and minimizing the influence on reception and reproduction of the original broadcast signal as much as possible.

  Further, according to the in-vehicle receiver according to the present invention, the background processing can be started immediately after the reception quality is lowered to a predetermined quality level and the first playback mode is switched to the second playback mode. Further, regardless of whether the reception quality is the predetermined quality level, that is, whether or not the information can be reproduced in the first reproduction form, the back quality is maintained in the period in which the second reproduction form is maintained. Since the ground processing can be performed, it is possible to perform the background processing without wasting time and minimizing the influence on reception and reproduction of the original broadcast signal as much as possible.

It is a block diagram which shows the structure of the terrestrial digital broadcast receiver which is a vehicle-mounted receiver which concerns on embodiment of this invention. It is a flowchart which shows an example of the procedure of the automatic switching process by the control part in the vehicle-mounted receiving apparatus shown in FIG. 1 with full segment reception and one segment reception. It is a figure which shows the relationship between the change of reception quality (C / N) and the switching of full segment reception and one segment reception in the case where automatic switching processing between full segment reception and one segment reception is performed according to the procedure shown in FIG. It is a flowchart which shows the procedure of the channel search process (background process) by the control part in the vehicle-mounted receiver shown in FIG. Reception quality (C / N), full-segment reception and one-segment reception when a relay channel is found in the channel search process executed in the process of automatically switching between full-segment reception and one-segment reception according to the procedure shown in FIG. 5 is a timing chart showing the relationship between switching and switching and channel search. It is a flowchart which shows the procedure of the EPG acquisition process (background process) in the control part in the vehicle-mounted receiving apparatus shown in FIG. It is a timing chart which shows the relationship between reception quality (C / N), switching between full segment reception and one segment reception, and EPG acquisition. It is a figure which shows the other relationship of the change of reception quality (C / N), and the switching of full segment reception and one segment reception. It is a flowchart which shows another example of the procedure of the automatic switching process by the control part in the vehicle-mounted receiving apparatus shown in FIG. 1 with full segment reception and one segment reception. FIG. 10 is a diagram illustrating a relationship between a change in reception quality (C / N) and switching between full segment reception and one segment reception when automatic switching processing between full segment reception and one segment reception is performed according to the procedure illustrated in FIG. 9. Changes in reception quality (C / N) in the case where a relay channel is not found in the channel search process executed in the process of automatically switching between full segment reception and one segment reception according to the procedure shown in FIG. It is a figure which shows the relationship with the switching with 1seg reception. Changes in reception quality (C / N) in the case where a relay channel is found in the channel search process executed in the process of automatically switching between full segment reception and one segment reception according to the procedure shown in FIG. It is a figure which shows the relationship with the switching with 1seg reception.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The in-vehicle receiving device according to the embodiment of the present invention is a terrestrial digital broadcast receiving device and is configured as shown in FIG.

  The in-vehicle receiver (terrestrial digital broadcast receiver) shown in FIG. 1 can receive digital terrestrial broadcasts. In this terrestrial digital broadcasting, as described above, the information rate using 12 segments out of 13 segments included in one channel is large (for example, by multi-level QAM) due to hierarchical transmission. A broadcast signal (hereinafter referred to as a full-segment broadcast signal (first broadcast signal)) and a strong hierarchical broadcast signal (hereinafter referred to as QPSK) modulated in a manner that is resistant to fluctuations in radio waves using the remaining one segment (hereinafter referred to as QPSK). A broadcast signal including a one-segment broadcast signal (referred to as a second broadcast signal) is provided for broadcasting. This broadcast signal is transmitted as an OFDM signal in which a plurality of carriers modulated based on information to be broadcast (audio, video, data, etc.) are converted into OFDM (Orthogonal Frequency Division Multiplexing).

  As shown in FIG. 1, the in-vehicle receiving device 10 that receives the broadcast signal (OFDM signal) transmitted hierarchically includes a control unit 11, a receiving unit 12 including four tuner units 12 a, 12 b, 12 c, and 12 d, switching Section 13, first OFDM demodulator 14 a, second OFDM demodulator 14 b, decoder 15, display processor 16, and digital / analog converter (D / A converter) 17. The control unit 11 includes a reception state determination unit 111, a switching control unit 112, a search processing unit 113, and an EPG creation unit 114. The in-vehicle receiving device 10 is connected to a center unit 20 provided on the instrument panel. The center unit 20 includes a display device 21 and an operation unit 22, and a speaker 25 is connected to the center unit 20.

  Each of the four tuner units 12a to 12d constituting the receiving unit 12 selects a transmission channel and receives a broadcast signal (OFDM signal) of the selected transmission channel. This broadcast signal includes the above-described weak-layer full-segment broadcast signal and strong-layer one-segment broadcast signal. The switching unit 13 maintains the state in which broadcast signals from the two tuner units 12a and 12b are always supplied to the first OFDM demodulation unit 14a under the control of the switching control unit 112 in the control unit 11. The broadcast signals from the two tuner units 12c and 12d are switched to either the first OFDM demodulator 14a or the second OFDM demodulator 14b.

  Each of the first OFDM demodulator 14a and the second OFDM demodulator 14b demodulates a broadcast signal (OFDM signal) input via the switching unit 13 to generate a digital reception signal (transport packet). The control unit 11 performs diversity combining of a plurality of (four or two) digital reception signals from the first OFDM demodulation unit 14a according to a predetermined algorithm, and an audio signal and a video signal are obtained from the combined reception signal obtained thereby. And other signals (data, EPG information, etc.). Then, the control unit 11 supplies the audio signal and the video signal to the decoder 15, and internally processes other signals such as data and EPG information. The decoder 15 decodes the audio signal and the video signal from the control unit 11. The decoded video signal obtained by decoding by the decoder 15 is subjected to predetermined display processing by the display processing unit 16 and is supplied to the center unit 20. The decoded audio signal obtained by decoding by the decoder 15 is converted to an analog audio signal by the D / A converter 17 and supplied to the center unit 20.

  In the center unit 20, the video of the broadcast program is displayed on the display device 21 based on the decoded video signal from the display processing unit 16, and the audio of the broadcast program is output from the speaker 25 based on the decoded audio signal.

  The reception state determination unit 111 in the control unit 11 receives the broadcast signal (OFDM signal) reception quality, for example, the ratio between the carrier power (C) and the noise power (N) based on the combined received signal obtained by diversity combining. C / N is calculated as a parameter representing reception quality, and reception quality is determined based on this CN. The search processing unit 113 in the control unit 11 searches for a receivable channel based on the digital reception signal from the second OFDM demodulation unit 14b that demodulates the broadcast signals (OFDM signals) from the two tuner units 12c and 12d. Perform the process. Details of this channel search process will be described later. The EPG creation unit 114 is an EPG (electronic program guide) based on the EPG information separated from the digital reception signal from the second OFDM demodulation unit 14b that demodulates the broadcast signals (OFDM signals) from the two tuner units 12c and 12d. Process to create. Details of the EPG creation processing will be described later. The channel search process by the search processing unit 113 and the EPG creation process by the EPG creation unit 114 will be described later in the background of the process related to reproduction (output) of information (audio, video) based on the received broadcast signal, for example. It is done at the timing.

  The control unit 11 includes a full-seg playback mode (first playback mode) that uses a weak-segment full-segment broadcast signal for information playback, and a one-segment playback mode (second playback mode) that uses a strong-layer one-segment broadcast signal for information playback. Are switched according to the reception quality determined by the reception state determination unit 111 (reproduction form switching means). For example, in the full segment playback mode, the control unit 11 supplies a portion corresponding to the full segment broadcast signal to the decoder 15 in the combined reception signal obtained by diversity combining, and in the one segment playback mode, the control unit 11 receives the combined reception signal obtained by diversity combining. A portion corresponding to the one-segment broadcasting signal is supplied to the decoder 15. Switching between the full-segment playback mode and the one-segment playback mode in the control unit 11 is performed, for example, according to the procedure shown in FIG.

  In FIG. 2, the reception state determination unit 111 determines whether or not the reception quality represented by C / N is equal to or lower than a predetermined quality level (threshold value) Thone-seg (S11). If the reception state determination unit 111 determines that the reception quality is good and not lower than the predetermined quality level Thone-seg (NO in S11), the control unit 11 maintains the full segment reproduction form (S12). As a result, in a reception environment in which the reception quality (C / N) exceeds a predetermined quality level Thone-seg, the full segment reproduction mode is maintained, and high-quality video and audio reproduction based on the weak segment full segment broadcast signal is performed. (Video display on the display device 21 and sound output from the speaker 25) are performed.

  As the vehicle travels, the broadcast signal reception environment deteriorates. For example, at time t1 in FIG. 3, the reception state determination unit 111 determines that the reception quality (C / N) is equal to or lower than a predetermined quality level Thone-seg. Then (YES in S11), the control unit 31 switches from the full-segment playback mode to the one-segment playback mode (S13: playback mode switching means). As a result, when the reception environment of the broadcast signal is bad and the reception quality (C / N) is lowered to a predetermined quality level Thone-seg, the one-segment playback mode is switched to using a strong one-segment broadcast signal that is resistant to noise and the like. Information (audio, video) is reproduced (video display, sound output).

  Thereafter, the control unit 11 determines whether or not the reception quality (C / N) is equal to or lower than a predetermined quality level Thone-seg (S14). If the reception quality (C / N) is not recovered and is equal to or lower than the predetermined quality level Tone-seg (YES in S14), the control unit 11 confirms that a timer T described later is zero (S15). YES), the one-segment playback mode is maintained (S16). In this way (S15 to S17), in the state where the reception quality is equal to or lower than the predetermined quality level “Thone-seg”, the one-segment playback mode is maintained.

  When the one-seg playback mode is maintained and the reception environment of the broadcast signal is improved by traveling of the vehicle and the reception quality (C / N) exceeds the predetermined quality level Thone-seg (NO in S14), The control unit 11 determines whether or not the timer T is zero (T = 0) (S17). If the timer T is zero (YES in S17), the timer T is started (S18). It is determined whether or not the timer T has reached a predetermined time To (S19). If the timer T has not reached the predetermined time To (NO in S19), the control unit 11 maintains the one-segment playback mode (S16). Thereafter, even if the reception quality (C / N) exceeds the predetermined quality level Thone-seg and the reception environment is good (NO in S14), the one-segment playback mode is maintained while the timer T operates (S14). , S17, S19, S16).

  In a situation where the reception environment of the broadcast signal is unstable, the reception quality (C / N) may temporarily drop below the predetermined quality level Thone-seg. In this case (YES in S14), the control unit 11 confirms that the timer T is not zero (NO in S15), resets the timer T (S20), and further maintains the one-segment playback mode (S16). Thereafter, when the reception quality (C / N) exceeds the predetermined quality level Thone-seg again by the recovery of the broadcast signal reception environment (NO in S14), the control unit 11 confirms that the timer T is zero. (YES in S17), the timer T is started again (S18). Then, the control unit 11 determines whether or not the timer T has reached the predetermined time To (S19). If the timer T has not reached the predetermined time To (NO in S19), the reception quality (C / N) Is over the predetermined quality level Thone-seg, but the one-segment playback mode is maintained (S16).

  For example, as in the situation between time t1 and time t2 in FIG. 3, the broadcast signal reception environment in which the reception quality (C / N) exceeds the predetermined quality level Thone-seg cannot be maintained for the predetermined time To. In an unstable situation, the one-segment playback mode is maintained while the start of the timer T (NO in S14, S17, S18, S19) and the reset (YES in S14, S15, S20) are repeated (S16). . Accordingly, in such a situation where the reception environment of the broadcast signal is unstable, information (audio, video) is reproduced (video display, sound output) using a one-segment broadcast signal of a strong hierarchy resistant to noise or the like.

  In the situation where the one-segment playback mode is maintained as described above (S16), the reception environment of the broadcast signal is improved and the reception quality (C / N) exceeds the predetermined quality level Thone-seg (in S14) NO), when the timer T reaches the predetermined time To (YES in S19), that is, as in the situation between the time t2 and the time t3 in FIG. 3, the reception quality (C / N) is the predetermined quality level Thone. When the state exceeding -seg continues for a predetermined time To, the control unit 11 returns to the full segment reproduction mode (time t3 in FIG. 3). This makes it possible to reproduce high-quality video and audio based on weak-segment full-segment broadcast signals from information (audio and video) reproduction (video display, sound output) using strong-segment one-segment broadcast signals that are resistant to noise, etc. (Video display, sound output).

  As described above, according to the reception quality (C / N), in the process of reproducing information (video, audio) while switching between a high-quality full-segment reproduction form and a one-segment reproduction form with poor quality, For example, the control unit 11 executes the channel search process as a background process in accordance with the procedure shown in FIG.

  For example, as shown in FIG. 5, the channel search process is allowed at the timing (time t1) when the reception quality (C / N) is lowered to a predetermined quality level Thone-seg and the full-segment playback mode is switched to the one-segment playback mode. The channel search process is started at the timing (time t1).

  When the switching control unit 112 in the control unit 11 controls the switching unit 13, the two tuner units 12a and 12b among the four tuner units 12a to 12d are connected to the first OFDM demodulating unit 14a. The remaining two tuner units 12c and 12d are connected to the second OFDM demodulator unit 14b and used for channel search. In parallel with the reproduction of information (video, audio) in the one-segment reproduction format using the broadcast signals of the channels selected by the two tuner units 12a and 12b, the control unit 11 (search processing unit 113) The remaining tuner units 12c and 12d are controlled to perform channel search processing (background processing) according to the procedure shown in FIG. Note that the broadcast signal of the channel that has been selected so far has been received using the four tuners 12a to 12d and diversity-combined (four-diversity combining). However, the two tuners 12a, Since the reception is switched to the reception using 12b, the reception quality (C / N) of the broadcast signal of the channel that has been selected until now, which is continued after the channel search process starts, is, for example, the channel search period (time) shown in FIG. It slightly decreases from the characteristic indicated by the broken line at time t1 to time t2) as indicated by the solid line (however, within the quality level range in which information can be reproduced in the one-segment reproduction form).

  Referring to FIG. 4, the search processing unit 113 (background processing timing control means) in the control unit 11 uses one channel frequency from the receivable frequency band defined in the already received NIT (Network Information Table). Is selected and set (S31), and it is determined whether or not a broadcast signal (OFDM signal) of the set channel frequency is received by the two tuner units 12c and 12d (S32). When the broadcast signal (OFDM signal) of the set channel frequency cannot be received (NO in S32), the search processing unit 113 is used in the switching process between the full segment reproduction mode and the one segment reproduction mode shown in FIG. It is determined whether or not the timer T has reached a predetermined time To (S36). If the reproduction of information in the one-segment reproduction mode is maintained and the timer T has not reached the predetermined time To (NO in S36), the search processing unit 113 has finished searching for all channels. It is determined whether or not (S37).

  If the search for all channels has not been completed (NO in S37), the search processing unit 113 sets the next channel frequency (S31), and two broadcast signals (OFDM signals) of the set channel frequency are set. It is determined whether or not the data is received by the tuner units 12c and 12d (S32). When a broadcast signal (OFDM signal) of the set channel frequency is received by the two tuner units 12c and 12d (YES in S32), the search processing unit 113 uses the received broadcast signal to obtain information in a full segment reproduction form. It is determined whether or not reproduction is possible, that is, whether or not the reception quality (C / N) exceeds a predetermined quality level Thone-seg (S33). Here, based on the reception results of the two tuners 12c and 12d, the reception quality when the four tuners 12a to 12d receive and combine the diversity is estimated and determined. If it is determined that the reception quality is equal to or less than the predetermined quality level Thone-seg and the information in the full-seg reproduction format cannot be reproduced by the received broadcast signal (NO in S33), the timer T is After confirming that the predetermined time To has not been reached (NO in S36) and that all channels have not been searched (NO in S37), the search processing unit 113 sets the next channel frequency ( S31).

  Furthermore, when the broadcast signal (OFDM signal) of the next set channel frequency is received (YES in S32), it is determined that the information can be reproduced in the full segment reproduction form by the received broadcast signal ( In S33, the search processing unit 113 broadcasts the channel of the received broadcast signal that is currently selected and the information (broadcast program video, broadcast program audio) is reproduced in a one-segment playback format. It is determined whether or not the relay channel is broadcasting the same program as the signal channel (S34). If it is determined that the channel of the received broadcast signal is not a relay channel (NO in S34), the timer T has not reached the predetermined time To (NO in S36), and all channels are searched. After confirming that is not completed (NO in S37), the search processing unit 113 further sets the next channel frequency (S31).

  In this way, the search processing unit 113 confirms that the timer T has not reached the predetermined time To (S36), sequentially changes the channel frequency (S37, S31), and the broadcast signal of that channel frequency is fully segmented. It is determined whether or not it is a broadcast signal of a relay channel capable of reproducing information in a reproduction form (S32 to S34). In the process, if it is determined that the broadcast signal of the set channel frequency is a broadcast signal of a relay channel capable of reproducing information in the full segment reproduction form (YES in S32, YES in S33, YES in S34), search processing The unit 113 decides to select the relay channel as a channel to be received and reproduced instead of the currently selected channel (S35), and ends the channel search process.

  Under the control of the switching control unit 111, the switching unit 13 connects the two tuners 12c and 12d used for the channel search process to the first OFDM demodulation unit 14a in the same manner as the other two tuners 12a and 12b. . Thus, for example, at time t2 shown in FIG. 5, information in the one-segment playback format using the broadcast signal of channel A that has been selected by the two tuners 12a and 12b (video of the broadcast program, broadcast program) Information in a full-segment playback format using a digital reception signal obtained by diversity combining (4 diversity combining) of the broadcast signal of the relay channel B selected by the four tuners 12a to 12d. Switching to playback of the same broadcast program video and audio of the same broadcast program. Thereafter, the reproduction of information (video, audio) of the same program using the broadcast signal of the relay channel B is maintained in the full segment reproduction form.

  In the process described above, when the timer T reaches the predetermined time To (YES in S36), the channel search process ends. In this case, since the state where the reception quality (C / N) exceeds the predetermined quality level is continued for a predetermined time To and returns to the full segment reproduction mode (YES in S19 in FIG. 2), the subsequent channel search process is not necessary. . If the search for all channels is completed in the process described above (YES in S37), the channel search process ends without finding a relay channel. In this case, the reproduction of information in the one-segment reproduction mode is continued using the broadcast signal of the channel that has been selected so far (using the four tuners 12a to 12d).

  According to the in-vehicle receiver 10 that performs the switching between the full segment reproduction mode and the one segment reproduction mode (see FIG. 2) and the channel search process (see FIGS. 4 and 5) as described above, the reception quality (C / N ) Is reduced to the predetermined quality level Thone-seg and switched from the full segment playback mode to the one segment playback mode, the channel search can be performed from the switching timing (for example, time t1 in FIG. 5) without waiting for a predetermined time as in the prior art. Since the process is started as a background process, no time is wasted. Further, even if the reception quality (C / N) returns to the state where the predetermined quality level Thone-seg capable of reproducing information in the full segment reproduction mode is restored, the one segment reproduction mode is maintained without switching to the full segment reproduction mode. Since the channel search process is performed during the period when the timer T is equal to or less than the predetermined time To, the reproduction of information originally performed in the full segment reproduction form is maintained in the one segment reproduction form by the channel search process. And there is little influence on the reception and reproduction of the broadcast signal. For this reason, the viewer (vehicle occupant) has little discomfort when the channel search process is executed.

  As described above, in accordance with the reception quality (C / N), information (video, audio) is being reproduced while switching between a high-quality full-segment reproduction form and a one-segment reproduction form with poor quality ( 2), the control unit 11 can execute the EPG information acquisition process as a background process, for example, according to the procedure shown in FIG.

  For example, as shown in FIG. 7, the reception quality (C / N) is reduced to a predetermined quality level Thone-seg, and the EPG information acquisition process is allowed at the timing (time t1) when the full segment playback mode is switched to the one segment playback mode. Then, the EPG information acquisition process is started at the timing (time t1).

  As in the case of the channel search process described above, in parallel with the reproduction of information (video, audio) in the one-segment reproduction form using the broadcast signals of the channels selected by the two tuner units 12a and 12b, The control unit 11 (EPG creation unit 114) controls the remaining tuner units 12c and 12d and performs EPG information acquisition processing (background processing) according to the procedure shown in FIG. Also in this case, the broadcast signal of the channel that has been selected so far has been received using the four tuners 12a to 12d and diversity-combined (four-diversity combining). However, with the start of the EPG information acquisition process, Since switching to reception using the tuners 12a and 12b is performed, the reception quality (C / N) of the broadcast signal of the channel that has been selected until now, which is continued after the start of the EPG acquisition process, can be obtained, for example, as shown in FIG. In the period (time t1 to time t2, time t3 to time t4, time t6 to time t7), the characteristic indicated by the broken line is slightly reduced to the characteristic indicated by the solid line (however, the information reproduction in the one-segment reproduction form is performed). Within the possible quality level range).

  Referring to FIG. 6, the EPG creation unit 114 (background processing timing control means) in the control unit 11 selects and sets one channel frequency from the current channel list (S41), and broadcasts the set channel frequency. It is determined whether or not the signal (OFDM signal) is received by the two tuner units 12c and 12d (S42). When the broadcast signal (OFDM signal) of the set channel frequency cannot be received (NO in S42), the EPG creation unit 114 is used in the switching process between the full segment reproduction mode and the one segment reproduction mode shown in FIG. It is determined whether or not the timer T has reached a predetermined time To (S45). If the reproduction of information in the one-segment reproduction mode is maintained and the timer T has not reached the predetermined time To (NO in S45), the EPG creation unit 114 has completed the processing for all channels. It is determined whether or not (S46).

  If processing for all channels has not been completed (NO in S46), the EPG creation unit 114 sets the next channel frequency (S41), and two broadcast signals (OFDM signals) of the set channel frequency are set. It is determined whether or not the data is received by the tuner units 12c and 12d (S42). When a broadcast signal (OFDM signal) of the set channel frequency is received by the two tuner units 12c and 12d (YES in S42), the EPG creation unit 114 transmits data including EPG information from the received broadcast signal. It is determined whether or not acquisition is possible, that is, whether or not the reception quality (C / N) exceeds a predetermined quality level Thone-seg (S43). When it is determined that the reception quality is equal to or less than the predetermined quality level Thone-seg and it is not possible to acquire data including EPG information from the received broadcast signal (NO in S43), the timer T is After confirming that the predetermined time To has not been reached (NO in S45) and that the search of all channels has not been completed (NO in S46), the EPG creation unit 114 sets the next channel frequency (S41). ).

  Further, a broadcast signal (OFDM signal) of the set next channel frequency is received (YES in S42), and it is determined that data including EPG information can be acquired from the received broadcast signal (S43). In step S44, the EPG creation unit 114 acquires EPG information (electronic program guide information) of the set channel from the received broadcast signal.

  In this way, the EPG creation unit 114 confirms that the timer T has not reached the predetermined time To (NO in S45) and that processing for all channels has not been completed (NO in S46). For example, EPG information is acquired for channels with good reception quality (C / N), such as the period from time t1 to t2 and the period from time t3 to time t4 in FIG. 7 (S41 to S46).

  Here, for example, at time t5 in FIG. 7, the reception quality of the selected broadcast signal is recovered, and the state where the reception quality (C / N) exceeds the predetermined quality level Thone-seg is the predetermined time To. When the timer T reaches the predetermined time To (YES in S45, YES in S19 in FIG. 2), the broadcast signals that have been selected so far are received by the four tuners 12a to 12d, and the broadcast signals are received. It switches to the reproduction of information (video, audio) in the full segment reproduction form using. At the same time, the EPG acquisition process ends. At this time, the control unit 11 stores information about the channel from which the EPG information is acquired.

  After that, for example, at time t6 in FIG. 7, when the reception quality (C / N) is reduced and the full segment playback mode is switched to the one segment playback mode, the procedure shown in FIG. 6 is followed at that timing (time t6). The EPG acquisition process is started again. At this time, acquisition of EPG information is started from a channel following the channel for which EPG information has already been acquired in the channel list. Thereafter, in the same manner as described above, EPG creation is performed in parallel with the reproduction of information (video, audio) in the one-segment reproduction form using the broadcast signals of the channels selected by the two tuner units 12a and 12b. The unit 114 controls the remaining tuner units 12c and 12d, and acquires EPG information for each channel according to the procedure shown in FIG. 6 (see, for example, the period from time t6 to time t7 in FIG. 7).

  When the EPG information acquisition process for all the channels listed in the channel list is completed in the above process (S46), the latest EPG information of each channel can be used.

  According to the in-vehicle receiver 10 that performs the switching between the full segment reproduction mode and the one segment reproduction mode (see FIG. 2) and the EPG acquisition process (see FIGS. 6 and 7) as described above, the reception quality (C / N ) Decreases to a predetermined quality level Thone-seg and switches from the full segment playback mode to the one segment playback mode, and from the switching timing (for example, see time t1 and time t6 in FIG. 7) without waiting for a predetermined time as in the prior art. Since the EPG acquisition process is started as a background process, no time is wasted. Further, even if the reception quality (C / N) returns to the state where the predetermined quality level Thone-seg capable of reproducing information in the full segment reproduction mode is restored, the one segment reproduction mode is maintained without switching to the full segment reproduction mode. Since the EPG acquisition process is performed during the period when the timer T is equal to or less than the predetermined time To, the reproduction of information originally performed in the full segment reproduction form is maintained in the one segment reproduction form by the EPG acquisition process. And there is little influence on the reception and reproduction of the broadcast signal. For this reason, the viewer (vehicle occupant) has little discomfort when the EPG acquisition process is executed.

  In the on-vehicle receiver 10 described above, the reception quality (C / N) is reduced to the predetermined quality level Thone-seg and switched from the full segment reproduction mode to the one segment reproduction mode. When the state exceeding the predetermined quality level Thone-seg is continued for a predetermined time period, the one-segment playback mode is restored to the full-seg playback mode. However, the present invention is not limited to this. For example, as shown in FIG. 8, the reception quality (C / N) is reduced after the reception quality (C / N) is lowered to a predetermined quality level Thone-seg and switched from the full segment reproduction mode to the one segment reproduction mode (time t1). May be returned from the one-segment playback mode to the full-segment playback mode when the quality level Thfull-seg higher than the predetermined quality level Thone-seg is exceeded (time t3). Also in this case, the reception quality (C / N) exceeds the predetermined quality level Thone-seg which is a reference for switching from the full-seg playback mode to the one-seg playback mode (time t2) and further exceeds the higher quality level Thfull-seg. Unless a certain period Tx elapses until (time t3), the full segment reproduction mode is not restored. Accordingly, background processing such as the above-described channel search processing (see FIG. 4) and EPG acquisition processing (see FIG. 6) can be performed using this certain period Tx.

  In the on-vehicle receiver 10 described above, the reception quality (C / N) decreases from the timing when the reception quality (C / N) decreases and switches from the full segment reproduction mode to the one segment reproduction mode until the timer T reaches a predetermined time To, that is, the reception quality (C / N). ) Is recovered and background processing (channel search processing, EPG information acquisition processing) is allowed until the one-segment playback mode returns to the full-seg playback mode (from time t1 to time t5 in FIG. 7). However, the background processing may be permitted until the predetermined time To elapses from the timing when the reception quality (C / N) is reduced and the full-segment playback mode is switched to the one-segment playback mode. Further, in consideration of switching between the full-segment playback mode and the one-segment playback mode as shown in FIG. 8, a time determined based on the time expected as the time Tx from the timing when the full-segment playback mode is switched to the one-segment playback mode. Alternatively, the background processing may be allowed for another arbitrarily determined time.

  Furthermore, switching between the full segment reproduction mode and the one segment reproduction mode can be performed according to the procedure shown in FIG.

  In this case, as in the above-described example (see FIG. 2), the full-segment playback mode is set while the reception quality (C / N) of the broadcast signal received by the receiving unit 12 exceeds the predetermined quality level Thone-seg. It is maintained (NO in S11, S12). Then, for example, when the reception quality becomes equal to or lower than a predetermined quality level Thone-seg at time t1 in FIG. 10 (YES in S11), information reproduction is switched from the full-segment reproduction form to the one-segment reproduction form (S13). . And the control part 11 starts the timer T (S51), and determines whether the timer T reached the fixed time Ta (S52). Until the timer T reaches the time Ta, the one-segment broadcasting is performed regardless of the reception quality (C / N) of the broadcast signal, that is, regardless of whether information can be reproduced in the full-segment reproduction form. The reproduction form is maintained.

  In the situation where the one-segment playback mode is maintained, for example, when the timer T reaches a certain time Ta at time t2 in FIG. 10 (YES in S52), the control unit 11 receives the signal again by the receiving unit 12. It is determined whether or not the reception quality (C / N) of the broadcast signal exceeds a predetermined quality level Thone-sge (S53). For example, when the reception quality (C / N) of the broadcast signal exceeds a predetermined quality level Thone-seg at time t3 in FIG. 10 (YES in S53), the control unit 11 resets the timer T. (S54), the reproduction of the information in the one-segment reproduction form is restored to the reproduction of the full-segment information (S55). Thereafter, as long as the reception quality (C / N) of the broadcast signal exceeding the predetermined quality level Thone-seg is maintained, information (video, audio) is continuously reproduced in the full segment reproduction form. Each time the reception quality (C / N) of the broadcast signal falls below the predetermined quality level “Thone-seg”, the process is switched to the one-segment playback mode and the above-described processing (S13, S51 to S55) is executed.

  In this way (see FIGS. 9 and 10), in the process of switching between the full segment playback mode and the one segment playback mode, for example, according to the procedure shown in FIG. 4 (To is replaced with Ta), the channel search processing is performed as background processing. As can be done. That is, the reception quality (C / N) of the broadcast signal received by the receiving unit 12 is lowered to a predetermined quality level Thone-seg or less, and the switching timing from the full segment reproduction mode to the one segment reproduction mode (time t1 in FIG. 10). The two tuners 12a and 12b in the receiving unit 12 are continuously used for receiving broadcast signals during the predetermined time Ta in which the one-seg reproduction form is maintained, and information (video, audio) is reproduced in the one-seg reproduction form. In addition, the channel search process using the remaining tuners 12c and 12d is allowed.

  When the channel search process does not find a relay channel within the predetermined time Ta, for example, as shown in FIG. 11, at the predetermined time Ta, the two tuners 12a to 12d are received from the reception and diversity combining at the four tuners 12a to 12d. By switching to 12d, the one-segment playback mode is maintained with the reception quality slightly lowered, and switching to reception and diversity combining with the four tuners 12a to 12d after the predetermined time Ta has elapsed (after time t2). It is done. When the reception quality of the broadcast signal exceeds the predetermined quality level Thone-seg (time t3), the one-segment playback mode is restored to the full-seg playback mode (see S51 to S55 in FIG. 9).

  On the other hand, for example, as shown in FIG. 12, the same program is broadcast by the channel search process at time tx before the predetermined time Ta has elapsed (time t2) from the timing (time t1) when switching to the one-segment playback mode. When the relay channel B is found, information in the one-segment playback format using the broadcast signal of the channel A that has been selected by the two tuners 12a and 12b until now (video of the broadcast program, audio of the broadcast program) Information in the full-segment playback form using the digital reception signal obtained by diversity combining (4 diver combining) of the broadcast signal of the relay channel B selected by the four tuners 12a to 12d Switching to playback of program video and audio of the same broadcast program). Thereafter, the reproduction of information (video, audio) of the same program using the broadcast signal of the relay channel B is maintained in the full segment reproduction form.

  According to the in-vehicle receiver 10 that switches between the full-segment playback mode and the one-segment generation mode (see FIG. 10) according to the procedure shown in FIG. 9 and performs the above-described channel search process (background processing) in the process. Since the channel search process can be started immediately after the reception quality is reduced to the predetermined quality level Thone-seg and switched from the full segment playback mode to the one segment playback mode, there is no waste of time. In addition, after switching to the one-segment playback mode, regardless of the reception quality of the broadcast signal, that is, regardless of whether or not the information can be played back in the full-segment playback mode, a certain period during which the one-segment playback mode is maintained Since the channel search process can be performed in Ta, the reproduction of information originally performed in the full segment reproduction form is not maintained in the one segment reproduction form by the channel search process, and the broadcast signal is received and reproduced. There is little influence on. For this reason, the viewer (vehicle occupant) has little discomfort when the channel search process is executed.

  Note that when switching between the full-segment playback mode and the one-segment generation mode (see FIG. 10) is performed according to the procedure shown in FIG. 9, the background processing is replaced with the channel search processing or in addition to the channel search processing. The EPG acquisition process can also be performed.

  The in-vehicle receiver according to the present invention allows background processing from the timing when the full-segment playback mode is switched to the one-segment playback mode, but the timing at which the background processing is actually started is different from the other processing. Must be prioritized, it is not necessary to accurately match the timing when the full segment playback mode is switched to the one segment playback mode.

  Two tuners 12c and 12d are used for the background processing. However, one tuner 12c (or 12d) may be used for the background processing. In this case, the three tuners can be used for receiving broadcast signals of channels that have been selected until now. Further, the number of tuners is not limited to four, and may be a number of two or more.

  As described above, the in-vehicle receiving apparatus according to the present invention performs background processing such as channel search without wasting time and minimizing the influence on reception and reproduction of the original broadcast signal as much as possible. In-vehicle that performs the background processing such as channel search while receiving the broadcast signal of the weak hierarchy and the broadcast signal of the strong hierarchy that is digitally broadcast by hierarchical transmission like terrestrial digital broadcasting. It is useful as a receiving device.

DESCRIPTION OF SYMBOLS 10 In-vehicle receiver 11 Control part 12 Reception part 12a-12b Reception unit 13 Switching part 14a 1st OFDM demodulation part 14b 2nd OFDM demodulation part 15 Decoder 16 Display processing part 17 Digital / analog converter (D / A conversion) vessel)
20 Center unit 21 Display device 22 Operation unit 25 Speaker 111 Reception state determination unit 112 Switching control unit 113 Search processing unit 114 EPG creation unit

Claims (5)

A broadcast signal including a first broadcast signal of a weak hierarchy and a second broadcast signal of a strong hierarchy that is digitally broadcast by hierarchical transmission is received by a reception unit having a predetermined number of reception units, and is received by the reception unit. A vehicle-mounted receiving device for reproducing information based on either the first broadcast signal or the second broadcast signal,
Second playback using the second broadcast signal for information playback from the first playback mode using the first broadcast signal for playback of information when the reception quality of the broadcast signal at the receiver is reduced to a predetermined quality level A playback mode switching means for switching from the second playback mode to the first playback mode when switching to a mode and continuing for a period of time when the reception quality exceeds the predetermined quality level;
From the timing of switching from the first playback mode to the second playback mode by the playback mode switching means, one or more reception units of a part of the predetermined number of reception units are used for receiving the broadcast signal, and the rest A vehicle-mounted receiving device comprising background processing timing control means that allows execution of predetermined background processing using one or a plurality of receiving units.   The background processing timing control means switches from the second reproduction form to the first reproduction form by the reproduction form switching means from the switching timing from the first reproduction form to the second reproduction form by the reproduction form switching means. The in-vehicle receiving device according to claim 1, wherein the background processing is allowed to be executed until returning. When the state in which the reception quality exceeds the predetermined quality level is continued for a predetermined period of time, the playback mode switching means returns from the second playback mode to the first playback mode,
The in-vehicle receiver according to claim 1, wherein the background processing timing control means permits the predetermined time from a switching timing from the first reproduction form to the second reproduction form by the reproduction form switching means.   4. The vehicle-mounted device according to claim 1, wherein the background processing timing control unit starts the background processing from a switching timing from the first playback mode to the second playback mode by the playback mode switching unit. 5. Receiving device. A broadcast signal including a first broadcast signal of a weak hierarchy and a second broadcast signal of a strong hierarchy that is digitally broadcast by hierarchical transmission is received by a reception unit having a predetermined number of reception units, and is received by the reception unit. A vehicle-mounted receiving device for reproducing information based on either the first broadcast signal or the second broadcast signal,
Second playback using the second broadcast signal for information playback from the first playback mode using the first broadcast signal for playback of information when the reception quality of the broadcast signal at the receiver is reduced to a predetermined quality level After switching from the first playback mode to the second playback mode for a certain time from the timing of switching from the first playback mode to the second playback mode, the reception quality exceeds the predetermined quality level after maintaining the second playback mode regardless of the reception quality. A playback mode switching means for returning from the second playback mode to the first playback mode;
One or more of a part of the predetermined number of receiving units in the predetermined time period in which the second playback mode is maintained from the switching timing from the first playback mode to the second playback mode by the playback mode switching unit. A vehicle-mounted receiving device comprising background processing timing control means that allows a predetermined background processing to be performed using the remaining one or a plurality of receiving units while using the receiving unit for receiving the broadcast signal.

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