JP2008016993A - Television broadcasting receiver and broadcasting frequency information acquiring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a time required for channel scanning processing with respect to a terrestrial digital TV broadcasting. <P>SOLUTION: A TV broadcasting receiver includes: a first broadcasting frequency determining means for determining a reception state relative to whole broadcasting frequencies during a period when a signal is outputted to a reproducing apparatus, after demodulating the digital TV broadcasting; a first storage means for storing information of the broadcasting frequency whose reception state is determined to be excellent by the first broadcasting frequency determining means; an input receiving means for receiving a prescribed input; a second broadcasting frequency determining means for determining whether or not the respective broadcasting frequencies corresponding to the information stored in the first storage means are the receptible broadcasting frequencies of the digital TV broadcasting, when the input receiving means receives the prescribed input; and a second storage means for storing the determination result by the broadcasting frequency determining means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention receives and demodulates simultaneous digital television (hereinafter, “TV” is referred to as “TV”) broadcast and analog TV broadcast, and uses the demodulated signal in one of the formats as a playback device. The present invention relates to an output TV broadcast receiver. The present invention also relates to a broadcast frequency information acquisition method for acquiring information on receivable digital television broadcast broadcast frequencies.

  In recent years, it has become common to process / manage audio and video in a digital format in a recording medium, equipment, or the like. The trend of digital encoding of audio and video in such recording media and devices has spread to the broadcasting related industry. In the broadcasting-related industry, the transition from terrestrial analog TV broadcasting to terrestrial digital TV broadcasting is currently in progress.

  This terrestrial digital TV broadcast is spreading. However, in order to shift TV broadcasting from terrestrial analog TV broadcasting to terrestrial digital TV broadcasting, large-scale capital investment, enormous time, labor, cost, etc. are required. Currently, the transition is gradually in progress, and there are situations where nationwide terrestrial digital TV broadcasting is available / not available. In addition, in order to view digital terrestrial TV broadcasting, a device corresponding to it is necessary. Viewers must purchase new equipment in order to view terrestrial digital TV broadcasts. Therefore, if the TV broadcast is integrated into the terrestrial digital TV broadcast at this stage, many viewers cannot view the TV broadcast. In view of these circumstances, simultaneous broadcasting of terrestrial digital TV broadcasting and terrestrial analog TV broadcasting (that is, a method of broadcasting a program having the same content at the same time in both digital and analog formats) is being implemented. .

  For example, the following Patent Document 1 is configured to receive both terrestrial digital TV broadcasts and terrestrial analog TV broadcasts in consideration of the scattered areas where terrestrial digital TV broadcasts are viewable / unavailable. A TV broadcast receiver is disclosed. According to the TV broadcast receiver described in Patent Document 1 below, channel scan processing is performed in parallel for terrestrial digital TV broadcast and terrestrial analog TV broadcast. Thereby, in the TV broadcast receiver described in Patent Document 1 below, it is possible to reduce the time required for scanning channels of both digital and analog TV broadcast formats.

The “channel scan process” here is a process for acquiring information on a channel that the TV broadcast receiver can currently receive favorably. The “channel” is a number assigned for convenience to the broadcast frequency of each broadcasting station, but in this specification, “channel” and “broadcast frequency” are treated as synonymous.
JP 2001-24537 A

  Here, when the TV broadcast receiver is provided in a moving body such as a vehicle, the following problem occurs. For example, when a moving body moves and straddles a broadcasting area (for example, when a moving body moves from a broadcasting area covered by one broadcasting station to a broadcasting area covered by another broadcasting station) The channel may change. In this case, the TV broadcast receiver cannot receive the terrestrial digital TV broadcast received before straddling the broadcast area. In order to continuously view the program, the viewer needs to perform a predetermined user operation and cause the TV broadcast receiver to execute a channel scan process for the terrestrial digital TV broadcast. When a channel scan process is executed in response to such a user operation, the TV broadcast receiver acquires channel information that can be received in a new broadcast area.

  As described in Patent Document 1, it takes time to perform channel scan processing for terrestrial digital TV broadcasting. However, even in the above-mentioned Patent Document 1, it is not possible to reduce the time required for the channel scan processing itself for terrestrial digital TV broadcasting. In addition, the time required for the channel scanning process increases in proportion to the number of channels to be scanned.

  In addition, the TV broadcast receiver cannot receive any TV broadcast while executing the channel scan process. Therefore, during execution of the channel scan process, no program is displayed on the playback device, and some viewers may feel uncomfortable or frustrated.

  Therefore, in view of the above circumstances, an object of the present invention is to provide a TV broadcast receiver and a broadcast frequency information acquisition method suitable for reducing the time required for channel scan processing for terrestrial digital TV broadcast.

  A TV broadcast receiver according to an aspect of the present invention that solves the above problems receives and demodulates simultaneous digital TV broadcasts and analog TV broadcasts, and uses the demodulated signal in one of the formats as a playback device. The present invention relates to a receiver capable of output. The TV broadcast receiver includes first broadcast frequency determination means for determining a reception state for all broadcast frequencies during a period in which a demodulated signal of digital TV broadcast is output to the playback device, The first storage means for storing information on the broadcast frequency determined to be good by the broadcast frequency determining means, the input receiving means for receiving a predetermined input, and the input receiving means has received the predetermined input A second broadcast frequency determining means for determining whether or not each of the broadcast frequencies corresponding to the information stored in the first storage means is a receivable digital TV broadcast frequency, and a broadcast frequency determination And a second storage means for storing the determination result by the means.

  According to the TV broadcast receiver configured as described above, it is possible to narrow down in advance the possible broadcast frequencies of the digital TV broadcast that can be received before performing the channel scan process for the digital TV broadcast. Therefore, when actually performing the channel scanning process, it is possible to operate so as to obtain information on the broadcast frequency of the digital TV broadcast that can be received from the information on the broadcast frequency narrowed down in advance. That is, according to the TV broadcast receiver according to the present invention, the objects to be scanned can be narrowed down in advance, so that the time required for the channel scanning process is reduced.

  The TV broadcast receiver may further include, for example, a channel selection means for selecting an analog TV broadcast. In this case, the first broadcast frequency determining means operates to determine the reception state with respect to the broadcast frequency selected by the channel selecting means. In addition, among the broadcast frequencies selected by the channel selection means, those having a reception power value higher than a predetermined threshold can be determined to be good.

  Here, the input receiving unit may be, for example, a user interface that receives an input by a user.

  In the TV broadcast receiver, the first broadcast frequency determination means and the first storage means may operate at predetermined timings.

  In the TV broadcast receiver, the second broadcast frequency determining means can operate to determine whether or not the received broadcast frequency includes information indicating that it is a digital TV broadcast, for example. The information indicating the digital TV broadcast here can be, for example, a TMCC (Transmission and Multiplexing Configuration and Control) signal.

  Also, a TV broadcast receiver according to another aspect of the present invention that solves the above-described problems is obtained by receiving and demodulating a plurality of types of television broadcasts including digital television broadcasts, and demodulating signals in any one of the formats. The present invention relates to a receiver that can output to a playback device. The TV broadcast receiver includes a reception state determination unit that determines reception states for all broadcast frequencies during a period in which a demodulated signal of digital television broadcast is output to the playback device, and a reception state determination unit. The storage means for storing the information of the broadcast frequency determined to be good by the reception means, the reception state of each broadcast frequency stored in the storage means is determined, and the information on the broadcast frequency of the receivable digital television broadcast is obtained. The broadcast frequency acquisition means for acquiring is provided.

  In addition, a TV broadcast receiver according to another aspect of the present invention that solves the above problems receives and demodulates a plurality of formats of TV broadcast including the first format, and outputs a demodulated signal of any format. The present invention relates to a receiver that can output to a playback device. The TV broadcast receiver includes reception state determination means for determining a reception state for all broadcast frequencies during a period in which the demodulated signal of the first format is output to the playback device, and reception state determination Storage means for storing the determination result by the means, and broadcast frequency acquisition means for acquiring information on the broadcast frequency of the first type of TV broadcast that can be received based on the determination result stored in the storage means. It is characterized by that.

  In addition, a TV broadcast receiver according to another aspect of the present invention that solves the above problems receives and demodulates a plurality of formats of TV broadcast including the first format, and outputs a demodulated signal of any format. The present invention relates to a receiver that can output to a playback device. This TV broadcast receiver includes a narrowing means for narrowing down broadcast frequencies having a good reception state among all broadcast frequencies, and a broadcast frequency of the first type of TV broadcast that can be received by each of the narrowed broadcast frequencies. It is characterized by comprising a broadcast frequency determining means for determining whether or not and a storage means for storing the determination result by the broadcast frequency determining means.

  Here, all broadcast frequencies in the TV broadcast receiver are all broadcast frequencies included in, for example, a UHF (Ultrahigh Frequency) band.

  Further, the TV broadcast receiver may be provided in a mobile body, for example.

  In addition, a broadcast frequency information acquisition method according to an aspect of the present invention that solves the above-described problems relates to a method for acquiring receivable broadcast frequency information of a digital television broadcast. This broadcast frequency information acquisition method includes the steps of receiving and demodulating a digital television broadcast and outputting the demodulated signal to a playback device, and during the period of outputting the demodulated signal to the playback device. A first broadcast frequency determination step for determining a reception state with respect to the broadcast frequency, and a first storage step for storing information on a broadcast frequency whose reception state is determined to be good in the first broadcast frequency determination step; Second broadcast frequency for determining whether or not each of the broadcast frequencies corresponding to the information stored in the first storage step is a receivable digital TV broadcast frequency in response to a predetermined input It is a method including a determination step and a second storage step for storing the determination result in the broadcast frequency determination step.

  According to such a broadcast frequency information acquisition method, it is possible to narrow down in advance the possible broadcast frequencies of the digital TV broadcast that can be received before performing the channel scan process for the digital TV broadcast. Therefore, when actually performing the channel scanning process, it is possible to operate so as to obtain information on the broadcast frequency of the digital TV broadcast that can be received from the information on the broadcast frequency narrowed down in advance. That is, according to the broadcast frequency information acquisition method according to the present invention, it is possible to narrow down in advance the target to be scanned, so that the time required for the channel scanning process is reduced.

  The broadcast frequency information acquisition method may further include a channel selection step for selecting an analog TV broadcast, for example. In this case, in the first broadcast frequency determination step, the reception state is determined for the broadcast frequency selected by the channel selection means. In addition, among the broadcast frequencies selected in the channel selection step, those having a reception power value higher than a predetermined threshold can be determined to be good.

  Here, for example, when the predetermined input does not exist for a predetermined time after completion of the first storage step, the broadcast frequency information acquisition method can return to the first broadcast frequency determination step.

  In the second broadcast frequency determination step, for example, it can be determined whether or not the received broadcast frequency includes information indicating digital TV broadcast.

  A broadcast frequency information acquisition method according to another aspect of the present invention that solves the above problem relates to a method for acquiring receivable broadcast frequency information of a digital television broadcast. This broadcast frequency information acquisition method includes the steps of receiving and demodulating a digital television broadcast and outputting the demodulated signal to a playback device, and during the period of outputting the demodulated signal to the playback device. A reception state determination step for determining the reception state with respect to the broadcast frequency, a storage step for storing information on the broadcast frequency for which the reception state is determined to be good in the reception state determination step, and each broadcast stored in the storage step A broadcast frequency acquisition step of determining a reception state of the frequency and acquiring information on a broadcast frequency of the receivable digital television broadcast.

  In addition, a broadcast frequency information acquisition method according to another aspect of the present invention that solves the above-described problem relates to a method for acquiring broadcast frequency information of a first type of television broadcast that can be received. The broadcast frequency information acquisition method includes the steps of receiving and demodulating the television broadcast of the first format and outputting the demodulated signal to a playback device, and outputting the demodulated signal to the playback device. A reception state determination step for determining a reception state for all broadcast frequencies, a storage step for storing a determination result in the reception state determination step, and reception based on the determination result stored in the storage step A broadcast frequency acquisition step of acquiring broadcast frequency information of a first possible type of TV broadcast.

  In addition, a broadcast frequency information acquisition method according to another aspect of the present invention that solves the above-described problem relates to a method for acquiring broadcast frequency information of a first type of television broadcast that can be received. This broadcast frequency information acquisition method includes a narrowing-down step for narrowing down broadcast frequencies having a good reception state among all broadcast frequencies, and broadcasting of a first type of TV broadcast that can receive each of the narrowed broadcast frequencies. It is a method including a broadcast frequency determination step for determining whether or not the frequency is present, and a storage step for storing a determination result obtained by the broadcast frequency determination step.

  According to the present invention, a TV broadcast receiver and a broadcast frequency information acquisition method suitable for reducing the time required for channel scan processing for terrestrial digital TV broadcast are provided.

  Hereinafter, the configuration and operation of the TV broadcast receiver according to the embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a video / audio output device 100 including a TV broadcast receiver according to an embodiment of the present invention. The video / audio output device 100 is mounted on, for example, a vehicle that is a moving body. The video / audio output device 100 is compatible with simultaneous broadcasting, and is designed to receive and process both terrestrial digital TV broadcasts and terrestrial analog TV broadcasts.

  The video / audio output device 100 includes a control unit 10, a digital TV antenna 11, a digital TV tuner 12, an OFDM (Orthogonal Frequency Division Multiplexing) demodulation unit 13, an MPEG (Moving Picture Experts Group) decoder 14, a video. Changeover switch 15, audio D / A converter 21, audio changeover switch 23, audio amplifier 24, analog TV antenna 31, analog TV tuner 32, analog reception signal demodulation unit 33, reception intensity detection unit 34, memory 40, display 50 , Speakers 60R and 60L, and a light receiving unit 70.

  The remote controller (hereinafter referred to as “remote controller”) 80 is provided with operation keys for operating the video / audio output device 100. When the user operates the remote controller 80, a control pulse corresponding to the operation is output from the remote controller 80. This control pulse is, for example, a signal conforming to the IrDA standard. When the light receiving unit 70 receives this control pulse, it passes it to the control unit 10. When the remote controller 80 is being operated, for example, the display on the display 50 may be switched to the operation screen, or character information relating to the operation may be superimposed on the image being displayed on the display 50. .

  The control unit 10 performs overall control of the entire video / audio output apparatus 100. The control unit 10 operates to control each component based on, for example, various programs installed therein and control pulses from the light receiving unit 70.

  Here, a series of signal processing in the video / audio output apparatus 100 will be described.

  First, processing for a received terrestrial digital TV broadcast signal (hereinafter referred to as “digital received signal”) will be described. The digital TV antenna 11 has a function of receiving an RF (Radio Frequency) signal of each channel of terrestrial digital TV broadcasting. Each RF signal received by the digital TV antenna 11 is input to the digital TV tuner 12.

  The digital TV tuner 12 selects a specific RF signal from the input RF signals. The specific RF signal selected here is an RF signal of a terrestrial digital TV broadcast channel designated by the control unit 10 (hereinafter referred to as “digital designated channel”). The digital TV tuner 12 converts the selected RF signal into an intermediate frequency (IF) signal that improves stable operation and selection characteristics. The IF signal after frequency conversion is input to the OFDM demodulator 13 after unnecessary frequency components are removed by a BPF (Band Pass Filter) (not shown).

  The channel selected by the digital TV tuner 12 is determined according to the channel selection by the user operation. Specifically, when the user operates the remote controller 80 to select a channel, a control pulse corresponding to the operation is output from the remote controller 80. When the light receiving unit 70 receives this control pulse and passes it to the control unit 10, the control unit 10 issues a command to the digital TV tuner 12 to select the RF signal of the digital designated channel. The digital TV tuner 12 executes tuning processing according to this command.

  The control unit 10 issues a command to the digital TV tuner 12 and writes information on the digital designated channel in the memory 40. Accordingly, the memory 40 always holds information on the channel of the terrestrial digital TV broadcast last selected by the user (hereinafter referred to as “digital last channel”). When the channel selection operation by the user is not performed (for example, immediately after the power is turned on), the control unit 10 refers to the memory 40 and instructs the digital TV tuner 12 to select the RF signal corresponding to the digital last channel. put out.

  The OFDM demodulator 13 performs A / D conversion on the input IF signal to convert it into a digital signal. Next, the converted digital signal is divided into, for example, several thousand carriers, and after being subjected to synthesis (for example, a known maximum ratio synthesis) by matching the phase for each carrier, demodulation is performed. Thereby, an MPEG-2 transport stream signal (hereinafter referred to as “TS signal”) is obtained. This TS signal is output to the MPEG decoder 14.

  The MPEG decoder 14 decodes the input TS signal. As a result, the TS signal is decoded into a digital TV broadcast video signal and a digital format audio signal. The decoded video signal is output to the video switch 15. The audio signal is output to the audio D / A converter 21.

  The video changeover switch 15 performs a switching operation in accordance with an instruction from the control unit 10 and outputs an input signal from either the MPEG decoder 14 or the analog reception signal demodulation unit 33 to the display 50. For example, when a user operation is performed so as to reproduce a terrestrial digital TV broadcast program, the video switch 15 is controlled to output an input signal from the MPEG decoder 14. When the video signal output from the video switch 15 is input to the display 50, a terrestrial digital TV broadcast program is displayed on the screen of the display 50.

  The audio D / A converter 21 D / A converts the audio signal from the MPEG decoder 14 and outputs it to the audio switch 23.

  The voice changeover switch 23 performs a switching operation according to a command from the control unit 10, and outputs an input signal from either the voice D / A converter 21 or the analog reception signal demodulation unit 33 to the audio amplifier 24. Here, since a user operation is performed to reproduce a terrestrial digital TV broadcast program, the audio selector switch 23 is controlled to be connected to connect the audio D / A converter 21 and the audio amplifier 24.

  The audio amplifier 24 amplifies the audio signal from the audio switch 23 and outputs it to the speakers 60R and 60L. Thereby, the sound of the terrestrial digital TV broadcast program is reproduced by the speakers 60R and 60L.

  Next, processing for the received terrestrial analog TV broadcast signal will be described. The analog TV antenna 31 has a function of receiving an RF signal of each channel of terrestrial analog TV broadcasting. Each RF signal received by the analog TV antenna 31 is input to the analog TV tuner 32.

  The analog TV tuner 32 selects a specific RF signal from the input RF signals. The specific RF signal selected here is an RF signal of a terrestrial analog TV broadcast channel designated by the control unit 10 (hereinafter referred to as “analog designated channel”). The analog TV tuner 32 converts the selected RF signal into an IF signal. Next, the converted IF signal is output to the analog reception signal demodulation unit 33. Here, the channel designated by the control unit 10 is also determined according to the channel selection by the user operation, as before. In addition, the control unit 10 writes information on the analog designated channel in the memory 40. Accordingly, the memory 40 always holds information on the channel of the terrestrial analog TV broadcast last selected by the user (hereinafter referred to as “analog last channel”). When the channel selection operation by the user is not performed (for example, immediately after the power is turned on), the control unit 10 refers to the memory 40 and instructs the analog TV tuner 32 to select the RF signal corresponding to the analog last channel. put out.

  The analog reception signal demodulation unit 33 separates the input IF signal into a video signal and an audio signal. Next, the separated video signal is AM (Amplitude Modulation) demodulated into a predetermined format video signal and output to the video switch 15. The separated audio signal is demodulated by FM (Frequency Modulation) and output to the audio changeover switch 23.

  For example, when a user operation is performed so as to reproduce a terrestrial analog TV broadcast program, the video switch 15 is controlled to output an input signal from the analog received signal demodulator 33. As a result, the video signal of the predetermined format is input to the display 50, and a terrestrial analog TV broadcast program is displayed on the screen of the display 50.

  In this case, the audio selector switch 23 is switching-controlled so as to connect the analog reception signal demodulator 33 and the audio amplifier 24. Therefore, the demodulated audio signal is input to the audio amplifier 24. When this audio signal is amplified by the audio amplifier 24 and output to the speakers 60R and 60L, the audio of the terrestrial analog TV broadcast program is reproduced by the speakers 60R and 60L.

  Next, a channel scan process executed by the video / audio output apparatus 100 of the present embodiment and a pre-channel scan process executed before the channel scan process will be described. First, the pre-channel scan process of this embodiment will be described with reference to the flowchart shown in FIG.

  The pre-channel scan process of the present embodiment is started when, for example, the power supply (not shown) of the video / audio output apparatus 100 is turned on, and is finished when the power supply is turned off. This process is executed at every predetermined timing.

  When the video / audio output device 100 is turned on, the control unit 10 controls the digital TV tuner 12 and the analog TV tuner 32 based on the digital last channel and the analog last channel stored in the memory 40, for example. . Here, for example, it is assumed that a user operation is performed so as to reproduce a terrestrial digital TV broadcast. Accordingly, each component of the video / audio output device 100 (system that performs processing on the digital reception signal) executes the above-described series of processing to generate a video / audio signal. Next, the generated video / audio signal is output to the display 50 and speakers 60R and 60L. Thereby, a terrestrial digital TV broadcast program is reproduced. In parallel with this series of processes, the pre-channel scan process shown in FIG. 2 is executed. That is, in such a case, the pre-channel scan process is executed during the terrestrial digital TV broadcast program reproduction.

  The control unit 10 includes a counter unit 10a. When the power of the video / audio output device 100 is turned on, the control unit 10 sets the count value n of the counter unit 10a to “13” (step 1, hereinafter, step is abbreviated as “S” in the specification and drawings). ). In the present embodiment, since the channel to be scanned is the UHF (Ultrahigh Frequency) band (“13” to “62” channel), the count value n is initially set to “13”.

  Following the processing of S1, the control unit 10 controls the analog TV tuner 32 so as to select a channel corresponding to the count value n. The analog TV tuner 32 selects an RF signal corresponding to the channel and converts it to an IF signal. Then, the converted IF signal is output to the reception intensity detection unit 34.

  The reception intensity detection unit 34 is a detection circuit for detecting the in-band signal level of the channel selected by the analog TV tuner 32. Therefore, when the pre-channel scanning process is started, the reception intensity detection unit 34 first detects the in-band signal level of the “13” channel. This in-band signal level represents the power value of the received signal of the channel to be processed (bandwidth is about 6 MHz). The reception intensity detection unit 34 detects the in-band signal level a of the input IF signal and transfers the result to the control unit 10 (S2).

  The control unit 10 determines whether or not the detection result (that is, the in-band signal level a) passed in the process of S2 is higher than a predetermined threshold A (S3). When it is determined that the in-band signal level a is higher than the predetermined threshold A (S3: YES), the control unit 10 can receive a TV broadcast corresponding to the channel to be processed and compares it on the display 50 or the like. It is determined that the image can be clearly reproduced, and the process proceeds to S4. Here, it is not possible to determine which type of TV broadcast the processing target channel belongs to. However, since the reception intensity detecting unit 34 simply detects the reception intensity, the detection result can be obtained for any channel of terrestrial digital TV broadcast or terrestrial analog TV broadcast.

  In the process of S4, the control unit 10 holds the information of the channel to be processed in, for example, its own cache memory (not shown), and proceeds to the process of S5. For example, when it is determined in the process of S3 that the in-band signal level “a” of the “13” channel is higher than the predetermined threshold A, the control unit 10 holds the information of the “13” channel in the cache memory. Hereinafter, for convenience of explanation, the channel information held in the cache memory is referred to as “pre-channel information”.

  When the in-band signal level a is determined to be equal to or lower than the predetermined threshold A in the process of S3 (S3: NO), the control unit 10 does not have a TV broadcast corresponding to the processing target channel in the current broadcast area. Alternatively, it is determined that the data cannot be received well and cannot be reproduced clearly on the display 50 or the like, and the process proceeds to S5.

  In the process of S5, the control unit 10 determines whether or not the count value n is “62”. When it is determined that the count value n is not “62” (S5: NO), the control unit 10 determines that the determination processing of the in-band signal level a for all channels is incomplete, and increments the count value n by 1. (S6), the process returns to S2. And the process after S2 is performed with respect to the channel used as the next process target.

  On the other hand, when it is determined that the count value n is “62” (S5: YES), the control unit 10 determines that the determination processing of the in-band signal level a for all channels is completed, and the cache The pre-channel information held in the memory is written into the first area of the memory 40 (S7). When the pre-channel information has already been written in the first area, the control unit 10 overwrites the new area with the new pre-channel information.

  After the process of S7, the control unit 10 shifts to a state of waiting for a predetermined time (S8). Then, after waiting for a predetermined time, the process returns to S1 and the above-described series of processes is executed again. As a result, the first area of the memory 40 always holds the latest prechannel information.

  As described above, the processes of S2 to S6 described above are repeatedly executed, so that only information on the channel in which the reception state is good among all the channels in the UHF band is stored in the first area of the memory 40 (that is, pre-processing is performed). Channel information) is written. By referring to the pre-channel information, the control unit 10 can know a channel that can be satisfactorily received in the broadcast area where the vehicle is currently located.

  FIG. 3 illustrates channel scan processing executed by the video / audio output device 100 of the present embodiment. First, the channel scan processing of this embodiment will be described with reference to the flowchart shown in FIG.

  The process of the flowchart of FIG. 3 is an interrupt process, and is started when a user operation is performed to scan a channel of terrestrial digital TV broadcasting. Such a user operation can be performed, for example, when a terrestrial digital TV broadcast program being reproduced cannot be reproduced. Such a situation includes, for example, when a vehicle straddles a broadcast area.

  First, the control unit 10 refers to the first area of the memory 40 and selects single pre-channel information (S11). Next, the digital TV tuner 12 is controlled so as to select a channel corresponding to the selected pre-channel information (hereinafter referred to as “channel selection channel”). The digital TV tuner 12 selects an RF signal corresponding to the selected channel and converts it into an IF signal. This IF signal is demodulated by the OFDM demodulator 13 to be a TS signal and decoded by the MPEG decoder 14. In the process of S11, the control unit 10 selects the pre-channel information with the smallest number from the pre-channel information stored in the first area of the memory 40.

  The control unit 10 communicates with the MPEG decoder 14 and tries to acquire channel information (for example, TMCC (Transmission and Multiplexing Configuration and Control) signal) that can be included in the channel selection channel signal (S12).

  When the TMCC signal is acquired as a result of the trial (S13: YES), the control unit 10 assumes that the channel selection channel is a terrestrial digital TV broadcast channel that can be received, and information on the channel selection channel (hereinafter, “ "Received channel information") is written in the second area of the memory 40 (S14), and the process proceeds to S15. The control unit 10 erases the data written in the second area before executing the writing process of S14.

  On the other hand, when the TMCC signal cannot be acquired (S13: NO), the control unit 10 broadcasts the selected channel not demodulated by the OFDM demodulator 13 and not decoded by the MPEG decoder 14 (that is, terrestrial analog TV broadcast). ), The process proceeds to S15 without writing the received channel information.

  In the process of S <b> 15, the control unit 10 determines whether there is unselected pre-channel information in the first area of the memory 40. When it is determined that there is unselected pre-channel information (S15: YES), the control unit 10 selects the pre-channel information with the smallest number from the unselected pre-channel information (S16), Return to processing. On the other hand, when it is determined that there is no unselected pre-channel information (S15: NO), the control unit 10 determines that the TMCC signal acquisition trial process has been performed on all the pre-channel information, and End the process.

  The control unit 10 refers to the reception channel information written in the second area of the memory 40 as a channel map of terrestrial digital TV broadcast that can be received in the current broadcast area, and executes a reception operation and the like.

  That is, according to the video / audio output apparatus of the present embodiment, the channel of the terrestrial digital TV broadcast to be scanned is determined by performing the pre-channel scan process during the terrestrial digital TV broadcast reproduction (or other operation). It is narrowed down in advance. By narrowing down the channels to be subjected to the channel scan process in advance, the time required for the process can be reduced. Also, such an effect can become more prominent as the number of channels to be scanned increases.

  Further, according to the video / audio output apparatus of the present embodiment, the time during which the program resulting from the channel scan process cannot be displayed can be reduced by reducing the time of the channel scan processing. Accordingly, there is a secondary effect that the discomfort and irritation that can be given to the viewer can be reduced.

  According to the audio / video output apparatus of the present embodiment, not only the narrowing-down process for the terrestrial digital TV broadcast channel but also the narrowing-down process for the terrestrial analog TV broadcast channel can be realized simultaneously by the pre-channel scan process.

  The above is the embodiment of the present invention. The present invention is not limited to these embodiments and can be modified in various ranges.

  The video / audio output apparatus including the TV broadcast receiver according to the present embodiment is mounted on a vehicle, but may be a device that is carried by a person in another embodiment.

It is the block diagram which showed the structure of the video / audio output device which equipped with the TV broadcast receiver of embodiment of this invention. It is the flowchart which showed the pre-channel scan process performed with the video / audio output device of embodiment of this invention. It is the flowchart which showed the channel scan process performed with the video / audio output device of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control part 11 Digital TV antenna 12 Digital TV tuner 13 OFDM demodulation part 14 MPEG decoder 15 Image | video changeover switch 21 Audio | voice D / A converter 23 Audio | voice changeover switch 24 Audio amplifier 31 Analog TV antenna 32 Analog TV tuner 33 Analog reception Signal demodulator 34 Reception intensity detector 40 Memory 50 Display 60R, 60L Speaker 70 Light receiver 80 Remote controller 100 Video / audio output device

Claims (20)

In a television broadcasting receiver capable of receiving and demodulating simultaneous digital television broadcasting and analog television broadcasting and outputting a demodulated signal in one of the formats to a playback device,
First broadcast frequency determination means for determining a reception state for all broadcast frequencies during a period in which a signal after demodulation of digital television broadcast is output to the playback device;
First storage means for storing information of the broadcast frequency determined to be good by the first broadcast frequency determination means;
An input receiving means for receiving a predetermined input;
Whether or not each of the broadcast frequencies corresponding to the information stored in the first storage means is a receivable digital television broadcast frequency when the input accepting means accepts the predetermined input. A second broadcast frequency determining means for determining;
And a second storage means for storing a determination result by the second broadcast frequency determination means. It further comprises a channel selection means for selecting an analog television broadcast,
2. The television broadcast receiver according to claim 1, wherein the first broadcast frequency determination unit determines a reception state with respect to a broadcast frequency selected by the channel selection unit.   The first broadcast frequency determination means determines that the reception frequency of the broadcast frequencies selected by the channel selection means is higher than a predetermined threshold value is good. The television broadcast receiver according to claim 2.   The television broadcast receiver according to claim 1, wherein the input receiving unit is a user interface that receives an input by a user.   5. The television broadcast receiver according to claim 1, wherein the first broadcast frequency determination unit and the first storage unit operate at predetermined timings. 6.   6. The method according to claim 1, wherein the second broadcast frequency determining means determines whether or not the received broadcast frequency includes information indicating that it is a digital television broadcast. The television broadcast receiver described in 1.   7. The television broadcast receiver according to claim 6, wherein the information indicating digital television broadcast is a TMCC (Transmission and Multiplexing Configuration and Control) signal. In a television broadcast receiver capable of receiving and demodulating a plurality of types of television broadcasts including digital television broadcasts and outputting a demodulated signal of any type to a playback device,
A reception state determination means for determining a reception state for all broadcast frequencies during a period in which a signal after demodulation of digital television broadcast is output to the playback device;
Storage means for storing information on broadcast frequencies whose reception status is determined to be good by the reception status determination means;
Broadcast frequency acquisition means for determining a reception state of each broadcast frequency stored in the storage means and acquiring information on receivable broadcast frequencies of digital television broadcasts. Receiving machine. In a television broadcast receiver capable of receiving and demodulating a plurality of types of television broadcasts including the first format and outputting a demodulated signal of any type to a playback device,
Receiving state determining means for determining a receiving state for all broadcast frequencies during a period of outputting the demodulated signal of the first format to the playback device;
Storage means for storing a determination result by the reception state determination means;
Broadcast frequency acquisition means for acquiring information on the broadcast frequency of the first type of television broadcast that can be received based on the determination result stored in the storage means. Broadcast receiver. In a television broadcast receiver capable of receiving and demodulating a plurality of types of television broadcasts including the first format and outputting a demodulated signal of any type to a playback device,
A narrowing-down means for narrowing down broadcast frequencies with good reception status from all broadcast frequencies,
Broadcast frequency determination means for determining whether or not each of the narrowed broadcast frequencies is a broadcast frequency of a first type of television broadcast that can be received;
A television broadcast receiver comprising: storage means for storing determination results by the broadcast frequency determination means.   The television broadcast receiver according to claim 1, wherein all the broadcast frequencies are all broadcast frequencies included in a UHF (Ultrahigh Frequency) band.   The television broadcast receiver according to claim 1, wherein the television broadcast receiver is provided in a moving body. In a broadcast frequency information acquisition method for acquiring information on a broadcast frequency of a receivable digital television broadcast,
Receiving and demodulating digital television broadcast and outputting the demodulated signal to a playback device;
A first broadcast frequency determination step for determining a reception state for all broadcast frequencies during a period of outputting the demodulated signal to the playback device;
A first storage step for storing information of a broadcast frequency whose reception state is determined to be good in the first broadcast frequency determination step;
In response to a predetermined input, a second broadcast for determining whether or not each of the broadcast frequencies corresponding to the information stored in the first storage step is a receivable digital television broadcast frequency A frequency determination step;
A second storage step of storing a determination result in the broadcast frequency determination step; A channel selection step for selecting an analog television broadcast;
14. The broadcast frequency information acquisition method according to claim 13, wherein in the first broadcast frequency determination step, a reception state is determined for the broadcast frequency selected in the channel selection step.   In the first broadcast frequency determination step, the broadcast frequency selected in the channel selection step is determined to have a good reception state when the reception power value is higher than a predetermined threshold value. The broadcast frequency information acquisition method according to claim 14.   16. The broadcast frequency information acquisition method according to claim 15, wherein when there is no predetermined input for a predetermined time after completion of the first storage step, the process returns to the first broadcast frequency determination step.   17. The method according to claim 13, wherein, in the second broadcast frequency determination step, it is determined whether or not the received broadcast frequency includes information indicating that it is a digital television broadcast. Broadcast frequency information acquisition method described in 1. In a broadcast frequency information acquisition method for acquiring information on a broadcast frequency of a receivable digital television broadcast,
Receiving and demodulating digital television broadcast and outputting the demodulated signal to a playback device;
A reception state determination step for determining reception states for all broadcast frequencies during a period in which the demodulated signal is output to the playback device;
A storage step of storing information of the broadcast frequency determined to be good in the reception state in the reception state determination step;
A broadcast frequency information acquisition method comprising: determining a reception state of each broadcast frequency stored in the storage step, and acquiring broadcast frequency information of a receivable digital television broadcast. In a broadcast frequency information acquisition method for acquiring information on a broadcast frequency of a first form of television broadcast that can be received,
Receiving and demodulating the television broadcast of the first format and outputting the demodulated signal to a playback device;
A reception state determination step of determining reception states for all broadcast frequencies during a period in which the demodulated signal is output to the playback device;
A storage step of storing a determination result in the reception state determination step;
A broadcast frequency information acquisition method comprising: a broadcast frequency acquisition step of acquiring information on the broadcast frequency of the first type of television broadcast that can be received based on the determination result stored in the storage step. In a broadcast frequency information acquisition method for acquiring information on a broadcast frequency of a first form of television broadcast that can be received,
A narrowing step to narrow down broadcast frequencies with good reception from all broadcast frequencies,
A broadcast frequency determination step for determining whether or not each of the narrowed broadcast frequencies is a broadcast frequency of a first type of television broadcast that can be received;
A storage step of storing a determination result obtained by the broadcast frequency determination step.

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