JP2007043619A - Terrestrial digital broadcasting receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain setting for a channel that is detected near a reception limit last time when performing channel scan, as a channel which is capable of reception even if it is not detected in the latest channel scan. <P>SOLUTION: A terrestrial digital broadcasting receiver comprises: a channel scan means 18a which detects a channel whose signal level is equal with or higher than a prescribed first threshold value; and a reception channel setting means 18c which refers to each of signal levels stored in accordance with channels which have not been detected when each of reception channels being set is not detected in the channel scan, and sets a detected channel as a reception channel while maintaining a setting state of the reception channel being set if that signal level is lower than or equal with a second threshold value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a terrestrial digital broadcast receiver that sets a reception channel by performing channel scanning.

  Since the start of digital terrestrial broadcasting, its broadcasting area has been expanded. Broadcast stations that broadcast terrestrial digital broadcasts differ from one broadcast area to another, and the frequency bands and physical channels of radio waves used also differ.

  Therefore, when a user purchases a television receiver or moves to a different broadcasting area, first set the user's residence area to the television receiver, then perform a channel scan to find out which physical channel It is necessary to investigate which broadcasts are being conducted.

  The setting of the user's residence area is performed in order to preferentially assign a broadcast broadcast in that area as an intra-area broadcasting station to a channel selection button of the remote controller. This regional setting includes a case where selection is made at the prefectural level as shown in FIG. 9 and a case where selection is made in a more detailed region within the prefectural state as shown in FIG.

  The regional settings for terrestrial digital broadcasting are sufficient at the prefectural level shown in FIG. 9, but in terrestrial analog broadcasting, settings are made in the detailed regional allocation as shown in FIG. Is set according to the detailed regional allocation of FIG.

  On the other hand, the television receiver holds a list of broadcast stations in each region for determining broadcast stations in and out of the area according to the residential area selected by the user. FIG. 11 shows a list of terrestrial digital broadcast stations and physical channels in the Kanto region as an example of the list of broadcast stations in the area. FIG. 11 shows what kinds of broadcasting stations exist in each area.

  In the case of the Kanto region, there is a concept of Kanto wide area, and except for Mito, it is possible to watch by adding the broadcasting of the local broadcasting station to the broadcasting of the broadcasting station in Tokyo. For example, in Chiba Prefecture, broadcasts from Tokyo broadcast stations (NHK General, NHK Education ... University of the Air) designated in the Kanto wide area and broadcasts from Chiba broadcast stations (Chiba Television) are judged as regional broadcast stations. Is done.

  When a region is set as described above and a regional broadcast station is selected, remote_control_key_id included in the TS (Transport Stream) information descriptor of the NIT (Network Information Table) included in the terrestrial digital broadcast of the selected regional broadcast station Thus, it is designated where the broadcast station is allocated among the position keys “1” to “12” of the remote controller.

  Broadcast stations outside the set area are set as out-of-area broadcast stations, but if the position key of the remote control with remote_control_key_id included in the broadcast of this out-of-area broadcast station is already assigned to the in-area broadcast station, the branch number Stored as a channel number.

  Hereinafter, this channel number will be described. The channel number in terrestrial digital broadcasting is represented by a 4-digit number, which is a 3-digit channel number + a 1-digit branch number. The 3-digit channel number is determined as follows.

[Formula 1]
Service type x 200 + remote_control_key_id x 10 + (service number + 1)
Here, the service types are “0” for television broadcasting, “1” for first data broadcasting, “2” for second data broadcasting, and “3” for partial reception. The service number is a number assigned by the broadcast station for each broadcast of the own station, and can be set from “0” to “7”. This service number is used when a plurality of broadcasts are performed from one broadcast station (for example, when three channels of SD (Standard Definition) broadcast are performed simultaneously).

  In the above formula 1, “service type × 200 + remote_control_key_id × 10” represents a two-digit number from the left. Here, in the case of television broadcasting with the service number “0”, this two-digit number = remote_control_key_id, which is the same as the position key of the assigned remote controller. For example, when remote_control_key_id is “1”, the two-digit number from the left is “01”, and when remote_control_key_id is “10”, the two-digit from the left is “10”.

  Also, in the formula 1, “service number + 1” represents the third digit from the left. Normally, it is “1”, but when a plurality of programs are broadcast from one broadcasting station, numbers “2”, “3”,.

  For example, when three channels of SD broadcast television are broadcast with respect to the position key “10” of the remote control, the service type is “0”, the remote_control_key_id is “10” as the position key, and the service number is “0”. ”,“ 1 ”, and“ 2 ”, the channel numbers are“ 101 ”,“ 102 ”, and“ 103 ”. Since the structure may change during broadcasting, the channel number may only be “101”, the channel numbers “101” and “102” may exist, and the channel number “101”. , “102”, “103”, and “104” may exist.

The three-digit channel numbers determined in this way are shown in Table 1.

  Further, when a plurality of broadcasts of the same remote_control_key_id are received from the regional broadcasting station and the regional broadcasting station, the regional broadcasting station and the regional broadcasting station are distinguished from each other by the branch number represented by one digit following the above three-digit number. The This branch number is “0” for the in-area broadcasting station (it is often omitted), and the outside broadcasting station is used from “1”. When there are a plurality of out-of-area broadcasting stations with the same remote_control_key_id, branch numbers “2”, “3”, “4”,. At this time, even if there is no in-area broadcast station with the same remote_control_key_id, the out-of-area broadcast station is assigned from the branch number “1”.

  In order to simplify the region setting operation performed by the user for use in assigning position keys and assigning channel numbers as described above, Patent Document 1 discloses that channel scanning is performed during initial setting of a television receiver. In other words, there is described a technique for detecting a carrier / noise ratio (c / n) ratio for each channel and estimating a channel area having the highest c / n ratio as a user's residential area.

  This technique makes it possible to easily set the user's residential area without complicated work by the user, but channel scanning must still be manually performed by the user's operation.

  The channel scan operation will be described with reference to the flowchart of FIG. First, when channel scanning is started by the user's operation on the television receiver, the channel of the physical channel number “13” is selected as the channel to be scanned (S31). This is because the terrestrial digital broadcast is broadcast from the 13th channel to the 62th channel of the UHF band, so the initial value of the physical channel number is set as “13”.

  When the channel with the physical channel number “13” is selected, it is determined whether there is terrestrial digital broadcasting of the physical channel (S32). This determination is normally performed by acquiring the c / n ratio in this physical channel. If this c / n ratio is equal to or greater than a set threshold (first threshold), this physical channel “13” is determined. Is determined to be present ("Yes" in S32). The value of the c / n ratio acquired here is stored together with the determination result.

  Thereafter, it is determined whether or not TMCC (Transmission and Multiplexing Configuration Control) information with the simplest modulation method is acquired from the received broadcast signal of terrestrial digital broadcasting (S33). When it is determined in step S33 (“Yes” in S33), complex modulation schemes such as NIT (Network Information Table), PAT (Program Association Table), and PMT (Program Map Table) are further used. It is determined whether or not the acquired information has been acquired (S34). When it is determined that these pieces of information have also been acquired (“Yes” in S34), it is determined that the terrestrial digital broadcast of this physical channel “13” can be received, and this physical channel “13” is registered ( S35).

  When the registration process is completed in step S35, when it is determined in step S32 that there is no terrestrial digital broadcast (“No” in S32), it is determined in step S33 that TMCC information has not been acquired. If it is determined in step S34 that information such as NIT, PAT, and PMT is not acquired ("No" in S34), it is determined whether the physical channel to be scanned is "62". (S36). Here, since the physical channel is “13”, the process proceeds to step S37 (“No” in S36), the physical channel number is incremented by 1 (S37), and “14” is set as the physical channel number to be scanned. Return to S32.

  The processing from step S32 to step S37 is repeated until the physical channel number becomes “62”.

  If it is determined in step S36 that the physical channel is “62” and all the physical channels have been scanned (“Yes” in S36), the channel scanning process is terminated.

  By performing the channel scan as described above, it is recognized which broadcasting station is broadcasting on which physical channel.

  This channel scan can be used when a user purchases a television receiver or moves to a different broadcast area (case (1)) or when the antenna is changed (case (2)). When the (relay station) opens (case (3)), when the broadcast station (relay station) increases the transmission output (case (4)), when the broadcast station (relay station) disappears (case (5)) ), Etc., also had to be performed with a television receiver in order to view in an appropriate and latest radio wave reception state.

  However, in cases (3) to (5), there is a problem that it is difficult for the user to notice the necessity of channel scanning unless such information is accidentally touched by the report.

  In case (1) or case (2), the necessity of channel scanning has occurred due to user-side factors, so the user can easily recognize the necessity. There was a problem that may not know.

In order to solve these problems and always allow viewing in the proper and latest radio wave reception state, the TV receiver automatically scans the channel under the control of a timer, etc., and the setting to the position key on the remote control is updated. It is possible to do.
JP 2004-312204 A

  However, by allowing the television receiver to automatically perform channel scanning, channels near the reception limit, which is the threshold, may or may not be detected depending on the radio wave condition at the time of scanning. There is a problem that the user may not be able to suddenly view a desired channel due to the update.

  The present invention has been made in view of the above circumstances, and when performing channel setting by channel scan, a channel detected near the previous reception limit can be received even if it is not detected by the latest channel scan. It is a first object to provide a terrestrial digital broadcast receiver capable of continuing setting as a channel.

  Also, if the remote_control_key_id value used to assign to the remote control position key obtained from the broadcast signal by channel scan is the same value for the newly detected channel and the channel that has already been set, Regardless of this, there has been a problem that a newly detected channel is replaced and assigned to the remote control position key, which may hinder the user's viewing.

  The present invention provides a terrestrial digital broadcast receiver capable of preventing other channels from being newly assigned to remote control position keys to which channels have already been assigned when setting channels by channel scanning. This is the second purpose.

  In order to achieve the above object, a terrestrial digital broadcast receiver according to claim 1 of the present invention selects each channel at a predetermined frequency interval, detects a signal level for each channel, and detects the detected signal level. Channel scanning means for executing a channel scan for detecting a channel that is equal to or greater than a predetermined first threshold, a signal level of the detected channel for each channel detected by the channel scan, and a broadcast station And channel setting means for setting the detected channel as a reception channel, and the channel setting means has a predetermined signal level assumed to change depending on the reception state. A second threshold value obtained by adding the variation amount to the first threshold value is set, and each of the received threshold values is set. When a channel is not detected in the current channel scan, the signal level stored in correspondence with each channel that has not been detected is referred to and the signal level is equal to or lower than the second threshold value. The reception channel setting means maintains the setting state of the reception channel that has already been set.

  The terrestrial digital broadcast receiver according to claim 2 selects each channel at a predetermined frequency interval, detects a signal level for each channel, and detects the signal level detected in advance. Channel information including channel scan means for performing channel scan for detecting a channel that is equal to or greater than the first threshold, and remote control key ID transmitted from the broadcast station for the detected channel for each channel detected by the channel scan. Channel setting means for assigning the remote control key ID to the detected channel and setting it as a receiving channel, and the channel setting means has each channel assigned to each reception channel already set. Program information including a remote control key ID equivalent to the remote control key ID Channels for delivering the If it is detected in this channel scan, the channel that is currently detected, characterized in that it is set as the receiving channel.

  According to the terrestrial digital broadcast receiver of the present invention, when setting a channel by channel scanning, a channel detected near the previous reception limit is a channel that can be received without being detected by the latest channel scan. Since the setting is continued, it is possible to prevent the inconvenience that the broadcast of the channel that the user has been able to watch before may suddenly become impossible to watch.

  Also, when setting a channel by channel scan, the channels assigned to the remote control position keys are automatically assigned to the remote control position keys that have already been assigned to other channels. It is possible to prevent inconvenience that the user's viewing is hindered by the change.

<First Embodiment>
A digital terrestrial broadcast receiver according to a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a terrestrial digital broadcast receiver 10 in the present embodiment. The terrestrial digital broadcast receiver 10 of this embodiment includes a tuner 11 that acquires a broadcast signal from broadcast radio waves received by an antenna 30 and selects a channel, a descrambler 12 that releases scrambled broadcast signal, A demultiplexer 13 that acquires video data and audio data from a broadcast signal and transmits them, a demultiplex RAM 14 that temporarily records video data and audio data, and a video decoder 15 that decodes compressed video data. An audio decoder 16 that decodes the compressed audio data, graphics 17 that superimposes a GUI (Graphical User Interface) screen on the decoded video data, and a CPU 18 that controls them.

  The operation when a broadcast signal is received by the terrestrial digital broadcast receiver 10 in the present embodiment will be described with reference to FIG. First, a broadcast signal is acquired from the radio wave received from the antenna 30 in the tuner 11, and a channel is selected from this broadcast signal.

  When the acquired broadcast signal is a pay broadcast or the like, it is scrambled, and the descrambler 12 releases the scramble by inserting a specific authentication card and confirming the charge. In addition, the free broadcast may be scrambled, and at that time, the descrambler 12 releases the scramble.

  Next, the broadcast signal descrambled by the demultiplexer 13 is acquired and separated into video data and audio data.

  After the separated video data and audio data are temporarily recorded in the demultiplexing RAM 14, the video data is sent to the video decoder 15 and the audio data is sent to the audio decoder 16.

  In the video decoder 15, the compressed video data is decoded, and then the GUI screen is superimposed on the graphics 17 and output as video.

  The audio decoder 16 decodes the compressed audio data and outputs it as sound.

  The components from the tuner 11 to the audio decoder 16 are connected to the CPU 18 by a bus, and the operation is controlled by the CPU 18.

  The CPU 18 further includes a ROM 19 for storing a program, a RAM 20 for storing CPU variables when the program is executed, a flash memory 21 for storing the correspondence between channels and broadcasting stations, and an RTC (Real Time) for holding time information. Clock) 22, a remote control I / F 23 that acquires and holds a command from infrared rays transmitted from the remote control, and a timer 24 that determines a set time by the RTC 22 and operates the CPU 18 are connected via a bus. It is configured.

  With such a configuration, SI / PSI information and data carousel information, which are information other than video data and audio data acquired by the demultiplexer 13, are temporarily recorded in the demultiplexing RAM, and then the CPU 18 To be acquired. These pieces of information acquired by the CPU 18 are rearranged into information for EPG (Electronic Program Guide) if this information is, for example, SI information, and a BML document is extracted from this information if it is data carousel information. And recorded in the RAM 20.

  The flash memory 21 is a nonvolatile memory, and its contents are retained even when the power is turned off. Therefore, which broadcast station is broadcast on which channel is stored in the flash memory 21.

  The RTC 22 is a watch, and may have a crystal oscillator inside and hold time information by itself, or may hold time information based on time data received as SI information from a broadcast. . In the latter case, time information TOT (Time Offset Table) in the SI information is acquired by the CPU 18 from the demultiplexing RAM 14 via the demultiplexing 13 and held in the RTC 22. In any case, the CPU 18 can acquire the time information from the RTC 22.

  In the remote control I / F 23, a command is acquired and held by infrared rays transmitted from the remote control. The held command is read by the CPU 18 and it is detected that the button on the remote controller has been operated.

  Further, as shown in FIG. 2, in the present embodiment, the CPU 18 includes an automatic channel scanning unit 18a, a channel information acquisition unit 18b, and a reception channel setting unit 18c.

  The automatic channel scanning means 18a has a first threshold value of a c / n ratio for determining whether or not the signal level is receivable, and performs channel scanning at a predetermined interval to obtain a c / n greater than or equal to the first threshold value. Terrestrial digital broadcasting is detected as a receiving channel.

  The channel information acquisition unit 18b acquires channel information including a broadcasting station, a physical channel, a c / n ratio, and remote_control_key_id for each channel detected as a reception channel each time a channel scan is executed.

  The reception channel setting means 18c acquires and stores the signal level of the detected channel and the channel information transmitted from the broadcast station for each channel detected by the channel scan, and uses the detected channel as the reception channel. Set. Here, the reception channel setting means 18c is set with a second threshold value obtained by adding a predetermined fluctuation amount of the signal level assumed to change depending on the reception state to the first threshold value. However, if the signal level is not detected in the current channel scan, the already stored signal level corresponding to each channel that has not been detected is referred to, and if the signal level is equal to or lower than the second threshold, it is already set. The setting state of the received channel is maintained.

  The automatic channel scan operation in the terrestrial digital broadcast receiver 10 of the present embodiment will be described with reference to the flowchart of FIG.

  First, when the time set in the timer 24 (2:00 AM in the present embodiment) is reached (“Yes” in S11), the automatic channel scanning means 18a is activated, and the user can watch with the terrestrial digital broadcast receiver 10. It is determined whether the recording is being performed or the recording by the reservation is performed (S12).

  When the terrestrial digital broadcast receiver 10 is used with the power turned on when viewed by the user, such as during viewing by the user or during scheduled recording (“Yes” in S12), channel scanning is not performed, and the process goes to step S11. Return and wait until 2:00 am the next day.

  On the other hand, when the user is in a power-off state (function standby state) as viewed from the user (“No” in S12), a channel scan is performed (S13).

  Here, when the terrestrial digital broadcast receiver 10 is in a function standby state, the CPU 18 is in a sleep state. This function standby state is a state in which the power is off and the power consumption is low when viewed from the user, but the power is turned on at the back to perform an operation unique to the digital terrestrial broadcasting receiver 10. The operations unique to the terrestrial digital broadcast receiver 10 include transfer of pay broadcast information using a telephone line, download of a program, or acquisition of program guide information. When the channel scan is performed, the CPU 18 comes out of the sleep state.

  Since the operation of the channel scan in step S13 is the same as the conventional method shown in FIG. 12, detailed description thereof is omitted.

  As a result of the channel scan, the received broadcast station, physical channel, other c / n ratio (not shown), remote_control_key_id, and various information as shown in FIG. Accumulated.

  Next, the channel information obtained by the previous channel scan and the channel information obtained by the current channel scan are compared to determine whether or not they are the same (S14). If the result of the determination is the same (“Yes” in S14), the function standby state is entered again and the process returns to step S11.

  On the other hand, if the result of determination in step S14 is different from the previously obtained channel information (“No” in S14), the c / n ratio is greater than or equal to the first threshold value and the first threshold value during the previous channel scan. Whether or not there is a channel that is determined to be receivable at a second threshold value or less that is set separately, and has not been determined to be receivable when the c / n ratio is less than the first threshold value in the current channel scan. A determination is made (S15). As a result of the determination, if there is a corresponding channel, the channel information related to this channel is not updated to the latest channel information, and the previous information is continued (S16).

  For example, the first threshold of c / n ratio for determining that reception is possible by channel scanning is 25 dB, and the second c / n ratio for determining whether or not channel information needs to be updated in step S15. A case where the threshold value is 30 dB will be described with reference to FIG.

  As shown in FIG. 5, in the previous channel scan, the c / n ratio of Chiba TV is 26 dB, and since it exceeds the first threshold of 25 dB, it is determined that reception is possible. It is not determined that reception is possible. However, it can be seen that, last time, the Chiba TV was determined to be receivable at a second threshold value of 30 dB or less, that is, it was detected near the determination line of 25 dB.

  For this reason, it is assumed that the reason why it is not possible to receive this time may be due to the fact that the reception state is not good, and the previous channel information is continued and the table is not updated again. .

  Next, when there is channel information different from the previous channel other than the channel in which the previous channel information was continued in step S16, it is updated to the latest channel information (S17).

  If there is no corresponding channel as a result of the determination in step S15 (“No” in S15), the channel information is updated to the latest channel information (S18).

  When the update in step S17 or step S18 is performed, the reception channel of the terrestrial digital broadcast receiver 10 is set based on the updated channel information by the reception channel setting means 18c (S19).

  When the reception channel is set, a flag for notifying the user of the setting content that is different from the previous setting due to the update is turned ON (S20). This flag is read when the power is turned on next time by the user, and when the flag is ON, a display for informing the setting contents different from the previous one is output on the screen.

  As an example of this display, FIG. 6 shows a state in which a display notifying that there is a channel that can be newly received is output on the screen. FIG. 6 notifies the user that “TV Kanagawa”, which has the physical channel number “18”, the remote control position key “3”, and the three-digit channel number “031”, can be newly received.

  According to the first embodiment described above, when channel setting is performed by channel scanning, the channel that has been detected near the reception limit and assigned to the position key of the remote controller is not detected by the latest channel scanning. However, since the allocation setting is continued, it is possible to eliminate the inconvenience that the broadcast of the channel that the user has been able to watch before cannot be suddenly watched.

  Further, since the user is notified using the screen when the channel information is different from the previous one, such as when a new channel can be received, the user can always grasp the latest channel information.

Second Embodiment
A digital terrestrial broadcast receiver according to a second embodiment of the present invention will be described. Detailed description of the configuration of the terrestrial digital receiver of this embodiment and the operation when a broadcast signal is received is the same as in the first embodiment.

  A different part is that the reception channel setting means 18c is present when a channel that transmits program information including remote_control_key_id equivalent to each remote_control_key_id assigned to each reception channel that has already been set is detected in this channel scan. The detected channel is not set as a receiving channel. In addition to this channel, the channel newly detected as the receiving channel by this channel scan acquires channel information including the remote_control_key_id transmitted from the broadcasting station of the detected channel. The remote_control_key_id is assigned to the detected channel and set as a reception channel.

  The automatic channel scan operation in the terrestrial digital broadcast receiver of this embodiment will be described with reference to the flowchart of FIG.

  In FIG. 7, the operations in steps S21 to S24 are the same as those in steps S11 to S14 in FIG. 3 in the first embodiment, and thus detailed description thereof is omitted.

  If the channel information obtained this time is different from the previously obtained channel information (“No” in S24) as a result of the determination in step S24, it is determined whether or not a receivable channel has newly increased (S25). When the channel is newly increased (“Yes” in S25), a channel having remote_control_key_id equal to the value of remote_control_key_id acquired from the broadcast of the increased channel is already in a channel that can be received. It is further determined whether or not (S26).

  As a result of the determination, if a channel having remote_control_key_id equal to the value of remote_control_key_id obtained from the broadcast of the increased channel is already in a receivable channel (“Yes” in S26), the receiving channel setting means By 18c, the channel assignment to the remote control position key by this remote_control_key_id is not updated, and the previous channel assignment is continued (S27).

  For example, a case where the same remote_control_key_id is acquired in different channels in the previous channel scan and the current channel scan will be described with reference to FIG.

  As shown in FIG. 8, “TV Saitama” is newly detected in the current channel scan, and its remote_control_key_id is “3”. However, this remote_control_key_id “3” has the same value as the remote_control_key_id of “TV Kanagawa” detected in the previous channel scan, and “TV Kanagawa” has already been assigned to the remote control position key.

  Therefore, although “TV Saitama” was detected in this channel scan, the assignment of the remote control position key is not updated, and the user uses the same remote control position key “3” as before and the same channel as before “TV Kanagawa” "".

  Furthermore, if there is a channel that has been newly increased in addition to the channel for which the previous allocation to the remote control position key has been continued in step S27, the allocation to the remote control position key is newly updated based on the acquired remote_control_key_id value. (S28).

  In addition, when there is no newly increased channel in step S25 (“No” in S25), or a channel having remote_control_key_id equal to the value of remote_control_key_id acquired from the broadcast of the channel increased in step S26 is already receivable. If it is not in the channel (“No” in S26), the assignment to the remote control position key is updated based on the value of remote_control_key_id of the latest channel information (S29).

  When the assignment to the remote control position key in step S28 or step S29 is updated, a flag for notifying the user of the setting contents different from the previous setting is turned ON by this update (S30). The description of this flag is as described in the first embodiment.

  According to the second embodiment described above, when setting a channel by channel scanning, in order to prevent another channel from being newly assigned to a remote control position key to which a channel has already been assigned, It is possible to eliminate the inconvenience of disturbing the viewing of the user by automatically changing the allocated channel.

  Further, it is possible to avoid a complicated setting in which two or more channels are assigned to one remote control position key, and to make the setting easy to use for the user.

  In the first embodiment and the second embodiment described above, the timer is used to determine whether the time set in step S11 or step S12 has been reached. When the time just before the time set by the low microcomputer (for example, 30 seconds before 2 am), the entire receiver may be turned on, and the processing from step S12 or step S22 onward may be performed. In this case, the CPU performs a normal program operation, but it appears to the user with the power off.

  In the first embodiment and the second embodiment, when a user operation or a reservation operation is performed in step S12 and step S22, it is determined whether the channel scan can be performed again at 2:00 am on the next day. However, the present invention is not limited to this, and channel scanning may be executed when a retry is made after 10 minutes on the same day, or when the user turns off the power and enters a function standby state.

  In the first and second embodiments, it is determined whether or not a channel scan can be executed every day at 2:00 am. However, if it is performed at a specific interval such as once a week or four times every day. The size of the interval is not limited. Also, irregular intervals such as 2:00 am and 4:00 am may be used.

1 is a block diagram showing a terrestrial digital broadcast receiver in a first embodiment of the present invention. It is a block diagram which shows the function of CPU of the terrestrial digital broadcast receiver in 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the terrestrial digital broadcast receiver in 1st Embodiment of this invention. It is a table | surface which shows an example of the result of the channel scan performed with the terrestrial digital broadcast receiver in 1st Embodiment of this invention. It is a table | surface which shows an example of the result of the channel scan performed with the terrestrial digital broadcast receiver in 1st Embodiment of this invention. It is a display example which shows the state as which the setting content changed by the channel scan performed with the digital terrestrial broadcasting receiver in 1st Embodiment of this invention was output on the screen. It is a flowchart which shows operation | movement of the terrestrial digital broadcast receiver in 2nd Embodiment of this invention. It is a table | surface which shows an example of the result of the channel scan performed with the terrestrial digital broadcast receiver in 2nd Embodiment of this invention. It is a table | surface which shows an example of the area setting used with the conventional broadcast receiver. It is a table | surface which shows an example of the area setting used with the conventional broadcast receiver. It is a table | surface which shows an example of the channel of the conventional terrestrial digital broadcasting. It is a flowchart which shows the channel scan operation | movement in the conventional digital terrestrial broadcasting receiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Digital terrestrial broadcast receiver 11 ... Tuner 12 ... Descrambler 13 ... Demultiplex 14 ... Demultiplex RAM
15 ... Video decoder 16 ... Audio decoder 17 ... Graphics 18 ... CPU
18a ... Automatic channel scanning means 18b ... Channel information acquisition means 18c ... Reception channel setting means 19 ... ROM
20 ... RAM
21 ... Flash memory 22 ... RTC
24 ... Timer 30 ... Antenna

Claims (2)

In terrestrial digital broadcast receivers,
Selects each channel at a predetermined frequency interval, detects the signal level for each channel, and executes a channel scan to detect a channel whose detected signal level is equal to or higher than a predetermined first threshold value. Channel scanning means to perform,
Channel setting means for acquiring and storing the signal level of the detected channel and channel information transmitted from the broadcasting station for each channel detected by the channel scan, and setting the detected channel as a reception channel; ,
Have
The channel setting means is set with a second threshold value obtained by adding a predetermined fluctuation amount of the signal level assumed to change depending on a reception state to the first threshold value. If it is not detected in the current channel scan, the signal level stored in correspondence with each channel that has not been detected is referred to, and if the signal level is equal to or lower than the second threshold, A terrestrial digital broadcast receiver, characterized in that it is a reception channel setting means for maintaining the set reception channel setting state. In terrestrial digital broadcast receivers,
Selects each channel at a predetermined frequency interval, detects the signal level for each channel, and executes a channel scan to detect a channel whose detected signal level is equal to or higher than a predetermined first threshold value. Channel scanning means to perform,
For each channel detected by the channel scan, channel information including the remote control key ID transmitted from the broadcasting station of the detected channel is acquired and stored, and the remote control key ID is assigned to the detected channel and received. Channel setting means for setting as a channel;
Have
If the channel for sending program information including the remote control key ID equivalent to the respective remote control key ID assigned to each reception channel that has already been set is detected in the current channel scan, the channel setting means A terrestrial digital broadcast receiver characterized in that the detected channel is not set as a reception channel.

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