JP4760352B2 - Broadcast receiver and synchronization protection control method - Google Patents

Description

  The present invention relates to a broadcast receiver and a synchronization protection control method, and more particularly to a broadcast receiver and a synchronization protection control method capable of shortening a channel selection operation time.

  The digital broadcast receiver performs synchronization processing using a synchronization signal or a synchronization pattern (hereinafter referred to as “synchronization signal”) included in the received digital broadcast signal.

  In the synchronization process, a state in which the synchronization signal in the received signal is detected at a predetermined timing and as a predetermined pattern is called a synchronized state (hereinafter referred to as a “synchronized state”). However, a state that cannot be detected at a predetermined timing and a state that cannot be detected as a predetermined pattern are referred to as a state out of synchronization (hereinafter referred to as “asynchronous state”).

  Further, synchronization protection processing is performed in the synchronization processing.

  Synchronization protection processing is based on continuous changes in the synchronization state for a short period of time, such as repeated determination of the synchronization state at a certain timing and the asynchronous state at the next timing, or disturbance of the broadcast signal for a very short time. This is performed in order to prevent deterioration in reception quality due to loss of synchronization due to the fact that only the synchronization signal cannot be received normally.

  In the synchronization protection process, a state in which the synchronization signal is continuously detected correctly a predetermined number of times (hereinafter referred to as “synchronization determination number”) is determined as a synchronization state, and the synchronization signal is determined a predetermined number of times (hereinafter referred to as “asynchronous determination number”). The state that cannot be detected correctly continuously is determined as an asynchronous state. Note that the synchronous determination count and the asynchronous determination count may be the same.

  As a device for controlling synchronization protection processing according to a reception state, a receiving device as shown in Patent Document 1 (Japanese Patent Laid-Open No. 5-63692) is known.

In the receiving apparatus described in Patent Document 1, when the reception state is good, the number of synchronization determinations and the number of asynchronous determinations are set to values larger than a predetermined value. On the other hand, when the reception state is bad, the number of synchronization determinations is set to a value smaller than the predetermined value.
JP-A-5-63692

  The first problem is that even if a conventional digital broadcast receiver is placed in an environment where the reception state is good, the broadcast is actually presented after the user performs a channel selection operation to view the broadcast. It takes a long time to be done.

  The reason is as follows.

  Even when the conventional digital broadcast receiver is arranged in an environment where the reception state is good, it is necessary to correctly detect the synchronization signal by the number of times of synchronization determination used at the time of channel selection and also at the time of continuous reception after channel selection. For this reason, at the time of channel selection, it takes time to receive the synchronization signal by the number of times of synchronization determination at the time of continuous reception.

  An object of the present invention is to provide a broadcast receiver and a synchronization protection control method that speed up the channel selection operation.

  In order to achieve the above object, the broadcast receiver of the present invention, when receiving a channel selection designation to designate a broadcast station, executes a channel selection operation for selecting a broadcast station designated by the channel designation. Then, a broadcast receiver that performs a continuous reception operation for continuously receiving the broadcast of the broadcast station, and outputs a broadcast signal including a synchronization signal output by the broadcast station designated by the channel selection designation. Receiving means for receiving, synchronization processing means for determining that a synchronization signal in a broadcast signal received by the receiving unit is continuously detected every predetermined time for a predetermined number of times, and the channel selection operation In some cases, it includes synchronization processing control means for making the predetermined number of times used by the synchronization processing means smaller than the predetermined number of times used by the synchronization processing means during the continuous reception operation.

  In addition, the synchronization protection control method of the present invention, when receiving a channel selection designation for designating a broadcast station, executes a channel selection operation for selecting a broadcast station designated by the channel designation, and then performs the broadcast A synchronization protection control method that is performed by a broadcast receiver that performs a continuous reception operation for continuously receiving a broadcast from a station, and that is a broadcast signal including a synchronization signal that is output by the broadcast station designated by the channel selection designation. Receiving step, a synchronization processing step for determining that the synchronization signal in the broadcast signal is in a synchronized state when the synchronization signal is continuously detected every predetermined time for a predetermined number of times, and the synchronization operation during the channel selection operation. A synchronization processing control step of making the predetermined number of times used in the state determination smaller than the predetermined number used in the synchronization state determination during the continuous reception operation.

  According to the above invention, during the channel selection operation, the predetermined number of times used for the determination of the synchronization state is smaller than the predetermined number of times used for the determination of the synchronization state during the continuous reception operation. For this reason, the determination time of the synchronization state at the time of channel selection becomes shorter than the determination time of the synchronization state at the time of continuous reception. Therefore, the channel selection operation can be speeded up.

  The broadcast receiver further includes a reception state determination unit that determines a reception state of the broadcast signal, and the synchronization processing control unit is based on a determination result of the reception state determination unit during the channel selection operation. It is desirable to change the predetermined number of times.

  According to the above invention, during the channel selection operation, the predetermined number of times used for the determination of the synchronization state is changed according to the reception state, so that stable reception can be realized.

  It is desirable that the synchronization processing control unit changes the predetermined number of times during the continuous reception operation based on a determination result of the reception state determination unit.

  According to the above invention, stable reception can be realized over the entire reception operation.

  It is desirable that the synchronization processing control means minimizes the predetermined number of times at the start of the channel selection operation among the predetermined number of times used by the synchronization processing means.

  According to the above invention, the channel selection operation can be speeded up.

  According to the present invention, it is possible to speed up the channel selection operation.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a broadcast receiver, specifically a digital broadcast receiver, according to an embodiment of the present invention.

  In FIG. 1, the digital broadcast receiver 1 includes a channel selection control unit 11, a frequency selection unit 12, a synchronization processing unit 13, a demodulation unit 14, a reception state determination unit 15, and a synchronization protection pattern determination unit 16. And reproducing means 17.

  When the digital broadcast receiver 1 receives a channel selection designation for designating a broadcast station, the digital broadcast receiver 1 performs a channel selection operation for selecting a broadcast station designated by the channel designation, and then broadcasts the broadcast station. Is continuously received.

  The channel selection control means 11 controls the entire channel selection operation and the continuous reception operation. When the channel selection control unit 11 receives a channel selection designation from the user, the channel selection control unit 11 sets frequency information indicating the frequency band of the broadcast station designated by the user in the frequency selection unit 12.

  The frequency selection unit 12 is an example of a reception unit, and extracts a broadcast (frequency band) RF signal (broadcast signal) designated by the channel selection control unit 11 from a broadcast wave received by the antenna 100. The broadcast station transmits an RF signal in which a synchronization signal appears periodically.

  The synchronization processing unit 13 detects a synchronization signal included in the RF signal extracted by the frequency selection unit 12, and based on the synchronization signal and the synchronization protection pattern designated by the synchronization protection pattern determination unit 16, the RF signal Perform synchronous processing.

  The synchronization protection pattern is the number of continuous detections of the synchronization signal necessary for determining the synchronization state, that is, the number of synchronization determinations (predetermined number).

  The synchronization process includes a synchronization determination process (synchronization protection process). In the synchronization determination process, the synchronization processing unit 13 determines that the synchronization state is in the synchronization state when the synchronization signal in the RF signal received by the frequency selection unit 12 is detected continuously for a predetermined number of times.

  Note that a synchronization pattern may be used as the synchronization signal.

  The demodulator 14 demodulates the broadcast data from the RF signal that has been synchronized by the synchronization processor 13.

  The reception state determination unit 15 determines the reception state of the RF signal received by the frequency selection unit 12. Specifically, the reception state determination unit 15 determines the reception state of the RF signal based on information provided from the frequency selection unit 12, the synchronization processing unit 13, and the demodulation unit 14.

  The synchronization protection pattern determination unit 16 is an example of a synchronization processing control unit, and at the time of channel selection operation, the synchronization processing unit 13 sets a channel synchronization protection pattern and performs channel selection synchronization processing. During operation, the synchronization processing means 13 is set with a synchronization protection pattern for continuous reception so as to perform synchronization processing for continuous reception.

  Specifically, the synchronization protection pattern determination means 16 stores a channel selection operation initial synchronization protection pattern and a channel selection synchronization protection pattern when the reception state is poor, as a channel selection synchronization protection pattern, and continuous reception. As the synchronization protection pattern, the normal reception synchronization protection pattern when the reception state is good and the normal reception synchronization protection pattern when the reception state is bad are stored.

  Note that the time required for the synchronization protection process using each synchronization protection pattern, specifically, the number of times of synchronization determination used as each synchronization protection pattern has the following relationship.

  Tuning protection initial synchronization protection pattern <Reception state failure tuning protection protection pattern <Reception state good normal reception synchronization protection pattern <Reception state failure normal reception synchronization protection pattern.

  The synchronization protection pattern determination means 16 includes an initial synchronization protection pattern for channel selection operation, a synchronization protection pattern for channel selection when the reception state is bad, a synchronization protection pattern for normal reception when the reception state is good, and a synchronization for normal reception when the reception state is bad. A synchronization protection pattern used by the synchronization processing means 13 is selected from the protection patterns.

  The reproduction means 17 reproduces the broadcast data demodulated by the demodulation means 14 and presents it to the user.

  Next, an outline of the operation will be described.

  When the channel selection operation is started by the channel selection control unit 11, the synchronization protection pattern determination unit 16 selects a synchronization protection pattern that the synchronization processing unit 13 uses for synchronization determination.

  At this time, the synchronization protection pattern determination means 16 selects the synchronization protection pattern with the minimum number of consecutive times that the synchronization signal necessary for determining the synchronization state is detected. As the synchronization protection pattern, a synchronization protection pattern may be used in which the synchronization state is determined by one detection, although it differs depending on the method of the synchronization signal.

  Next, the reception state determination unit 15 determines the reception state based on the operation states of the frequency selection unit 12, the synchronization processing unit 13, and the demodulation unit 14.

  The synchronization protection pattern determination unit 16 changes the synchronization protection pattern when the determination result of the reception state determination unit 15 is bad.

  The number of times of continuous detection of the synchronization signal in the changed synchronization protection pattern is larger than the number of times in the synchronization protection pattern set first, and smaller than the number of times in the synchronization protection pattern set after the channel selection operation is completed.

  For this reason, if the reception state is good at the start of channel selection, a synchronization protection pattern is used that minimizes the number of consecutive detections of the synchronization signal necessary for determining the synchronization state. Time is the shortest. As a result, the time for the channel selection operation is shortened.

  Next, the operation will be specifically described.

  FIG. 2 is a flowchart for explaining the operation of the synchronization protection pattern determination means 16. Hereinafter, the operation of the digital broadcast receiver 1 will be described with reference to FIGS. 1 and 2.

  When the channel selection control unit 11 receives a channel selection operation (channel selection designation) by the user, the channel selection control unit 11 starts the channel selection operation, and the frequency selection unit 12 uses the frequency information of the broadcasting station specified by the user in the channel selection operation. In addition, a tuning operation start notification to start the tuning operation is provided to the synchronization processing unit 13, the demodulation unit 14, the reception state determination unit 15, and the synchronization protection pattern determination unit 16.

  Upon receiving the channel selection operation start notification, the synchronization protection pattern determination unit 16 selects an initial synchronization protection pattern for channel selection operation that requires the minimum time for the synchronization protection processing from a plurality of types of synchronization protection patterns. (Step 201).

  In the initial synchronization protection pattern for channel selection operation, the number of synchronization determinations is set to the minimum (for example, once) among the synchronization protection patterns.

  When the frequency information is set, the frequency selection unit 12 extracts an RF signal in the frequency band indicated by the frequency information from the broadcast wave received by the antenna 100.

  Further, the frequency selection unit 12 informs the reception state determination unit 15 of information related to the strength of the reception signal (reception state information). As information regarding the strength of the received signal, the value of AGC in the frequency selection means 12 or the state of the attenuator is used.

  When receiving the received signal strength information, the receiving state determining means 15 determines the receiving state based on the received information.

  Specifically, the reception state determination means 15 determines that the strength of the received signal is good (the reception state is good) when the strength of the received signal exceeds the first predetermined value, and the determination result Is notified to the synchronization protection pattern determination means 16. On the other hand, when the strength of the received signal is equal to or less than the first predetermined value, the reception state determining means 15 determines that the strength of the received signal is not good (the reception state is not good), and the determination result is synchronously protected. Notify the pattern determination means 16.

  Upon receiving the received signal strength determination result (step 202), the synchronization protection pattern determination unit 16 selects a synchronization protection pattern based on the determination result (step 203).

  When it is determined that the received signal strength is good, the synchronization protection pattern determination unit 16 maintains the initial synchronization protection pattern for channel selection operation that is initially set.

  On the other hand, if it is determined that the strength of the received signal is not good, the synchronization protection pattern determination means 16 selects the synchronization protection pattern for tuning when the reception state is poor, and synchronizes the selected synchronization protection pattern. The processing unit 13 is set (step 204).

  The synchronization processing unit 13 detects the synchronization signal from the RF signal extracted by the frequency selection unit 12 and performs synchronization processing. Furthermore, the synchronization processing means 13 executes the RF signal synchronization protection processing using the synchronization protection pattern designated by the synchronization protection pattern determination means 16.

  The synchronization processing unit 13 further notifies the reception state determination unit 15 of reception state information indicating the reception state. As this reception state information, a C / N value (carrier noise ratio) estimated from the detection state of the synchronization signal or the like is used.

  When receiving state information (specifically, C / N value) is received from the synchronization processing unit 13, the receiving state determining unit 15 determines the receiving state based on the C / N value.

  Specifically, the reception state determination unit 15 determines that the quality of the reception signal is good (the reception state is good) when the value of C / N exceeds the second predetermined value, and the determination result Is notified to the synchronization protection pattern determination means 16. On the other hand, when the C / N value is equal to or less than the second predetermined value, the reception state determination unit 15 determines that the quality of the reception signal is not good (the reception state is not good), and the determination result is synchronously protected. Notify the pattern determination means 16.

  When the synchronization protection pattern determination means 16 receives the reception signal quality determination result (step 205), it selects a synchronization protection pattern based on the determination result (step 206).

  If it is determined that the received signal quality is good, the synchronization protection pattern determination unit 16 maintains the synchronization protection pattern set in the synchronization processing unit 13.

  On the other hand, if it is determined that the received signal quality is not good, the synchronization protection pattern determination means 16 selects the synchronization protection pattern for tuning when the reception state is poor, and performs synchronization processing on the selected synchronization protection pattern Set to the means 13 (step 207).

  The demodulator 14 demodulates the RF signal subjected to the synchronization processing by the synchronization processor 13 to generate broadcast data, and outputs the broadcast data to the reproduction unit 17.

  The demodulator 14 notifies the channel selection controller 11 of the start of demodulated data output when broadcast data can be output, and is estimated from error correction processing included in the demodulator. The received bit error rate (BER) is notified to the reception state determination means 15 as reception state information.

  When receiving state information (specifically, BER) is received from the demodulating unit 14, the receiving state determining unit 15 determines the receiving state based on the BER value.

  Specifically, when the BER value is lower than the third predetermined value, the reception state determination unit 15 determines that the demodulation state is good (the reception state is good), and uses the determination result as the synchronization protection pattern. The determination means 16 is notified. On the other hand, when the BER value is equal to or greater than the third predetermined value, the reception state determination unit 15 determines that the demodulation state is not good (the reception state is not good), and uses the determination result as the synchronization protection pattern determination unit 16. Notify

  When receiving the determination result of the demodulation state (step 208), the synchronization protection pattern determination unit 16 selects a synchronization protection pattern based on the determination result (step 209).

  When the demodulation state is determined to be good, the synchronization protection pattern determination unit 16 maintains the synchronization protection pattern set in the synchronization processing unit 13.

  On the other hand, if it is determined that the received signal quality is not good, the synchronization protection pattern determination means 16 selects the synchronization protection pattern for tuning when the reception state is poor, and performs synchronization processing on the selected synchronization protection pattern Set to the means 13 (step 210).

  When receiving the broadcast data from the demodulating unit 14, the reproducing unit 17 reproduces the broadcast data and provides the channel selection control unit 11 with a notification of reproduction start.

  When the channel selection control unit 11 receives the notification of the reproduction start from the reproduction unit 17, the channel selection control unit 11 ends the channel selection operation and then starts the continuous reception operation, and the synchronization protection pattern determination unit 16, the synchronization processing unit 13, the demodulation unit. 14. Provide a channel selection operation completion notification to the reception state determination means 15.

  When receiving the channel selection operation completion notification from the channel selection control unit 11 (step 211), the synchronization protection pattern determination unit 16 selects the continuous reception synchronization protection pattern used in the normal reception state (step 212).

  Specifically, when the initial synchronization protection pattern for channel selection operation is set in the synchronization processing means 13, the synchronization protection pattern determination unit 16 sets the setting to the synchronization protection pattern for normal reception when the reception state is good. Change (step 214).

  On the other hand, the synchronization protection pattern determination means 16 changes the setting to the synchronization protection pattern for normal reception when the reception condition is bad when the synchronization processing pattern is set in the synchronization processing means 13 when the reception condition is bad. (Step 213).

  As described above, the setting of the number of continuous detections of the synchronization signal necessary for the synchronization state determination is as follows. “Initial synchronization protection pattern for channel selection operation <Synchronization protection pattern for channel selection when reception condition is poor <Normal reception when reception state is good” Synchronization protection pattern <normal reception synchronization protection pattern when reception state is poor ”.

  For this reason, in the channel selection operation when the reception state is good, the number of continuous detections of the synchronization signal (the number of synchronization determinations) necessary to determine the synchronization state in the synchronization protection until the channel selection operation ends. The minimum number of times set at the start of channel selection is maintained.

  For this reason, the time required to receive the number of synchronization signals necessary to determine the synchronization state is the shortest.

  Furthermore, even if it is determined in steps 203, 206 and 209 that the reception state is not good, the number of continuous detections of the synchronization signal set by the tuning protection pattern for channel selection when the reception state is bad is the synchronization protection pattern for continuous reception. It is less than the number of continuous detections of the sync signal set in.

  As a result, the channel selection time can be shortened compared to using the synchronization protection pattern used in the normal reception state.

  Further, after the channel selection operation is completed, the synchronization protection pattern determination unit 16 switches the channel selection synchronization protection pattern set in the synchronization processing unit 13 to the synchronization protection pattern for continuous reception. For this reason, more stable reception and shortening of the channel selection operation time can be realized.

  According to the present embodiment, the following effects can be obtained.

  The first effect is that when the broadcast wave reception state is good, the time required from the user performing the channel selection operation until the broadcast reproduction is started is shortened.

  The reason is as follows.

  When it is determined that the reception state is good at the start of channel selection, the synchronization protection pattern determination unit 16 sets a synchronization protection pattern in the synchronization processing unit 13 that minimizes the time required for the synchronization protection process. For this reason, the time until the synchronization processing unit 13 determines that the synchronization state is established is shortened, and as a result, the time until the demodulation unit 14 outputs the data is shortened. Therefore, the reproduction means 17 can quickly acquire data necessary for the reproduction operation.

  The second effect is that the stability of normal reception does not deteriorate due to the time shortening process of the channel selection operation.

  The reason is that the synchronization protection patterns are divided into those for channel selection and those for continuous reception.

  According to the present embodiment, the following operational effects can be obtained.

  The synchronization protection pattern determination unit 16 makes the synchronization determination number used by the synchronization processing unit 13 during the channel selection operation smaller than the synchronization determination number used by the synchronization processing unit 13 during the continuous reception operation. Therefore, the synchronization determination processing time at the time of channel selection is shorter than the synchronization determination processing time at the time of continuous reception. Therefore, the channel selection operation can be speeded up.

  In this embodiment, the synchronization protection pattern determination unit 16 changes the number of synchronization determinations based on the determination result of the reception state determination unit 15 during the channel selection operation. In this case, stable reception can be realized.

  In this embodiment, the synchronization protection pattern determination unit 16 changes the number of synchronization determinations based on the determination result of the reception state determination unit 15 during the continuous reception operation. In this case, stable reception can be realized over the entire reception operation.

  Further, in this embodiment, the synchronization protection pattern determination unit 16 makes the number of synchronization determinations at the start of the channel selection operation the smallest among the number of synchronization determinations used by the synchronization processing unit 13. In this case, the channel selection operation can be speeded up.

  In the embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

1 is a block diagram showing an embodiment of the present invention. It is a flowchart for demonstrating operation | movement of a synchronous protection pattern determination means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital broadcast receiver 11 Channel selection control means 12 Frequency selection means 13 Synchronization processing means 14 Demodulation means 15 Reception state determination means 16 Synchronization protection pattern determination means 17 Playback means 100 Antenna

Claims (8)

Upon receiving a channel designation for designating a broadcast station, a channel selection operation for selecting the broadcast station designated by the channel designation is performed, and then continuous reception for continuously receiving the broadcast of the broadcast station A broadcast receiver that performs an operation,
Receiving means for receiving a broadcast signal including a synchronization signal output by the broadcast station designated by the channel selection designation;
Synchronization processing means for determining that the synchronization signal is in a synchronized state when the synchronization signal in the broadcast signal received by the receiving unit is continuously detected a predetermined number of times every predetermined time;
A broadcast receiver comprising: synchronization processing control means for making the predetermined number of times used by the synchronization processing means during the channel selection operation less than the predetermined number of times used by the synchronization processing means during the continuous reception operation. The broadcast receiver according to claim 1,
Further including a reception state determination means for determining a reception state of the broadcast signal,
The synchronization processing control unit is a broadcast receiver that changes the predetermined number of times based on a determination result of the reception state determination unit during the channel selection operation. The broadcast receiver according to claim 2,
The synchronization processing control unit is a broadcast receiver that changes the predetermined number of times based on a determination result of the reception state determination unit during the continuous reception operation. The broadcast receiver according to claim 2 or 3,
The synchronization processing control unit is a broadcast receiver in which the predetermined number of times at the start of the channel selection operation is minimized among the predetermined number of times used by the synchronization processing unit. Upon receiving a channel designation for designating a broadcast station, a channel selection operation for selecting the broadcast station designated by the channel designation is performed, and then continuous reception for continuously receiving the broadcast of the broadcast station A synchronization protection control method performed by a broadcast receiver that performs an operation,
A receiving step of receiving a broadcast signal including a synchronization signal output by the broadcast station designated by the channel selection designation;
A synchronization processing step for determining that the synchronization signal in the broadcast signal is in a synchronized state when it is continuously detected a predetermined number of times every predetermined time;
A synchronization processing control step for reducing the predetermined number of times used for the determination of the synchronization state during the channel selection operation to be less than the predetermined number of times used for the determination of the synchronization state during the continuous reception operation. Control method. In the synchronous protection control method according to claim 5,
A reception state determination step of determining a reception state of the broadcast signal;
In the synchronization processing control step, the synchronization protection control method of changing the predetermined number of times based on a determination result of the reception state during the channel selection operation. In the synchronous protection control method according to claim 6,
In the synchronization processing control step, the synchronization protection control method of changing the predetermined number of times based on a determination result of the reception state during the continuous reception operation. In the synchronous protection control method according to claim 6 or 7,
In the synchronization processing control step, a synchronization protection control method wherein the predetermined number of times at the start of the channel selection operation is minimized among the predetermined number of times used in the synchronization processing.

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