JP2010193092A - Broadcast receiver and method of controlling same - Google Patents

Abstract

An object of the present invention is to adaptively select a plurality of tuners having different interference wave rejection capabilities and power consumption, thereby realizing a stable reception environment and reducing wasteful power consumption.
A broadcast receiving apparatus includes an A method tuner unit with low power consumption and a B method tuner unit with high power consumption but high interference wave rejection capability. In the first reception mode, the system control unit 111 uses the signal received by the A method tuner unit 103 to control the power supply to the B method tuner unit 104 to be stopped. When the C / N value of the received signal by the A system tuner unit 103 becomes smaller than the determination reference value, the mode shifts to the second reception mode, and the system control unit 111 uses the signal received by the B system tuner unit 104 to use the A system tuner. The power supply to the unit 103 is stopped. Thereafter, when the prediction result of the C / N value related to the A method tuner unit 103 exceeds the determination reference value, the system control unit 111 returns to the first reception mode.
[Selection] Figure 1

Description

  The present invention relates to a broadcast receiving apparatus capable of preventing an increase in power consumption while enhancing broadcast wave reception capability, and a control method thereof.

  The broadcast receiving apparatus includes a circuit that receives a broadcast signal transmitted from a broadcast station, extracts only a signal in a band including a viewing program from the received signal, and transmits the extracted signal to a processing block. This circuit is called a so-called analog RF (Radio Frequency) front end unit, and various reception methods have been proposed. Examples of the reception method include a single conversion method equipped with one local OSC (Oscillator) and a single conversion Low IF (Low Intermediate Frequency) method. Further, a double conversion method in which two local OSCs are installed is known. Each of these reception methods is greatly different in ability to eliminate interference waves and power consumption depending on the circuit configuration. In general, the double conversion method has a high ability to eliminate interference waves such as image interference, but since the circuit scale becomes large, power consumption tends to increase accordingly. On the other hand, the single conversion method has a merit in terms of power consumption due to the small number of parts, although the interference wave rejection capability is inferior.

  As described above, each tuner reception method has advantages and disadvantages depending on the circuit configuration, and these are generally in a trade-off relationship. In the following description, a tuner having a simple circuit configuration and low power consumption is referred to as an A method tuner, and a tuner based on a reception method that consumes more power but has a high interference wave rejection capability is referred to as a B method tuner. I will call it. Here, a broadcast receiving apparatus in which the two-system tuner is mounted on one apparatus is assumed. In a normal reception state where there is no problem with the reception status, this apparatus controls so that broadcasts are received by the A-type tuner, and cuts off power supply to the B-type tuner. After that, when an interference signal mixed in the broadcast wave is input and reception by the A method tuner becomes difficult, control is performed so that the B method tuner receives the broadcast, and the power supply to the A method tuner is cut off. To do. By performing such switching control, it is considered that high sensitivity of the tuner can be realized while reducing power consumption.

As a technique for realizing such a method, for example, in the technique disclosed in Patent Document 1, when the signal quality deteriorates during program viewing by high-layer transmission, switching to low-layer transmission is performed. At that time, a BER (Bit Error Rate) value that is a measure of the quality of the received signal and a C / N (Carrier to
A method using a noise ratio value has been proposed. Therefore, by applying this method and monitoring the BER value and the received C / N value, when it is determined that reception by the A method tuner is impossible, a method of switching to the B method tuner can be considered. In this way, switching from the B-type tuner to the A-type tuner can be similarly realized.

JP 2002-118611 A

  However, when two tuners are used using the method of Patent Document 1, switching from the B-system tuner to the A-system tuner cannot be performed immediately. That is, in order to switch from the B method tuner to the A method tuner when the interference wave is alleviated and the reception situation is improved, the A method tuner is first turned on. Then, it is necessary to check whether or not reception that can withstand viewing is possible even with the A method tuner.

  The reason why the switching from the B system tuner to the A system tuner cannot be performed immediately is due to the fact that the A system tuner is inferior in the interference wave rejection capability. Therefore, when switching from the B method tuner to the A method tuner, it is necessary to check the reception C / N value of the A method tuner after the A method tuner is activated. Then, a determination is made as to whether switching to the A-type tuner is possible without any problem in the reception state. For this reason, every time the received C / N value is confirmed, energization and de-energization of the A-type tuner are repeated. Therefore, there is a problem that wasteful power is consumed, which is against the demand for power saving.

  Therefore, the present invention realizes a stable reception environment by adaptively selecting a tuner with excellent interference wave rejection capability and a tuner with low power consumption, and reduces the generation of wasteful power consumption when switching tuners. With the goal.

  The apparatus according to the present invention includes: a first broadcast receiving unit with low power consumption; a second broadcast receiving unit with high power consumption but high interference wave rejection capability compared to the first broadcast receiving unit; Based on a value representing the quality of the received signal by the second broadcast receiving means, a detecting means for obtaining a value representing the quality of each received signal by the first broadcast receiving means, the second broadcast receiving means A predicting means for predicting a value representing the quality of a received signal by the first broadcast receiving means; a first reception mode by the first broadcast receiving means; and a second reception mode by the second broadcast receiving means. And a control means for controlling the transition process. In the first reception mode, the control unit uses a reception signal from the first broadcast reception unit and stops power supply to the second broadcast reception unit. In the second reception mode, the control unit The received signal from the second broadcast receiving means is used and the power supply to the first broadcast receiving means is stopped, and the value representing the quality of the received signal from the first broadcast receiving means becomes smaller than the criterion value. The first reception mode is shifted to the second reception mode, and the prediction result of the value indicating the quality of the received signal by the first broadcast receiving means in the second reception mode is the determination. When the reference value is exceeded, the second reception mode is returned to the first reception mode.

The method according to the present invention includes a first broadcast receiving unit that consumes less power, and a second broadcast receiving unit that consumes more power but has a higher ability to eliminate interference waves than the first broadcast receiving unit. A control method for a broadcast receiving apparatus, which includes the following steps.
A step of detecting a value representing the quality of the received signal received by the first broadcast receiving means and the second broadcast receiving means, respectively;
Predicting a value representing the quality of the received signal from the first broadcast receiving means based on a value representing the quality of the received signal from the second broadcast receiving means.
In the first reception mode, the step of using the received signal from the first broadcast receiving means and stopping the power supply to the second broadcast receiving means.
In the second reception mode, the step of using the received signal from the second broadcast receiving unit and stopping the power supply to the first broadcast receiving unit.
When the value indicating the quality of the received signal by the first broadcast receiving means becomes smaller than the determination reference value, the first reception mode is shifted to the second reception mode, and the second reception is performed. Returning to the first reception mode from the second reception mode when the prediction result of the value representing the quality of the received signal by the first broadcast receiving means exceeds the criterion value in the mode.

  According to the present invention, a stable reception environment can be realized by adaptively selecting a first broadcast receiving unit that is advantageous in terms of interference wave rejection capability and a second broadcast receiving unit that is advantageous in terms of power consumption. However, the power consumption of the apparatus can be reduced as much as possible.

It is a block diagram which shows roughly the function structure of the broadcast receiver which concerns on 1st Embodiment of this invention. It is the correlation diagram which illustrated the relationship between C / N value and jamming wave level about each receiving system. It is the correlation diagram which illustrated the relationship between C / N value and jamming wave level for every channel in each receiving system. It is explanatory drawing which shows an example of the conversion table produced based on the correlation diagram for every channel shown in FIG. 3, and stored in a memory | storage part. 6 is a flowchart illustrating a flow of a switching process from an A method tuner unit to a B method tuner unit in the first embodiment. 6 is a flowchart illustrating a flow of switching processing from a B-type tuner unit to an A-type tuner unit in the first embodiment. It is a block diagram which shows roughly the function structure of the broadcast receiver which concerns on 2nd Embodiment of this invention. 9 is a flowchart illustrating a flow of switching processing from an A-type tuner unit to a B-type tuner unit in the second embodiment. 10 is a flowchart illustrating a flow of switching processing from a B-type tuner unit to an A-type tuner unit in the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a functional configuration of the broadcast receiving apparatus 100 according to the first embodiment, and schematically shows a flow of broadcast reception data.

  The broadcast receiving apparatus 100 includes an antenna unit 101, an A method tuner unit 103 as a first broadcast receiving unit, and a B method tuner unit 104 as a second broadcast receiving unit. Terrestrial digital (abbreviation for digital terrestrial broadcasting) demodulation units 105a and 105b are respectively arranged after the tuner units. Further, a TS decoder unit 107 and a display unit 109 are provided. A system control unit 111, a limit C / N detection unit 112, a C / N data storage unit 113, and a return C / N detection unit 114 are connected to each other via a common bus 110 so as to be able to transmit and receive information. The common bus 110 is a bus for transmitting and receiving various data and commands (information related to control; control information) between the functional blocks. For simplification of illustration, the connection between each functional block and the common bus is omitted in FIG. 1 (this also applies to FIG. 7 described later).

  The antenna unit 101 is an antenna for receiving terrestrial digital broadcasting. Signals received by the antenna unit 101 are sent to the A method tuner unit 103 and the B method tuner unit 104, which have different reception methods.

  The A method tuner unit 103 extracts a frequency band corresponding to the physical channel of the viewing program selected by the user's selection operation from the terrestrial digital broadcast signal received from the antenna unit 101. The A method tuner unit 103 extracts an OFDM (Orthogonal Frequency Division Multiplexing) baseband signal corresponding to the frequency band. The A method tuner unit 103 transmits the extracted OFDM baseband signal (OFDM signal) to the terrestrial digital demodulation unit 105a. Switching of physical channels based on user operations or the like is performed by an instruction from the system control unit 111 to the A-type tuner unit 103. As a receiving method of the A method tuner unit 103, for example, a single conversion method is used. That is, the A method tuner unit 103 consumes less power than the B method tuner unit 104.

  The B system tuner unit 104 has the same function as the A system tuner unit 103, but is configured according to a different reception system. With respect to the B-system tuner unit 104, this embodiment uses a tuner that has an interference wave rejection capability that is higher by several dB to several tens dB than the A-system tuner unit 103. Accordingly, the tuner section needs to be added on the circuit configuration, and power consumption increases. For the B method tuner unit 104, for example, a double conversion method is used as a reception method.

  The terrestrial digital demodulation units 105a and 105b have a demodulation processing unit and a decoding processing unit therein. The OFDM signals received from the A-system tuner unit 103 and the B-system tuner unit 104 are sent to the corresponding demodulation processing units, and the demodulated signals are decoded by the respective decoding processing units. The decoded signal is output to the TS decoder unit 107 as MPEG-TS data.

Hereinafter, functions of the terrestrial digital demodulation units 105a and 105b will be described.
In accordance with a control instruction from the system control unit 111, the A method tuner unit 103 and the B method tuner unit 104 output the received C / N value and BER value of the received signal. The BER value is used as a guideline for tuner sensitivity, but the reception C / N value and the BER value are correlated. Therefore, in the present embodiment, the received C / N value is used as a guideline for tuner sensitivity. The “reception C / N value” is a ratio between the level of the signal transmitted from the broadcasting station and the level of the interference wave generated in the transmission path or the receiver, and the value is an index representing the quality of the received signal. Available as

  When a signal with a high reception C / N value is processed by the terrestrial digital demodulation units 105a and 105b, a video signal or the like can be received without causing a data error. Conversely, when the received C / N value is low, a data error occurs and so-called block noise starts to occur in the display video. Further, when the received C / N value becomes lower, video display becomes impossible. A reception C / N value necessary for preventing a data error from occurring is called a “required C / N value” and is determined by a modulation method. When the interference wave that affects the broadcast wave of the channel to be received (hereinafter referred to as the desired wave) becomes large and the quality of the received signal deteriorates, the reception C / N value decreases. In general, the ability to eliminate interfering waves varies greatly depending on the reception method of the tuner. If the tuner section has a high ability to eliminate this interference wave, the received C / N value is improved by the eliminated level.

  FIG. 2 shows an example of C / N characteristics at the time of interference wave input for the A method tuner unit 103 and the B method tuner unit 104. The vertical axis represents the C / N value, and the horizontal axis represents the interference wave level. A dotted graph line represents the characteristic of the A-type tuner unit 103, and a solid line represents a characteristic of the B-type tuner unit 104. A point P1 is an intersection of a horizontal line indicating a data error occurrence level and a dotted graph line. In the region on the left side of this point, reception is possible by both tuner units. Point P2 is an intersection of a horizontal line indicating a data error occurrence level and a solid graph line. In the area between P2 and P1, only the B-type tuner unit 104 can receive, and in the area on the right side of P2, neither can be received by the tuner unit.

Hereinafter, the received C / N value obtained from the terrestrial digital demodulation unit 105 a indicates the received C / N value of the signal that has passed through the A-system tuner unit 103. The received C / N value obtained from the terrestrial digital demodulating unit 105 b indicates the received C / N value of the signal that has passed through the B-system tuner unit 104.
The TS decoder unit 107 generates a digital video signal by decoding the MPEG-TS format signal decoded by the terrestrial digital demodulation units 105a and 105b. This digital video signal is output to the display unit 109.

  The display unit 109 includes a D / A converter, a monitor control circuit, a monitor (display panel), and the like (not shown). The display unit 109 displays an image on the display panel according to the digital video signal received from the TS decoder unit 107. Note that a display panel having an electron-emitting device, a liquid crystal display panel, a plasma display panel, an organic EL display panel, or the like may be used as the display panel.

  The system control unit 111 is configured using a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a program is stored, a Work RAM (Random Access Memory), and the like, and controls the various functions. For example, in the process of calculating the C / N characteristic of the received signal that has passed through the path of the A method tuner unit 103, the system control unit 111 issues a command to the A method tuner unit 103 and the terrestrial digital demodulation unit 105a. As a result, the received C / N value for the received broadcast wave is obtained via the common bus 110, and the received C / N value data is stored in the C / N data storage unit 113.

  The limit C / N detection unit 112 constitutes a C / N detection unit that obtains a reception C / N value, and in accordance with a command from the system control unit 111, a received C / N value for a signal received by the A method tuner unit 103 Monitoring. When the received C / N value falls below the limit C / N value, the limit C / N detection unit 112 immediately notifies the system control unit 111 accordingly. Here, the “limit C / N value” refers to a received C / N value immediately before the tuner unit becomes unable to receive when receiving by the A method tuner unit 103. For this value, for example, a value about several dB larger than the required C / N value may be taken. Therefore, the limit C / N value is determined by the required C / N value. The system control unit 111 recognizes a required C / N value from TMCC (Transmission and Multiplexing Configuration Control) regarding the current broadcast wave modulation method, and sets a limit C / N value according to this value.

  As shown in FIG. 3, the C / N data storage unit 113 acquires the C / N characteristic for the interference wave in each of the A method tuner unit 103 and the B method tuner unit 104 for each channel. FIG. 3 exemplifies C / N characteristics for the channels 1 to 3 for each tuner unit, and the individual characteristics are the same as those in FIG.

  Based on such characteristics for each channel, a conversion table is created from the received C / N values as shown in FIG. FIG. 4 exemplifies the correspondence relationship of the received C / N values related to the A-system tuner unit 103 and the B-system tuner unit 104 for the channels 1 to 3. The C / N data storage unit 113 holds such data. For example, as shown in the figure, in the case of channel 1 (see CH1), the B-system tuner unit 104 receives a broadcast wave, and checks the received C / N value (for example, 30 dB), thereby using the conversion table and the A-system tuner. The reception C / N value (for example, 20 dB) of the unit 103 can be estimated. Hereinafter, the estimated C / N value is referred to as “C / N predicted value”. The C / N characteristics and conversion table data may be input to the apparatus before the product is shipped and stored in the C / N data storage unit 113 in advance.

  The return C / N detection unit 114 monitors the received C / N value for the signal received by the B-system tuner unit 104 in accordance with an instruction from the system control unit 111. The return C / N detection unit 114 constitutes a C / N prediction unit for predicting the reception C / N value of the A method tuner unit 103 based on the reception C / N value of the B method tuner unit 104. The received C / N value is converted into a C / N predicted value by the conversion table. If the predicted C / N value falls below the return C / N value, the C / N detection unit 114 immediately returns to that effect and notifies the system control unit 111 of the fact. Here, the “return C / N value” refers to a reception C / N value that can be received by the A method tuner unit 103 at the time of reception by the B method tuner unit 104. For this value, as with the limit C / N value, for example, a value larger by several dB than the required C / N value may be taken. Therefore, the return C / N value is determined by the required C / N value in the same manner as the limit C / N value, and is set by the system control unit 111 based on the current broadcast wave modulation method by TMCC.

  Hereinafter, in the normal reception state where the influence of the interference wave is small, viewing is performed by the A method tuner unit 103, and when a data error occurs in the A method tuner unit 103 when receiving the interference wave, the B method tuner unit 104 is referred to. Is switched. In a reception state in which interference waves are mixed, viewing is performed using the B-system tuner unit 104. Thereafter, when the interference signal is eased step by step and it is determined that the A method tuner unit 103 can receive the signal, the switching from the B method tuner unit 104 to the A method tuner unit 103 is performed. Note that the tuner unit and the terrestrial digital demodulation unit that are not used are in a state where the power supply is cut off.

  First, switching control processing from the A-system tuner unit 103 to the B-system tuner unit 104 will be described with reference to FIG. Hereinafter, the mode in which the influence of the interference wave is small and the A-system tuner unit 103 receives the broadcast wave without any problem is referred to as a first reception mode. A mode in which the reception state deteriorates and switching to the B-type tuner unit 104 is required is referred to as a second reception mode. In the latter reception mode, there is a high probability that the A-system tuner unit 103 cannot maintain good broadcast reception or cause trouble in video display or the like.

A transition process from the first reception mode to the second reception mode will be described below.
First, the system control unit 111 issues a command to the limit C / N detection unit 112. In response to this command, the limit C / N detection unit 112 requests the terrestrial digital demodulation unit 105a for the received C / N value of the A method tuner unit 103 (see S201).

  Next, the limit C / N detector 112 determines whether or not the obtained received C / N value is equal to or greater than the limit C / N value (see S202). That is, the limit C / N value is a determination reference value related to the received C / N value. As a result, when it is determined that the received C / N value is less than the limit C / N value, the limit C / N detection unit 112 transmits information indicating that to the system control unit 111, and proceeds to step S203. Here, the system control unit 111 receives the information and performs control to turn on the power to the B-system tuner unit 104 and the terrestrial digital demodulation unit 105b. At this time, the TS decoder unit 107 receives both the data that has passed through the A system tuner unit 103 and the data that has passed through the B system tuner unit 104. The system control unit 111 confirms that TS data is output from the terrestrial digital demodulation unit 105b after the power to the B-system tuner unit 104 is turned on. The system control unit 111 switches the TS data supplied to the TS decoder unit 107 from the TS data received by the A method tuner unit 103 to the TS data received by the B method tuner unit 104. After confirming the end of the TS data switching, the system control unit 111 stops the power supply to the A method tuner unit 103 and the terrestrial digital demodulation unit 105a (see step S204).

  On the other hand, if it is determined in step S202 that the received C / N value of the A-system tuner unit 103 is greater than or equal to the limit C / N value, the process proceeds to step S205. Here, the system control unit 111 waits for a while, issues a command for confirming the received C / N value to the limit C / N detection unit 112 again, and monitors the received C / N value.

  Next, transition processing from the second reception mode to the first reception mode will be described with reference to FIG. In this case, the reception status is improved as a result of the stepwise relaxation of the interference wave, and a switching control process for returning from the B-system tuner unit 104 to the A-system tuner unit 103 is performed.

  As a premise, it is assumed that the apparatus receives a desired wave including an interference wave with respect to a broadcast wave input to a television receiver or the like. Then, the broadcast wave received by the B-type tuner unit 104 is processed by the terrestrial digital demodulation unit 105b and the TS decoder unit 107, and the display unit 109 performs display according to the image data obtained via these.

  First, the system control unit 111 issues a command to the return C / N detection unit 114. Upon receiving the command, the return C / N detection unit 114 requests the terrestrial digital demodulation unit 105b to check the received C / N value of the B-system tuner unit 104 that is currently energized (see S301). Thereby, the received C / N value via the B-system tuner unit 104 is obtained at the present time.

  After that, the return C / N detection unit 114 uses the data in the conversion table in the C / N data storage unit 113, and the received C / N value of the current B method tuner unit 104 from the A method tuner unit 103. Conversion to a C / N predicted value is performed (see S302). That is, by using the conversion table, a received C / N value estimated for the A-system tuner unit 103, that is, a C / N predicted value is obtained.

  Next, the return C / N detection unit 114 determines whether or not the obtained C / N prediction value exceeds the return C / N value, that is, whether the A-system tuner unit 103 can also receive the signal (see S303). . The return C / N value becomes a determination reference value related to the C / N predicted value. As a result, when the C / N predicted value returns and exceeds the C / N value, and it is determined that the reception by the A method tuner unit 103 is possible, information indicating that is transmitted to the system control unit 111. Then, the process proceeds to step S304. The system control unit 111 receives the information and controls to turn on the A-system tuner unit 103 and the terrestrial digital demodulation unit 105a (see S304). At this time, the TS decoder unit 107 receives both the data that has passed through the A system tuner unit 103 and the data that has passed through the B system tuner unit 104.

  The system control unit 111 confirms the TS output from the terrestrial digital demodulation unit 105b after turning on the power to the B system tuner unit 104. Thereafter, the system control unit 111 switches the TS data supplied to the TS decoder unit 107 from data received by the B method tuner unit 104 to data received by the A method tuner unit 103. After confirming that the switching of the TS data is completed, the system control unit 111 stops the power supply to the B-system tuner unit 104 and the terrestrial digital demodulation unit 105b (see S305).

  On the other hand, if it is determined in step S303 that the predicted C / N value is less than or equal to the return C / N value, the system control unit 111 waits for a while (see S306). Then, the system control unit 111 issues a command for confirming the reception C / N value of the B method tuner unit 104 to the return C / N detection unit 114 again, and sets the reception C / N value of the B method tuner unit 104. Monitor.

  As described above, according to the present embodiment, in the transition process from the A-system tuner unit 103 to the B-system tuner unit 104, the reception C / N value is acquired after the reception C / N value of the A-system tuner unit 103 is acquired. And the limit C / N value is compared. When the received C / N value falls below the limit C / N value, the switching to the B-system tuner unit 104 is performed smoothly. Thereby, switching of the tuner unit can be realized without interruption of the video.

  Further, in the transition processing from the B-system tuner unit 104 to the A-system tuner unit 103, the C / N prediction value is calculated using the conversion table of the C / N data storage unit 113. That is, based on the received C / N value of the B method tuner unit 104, the received C / N value of the A method tuner unit 103 can be predicted by using the conversion table of the C / N data storage unit 113. Then, the C / N predicted value of the A method tuner unit 103 is compared with the return C / N value. When the C / N predicted value returns and exceeds the C / N value, switching to the A method tuner unit 103 is possible.

  Thus, it is possible to adaptively select a tuner (B-system tuner unit 104 in this example) that has merit in interference wave rejection capability and a tuner (A-system tuner unit 103 in this example) that has merit in power consumption. As a result, a stable reception environment can be realized, and wasteful power can be prevented from being consumed in the determination for switching the tuner.

  The operation control described above may be configured to be performed when the broadcast receiving apparatus is set in the power saving mode. In that case, after the user sends an operation instruction to the apparatus using an operation unit such as a remote controller (not shown) and sets the apparatus to the power saving mode, the switching control of the tuner unit is started.

  Next, a second embodiment according to the present invention will be described. In digital terrestrial broadcasting, an encoding method capable of correcting an error with respect to data when a broadcast wave is received is used. In other words, even if instantaneous interference waves are mixed, if the occurrence interval is within a correctable time (if the bitstream where the error occurred is far away), the data error is corrected and the error Can be restored to no data.

  In the first embodiment, when the received C / N value is detected in the switching process of the tuner unit, switching control is performed regardless of the possibility of error correction. For example, a situation is assumed in which the received C / N value of the A method tuner unit 103 instantaneously changes when the received C / N value is detected in the switching process from the A method tuner unit 103 to the B method tuner unit 104. Even if the influence on the data due to the change is error correctable, that is, within the data error correction capability, if the received C / N value falls below the limit C / N value, the tuner switching control is performed. It can happen. This switching operation reduces the power saving effect of power consumption.

On the contrary, in the first embodiment, when switching from the B-system tuner unit 104 to the A-system tuner unit 103, it is assumed that the received C / N value instantaneously returns and exceeds the C / N value. In this case, a stable reception C / N value may not continue. Therefore, in the second embodiment, the following is devised for the switching method of the two tuner sections.
That is, processing for confirming the tendency of the change in the received C / N value over a predetermined period is performed. In switching from the A-system tuner unit 103 to the B-system tuner unit 104, it is determined whether or not the received C / N value tends to continue to decrease over a predetermined period, and the tuner is determined according to the result. Part switching control is performed. In switching from the B-system tuner unit 104 to the A-system tuner unit 103, it is determined whether or not the received C / N value tends to stabilize and continue over a predetermined period. Accordingly, the tuner switching control is performed.

  Hereinafter, the shortest time length period that does not affect the data even if the reception C / N value is instantaneously reduced is referred to as a “limit C / N period”. In addition, when using the B-type tuner, the shortest time length period during which it can be determined that a stable received C / N value can be acquired is referred to as a “return C / N period”. Note that the return C / N period may be set to the same level as the limit C / N period, for example.

  FIG. 7 is a block diagram showing the main part of the functional configuration of the broadcast receiving apparatus 200 according to the second embodiment. As shown in the figure, this embodiment further includes a C / N statistics management unit 215 in addition to the configuration according to the first embodiment shown in FIG. Of the constituent elements according to the present embodiment, the same parts as those in the first embodiment are used by using the reference numerals obtained by adding “100” to the reference numerals assigned to the constituent elements according to the first embodiment. The description of is omitted. And the difference of both embodiment is mainly demonstrated.

  As in the first embodiment, the limit C / N detection unit 212 is used for switching control of the tuner unit when the A method tuner unit 203 is energized and the B method tuner unit 204 is not energized. The The limit C / N detection unit 212 receives a command from the system control unit 211, and requests the terrestrial digital demodulation unit 205a for the received C / N value of the A method tuner unit 203 currently used. The acquired received C / N value is transmitted to the C / N statistics management unit 215. The C / N statistics management unit 215 holds the received C / N value received, and compares this received C / N value with the limit C / N value. As a result, when the received C / N value continues to fall below the limit C / N value for a time exceeding the length of the limit C / N period, information indicating that is sent from the C / N statistics management unit 215 to the limit. It is sent to the C / N detector 212. The limit C / N detection unit 212 transmits information to the system control unit 211 based on the information.

  Similar to the first embodiment, the return C / N detection unit 214 is used for switching control of the tuner unit when the B method tuner unit 204 is in the energized state and the A method tuner unit 203 is in the non-energized state. Is done. The return C / N detection unit 214 receives a command from the system control unit 211 and requests the terrestrial digital demodulation unit 205b for the received C / N value of the B-system tuner unit 104 currently used. Based on the acquired received C / N value, conversion to a C / N prediction value is performed by the A method tuner unit 203 using the conversion table of the C / N data storage unit 213. The return C / N detection unit 214 sends the C / N predicted value data to the C / N statistics management unit 215. The C / N statistics management unit 215 holds the received C / N prediction value, and compares this C / N prediction value with the return C / N value. When the C / N prediction value continues to exceed the return C / N value for a time exceeding the length of the return C / N period, information indicating that is returned from the C / N statistics management unit 215. It is sent to the detection unit 214. The return C / N detection unit 214 transmits information to the system control unit 211 based on the information.

  The C / N statistics management unit 215 acquires the received C / N value or the C / N predicted value from the corresponding circuit unit according to an instruction from the limit C / N detection unit 212 or the return C / N detection unit 214. This is temporarily stored. The processing contents differ between the case where the received C / N value is obtained from the limit C / N detection unit 212 and the case where the C / N prediction value is obtained from the return C / N detection unit 212 as follows.

  First, when the C / N statistics management unit 215 obtains a received C / N value from the limit C / N detection unit 212, when the received C / N value falls below the limit C / N value, the C / N The statistics management unit 215 starts a time measuring operation using a timer managed by the statistics management unit 215. During this time, the reception C / N value is continuously inquired, and the reception C / N value is continuously monitored. If the received C / N value continues to fall below the limit C / N value until the limit C / N period elapses, the C / N statistics management unit 215 displays information indicating that fact to the limit C / N detection unit. 212.

  On the other hand, when the C / N statistics management unit 215 acquires a C / N predicted value in response to an instruction from the return C / N detection unit 214, the C / N predicted value exceeds the returned C / N value. At this time, the C / N statistics management unit 215 starts the time counting operation using a timer managed by itself. During this time, C / N prediction values are continuously inquired, and monitoring of the C / N prediction values is continued. If the C / N prediction value continues to exceed the return C / N value until the return C / N period elapses, the C / N statistics management unit 215 returns information indicating that to the return C / N detection unit. Send to 214.

  Hereinafter, in the broadcast receiving apparatus according to the second embodiment, a tuner unit switching timing control method using the above-described C / N statistics management unit 215 will be described in detail with reference to FIGS. 8 and 9.

First, switching control processing from the A-system tuner unit 203 to the B-system tuner unit 204 when receiving an interference wave will be described with reference to the flowchart of FIG.
A situation is assumed in which there is no interference wave and the A-mode tuner unit 203 receives a broadcast wave in a good state. At this time, the system control unit 211 issues a command to the limit C / N detection unit 212. Upon receiving this command, the limit C / N detection unit 212 requests the reception C / N value from the terrestrial digital demodulation unit 205a in order to obtain the reception C / N value of the A-system tuner unit 203 (see S401). Next, the limit C / N detection unit 212 transmits the obtained reception C / N value to the C / N statistics management unit 215 (see S402).

  The C / N statistics management unit 215 compares the received C / N value with a preset limit C / N value, and determines whether or not the received C / N value is below the limit C / N value. (See S403). As a result, when it is determined that the received C / N value is lower than the limit C / N value, the C / N statistics management unit 215 starts a timer operation managed by itself (see S404). The C / N statistics management unit 215 continuously inquires the terrestrial digital demodulation unit 205a for the current received C / N value. Then, the C / N statistics management unit 215 determines whether or not the received C / N value is below the limit C / N value continuously for a period exceeding the limit C / N period (see S405). In other words, the length of the limit C / N period means the first determination reference time for determining the duration of the state where the received C / N value is below the limit C / N value. When it is determined that the received C / N value is below the limit C / N value over a period exceeding the limit C / N period, the C / N statistics management unit 215 passes through the limit C / N detection unit 212. Then, information indicating that is transmitted to the system control unit 211 (see S406).

  Next, the system control unit 211 controls the power supply to the B-type tuner unit 104 and the terrestrial digital demodulation unit 205b (see S407). After a while, the system control unit 211 controls to stop the power supply to the A method tuner unit 103 and the terrestrial digital demodulation unit 205a (see S408).

  If it is determined in step S403 that the received C / N value is greater than or equal to the limit C / N value, the system control unit 211 waits for a while (see step S410), and then returns to step S401. If the C / N statistics management unit 215 determines in step S405 that the received C / N value has exceeded the limit C / N value within the limit C / N period, the C / N statistics management unit 215 stops the timing operation of the built-in timer. The timer time is cleared to zero (see S409). Then, the system control unit 211 waits for a while (see S410) and returns to S401.

Hereinafter, switching control from the B method tuner unit 104 to the A method tuner unit 103 will be described with reference to the flowchart of FIG.
A situation is assumed in which a broadcast wave is received by the B-system tuner unit 204. At this time, the system control unit 211 issues a command to the return C / N detection unit 214. In response to this command, the return C / N detection unit 214 requests the reception C / N value from the terrestrial digital demodulation unit 205b in order to obtain the reception C / N value of the B-system tuner unit 204 (see S501). . Next, the return C / N detection unit 214 performs conversion into a C / N prediction value using the conversion table of the C / N data storage unit 213 based on the obtained reception C / N value, and performs prediction. A result is obtained (see S502). Then, the return C / N detection unit 214 transmits the C / N predicted value to the C / N statistics management unit 215 (see S503).

  The C / N statistics management unit 215 compares the C / N predicted value with a preset return C / N value, and determines whether or not the C / N predicted value exceeds the return C / N value ( (Refer to S504). As a result, when it is determined that the C / N predicted value has returned and exceeded the C / N value, the C / N statistics management unit 215 starts the timer operation managed by itself (see S505). Then, the C / N statistics management unit 215 continuously inquires the terrestrial digital demodulation unit 205b for the current received C / N value.

  The C / N statistics management unit 215 determines whether or not the C / N prediction value continues to exceed the return C / N value over a period exceeding the return C / N period (see S506). That is, the length of the return C / N period means the second determination reference time for determining the duration of the state where the C / N predicted value exceeds the return C / N value. As a result, when it is determined that the C / N prediction value exceeds the return C / N value beyond the return C / N period, the C / N statistics management unit 215 passes through the return C / N detection unit 214. Information indicating that fact is transmitted to the system control unit 211 (see S507). Then, the system control unit 211 controls the power supply to the A-type tuner unit 203 and the terrestrial digital demodulation unit 205a (see S508). After a while, the system control unit 211 controls to stop the power supply to the B-system tuner unit 204 and the terrestrial digital demodulation unit 205b (see S509).

  If it is determined in step S504 that the predicted C / N value is less than or equal to the returned C / N value, the system control unit 211 waits for a while (see S511) and returns to S501. In step S506, if the C / N statistics management unit 215 determines that the C / N predicted value may have fallen below the return C / N value within the return C / N period, it stops the operation of the built-in timer, The timer time is cleared (see S510). Then, the system control unit 211 waits for a while (see S511) and returns to S501.

  As described above, according to the second embodiment, by monitoring the tendency of the reception C / N value over a certain period, the influence of the instantaneous decrease in the reception C / N value due to the generation of pulse noise. And correct judgment processing can be performed. For this reason, it is possible to reduce the frequency with which the tuner unit is unnecessarily switched, and as a result, it is possible to increase the power saving effect.

100, 200 Broadcast receiving apparatus 103, 203 A type tuner unit 104, 204 B type tuner unit 105a, 105b, 205a, 205b Terrestrial digital demodulation unit 107, 207 TS decoder unit 111, 211 System control unit 112, 212 Limit C / N Detection unit 113, 213 C / N data storage unit 114, 214 Return C / N detection unit 215 C / N statistics management unit

Claims (4)

First broadcast receiving means with low power consumption;
A second broadcast receiving means that consumes more power than the first broadcast receiving means but has a high ability to eliminate interference waves;
Detecting means for obtaining values representing the quality of the respective received signals by the first broadcast receiving means and the second broadcast receiving means;
Predicting means for predicting a value representing the quality of the received signal by the first broadcast receiving means based on a value representing the quality of the received signal by the second broadcast receiving means;
Control means for controlling transition processing between the first reception mode by the first broadcast receiving means and the second reception mode by the second broadcast receiving means,
The control means includes
In the first reception mode, the signal received by the first broadcast receiving means is used and the power supply to the second broadcast receiving means is stopped,
In the second reception mode, the signal received by the second broadcast receiving means is used and the power supply to the first broadcast receiving means is stopped,
When the value representing the quality of the received signal by the first broadcast receiving means is smaller than the determination reference value, the mode is shifted from the first receiving mode to the second receiving mode, and the second receiving mode is set. When the prediction result of the value indicating the quality of the received signal by the first broadcast receiving means exceeds the determination reference value, the second reception mode is returned to the first reception mode. Broadcast receiving device. The control means includes
When it is determined that the value representing the quality of the received signal by the first broadcast receiving means is smaller than the determination reference value and has continued beyond the first determination reference time, the first reception mode is changed to the first reception mode. The broadcast receiving apparatus according to claim 1, wherein a transition process to the second reception mode is performed. The control means includes
When it is determined that the prediction result of the value representing the quality of the received signal by the first broadcast receiving means exceeds the determination reference value and this state has continued beyond the second determination reference time, The broadcast receiving apparatus according to claim 2, wherein a transition process from the second reception mode to the first reception mode is performed. A control method of a broadcast receiving apparatus comprising a first broadcast receiving means with low power consumption and a second broadcast receiving means with high power consumption but high interference wave rejection capability compared to the first broadcast receiving means There,
Detecting values representing the quality of received signals respectively received by the first broadcast receiving means and the second broadcast receiving means;
Predicting a value representing the quality of the received signal by the first broadcast receiving means based on a value representing the quality of the received signal by the second broadcast receiving means;
Using a received signal from the first broadcast receiving means and stopping power supply to the second broadcast receiving means in the first reception mode;
Using a received signal from the second broadcast receiving means in the second reception mode and stopping power supply to the first broadcast receiving means;
When the value representing the quality of the received signal by the first broadcast receiving means is smaller than the determination reference value, the mode is shifted from the first receiving mode to the second receiving mode, and the second receiving mode is set. And a step of returning from the second reception mode to the first reception mode when a prediction result of a value representing the quality of the received signal by the first broadcast reception means exceeds the determination reference value. A control method for a broadcast receiving apparatus.

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