Abstract:
According to one embodiment, a TV signal receiving apparatus includes a plurality of tuners which receive TV signals and an auto scan controller. The controller executes an auto scan function of scanning an entire range of a frequency band, which is receivable by said plurality of tuners, by scanning a predetermined unit of a frequency and of detecting a channel viewable at an area located therein at the time of scanning, in parallel by using the plurality of tuners.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2006-78282, filed Mar. 22, 2006, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments of the present invention relates to a control technology for reducing a time required for an auto scanning of automatically retrieving a channel which is viewable in each area. 
         [0004]    2. Description of the Related Art 
         [0005]    The TV signal receiving apparatus applied to, for example, a TV unit, a DVD recorder, an HDD recorder and a personal computer includes a scanning function of automatically detecting a channel which is viewable in each area, which is sometimes called auto scan, in order to improve convenience of each user using such a product in various areas. For example, Jpn. Pat. Appln. KOKAI Publication No. 2005-277790 gives a variety of proposals for preventing omission of detection or detection failure have been made about this scan function. 
         [0006]    As a method for detecting a channel which is viewable in each area, there is a method of scanning an entire range of the frequency band which is receivable by a tuner by scanning a predetermined unit of frequency. That is, a range of 41 MHz to 870 MHz is checked entirely by scanning a unit of 0.25 MHz or 1 MHz. 
         [0007]    According to this channel detection method, a determination upon whether or not a TV signal is receivable is repeated the number of times equivalent to a frequency range corresponding to be detected divided by the scanning unit. Since most of the frequencies are not receivable, much time is required. The reason is that this channel detection method requires waiting until a predetermined standby time for reception has passed, which is frequently during scanning of the frequencies. 
         [0008]    On the other hand, products having a plurality of turners have been proposed in order to enable recording a program during viewing another program or recording different two programs at the same time. However, no improvement is made on time consumed for scanning of a channel in this kind of product. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0009]      FIG. 1  is an exemplary diagram showing the schematic configuration of an information processing apparatus according to an embodiment of the present invention; 
           [0010]      FIG. 2  is an exemplary block diagram showing the scan function of a TV application program which operates in the information processing apparatus of the same embodiment; 
           [0011]      FIG. 3  is an exemplary diagram for explaining a basic principle of auto scan executed by the TV application program which operates in the information processing apparatus of the same embodiment; 
           [0012]      FIG. 4  is an exemplary flow chart showing the operation procedure of the auto scan executed by the TV application program which operates in the information processing apparatus of the same embodiment; 
           [0013]      FIG. 5  is an exemplary diagram for explaining a first modification of the auto scan executed by the TV application program which operates in the information processing apparatus of the same embodiment; and 
           [0014]      FIG. 6  is an exemplary diagram for explaining a second modification of the auto scan executed by the TV application program which operates in the information processing apparatus of the same embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. 
         [0016]      FIG. 1  is a diagram showing the schematic configuration of an information processing apparatus according to an embodiment of the present invention. The information processing apparatus of this embodiment is embodied as a personal computer for ordinary user such as a notebook type and disk top type ones, which includes TV function of receiving TV signal for viewing, recording and reproducing TV pictures. 
         [0017]    As shown in  FIG. 1 , the computer includes a CPU  11 , a north bridge  12 , a system memory  13 , a graphics controller  14 , a video RAM  15 , an LCD (liquid crystal display)  16 , a south bridge  17 , a BIOS (basic input output system)-ROM  18 , a hard disk drive (HDD)  19 , an optical disk drive (ODD)  20 , two TV broadcasting tuners  21 A,  21 B, an embedded controller/keyboard controller (EC/KBC)  22 , a keyboard  23 , a touch pad  24 , and a network controller  25 . 
         [0018]    The computer provides a high performance TV function of recording a program while another program is being viewed and recording different two programs at the same time by being equipped with two TV broadcasting tuners  21 A,  21 B. The TV function is achieved by TV application program  100  loaded on the system memory  13  and executed by the CPU  11 . Further, the HDD  19  stores a channel table  110  for recording information which is control data of the TV application program  100  and which indicates which channel is viewable in an area where the computer is used. 
         [0019]    The CPU  11  is a processor for controlling the operation of the computer, which executes various programs loaded from the HDD  19  to the system memory  13 , such as an operating system and a TV application program. Further, the CPU  11  executes a system BIOS which is stored in the BIOS-ROM  18 . The system BIOS is a program for hardware control. The system BIOS includes a TV tuner driver for controlling the TV broadcasting tuners  21 A,  21 B, which are hardware, with the TV application program  100 , which is software. 
         [0020]    The north bridge  12  is a bridge device for connecting between a local bus of the CPU  11  and the south bridge  17 . The north bridge  12  incorporates a memory controller for controlling the system memory  13 . Further, the north bridge  12  has a function of communicating with the graphics controller  14  through a bus. 
         [0021]    The graphics controller  14  is a display controller for controlling the LCD  16  used as a display monitor of the computer  10 . The VRAM  15  is a memory device used as a work area when the graphics controller  105  generates video data. 
         [0022]    The south bridge  17  controls each device on an LPC (low pin count) and each device on a PCI (peripheral component interconnect). The south bridge  17  incorporates an IDE (integrated drive electronics) controller for controlling the HDD  19  and ODD  20 . Further, the south bridge  17  has a function of communicating with the TV broadcasting tuners  21 A,  21 B. The TV broadcasting tuners  21 A,  21 B are tuning modules for receiving TV signals of a specific channel. 
         [0023]    The EC/KBC  22  is a 1-chip microcomputer on which an embedded controller for power control and a keyboard controller for controlling the keyboard  23  and touch pad  24  are integrated. The network controller  25  is a communication device for executing radio communication based on the IEEE 802.11 standard or executing serial bus communication based on the IEEE 1394 standard, for example. 
         [0024]    The TV function provided by the computer having such a configuration includes a scan function (auto scan) of automatically detecting a channel which is viewable in each area in order to improve convenience of each user using the product in respective areas. According to one embodiment of the invention, auto scanning is conducted in a frequency range of 41 MHz to 870 MHz by units of 1 MHz. Then, the TV application program  100  for achieving the TV function on the computer executes independent control for reducing a time required for the scan function, and these points will be described below. 
         [0025]      FIG. 2  is a block diagram showing the scan function of the TV application program  100 . As shown in  FIG. 2 , the TV application program  100  includes an auto scan module  101  for achieving the scan function. 
         [0026]    The auto scan module  101  drives two TV broadcasting tuners  21 A,  21 B, which are hardware, with two TV tuner drivers  120 A,  120 B so as to execute the two scanning operations in parallel for detecting a channel and records the result on a channel table  110 . That is, the auto scan modules  101  reduces a time required for scanning function by executing the two scanning operations in parallel. The basic principle of the control performed for above-mentioned operations will be described with reference to  FIG. 3 . In the meantime, on the channel table  110 , information indicating whether or not each frequency of every 1 MHz in the frequency range of 41 MHz to 870 MHz has been already scanned, and information indicating whether or not a channel through which a program is viewable has been detected, is recorded. 
         [0027]    The auto scan module  101  generates a first task (context 1) of scanning starting from a frequency of 41 MHz and progressing the scanning while incrementing the frequency by 1 MHz each and a second task (context 2) of scanning starting from a frequency of 870 MHz and progressing the scanning while decrementing the frequency by 1 MHz each. Then, the auto scan module  101  controls the context 1 using the TV broadcasting tuner  21 A and the context 2 using the TV broadcasting tuner  21 B. 
         [0028]    Information indicating whether or not each frequency to be scanned has been already scanned is recorded on the channel table  110 . Thus, the respective processing can be terminated at a time when the processing of both the context 1 and context 2 has progressed so that the scanned frequencies begin to overlap each other. If a large difference occurs in the frequency scanning rate (progress) of the context 1 and the context 2 due to environmental conditions, such as channels viewable in that area are disproportionate on either side of the frequency range (e.g., more or less viewable channels near 41 MHz or 870 MHz), the context on a side progressing fast scans more frequently than the content on a side progressing late (scans more than half the total frequencies to be scanned), so that the required time can be reduced without being affected by the environment. 
         [0029]      FIG. 4  is a flow chart showing the operating procedure of the auto scan to be executed on this computer. 
         [0030]    The auto scan module  101  sets the frequency of the TV broadcasting tuner  21 A to 41 MHz through the TV tuner driver  120 A (block A 1 ) and at the same time, sets the frequency of the TV broadcasting tuner  21 B to 870 MHz through the TV tuner driver  120 B (block A 6 ). 
         [0031]    After the settings end, the auto scan module  101  checks whether the TV broadcasting tuner  21 A can receive a synchronous signal of TV signal (block A 2 ). If it can receive (YES in block A 2 ), the auto scan module  101  records the channel information on the channel table  110  (block A 3 ). On the other hand, the auto scan module  101  checks whether or not the TV broadcasting tuner  21 B can receive a synchronous signal of the TV signal (block A 7 ). If it can receive (YES in block A 7 ), the auto scan module  101  records the channel information on the channel table  110  (block A 8 ). 
         [0032]    Next, the auto scan module  101  checks whether or not the frequency produced by incrementing a frequency set for the TV broadcasting tuner  21 A by 1 MHz is already processed (block A 4 ). Unless it is processed (NO in block A 4 ), the auto scan module  101  sets the frequency of the TV broadcasting tuner  21 A to a frequency incremented by 1 MHz from a current frequency (block A 5 ), and the processing from block A 2  is repeated. On the other hand, the auto scan module  101  checks whether or not the frequency produced by decrementing the frequency set for the TV broadcasting tuner  21 B by 1 MHz (block A 9 ). Unless it is processed (NO in block A 9 ), the auto scan module  101  sets the frequency of the TV broadcasting tuner  21 B to the frequency decremented by 1 MHz from a current frequency (block A 10 ), and the processing from block A 7  is repeated. 
         [0033]    If the frequency produced by incrementing the frequency of the TV broadcasting tuner  21 A by 1 MHz is already processed (YES in block A 4 ), the auto scan module  101  terminates the scanning operation using the TV broadcasting tuner  21 A. If the frequency produced by decrementing the frequency of the TV broadcasting tuner  21 B by 1 MHz is already processed (YES in block A 9 ), the scanning operation using the TV broadcasting is terminated. 
         [0034]    As described above, the auto scan module  101  included in the TV application program  100  controls the two scanning operations using the TV broadcasting tuners  21 A,  21 B in parallel. Therefore, the computer achieves reduction of the time required by the scanning function. 
         [0035]    A case where the TV broadcasting tuners  21 A,  21 B are provided is presumed. However, if three TV broadcasting tuners are provided, the embodiment may be modified such that the control as shown in  FIG. 5  is executed. According to the example shown in  FIG. 5 , the first task (context 1) of scanning starting from a frequency of 41 MHz, a second task (context 2) of scanning starting from a frequency of 42 MHz, and a third task (context 3) of starting the scanning from the frequency of 43 MHz are generated. Then, the contexts 1 to 3 progress the scanning while incrementing the frequency by 3 MHz each. 
         [0036]    In this case, a difference in progress between the each context cannot be controlled. However, reduction of the required time can be expected sufficiently because the three scanning operations are executed simultaneously. 
         [0037]    If a multithread type task which enables a plurality of processing units to be executed internally in parallel can be generated, the control for reducing the required time for the scanning function can be realized by allocating unprocessed frequencies to each TV broadcasting tuner dynamically as shown in  FIG. 6 . 
         [0038]    Further, it is effective enough to divide the range of 41 MHz to 870 MHz equally by the number of TV broadcasting tuners and generate a task for each and executes the tasks in parallel. 
         [0039]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.