Abstract:
To provide a broadcasting receiving apparatus including a receiving section configured to receive a digital broadcasting signal, a processing section configured to recover and reproduce a program from the digital broadcasting signal received by the receiving section, a display section configured to display the program recovered by the processing section, a PCR processing section configured to extract a PCR value from a TS signal, a phase comparing section so that the PCR value extracted from the PCR processing section is compared to a counter value of 42 bits, a PWM generating section that is configured so that the phase difference from the phase comparing section to generate a PWM value, and a memory configured to store the PWM value generated by the PWM generating section therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-279923, filed Sep. 27, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a broadcasting receiving apparatus of receiving a TV broadcasting or the like and a method of producing a reference signal using the same.  
         [0004]     2. Description of the Related Art  
         [0005]     As is well known, in recent years, digitalization of the TV broadcasting has been promoted. For example, in Japan, not only a satellite digital broadcasting such as a BS (broadcasting satellite) digital broadcasting and a 110-degree CS (communication satellite) digital broadcasting but also a digital terrestrial broadcasting has been started.  
         [0006]     Then, according to a digital broadcasting receiving apparatus of receiving such a digital television broadcasting, for example, by connecting a high-capacity digital recording device such as an HDD (hard disk drive) thereto, it is possible to record the received program digitally and reproduce the recorded program.  
         [0007]     Further, in the present day, with respect to one digital broadcasting receiving apparatus, by connecting a plurality of digital recording devices and making it into a network, it is possible for the digital broadcasting receiving apparatus to designate an arbitrary digital recording device so that the designated digital recording device can record the program or designate an arbitrary digital recording device so that the designated digital recording device can reproduce the program.  
         [0008]     In the meantime, according to such a digital broadcasting receiving apparatus making it possible to network-connect a plurality of digital recording devices, a user can easily manage the program recorded in each digital recording device and it is important to retrieve a desired recorded program rapidly and reproduce it.  
         [0009]     According to Jpn. Pat. Appln. KOKAI Publication No. 10-136275, there is disclosed a configuration that a television receiving apparatus provided with an Internet receiving function can recognize a connection condition by a phone line even when a speaker outputs a voice of a television signal.  
         [0010]     Such a digital broadcasting receiving apparatus processes an analog signal such as an analog broadcasting because the current analog broadcasting is to be continued till 2011. In order for the digital broadcasting receiving apparatus to make the analog broadcasting viewable, at first, encoding an analog signal into an MPEG (moving picture experts group) 2 and decoding the encoded signal, and then, the analog signal becomes viewable by carrying out the imaging processing.  
         [0011]     In order to encode such an analog signal into an MPEG 2 once, for example, in the case of MPEG-TS (transport stream) recording, it is necessary to satisfy a standard of MPEG 27 MHz±30 ppm.  
         [0012]     In the case of the digital broadcasting, the digital signal is encoded in accordance with this standard at the broadcast station, and upon decoding, the signal is tuned from a PCR (program clock reference) value to approximately 27.0 MHz by VCXO (voltage controlled crystal oscillator) control.  
         [0013]     In the case of the analog broadcasting, since such a PCR value is not set, in order to tune to 27 MHz in the VCXO circuit, an offset value of PWM (pulse width modulation) should be tune to 27.0 MHz while measuring the value.  
         [0014]     However, the VCXO circuit has a problem such that an offset value of PWM is different for each apparatus since the oscillation frequency of a crystal oscillator and a load capacity are varied for each apparatus and it is not possible to accurately tune the signal to 27 MHz±30 ppm as a standard value of MPEG.  
       BRIEF SUMMARY OF THE INVENTION  
       [0015]     According to one aspect of the present invention, there is provided a broadcasting receiving apparatus comprising: a receiving section configured to receive a digital broadcasting signal; a processing section configured to recover and reproduce a program from the digital broadcasting signal received by the receiving section; a display section configured to display the program recovered by the processing section; a PCR processing section configured to extract a PCR value from a TS signal; a phase comparing section that is configured so that the PCR value extracted from the PCR processing section is inputted therein to be compared to a counter value of 42 bits; a PWM generating section that is configured so that the phase difference is inputted from the phase comparing section to generate a PWM value; and a memory configured to store the PWM value generated by the PWM generating section therein. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0016]      FIG. 1  is a block diagram explaining a main signal processing system of a digital television broadcasting receiving apparatus according to an embodiment of the present invention;  
         [0017]      FIG. 2  is a block diagram explaining a signal processing section and a VCXO oscillation circuit of the digital television broadcasting receiving apparatus according to the embodiment;  
         [0018]      FIG. 3  is a flow chart illustrating an adjustment routine of an oscillation frequency of the VCXO oscillation circuit according to the embodiment;  
         [0019]      FIG. 4  is a flow chart illustrating the operation of the digital television broadcasting receiving apparatus according to the embodiment upon receiving analog broadcasting;  
         [0020]      FIG. 5  is a flow chart illustrating the adjustment routine of the oscillation frequency of the VCXO oscillation circuit according to the embodiment; and  
         [0021]      FIG. 6  is a flow chart illustrating the adjustment routine of the oscillation frequency of the VCXO oscillation circuit according to the embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]     With reference to the drawings, an embodiment of the present invention will be described below.  FIG. 1  shows a main signal processing system of a digital television broadcasting receiving apparatus  11  according to an embodiment of the present invention. In other words, a satellite digital television broadcast signal received by an antenna  43  for receiving BS/CS digital broadcasting is supplied to a tuner  45  for a satellite digital broadcasting via an input terminal  44  so that a broadcast signal of a desired channel is selected.  
         [0023]     Then, the broadcast signal selected by the tuner  45  is supplied to a PSK (phase shift keying) demodulator  46  to be demodulated to a digital image signal and a digital voice signal and then, this signal is outputted to a signal processing section  47 .  
         [0024]     In addition, a digital terrestrial television broadcasting signal received by an antenna  48  for receiving a digital terrestrial broadcasting is supplied to a tuner  50  for a digital terrestrial broadcasting via an input terminal  49  so that a broadcast signal of a desired channel is selected.  
         [0025]     Then, the broadcast signal selected by the tuner  50  is supplied to an OFDM (orthogonal frequency division multiplexing) demodulator  51  to be demodulated to a digital image signal and a digital voice signal and then, this signal is outputted to the above-mentioned signal processing section  47 .  
         [0026]     Here, the signal processing section  47  selectively applies predetermined digital signal processing to the digital image signal and the digital voice signal supplied from the PSK demodulator  46  and the digital image signal and the digital voice signal supplied from the OFDM demodulator  51  and outputs these signals to a graphic processing section  54  and a voice processing section  55 .  
         [0027]     Among these sections, the graphic processing section  54  has a function to superimpose an OSD signal generated by an OSD (on screen display) signal generating section  57  on the digital image signal to be supplied from the signal processing section  47  and output the OSD signal. In addition, the graphic processing section  54  can selectively output the output image signal of the signal processing section  47  and the OSD signal as the output of the OSD signal generating section  57 , and can output the combination of the both outputs so that each output configures a half of a screen.  
         [0028]     Then, the digital image signal outputted form the graphic processing section  54  is supplied to an image processing section  58 . The image processing section  58  converts the inputted digital image signal into the analog image signal of a format capable of being displayed on an image display  14 , and it outputs the signal to the image display  14  to be displayed and be guided to the outside via an output terminal  59 .  
         [0029]     In addition, the voice processing section  55  converts the digital voice signal inputted from the signal processing section  47  into an analog voice signal of a format capable of being reproduced by the speaker  15 , and it outputs the signal to the speaker  15  so that the voice of the signal is reproduced to be guided to the outside via an output terminal  60 .  
         [0030]     Here, in the digital television broadcasting receiving apparatus  11 , its all operations including various receiving operations are totally controlled by a control section  61 . The control section  61  incorporates a CPU (central processing unit) or the like, receives the operation information from an operation section  16  or the control section  61  receives the operation information transmitted from a remote controller  17  via a light receiving section  18  to control each section so that the content of the operation is reflected on each section.  
         [0031]     In this case, the control section  61  mainly uses a ROM (read only memory)  62  in which a control program to be executed by the CPU is stored, a RAM (random access memory)  63  providing an operation area to the CPU, and a non-volatile memory  64  in which various setting information and the control information or the like are stored.  
         [0032]     In the control section  61 , a first memory card  19  is connected to a wearable card holder  66  via a card I/F (interface)  65 . Thereby, the control section  61  can transmit the information to the first memory card  19  fitted to the card holder  66  via the card I/F  65 .  
         [0033]     In the control section  61 , a second memory card  20  is connected to a wearable card holder  68  via a card I/F  67 . Thereby, the control section  61  can transmit the information to the second memory card  20  fitted to the card holder  68  via the card I/F  67 .  
         [0034]     In addition, the control section  61  is connected to a first LAN (local area network) terminal  21  via a communication I/F  69 . Thereby, the control section  61  can transfer the information to an HDD associated with the LAN connected to the first LAN terminal  21  via the communication I/F  69 . In this case, the control section  61  has a DHCP (dynamic host configuration protocol) server function and controls the operations by allocating an IP (internet protocol) address to the HDD associated with the LAN that is connected to the first LAN terminal  21 .  
         [0035]     Further, the control section  61  is connected to a second LAN terminal  22  via a communication I/F  70 . Thereby, the control section  61  can transmit the information to each device connected to the second LAN terminal  22  (for example, a personal computer, a mobile terminal, and a cellular phone or the like) via a communication I/F  70 .  
         [0036]     The control section  61  is connected to a USB terminal  23  via a USB (universal serial bus) I/F  71 . Thereby, the control section  61  can transmit the information to each device connected to the USB terminal  23  (for example, a personal computer, a mobile terminal, and a cellular phone or the like) via the USB I/F  71 .  
         [0037]     Further, the control section  61  is connected to an i. Link terminal  24  via an i. Link I/F  72 . Thereby, the control section  61  can transmit the information to each device connected to the i. Link terminal  24  (for example, a personal computer, a mobile terminal, and a cellular phone or the like) via the i. Link I/F  72 .  
         [0038]      FIG. 2  shows the details of the above-mentioned signal processing section  47 . As shown in  FIG. 2 , a TS (transport stream) signal inputted from a demodulation section of a digital broadcasting wave is inputted in a TSP (transport stream demultiplexing processor) processing section  201  of the signal processing section  47 . In the broadcasting wave down converted by a tuner section, a signal of a desired frequency is selected and an I/Q signal is outputted. The I/Q signal outputted from the tuner section is demodulated and its error is corrected by a demodulation section and an MPEG transport stream (TS) is outputted.  
         [0039]     In addition, from the TS outputted from the demodulation section, the MPEG-TS separation (TSP) processing section  201  of the signal processing section  47  picks up PES (packetized elementary stream) as the image and voice data encoded from among the TS, the SI (service information) data for displaying the EPG (electronic program guide), and the PCR data as the common clock reference data for synchronizing decoding with display on a screen of each basic stream, and the MPEG-TS separation (TSP) processing section  201  transfers the image and voice data to an MPEG decoding section  206  and transfers the SI data to the RAM  63  as an operation memory to be processed by the CPU of the control section  61 .  
         [0040]     The PCR data is stored in a PCR value storage register  202  inside the TSP once, and then, the PCR data is transferred to a phase comparing section  204  in order to synchronize the PCR data with an oscillation circuit at the outside.  
         [0041]     A phase difference acquired by the phase comparing section  204  is transmitted to a PWM generating section  203  to calculate a pulse period (a period of LOW) of the PWM output and output a rectangular wave of the same period. The outputted rectangular wave is transmitted to an LPF  208  of a VCXO oscillation circuit  207  to be converted into a signal of a DC level. The converted signal of a DC level is transmitted to a VCXO circuit  209  to be used as a reference voltage of the circuit. In the VCXO circuit  209 , the oscillation frequency of a basic CLK is changed in accordance with the reference voltage. Here, there is no specific regulation, however, as a variable width of the frequency, a specified value of the MPEG 2 (±30 ppm)+a deviation of a crystal oscillator (±20 ppm)=±100 ppm is assumed.  
         [0042]     Subsequently, the CLK (54 MHz or 27 MHz) oscillated by the VCXO circuit  209  is inputted in a STC counter  205  to be converted into the data of 42 bits. The counter value of 42 bits is inputted in the phase comparing section  204  as described above and the phase thereof is compared to that of the PCR value of the digital broadcasting wave.  
         [0043]     The PCR value of 42 bits is only acquired when receiving the digital broadcasting, so that when receiving the analog broadcasting, the PWM circuit  203  outputs the data of an initial value. The initial value is converted into a DC value by the LPF  208  to be used as a reference voltage in the VCXO circuit  209 . In the VCXO circuit  209 , the oscillation frequency is deviated for each unit (a complete product that electronic parts are mounted on a substrate) to be manufactured due to a variation of the crystal oscillator and a variation of a capacity of capacitor used for the oscillation circuit or the like (normally, referred to as a free run condition).  
         [0044]     The broadcasting receiving apparatus according to the invention uses the basic CLK of the VCXO circuit upon the encode processing in the encoder processing of the MPEG 2, so that even in the free run condition, it is necessary to control the deviation of the oscillation frequency of the VCXO circuit  209  to ±30 ppm.  
         [0045]     According to the invention, for example, upon a test of a unit on a factory shipment, a digital broadcasting signal generated as the basic signal is inputted in the tuner section of the unit to generate a reference signal and the reference signal is stored in a memory area. The digital broadcasting signal in this case is MPEG-encoded and is modulated into a digital broadcasting wave (an OFDM signal) with the variation of the PCR value controlled not more than 2 ppm.  
         [0046]     Next, with reference to  FIG. 3 , an adjustment routine of an oscillation frequency of the present invention will be described below. As shown in  FIG. 3 , the adjustment of the oscillation frequency is started (S 11 ). Subsequently, on the factory shipment or the like, the digital broadcasting signal is inputted for each apparatus as the digital signal for reference. The inputted signal is inputted in the TSP processing section  201  of the signal processing section  47  via the tuner section (S 12 ).  
         [0047]     Subsequently, the PCR value is extracted from the received TS signal by the TSP processing section  201  of the signal processing section  27  (S 13 ). Then, as described above, the PCR value extracted by the TSP processing section  201  is inputted in the VCXO oscillation circuit  207  via the PCR value storage register  202 , the phase comparing section  204 , and the PWM generating section  203  to be VCXO-oscillated (S 14 ). In other words, the TSP processing section  201  reads the PCR value, and the VCXO oscillation circuit  207  generates an oscillation frequency (CLK) at a value near to the PCR value with respect to the value of which phase is compared to the PCR value and of which PWM is generated.  
         [0048]     Subsequently, the oscillation frequency (CLK) is inputted in the STC counter  205  to be compared to the PCR value. In this case, if there is an error, the PWM of which error is corrected is generated (S 15 ). The PWM value acquired in this time is stored in the non-volatile memory  64  that is connected to the signal processing section  47  (S 16 ). With respect to the PWM value to be stored in the non-volatile memory  64 , basically, rewriting is not assumed. Thus, the adjustment of the VCXO oscillation circuit  207 , which is carried out upon the test of the unit is terminated (S 17 ).  
         [0049]     Next, with reference to  FIG. 4 , the operation upon receiving the analog broadcasting of the present invention in the real TV set operation will be described below.  
         [0050]     Then, a system of the receiving apparatus is initialized (S 22 ). Upon initialization of the signal processing section  47 , the adjusted PWM value on the factory shipment as described in  FIG. 3  is read from the non-volatile memory  64  (S 23 ).  
         [0051]     Subsequently, the read PWM value is saved as the initial value of the PWM generating section  203  (S 24 ) to terminate the processing (S 25 ). The PWM generating section  203  outputs a signal in accordance with the PWM value and the VCXO circuit  209  can be always operated in accordance with the center frequency.  
         [0052]     If the apparatus can receive the digital broadcasting, the PCR value is always updated in the TSP to be operated, so that it is not necessary to read the PWM stored in the non-volatile memory  64 .  
         [0053]     As shown in the flow charts in  FIGS. 5 and 6 , when the electronic wave cannot be received due to a reception difficulty or the like in the digital broadcasting, and when a signal line is pulled out in the middle (NO in S 32  of  FIG. 5 ), or when the input detection of the TS or update of the PCR value is not carried out for a certain period of time in the TSP (NO in S 42  of  FIG. 6 ), reading the PWM value stored in the non-volatile memory  64  (S 33  in  FIG. 5  and S 43  in  FIG. 6 ), the initial value is saved in the PWM generating section  203  (S 34  in  FIG. 5  and S 44  in  FIG. 6 ).  
         [0054]     Thus, when the digital signal cannot be received, namely, when the analog broadcasting should be received, it is possible to always operate the PWM generating section  203  due to the data of reading the PWM value that is set in the unit step of a factory so as to acquire a center frequency in the VCXO circuit  209 .  
         [0055]     According to the invention, recording the PWM value when the VCXO control is carried out from the PCR value in the memory area on the factory shipment, upon encoding the analog broadcasting in the MPEG 2 in fact, reading the corrected value of the memory area, the VCXO circuit is controlled. Thus, it is possible to tune the analog signal to a center value of 27.0 MHz that is a standard of the MPEG 2 and the present broadcasting receiving apparatus can receive the analog broadcasting in a good condition.  
         [0056]     In the meantime, the present invention is not limited to the above-described embodiment as it is and in execution phase, structural elements can be variously modified within a range not departed from a spirit of the present invention. In addition, by appropriately combining a plurality of structural elements disclosed in the above-described embodiment, various kinds of inventions can be made. For example, some structural elements may be deleted from all structural elements indicated in the embodiment. Further, the structural elements in a different embodiment may be appropriately combined.