JP2007089038A - Receiver and tuning method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of executing channel scan processing speedily with the television broadcasting of a plurality of channels having different bandwidths as object to be received, and to provide a method of tuning the receiver. <P>SOLUTION: A main control section 14 executes tuning processing in a TV signal that uses TV channel scan information, and predicts the bandwidth to be demodulated from the TV channel scan information of the TV signal whose channel has been scanned. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a receiving apparatus for receiving and demodulating a television broadcast having an arbitrary bandwidth for a television broadcast of a plurality of channels having different bandwidths, and a tuning method for the receiving apparatus.

Conventionally, as a channel search technology for TV (television) broadcasting, digital TV signals / analog TV signals are detected, and when an analog TV signal is detected, the mode detection process of the digital TV signal is skipped to speed up the channel search. There is technology to do. There is also a technology for presetting a television receiver with a frequency band such as VHF and UHF and a television standard such as NTSC, PAL and SECM for each country and region information.
JP 2001-230689 A JP 7-212665 A

  The digital TV reception method requires a longer time to capture the TV signal than the conventional analog TV method. In the DVB-T system, which is a standard for European digital TV reception systems, there are three types of bandwidth options: 8 MHz, 7 MHz, and 6 MHz in descending order of bandwidth. In order to receive a DVB-T TV signal and determine which of these three bandwidths the received TV signal is, the automatic gain control (AGC) or carrier signal is used in each of the above bands. It is necessary to redo pull-in and symbol rate pull-in. In particular, in a tuning process that scans all the channels to be received, if the number of channels to be scanned is large, the SAW of the front end tuner follows each bandwidth (6 MHz, 7 MHz, 8 MHz) for each channel. (Surface Acoustic Wave) Since a process of attempting demodulation by switching the bandwidth of a filter, a digital TV demodulator, or the like in a predetermined order, this process requires a large amount of time.

  The present invention has been made in view of the above circumstances, and performs a channel scanning process (channel scanning process) at high speed in a tuning process for receiving television broadcasts of a plurality of channels having different bandwidths. It is an object of the present invention to provide a receiving apparatus and a tuning method for the receiving apparatus.

  The present invention provides a receiving apparatus that receives and demodulates a television broadcast of a plurality of channels having different bandwidths and receives and demodulates a television broadcast of an arbitrary bandwidth. For each of the scanned center frequencies, it is provided with processing means for creating channel scan information including the presence / absence of a received signal and a bandwidth and storing the created channel scan information so that the created channel scan information can be updated and deleted. Features. Further, prior to the start of demodulation of the received television broadcast, the processing means refers to the channel scanning information, selects a first candidate from a plurality of bandwidth candidates used for demodulation, and sets the bandwidth of the candidate. And means for starting demodulation of the received television broadcast.

  Further, the present invention provides a receiving apparatus for receiving and demodulating a television broadcast of an arbitrary bandwidth for receiving a television broadcast of a plurality of channels having different bandwidths. It is characterized by comprising processing means for executing channel scanning for determining each channel by using the bandwidth of the television broadcast successfully demodulated with the highest priority.

  The present invention also provides a receiving apparatus tuning method for receiving and demodulating a television broadcast of an arbitrary bandwidth for a television broadcast of a plurality of channels having different bandwidths. When determining the bandwidth for each channel, the bandwidth of the television broadcast that has been successfully demodulated is used with the highest priority, and the bandwidth of the television broadcast of another channel to be received next is determined. And

  In the tuning process for receiving television broadcasts of a plurality of channels having different bandwidths, the channel scanning process can be executed at high speed.

  The bandwidth of the DVB-T described above varies depending on the country or region. However, if the bandwidth of the scanned channel (bandwidth of the channel successfully demodulated) can be known during channel scanning, the subsequent channel to be scanned subsequently. Can be predicted with a relatively high probability. In the embodiment of the present invention, a channel search is performed using this predicted bandwidth. A channel scan information table is created as a component for performing channel search using the predicted bandwidth, and channel search is performed using this channel scan information.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of the receiving apparatus according to the first embodiment of the present invention. The receiver according to the first embodiment of the present invention shown in FIG. 1 is, for example, a TV receiver, a CATV set top box (STB), or a UCDR (Unidirectional Cable Digital Receiver) standardized in North America. It is applicable to. The configuration example shown in FIG. 1 has an external interface for connecting the receiving apparatus according to the embodiment of the present invention to an external apparatus such as a TV receiver (TV monitor) or a video apparatus, and through this external interface, A user interface mechanism in which a receiving device receives an instruction of channel scanning (channel search) corresponding to, for example, a country or region from an external device, and inputs an instruction of channel scanning corresponding to the country or region to the receiving device. It is also possible to provide.

  1 includes an antenna 11, a front-end tuner unit 12, a digital TV receiving unit 13, a main control unit 14, a memory 15, a power supply control unit 16, an external interface (IF) 17 unit, and the like. Is done.

  The front end tuner unit 12 receives a TV signal (TV broadcast wave) incident on the antenna 11 based on a channel frequency and a bandwidth according to an instruction from the main control unit 14, and sends it to the digital TV receiving unit 13. The front end tuner unit 12 is provided with a SAW filter to be controlled that switches the bandwidth in accordance with the bandwidth of the received channel.

  The digital TV receiver 13 receives a TV signal from the front-end tuner 12, performs OFDM (Orthogononal Frequency Division Multiplexing) and VSB (Vrstigial Sideband) demodulation and error correction processing, and extracts an MPEG TS stream. A plurality of video, audio, and data streams that are multiplexed are separated, and the selected video, audio, and data are output.

  The main control unit 14 controls the entire apparatus in the receiving apparatus 10, and in this embodiment, the TV signal tuning process shown in FIG. 4 using the TV channel scanning information shown in FIG. 3 is executed.

  The memory unit 15 is configured using, for example, an EEPROM, a flash memory, a DRAM, or the like. In this embodiment, the TV channel scan created and managed by the main control unit 14 under the control of the main control unit 14. A table of information (see reference numeral 50 shown in FIG. 3) is stored.

  The power supply control unit 16 controls supply of operation power to each component constituting the receiving device 10. The external interface unit 17 is an interface (video output, audio output, RCA output, S-Video output, IEEE 1394, Ethernet (connection) for connecting the receiving apparatus 10 to an external apparatus 20 such as a TV receiver (TV monitor) or a video apparatus. (Registered trademark), IEEE802.11, etc.).

  FIG. 2 shows the configuration of the receiving apparatus according to the second embodiment of the present invention. The receiving apparatus in the second embodiment of the present invention shown in FIG. 2 is realized by a part of a personal computer and a TV tuner board connected to the personal computer. In the second embodiment, an example in which the processing function for executing the tuning process of the TV signal shown in FIG. 4 with reference to the TV channel scanning information shown in FIG. 3 is realized on the personal computer side is shown. The function can also be realized by the control unit of the TV tuner board.

  2 is implemented by a TV tuner board 30, a TV reception application (TV-APP) 41 provided in the personal computer 40, and a TV tuner board driver (TVboard-DRV) 42.

  The TV tuner board 30 includes an antenna 31, a front end tuner unit 32, a digital TV demodulation unit 33, an MPEG demultiplexer unit 34, a control unit 35, a memory 36, a power supply control unit 37, an external interface unit 38, and the like. The In this embodiment, the MPEG demultiplexer unit 34, the control unit 35, and the external interface unit 38 are provided in the PCI controller 30A, respectively, and the TV tuner board 30 and the personal computer 40 are connected to the PCI bus as an example. It shows. In addition to the PCI bus connection, the TV tuner board 30 and the personal computer 40 may be interface-connected by USB, Ethernet, Wireless Lan or the like, and the MPEG demultiplexer unit 34 is provided in the personal computer 40. It is good.

  The front end tuner unit 32 receives the TV signal incident on the antenna 11 based on the channel frequency and bandwidth according to the instruction of the driver 42, and sends it to the digital TV demodulation unit 33. The front end tuner unit 32 is provided with a SAW filter to be controlled for switching the bandwidth.

  The digital TV demodulator 33 performs OFDM and VSB demodulation and error correction processing, and extracts an MPEG TS stream. The MPEG demultiplexer unit 34 separates a plurality of video, audio, and data streams multiplexed in the TS stream, and outputs selected video, audio, data, and the like. The control unit 35 controls each unit of the TV tuner board 30. Here, the front end tuner unit 32 and the digital TV demodulation unit 33 are controlled in accordance with the channel search instruction received from the driver 42. The power supply control unit 37 controls supply of operation power to the front end tuner unit 32 and the digital TV demodulation unit 33. The external interface unit 38 performs a PCI bus connection with the personal computer 40.

  The TV reception application 41 provided in the personal computer 40 has a channel scanning table for each country and region, and in the setup operation for TV reception, a channel scanning instruction specifying a country or region is performed. The TV signal tuning process shown in FIG. 4 using the TV channel scanning information shown in FIG. 3 is executed. The TV tuner board driver 42 controls the front end tuner unit 32 and the digital TV demodulation unit 33 via the control unit 35 in accordance with an instruction from the TV reception application 41. Specifically, the frequency is set in the front end tuner unit 32, the bandwidth is set in the front end tuner unit 32 and the digital TV demodulation unit 33, and when the demodulation is successful, the TV reception application 41 is notified of the fact. To do.

  An example of TV channel scanning information used for tuning processing in each of the above embodiments is shown in FIG. Here, an example of the result of channel scanning in an area where the bandwidth is 6 MHz is shown. The TV channel scanning information in this embodiment includes information indicating the frequency, the presence / absence of a signal, and the bandwidth. This TV channel scanning information is created each time the channel is scanned, and is stored in the channel scanning information table 50 each time. In the tuning process, the channel scanning process is executed with reference to the bandwidth stored in the channel scanning information table 50. For example, if a carrier signal with a frequency of 112 MHz detects a TV signal of a predetermined level or higher (with a signal), and the detected TV signal is successfully demodulated with a bandwidth of, for example, 6 MHz, then a TV signal is detected with a frequency of 118 MHz. Then, referring to the determined bandwidth (6 MHz) in the TV signal having a frequency of 112 MHz, this bandwidth of 6 MHz is the highest priority among a plurality of bandwidth candidates (8 MHz / 7 MHz / 6 MHz) used for demodulation. This is selected as a candidate (first candidate), and the 118 MHz TV signal is demodulated using the first candidate (bandwidth 6 MHz). As described above, the TV channel scanning information is referred to prior to the start of the demodulation of the TV signal, and the demodulation bandwidth is predicted from the TV channel scanning information of the channel-scanned TV signal, thereby succeeding in the demodulation with the first bandwidth. Can increase the probability of the channel scanning, and the processing speed of channel scanning can be increased. Thereby, the time required for the tuning process can be shortened.

  The processing procedure of the tuning process in each of the above embodiments is shown in FIG. The tuning process shown in FIG. 4 is executed by the main control unit 14 in the first embodiment, and is executed by the TV reception application 41 in the second embodiment.

  In this tuning process, according to the channel scanning instruction specifying the country or region, the frequency is set in the front-end tuner unit (12/32), the bandwidth for starting demodulation is selected, and the selected bandwidth is set to the front-end tuner. After setting the SAW filter and demodulator (13/33) of the unit (12/32), demodulation is started (steps S11 to S14). At this time, in the first channel scan, for example, the frequency of the lowest channel to be received is set in the front-end tuner section (12/32), and the channel scan information table 50 has not been created yet. After setting the bandwidth according to the rank in the SAW filter and the demodulator (13/33), the demodulation is started.

  After a set time (sleep 100 msec) spent for demodulation processing (step S15), the presence / absence of a TV signal is determined (step S16), and when it is determined that there is a signal, the success / failure of demodulation is determined (step S17).

  Here, when the demodulation is successful, the content (frequency, signal presence, bandwidth) of the corresponding channel scan is stored in the channel scan information table 50 as TV channel scan information, and then the channel scan is performed with the next frequency setting. (Steps S11 to S18). When it is determined in the TV signal presence / absence determination (step S16) that there is no signal, the content (frequency, no signal) of the corresponding channel scan is stored in the channel scan information table 50 as TV channel scan information, and then Channel scanning is executed by setting the frequency (steps S11 to S18). Further, when demodulation fails with the first (first candidate) bandwidth, demodulation is started again with the second candidate bandwidth (steps S18, S12 to S17). Demodulation is attempted in all bandwidths (6 MHz / 7 MHz / 8 MHz), and when the demodulation fails, the channel scanning is terminated and channel scanning is performed with the next frequency setting (steps S11 to S18).

  In the channel scanning after the TV channel scanning information successfully demodulated is stored in the channel scanning information table 50, the TV channel scanning information stored in the channel scanning information table 50 is referred to first (first candidate). Is selected (step S12).

  As described above, the TV channel scanning information is referred to prior to the start of the demodulation of the TV signal, and the demodulation bandwidth is predicted from the TV channel scanning information of the channel-scanned TV signal, thereby succeeding in the demodulation with the first bandwidth. Can increase the probability of the channel scanning, and the processing speed of channel scanning can be increased.

  In the DVB-T specification, which is the standard of the European digital TV broadcasting system described above, the broadcaster can select the TV signal bandwidth from 6 MHz, 7 MHz, and 8 MHz. However, in general, when the bandwidth of the TV signal is different, it is necessary to simultaneously switch the setting of the bandwidth of the SAW filter provided in the front end tuner (12/32) and the bandwidth of the digital TV demodulator (13/33).

  At this time, when the above-described bandwidth setting by prediction is not applied, the bandwidth is always changed in the order of 6 MHz, 7 MHz, and 8 MHz to check whether or not the demodulation of the TV signal is successful. If the width is 8 MHz, the total time of two sleeps, 200 msec, is wasted time.

  In general, the bandwidth of a TV signal is often constant for each broadcaster and country. For example, a broadcaster or country using 8 MHz often operates with the same bandwidth (8 MHz) for each channel.

  Therefore, by applying the bandwidth setting based on the prediction of the above-described embodiment, for example, the TV signal is successfully demodulated at a certain channel scanning frequency. If the bandwidth at this time is 8 MHz, the next channel scanning is performed. By first selecting a bandwidth of 8 MHz and starting demodulation, it is possible to increase the probability of success when demodulating the first bandwidth setting after setting the front-end frequency, depending on the setting of each bandwidth of 6 MHz and 7 MHz. By omitting the demodulation process, it is possible to save the unnecessary 200 msec sleep time required for the demodulation process.

  In the above-described embodiment, the first candidate bandwidth is selected based on TV channel scanning information of a nearby frequency. For example, the bandwidth may be selected from the bandwidth options shown in FIG. For example, in Germany, for the VHF band, select the order of 7 MHz → 8 MHz, for the UHF band, select the order of 8 MHz → 7 MHz, and for channel scanning in the UK, select only 8 MHz. Each tuning process can be further speeded up by selecting the most appropriate bandwidth setting order according to the above.

The block diagram which shows the structure of the receiver which concerns on 1st Embodiment of this invention. The block diagram which shows the structure of the receiver which concerns on 2nd Embodiment of this invention. The figure which shows the structural example of the channel scanning information table used for each said embodiment. The flowchart which shows the procedure of the tuning process applied to each said embodiment. The figure which shows an example of the table which provides the choice of the bandwidth applicable to each said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Receiver, 11 ... Antenna, 12 ... Front end tuner part, 13 ... Digital TV receiver part, 14 ... Main control part, 15 ... Memory, 16 ... Power supply control part, 17 ... External interface (IF), 30 ... TV Tuner board, 30A ... PCI controller, 31 ... antenna, 32 ... front end tuner unit, 33 ... digital TV demodulation unit, 34 ... MPEG demultiplexer unit, 35 ... control unit, 36 ... memory, 37 ... power control unit, 38 ... External interface unit, 40... Personal computer, 41... TV reception application (TV-APP), 42... TV tuner board driver (TVboard-DRV), 50.

Claims (7)

In a receiving apparatus for receiving and demodulating a television broadcast of an arbitrary bandwidth, receiving a television broadcast of a plurality of channels having different bandwidths,
When scanning all channels to be received, channel scanning information including the presence / absence of received signal and bandwidth is created for each scanned center frequency, and the created channel scanning information can be updated and deleted. A receiving device comprising processing means for storing.   Prior to starting demodulation of the received television broadcast, the processing means refers to the channel scanning information, selects a first candidate from a plurality of bandwidth candidates used for demodulation, and uses the bandwidth of the candidate The receiving apparatus according to claim 1, further comprising means for starting demodulation of the received television broadcast.   The receiving apparatus according to claim 2, wherein the processing unit determines the first candidate based on channel scanning information of adjacent or nearby frequencies.   4. The receiving apparatus according to claim 3, wherein the processing means includes means for determining a bandwidth candidate to be used for the scanning based on designation of a country or a region.   4. The receiving apparatus according to claim 3, wherein the processing means includes means for determining a bandwidth candidate used for the scanning and a bandwidth candidate rank used for the scanning based on designation of a country or a region. In a receiving apparatus for receiving and demodulating a television broadcast of an arbitrary bandwidth, receiving a television broadcast of a plurality of channels having different bandwidths,
A receiving apparatus comprising: processing means for executing channel scanning for determining the bandwidth of a received television broadcast for each channel by using the bandwidth of the television broadcast that has been successfully demodulated with the highest priority. In a tuning method of a receiving apparatus for receiving and demodulating a television broadcast of an arbitrary bandwidth, targeting a television broadcast of a plurality of channels having different bandwidths,
When determining the bandwidth of the received television broadcast for each channel, the bandwidth of the television broadcast that has been successfully demodulated is used with the highest priority, and the bandwidth of the next received television broadcast is determined. A tuning method for a receiving apparatus, characterized by performing processing.

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