Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/21—Server components or server architectures
  • H04N21/214—Specialised server platform, e.g. server located in an airplane, hotel, hospital
  • H04N21/2146—Specialised server platform, e.g. server located in an airplane, hotel, hospital located in mass transportation means, e.g. aircraft, train or bus
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/41—Structure of client; Structure of client peripherals
  • H04N21/426—Internal components of the client ; Characteristics thereof
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
  • H04N21/434—Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream
  • H04N21/4345—Extraction or processing of SI, e.g. extracting service information from an MPEG stream
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
  • H04N21/438—Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network
  • H04N21/4383—Accessing a communication channel
  • H04N21/4384—Accessing a communication channel involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/45—Management operations performed by the client for facilitating the reception of or the interaction with the content or administrating data related to the end-user or to the client device itself, e.g. learning user preferences for recommending movies, resolving scheduling conflicts
  • H04N21/4508—Management of client data or end-user data
  • H04N21/4524—Management of client data or end-user data involving the geographical location of the client
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
  • H04N5/50—Tuning indicators; Automatic tuning control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/015—High-definition television systems

Definitions

• the present invention relates to a broadcast receiver, for example, a digital broadcast receiver.
• the present invention relates to a digital broadcast document receiver having a broadcast channel detecting device for searching and detecting a channel that actually provides a broadcast, that is, a broadcast channel, from a plurality of fixed channels.
• the broadcast channel detection device detects the above-mentioned broadcast channels while sequentially searching for a large number of channels, so-called “channel search”, or a plurality of broadcast station channels that can be received for each region. This is an indispensable device for performing “auto-preset”, which stores in advance the desired broadcast station by a simple selection operation later.
• digital broadcast receivers such as terrestrial digital broadcast receivers and satellite digital broadcast transceivers that need to quickly capture only broadcast channels from a very large number of specified channels, such as 50 channels
• the broadcast channel detection device plays an important role.
• Tuner tuning section b) The mode / guard search section
• the tuner tuning unit in a) is a circuit portion for individually receiving a plurality of prescribed channels one by one, and is a front end including a so-called high-frequency amplifier, a frequency converter, a filter, and the like.
• the mode Z guard search unit of the above b) receives the frame signal received by the OFDM (Orthogonal Frequency Division Multiplexing) reception method suitable for constituting a digital broadcast receiver, and (Ii) search for the mode in which the frame signal was received in any of the various transmission modes such as mode 1, mode 2, and mode 3, and (ii)
• the "guard” is a circuit portion for searching for the appearance phase of a so-called guard interpal to prevent interference between a so-called effective symbol and an adjacent effective symbol.
• the OFDM frame synchronization unit of c) is one important circuit part of the OFDM demodulation unit in the OFDM receiver, and if the frame synchronization is established for the reception signal on the selected channel. However, it is confirmed that this received signal is a received signal by any broadcast wave. After this confirmation, OFDM demodulation is performed by an OFDM demodulation circuit via an FFT (Fast Fourier Transformer) that converts the received signal from a signal on the time axis to a signal on the frequency axis. Further, decoding processing by an MPEG (Moving Picture Experts Group) decoder and video Z audio reproduction processing are performed to obtain video (TV) information. And provide audio information to the user.
• FFT Fast Fourier Transformer
• the broadcast channel detecting device of the digital broadcast receiver to which the present invention is applied is used for, for example, the above-mentioned “channel search”, it is important to find a broadcast channel at high speed. If this search were not done quickly, it would be annoying to users.
• Known documents related to the present invention include, for example, the following [Patent Document 1] to [Patent Document 4].
• Patent Document 1 is to search for another station with one tuner while receiving one station with one tuner.
• Patent Document 2 divides the scan band into two, Patent Document 3 discloses that auto-preset is performed separately by two tuners. Patent Document 3 compares the audio outputs of the two tuners to prevent a program having the same content from being duplicated and stored in an auto memory. ] Is to perform auto preset by alternately searching two tuners.
• Patent Document 1 Japanese Patent Application Laid-Open No. 2000-320202
• Patent Document 2 Japanese Patent Application Laid-Open No. Hei 5-2-188081
• Patent Document 3 Japanese Patent Application Laid-Open No. Hei 7-2 3 1 2 4 5
• Patent Document 4 Japanese Patent Application Laid-Open No. 10-1503446 Disclosure of the Invention
• the digital broadcast receiver's broadcast channel detection device In such a case, it is necessary to acquire broadcast channels at high speed from a large number of channels. Therefore, when the "channel search time" required for each of the components a), b) and c) described above is examined, the following is obtained. However, it is shown by the estimated time.
• Tuner tuning time is “50 ms”. However, this is the case when the tuner is synchronized with PLL.
• Mode guard The search time is “100 ms”. However, it is the Z guard search time for all modes in the prescribed 12 ways.
• 1 to 4 of the frame signal length in the OFDM system is the guard interpal.
• the frame signal length under mode 3 is the longest, under mode 2 it is 12 length, and under mode 1 it is 14 length under mode 3.
• the establishment time of OFDM frame synchronization is “205 to 411 ms”. This is a period of one to two frames.
• the reason for detecting two frames, that is, two frame synchronizations, is as follows.
• the case where one frame is sufficient is the case where the beginning of the frame has just arrived after the input of the received signal. However, if the beginning of a frame has already passed just before the start of input of a received signal, the frame synchronization detection operation must be started after the beginning of the next frame has come. It is in this case that the above two frames are required.
• “205 to 411 ms” in c) above is the “Mode 3” described above. This is the numerical value obtained for the longest frame having a quarter-length guard pal in the case of. That is, the above 205 ms is a numerical value obtained as 204 symbols XI. 25 ms 225 ms.
• the total search time of the broadcast channel is “355-561 ms”. Therefore, the average time is “458 ms”. This is about 0.5 seconds. For example, if there are 50 channels, the time required to complete the entire channel search is at least 25 seconds', which is extremely long. This is the problem.
• an object of the present invention is to provide a digital broadcast receiver having a broadcast channel detecting device capable of performing a faster channel search than in the past, in view of the above problems.
• FIG. 1 is a basic configuration diagram of a broadcast channel detecting device provided in a digital broadcast receiver according to the present invention.
• reference numeral 10 at the left end indicates a general digital broadcast receiver, and its schematic configuration is composed of an antenna 11 for receiving a radio channel, and a desired one of a number of received channels ( (Broadcast)), an OFDM demodulation unit 13 for OFDM demodulating the received signal of the selected channel, and demodulation. It comprises a video / audio reproduction processing section 14 for reproducing broadcast content from the adjusted received signal, and a display DISP and a speaker SP for allowing the user to view the reproduced video information and audio information.
• a video / audio reproduction processing section 14 for reproducing broadcast content from the adjusted received signal
• DISP and a speaker SP for allowing the user to view the reproduced video information and audio information.
• the present invention relates to such a digital broadcast receiver 10, and particularly to a broadcast channel detecting device 20 provided therein.
• the broadcast channel detecting device 20 basically includes a periodic signal detecting means 21, a periodic distribution determining means 22, and a determining means 23.
• the result of the judgment by the judging means 23 is stored in the memory 24, and is fed back to the channel selecting means 12 for the next channel selection.
• the functions of these three means 21, 22, and 23 are as follows.
• the periodic signal detecting means 21 receives the selected received signal as an input. , Which detects periodic signals that appear at almost constant timing
• the next stage periodic distribution determining means 22 determines the distribution state of the periodic signal group detected by the periodic signal detecting means 21 a plurality of times.
• the determining means 23 determines that there is “digital broadcasting”, and does not fall within the predetermined width. If there is no digital broadcast, it is judged as "no digital broadcast”. (0 0 2 3)
• the present invention pays attention to this point, and estimates the existence of the broadcast channel equivalently with high accuracy without executing “frame synchronization”. Specifically, attention is paid to the distribution of the above-described group of periodic signals (described in detail below), and the estimation is made from this distribution.
• the invention's effect is paid to the distribution of the above-described group of periodic signals (described in detail below), and the estimation is made from this distribution.
• the conventional process of "confirmation of completion of frame synchronization", which requires the longest time, is eliminated, so that a higher-speed broadcast channel search is realized than before.
• FIG. 1 is a basic configuration diagram of a broadcast channel detecting device provided in a digital broadcast receiver according to the present invention.
• FIG. 2 is a block diagram showing the basic configuration of FIG. 1 in a somewhat concrete form.
• FIG. 3 is a timing chart for explaining the autocorrelation peak.
• FIG. 4 is a diagram illustrating a configuration example of the autocorrelator.
• Fig. 5 is a diagram showing the distribution of the autocorrelation peak when there is digital television broadcasting.
• Figure 6 is a diagram showing the distribution of the autocorrelation peak when there is no digital television broadcast.
• FIG. 7 is a diagram illustrating a first configuration example of the determination means 23.
• FIG. 8 is a diagram illustrating a second configuration example of the determination means 23.
• FIG. 9 is a diagram illustrating a configuration example of the reception environment estimating means. BEST MODE FOR CARRYING OUT THE INVENTION
• FIG. 2 is a block diagram showing the basic configuration of FIG. 1 in a somewhat concrete form, and shows a broadcast channel detecting device 20 provided in the digital broadcast receiver 10.
• the channel selecting means 12 in FIG. 1 is shown as an RFIF section 15 in FIG.
• a level detector 16 for so-called AGC control is also shown.
• an A / D converter (A / D) and a quadrature demodulator which are the most basic components of a digital broadcast receiver, are also included. And illustrated. The output from this quadrature demodulator is a so-called I / Q signal.
• FIG. 2 shows a digital broadcasting receiver having a one-branch configuration, for example, if a carrier branch diversity configuration having three branches is used, an OFDM demodulator 1 is provided via a di-parity circuit DIV shown on the right side of FIG. 9 is input with the received signal from each FFT 18 of the three branches.
• the digital broadcast receiver 10 has a carrier diversity configuration having a plurality of branches
• the above-mentioned periodic signal detecting means 21 and the periodic distribution determining means 22 are determined for each branch. Means 2 and 3 will be provided. If there are N branches, the channel search can be finished in 1 Z N times.
• the device 20 is originally a self-contained component of the digital broadcast receiver 10 '. It can be composed of one of the correlator 31 and the synchronous loop filter 32, the CPU 33, and the memory 24.
• this synchronous loop filter 32 is usually It has both a frequency-locked loop filter (LF) 32F and a time-locked loop filter (LF) 32T, but only one of these two loop filters (32F, 32T). The purpose of the detection is achieved.
• LF frequency-locked loop filter
• LF time-locked loop filter
• the periodic signal detection means 21 includes the autocorrelator 31 constituting the digital broadcast receiver 10.
• the autocorrelator 31 outputs the autocorrelator 31 and exceeds the predetermined threshold.
• the peak (P described later) is detected as a periodic signal.
• the periodic signal detection means 21 A filter output that is output from one of the synchronous loop filter 32 F and the time synchronous loop filter 32 T in conjunction with the autocorrelation peak (P described later) and exceeds a predetermined threshold value is detected as a periodic signal. Can also be issued.
• the period distribution finding means 22 and the judging means 23 in FIG. 1 have a software configuration using CPU 33 in the case of FIG.
• these means-22 and 23 may be hardware-construction-and b-. That way, the burden on CPU 34 is reduced.
• the autocorrelation peak is obtained by the autocorrelator 31 described above, and is usually referred to as the “mode / guard 'search section” described above. To fulfill the function of. This is shown graphically.
• Figure 3 is a timing chart for explaining the autocorrelation peak.
• one frame of an OFDM frame signal is composed of an “effective symbol” and a “guard interpal” G.
• the guardinterpal G is a copy of the end E of the effective symbol part.
• the above-mentioned mode Z guard search section first assumes that the frame signal was received in mode 1 and uses the signal delayed by the frame length of mode 1 (see (b) in Fig. 3). Take autocorrelation. However, in this case, no autocorrelation peak can be obtained. Then, assuming that the frame signal was received in mode 2, autocorrelation is again performed using a signal delayed by the frame length of mode 2 (see (c) in Fig. 3). But also in this case, no auto-correlation peak is obtained.
• FIG. 4 is a diagram illustrating a configuration example of the autocorrelator.
• the autocorrelator 31 mainly includes a correlation operation section 35 and a delay section 36.
• the frame signal directly input to the correlation operation unit 35 corresponds to (a) in FIG. 3, and the signal input through the delay unit 36 is (b), (c) and (D). That is, under the control of the delay amount setting unit 37, the delay unit 36 sequentially gives three delay times corresponding to Mode 1, Mode 2 and Mode 3 to the above-mentioned frame signal, and Input to the calculation unit 35. As a result, the autocorrelation peak P is finally obtained.
• the present inventor observed the behavior of the autocorrelation peak P, and found a certain fact.
• This fact means that the autocorrelation peak P, in particular, an autocorrelation peak exceeding a predetermined threshold: P was observed in a time series and the statistics were collected.
• a certain feature was found in the distribution of the group of signals. This feature is that the distribution width of the above group falls within the predetermined width when the channels are sequentially selected, and especially when a channel providing digital television broadcasting is selected. This will be described with reference to the drawings.
• Figure 5 shows the distribution of autocorrelation peaks when there is digital television broadcasting.
• Figure 6 shows the distribution of the autocorrelation peak when there is no digital television broadcasting.
• the autocorrelation peak P appears quite randomly, its envelope looks like the curve P2, and has no periodicity.
• a very large autocorrelation peak is caused, for example, by the synchronizing signal of an analog TV broadcast.
• the envelope of the autocorrelation peak P exceeding a predetermined threshold will be distributed at one point on the curve P1 for the signal received from that channel.
• the width of the distribution tends to fall within the predetermined width W.
• the width of the distribution can be considered to be due to the effects of reflected waves from buildings and mountains (for vehicles), and also to the effect of airplanes flying nearby (for homes). in the case of) .
• the above-described periodic distribution determining means 22 determines the distribution state of the group of the autocorrelation peaks P (the periodic signals described above), and it is necessary to observe the distribution over a certain period of time. is there.
• the periodic distribution determining means 22 repeatedly detects a periodic signal (autocorrelation peak P) over a specified time (for example, 50 ms), and generates a periodic signal (P) group. Determine the distribution state.
• the periodic distribution determining means 2-2 detects the periodic signal (autocorrelation peak P) that appears repeatedly until the number of times reaches a specified number (for example, 30 times). Determine the distribution of the group of sex signals (P).
• the period distribution indexing means 22 is realized by a software configuration using the CPU 33, but is not limited to this, and may be a hardware configuration.
• a ring buffer can be used . If one round of the ring-shaped memory corresponds to one frame length, if there is a digital TV broadcast, the logical "1" (or "0") is concentrated at one place in the ring. And appear.
• the distribution information is given to the determining means 23 of the next stage, and the distribution is determined by a predetermined method. A determination is made as to whether the width is within the width W, ie, whether there is a digital television broadcast.
• FIG. 7 is a diagram showing a first configuration example of the determination means 23,
• FIG. 8 is a diagram showing a second configuration example of the determination means 23. Although both are expressed as a hardware configuration, it is actually preferable to use a software configuration using CPU 33.
• the judgment means 23 includes a standard deviation calculating unit 41 for calculating the standard deviation of the distribution of the group of autocorrelation peaks (periodic signals), and calculates the standard deviation from the calculated standard deviation.
• the determination unit 42 determines whether or not the width is within the predetermined width W.
• the judging means 23 determines the maximum value and the minimum value (right end and left end of W in FIG. 5) of the distribution of the autocorrelation peak (periodic signal) group by the maximum Z minimum Then, the difference between the maximum value and the minimum value is obtained by the maximum / minimum difference calculation unit 44, and from the size, the determination unit 45 determines whether or not the difference is within a predetermined width W.
• a level detector 16 for detecting the level of the received signal is provided at a stage subsequent to the channel selecting means 12 so that the level of the received signal of the selected channel is a predetermined value. In the following cases, it is determined that there is no broadcast (both digital and analog), and the next channel is selected by the channel selection means 12. According to the first example, a channel that clearly has no broadcast is removed before receiving the detection operation by the broadcast channel detection device 20 in FIG. And faster channel search is expected.
• a list of digital broadcasts that can be received is arranged in order from the digital broadcast of the channel with the higher level of the received signal detected by the level detector 16 to the digital broadcast of the channel with the lower level.
• the level detected by the level detector 16 is recorded in the memory 24 by the CPU 33, and the levels are sorted from large to small, and stored as a table in the memory 24.
• the likelihood of the determination is determined by the frame synchronization section 17 (see FIG. 2) constituting the digital broadcast receiver 10. Determined by establishing frame synchronization in). For example, of the 50 channels, for example, 15 channels are searched by the broadcast channel detection device 20 and the picker is searched. After that, if you check the completion of the original frame synchronization only for the 15th channel, you can perform an extremely accurate channel search. However, every time the 15 channels are searched one by one, that is, each time the broadcast channel detection device 20 determines that digital broadcasting is present, the completion of frame synchronization may be checked every time.
• decoding is performed on the transport stream extracted from the received signal of the channel, and the name of the broadcasting station is changed. Get it. Further, a channel number may be obtained. Note that the acquisition of the broadcast station name or the like may be performed, for example, after all the searches for 50 channels have been completed, or may be performed each time the channel search is completed one by one.
• the determination means 23 arranges the above-mentioned group distribution within a predetermined width W (FIG. 5) from a small digital broadcast to a digital broadcast with a large variation, and receives Display a list of possible digital broadcasts to the user.
• W predetermined width
• the determination means 23 arranges the above-mentioned group distribution within a predetermined width W (FIG. 5) from a small digital broadcast to a digital broadcast with a large variation, and receives Display a list of possible digital broadcasts to the user.
• a list of digital broadcasts that can be received is arranged in order from a channel having good reception quality of the received signal. To the user. This can also be performed in the same manner as in the second example described above.
• Preferred channels may be arranged in order, or each time a channel search is completed, it may be arranged in order while sorting.
• a bit error rate (BER) that is constantly calculated can be used.
• the remaining branch is provided.
• search for broadcast channels This can be used when taking the (DIV) carrier dipolar configuration as shown in the right end of Fig. 2, and while the channel search continues, the digital broadcast is first seen and immediately seen by the user. Can be heard.
• a receiving environment estimating means for estimating the receiving environment of the digital broadcast receiver 10, and according to the receiving environment, a predetermined width W ( Fig. 5) should be variable in width.
• FIG. 9 is a diagram showing a configuration example of the reception environment estimating means.
• the receiving environment estimating means 46 transmits the navigation information from the navigation device 47, the position information from the GPS device 48, and the vehicle speed information from the vehicle speed meter 49 to the CPU 33 in FIG. It has a configuration for inputting.
• the CPU 33 can know under what kind of running condition the vehicle is, and as a result, can estimate under what kind of receiving environment. (0 0 6 0)
• the above-mentioned predetermined width W should be widened so that as many broadcast channels as possible can be captured.
• the predetermined width W should be narrowed to make it difficult to search for the wrong broadcast channel.
• the digital broadcast receiver 10 according to the present invention incorporating the above-described broadcast channel detecting device 20 will be described.
• This is a digital broadcast receiver 10 provided with the broadcast channel detection device 20 described in detail above, which shifts from the currently receiving channel to digital broadcasting of another channel adjacent on the frequency axis.
• the adjacent channel is not determined.
• This is a digital broadcast receiver that is configured to shift the search to the channel that was started.
• the channel that the user is When the user desires to watch a broadcast of an adjacent channel instead of a channel (digital broadcasting), if a predetermined seek button is pressed, the adjacent channel starts to seek automatically, but as described above, the broadcast channel according to the present invention. Since the detection device 20 is mounted, the channel seek is completed in a very short time.
• the present invention can be used when a digital broadcast receiver having a channel search has a receiving mechanism capable of extracting a signal component having a constant periodicity.

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• Aviation & Aerospace Engineering (AREA)
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• Circuits Of Receivers In General (AREA)

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• 2004
  • 2004-05-12 JP JP2004142153A patent/JP4606062B2/ja not_active Expired - Fee Related
• 2005
  • 2005-04-26 EP EP05736809A patent/EP1746733A4/en not_active Withdrawn
  • 2005-04-26 CN CNB2005800150760A patent/CN100566187C/zh not_active Expired - Fee Related
  • 2005-04-26 US US11/596,110 patent/US8004618B2/en not_active Expired - Fee Related
  • 2005-04-26 WO PCT/JP2005/008381 patent/WO2005109654A1/ja not_active Ceased
  • 2005-04-26 KR KR1020067021710A patent/KR101087174B1/ko not_active Expired - Fee Related

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