KR20060069217A - Digital multimedia signal receiver for channel modulation mode auto-searching according channel table and channel modulation mode auto-searching method thereof - Google Patents

Abstract

Provided are a digital multimedia signal receiver capable of automatically searching a modulation mode of a channel with reference to a channel table, and a method for automatically searching a channel modulation mode thereof. The digital multimedia signal receiver includes a single carrier processing unit for processing a single carrier modulated signal output from a tuner, an A / D converter, a switch, and a switch which receives a multimedia signal in one of a single carrier modulation mode and a multicarrier modulation mode. A multi-carrier processor for processing a multi-carrier modulated signal output from the multi-carrier processing unit, and a control unit for generating a switch control signal for controlling the switch with reference to a pre-stored channel table. The switching operation is applied to any one of a processor and a multicarrier processor, and the channel table includes channels and modulation modes of the respective channels. Accordingly, both a single carrier modulation signal and a multicarrier modulation signal can be processed, and the modulation mode of the channel can be automatically searched with reference to the channel table.

Digital Broadcast Receivers, Single Carrier, Multi Carrier

Description

Digital multimedia signal receiver for channel modulation mode auto-searching method that can automatically detect modulation mode of channel with reference to channel table about}

1 is a block diagram showing a multi-carrier digital broadcast receiver according to the prior art;

2 is a block diagram showing a single carrier digital broadcast receiver according to the prior art;

3 is a block diagram showing a digital multimedia signal receiver according to a first embodiment of the present invention;

4 is a view showing in detail the structure of a single carrier processing unit and a multi-carrier processing unit of FIG.

5 is a block diagram illustrating in detail the structure of the controller of FIG. 3;

6A, 6B, and 6C illustrate a process of generating a channel table in the memory of FIG. 5;

7A and 7B are diagrams each showing an example of the structure of a data frame of a single carrier modulated signal with a PN sequence and a data frame of a multicarrier modulated signal;

8 is a block diagram showing a digital multimedia signal receiver according to a second embodiment of the present invention;

9A and 9B are flowcharts illustrating a process of generating and using a channel table according to the present invention; and

FIG. 10 is a flowchart illustrating a channel table generation process performed by the digital multimedia signal receiver of FIG. 3.

Explanation of symbols on the main parts of the drawings

310: tuner 320: A / D converter

330: switch 340: single carrier processing unit

350: multicarrier processing unit 360: first indicating unit

370: second indicating unit 380: control unit

The present invention relates to a digital multimedia signal receiver for processing a single carrier modulated signal and a multicarrier modulated signal. More particularly, the present invention relates to a digital multimedia signal receiver capable of automatically detecting a modulation mode of a channel with reference to a channel table, and a channel modulation thereof. The present invention relates to a mode automatic search method.

With the advent of the multimedia communication and broadcasting era, countries around the world are digitizing analog broadcasts. In particular, developed countries such as the United States, Europe and Japan have already been developed and implemented in digital broadcasting systems. Due to this rapid development, different standards for digital broadcasting have been proposed in each country.

On December 24, 1996, the Federal Communications Commission (FCC) approved the Advanced Television Systems Committee (ATSC) digital TV standard as the next generation TV broadcast standard. Terrestrial broadcasters should comply with the ATSC standard for video / audio compression protocols, packet data transmission structures, and modulation and transmission systems. However, the protocol for the video format was not specified and was reserved by the industry.

The ATSC digital TV standard is for high-quality video, audio, and additional data transmission in the 6 MHz band using a single carrier VSB scheme, which simultaneously supports terrestrial broadcast mode and high-speed cable broadcast mode. At the heart of this approach is the 8-VSB approach, which modulates the digital signal by complementing the existing analog BSB approach.

In Europe, a coded orthogonal frequency division multiplexing (COFDM) system has been adopted as the DVB-T (Digital Video Broadcasting Terrestrial) standard, which has advantages in high frequency efficiency and interference prevention.

In addition, it is proposed as a digital multimedia broadcasting technique using various modulation methods. These techniques can be classified into a multi-carrier technique and a single carrier technique. Thus, conventional digital multimedia receivers are classified into multi-carrier digital receivers and single-carrier digital receivers.

1 is a block diagram illustrating a multi-carrier digital broadcast receiver according to the prior art.

The conventional multi-carrier digital broadcast receiver includes a tuner 110 for receiving a multi-carrier modulated digital multimedia signal, an A / D converter 120 for converting a signal output from the tuner 110 into a digital signal, and an A / D converter ( Demodulator 130 for demodulating a multi-carrier modulated signal output from 120, FFT unit 140, fast demodulating the Fourier Transform (FFT) to the signal output from the demodulator 130, demodulator 130 or the synchronization unit 150 for synchronizing the demodulator 130 using the signal output from the FFT unit 140, the equalizer 160 for equalizing the signal output from the FFT unit 140, the equalizer And a descrambler 180 that outputs an MPEG stream by descrambling the signal output from the FEC unit 170 to perform forward error correction (FEC) on the signal output from the 160. .

2 is a block diagram illustrating a single carrier digital broadcast receiver according to the prior art.

The conventional single carrier digital broadcast receiver includes a tuner 210 for receiving a single carrier modulated digital multimedia signal, an A / D converter 220 for converting a signal output from the tuner 210 into a digital signal, and an A / D converter ( In the demodulator 230 for demodulating a single carrier modulated signal output from the 220, the synchronization unit 240 for synchronizing the demodulator 230 by using the signal output from the demodulator 230, in the synchronization unit 240 An equalizer 250 for equalizing the output signal, an FEC unit 260 for performing FEC on the signal output from the equalizer 250, and a signal output from the FEC unit 260 to descramble the outputted MPEG stream. The descrambler 270 is included.

As is known, a receiver according to the prior art cannot simultaneously receive a multicarrier modulated signal and a single carrier modulated signal, and a conventional receiver cannot operate in a different digital broadcasting system.

Accordingly, an object of the present invention is to provide a digital multimedia signal receiver capable of automatically searching a modulation mode of a channel with reference to a channel table and a method for automatically searching a channel modulation mode thereof.

According to the present invention for achieving the above object, a digital multimedia signal receiver capable of processing a single carrier modulated signal and a multicarrier modulated signal, a tuner for receiving a multimedia signal of any one of a single carrier modulation mode and a multi-carrier modulation mode ; An A / D converter converting the signal output from the tuner into a digital signal; A switch for switching the digital signal output from the A / D converter; A single carrier processing unit processing a single carrier modulated signal output from the switch; A multicarrier processor for processing a multicarrier modulated signal output from the switch; And a controller configured to generate a switch control signal for controlling the switch with reference to a pre-stored channel table, wherein the switch is configured to output the digital signal to the single carrier processing unit according to the switch control signal output from the controller. And a switching operation to be applied to any one of the multicarrier processing unit, and the channel table includes channels and modulation modes of each channel.

The single carrier processing unit may include: a demodulator configured to demodulate the digital signal output from the switch if the multimedia signal is a single carrier modulated signal; A synchronization unit for synchronizing the demodulator by using a demodulation signal output from the demodulator; An equalizer which equalizes the demodulated signal output from the demodulator; An FEC unit performing forward error correction (FEC) on the equalized signal output from the equalizer; And a descrambler for descrambling the FEC signal output from the FEC unit to generate an MPEG stream, wherein the multicarrier processing unit comprises: the digital output from the switch if the multimedia signal is a multicarrier modulated signal; A demodulator for demodulating a signal; An FFT unit performing a fast fourier transform (FFT) on the digital signal output from the demodulator; A synchronization unit for synchronizing the demodulator by using the demodulation signal output from the demodulator or the FFT signal output from the FFT unit; An equalizer for equalizing the FFT signal output from the FFT unit; An FEC unit which performs FEC on the equalization signal output from the equalization unit; And a descrambler for descrambling the FEC signal output from the FEC unit to generate an MPEG stream.

The control unit may include a memory for storing the channel table.

The memory may be a flash memory or a nonvolatile memory.

On the other hand, according to the present invention, a channel modulation mode automatic search method of a digital multimedia signal receiver capable of processing a single carrier modulated signal and a multi-carrier modulated signal, the method comprising: receiving a multimedia signal selected by a user; Determining a modulation mode of the selected multimedia signal with reference to a channel table; Processing the selected multimedia signal according to the determined modulation mode.

The channel table may include channels and modulation modes of each channel.

The channel table may be pre-stored in a predetermined memory.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

3 is a block diagram illustrating a digital multimedia signal receiver according to a first embodiment of the present invention.

As shown in FIG. 3, the digital multimedia signal receiver includes a tuner 310, an A / D converter 320, a switch 330, a single carrier processor 340, a multicarrier processor 350, and a first indicator 360. ), A second indicating unit 370 and a control unit 380.

The tuner 310 tunes the received digital multimedia signal and searches for a channel of the signal according to the channel selection signal output from the controller 380.

The A / D converter 320 converts the signal output from the tuner 310 into a digital signal.

The switch 330 switches the signal to the processing unit according to the switch control signal output from the controller 380. In the single carrier modulation mode, the digital signal from the A / D converter 320 passes through the switch 330 and is input to the single carrier processing unit 340. In the multicarrier modulation mode, the digital signal from the A / D converter 320 is input to the multicarrier processing unit 350 through the switch 330. In an embodiment of the present invention, the switch 330 is illustrated as switching to a single carrier processing unit 340 by default.

The single carrier processor 340 processes a digital multimedia signal in a single carrier modulation mode, and the multicarrier processor 350 processes a digital multimedia signal in a multicarrier modulation mode. Detailed structures of the single carrier processor 340 and the multicarrier processor 350 will be described later with reference to FIG. 4.

The first indicating unit 360 detects a signal output from the single carrier processing unit 340 and generates the indicating signal 1. On the other hand, the second indicating unit 370 detects a detection signal output from the multi-carrier processing unit 350 and generates an indication signal 2 according to the detection signal.

When a specific user inputs a command for pre-channel search, the controller 380 controls the tuner 310 to search all channels, detects modulation modes of all channels, and provides information on modulation modes of each channel. It is stored in the channel table preset in the memory of the controller 380 shown in FIG.

More specifically, for example, when receiving a channel pre-search command from a specific user, the controller 380 first controls the tuner 310 to search all channels, and controls the switch 330 to A / D. The digital signal output from the converter 320 is input to the single carrier processing unit 340, and it is determined whether the modulation mode of the corresponding channel signal is single carrier modulation according to the indication signal 1 output from the first indicating unit 360. do. Subsequently, the controller 380 controls the tuner 310 to search all channels, and controls the switch 330 so that the digital signal output from the A / D converter 320 is input to the multi-carrier processor 350. In accordance with the indication signal 2 output from the second indicating unit 370, it is determined whether the modulation mode of the corresponding channel signal is multi-carrier modulation.

Accordingly, modulation modes of all channels are determined and stored in the channel table preset in the memory of the controller 380. In addition, when the user selects a specific channel, the controller 380 retrieves the corresponding modulation mode of the currently selected channel from the channel table and controls the switch 330 to switch to the corresponding processing unit according to the search result.

The above embodiments are merely examples, and various substitutions, modifications, and variations are possible. For example, only one indicator may be used to receive detection signals from the single carrier processor 340 and the multicarrier processor 350.

4 is a diagram illustrating in detail the structures of the single carrier processor 340 and the multicarrier processor 350 of FIG. 3.

As shown in FIG. 4, the single carrier processor 340 includes a demodulator 4301, a synchronizer 4401, an equalizer 4501, an FEC unit 4601, and a descrambler 4701. The demodulator 4301, synchronizer 4401, equalizer 4501, FEC unit 4601, and descrambler 4701 are the same as the corresponding components of Fig. 2, and thus a detailed description thereof will be omitted here.

The multicarrier processor 350 includes a demodulator 4302, an FFT unit 4402, a synchronizer 4502, an equalizer 4602, an FEC unit 4702, and a descrambler 4802. The demodulator 4302, the FFT unit 4402, the synchronization unit 4502, the equalizer 4602, the FEC unit 4702, and the descrambler 4802 are the same as the corresponding components of FIG. Is omitted here.

Referring to FIG. 4, for example, the first indicating unit 360 detects a detection signal. In this case, the detection signal is a BER (Bit Error Rate) of the signal on which the FEC output from the FEC unit 4601 is performed. If the BER is smaller than the predetermined threshold, i.e., the corresponding appropriate processing unit is used or the reception state of the single carrier processing unit 340 is good, the first indicating unit 360 is set to "High" and corresponds to "High". Outputs an indicating signal (1). If the BER is larger than a predetermined threshold, i.e., an unsuitable inappropriate processing unit is used or the reception state is bad, the first indicator 360 is set to "Low" and outputs the corresponding indication signal 1 of "Low". . According to the indication signal 1, the controller 380 may determine whether the modulation mode of the signal of the channel is a single carrier mode.

Alternatively, the first indicating unit 360 receives a signal output from the synchronization unit 4401, the equalizer 4501, or the descrambler 4701 as a detection signal. Depending on the specific conditions and needs of these detection signals, a single detection signal may be used or a combination thereof may be used, so that one or more indicators 360 may be used. The second indicating unit 370 operates in the same manner as the first indicating unit 360. The only difference is that the detection signal is received from the multi-carrier processing unit 350, and thus a detailed description thereof will be omitted herein.

In addition, other single components indicating the modulation mode may be used to determine the modulation mode of the received digital multimedia signal.

5 is a block diagram illustrating in detail the structure of the controller of FIG. 3 according to the first embodiment of the present invention. As shown in FIG. 5, the controller includes a central processing unit 500 and a memory 510.

Upon receiving a channel pre-search command from a specific user, the central processing unit 500 first outputs a channel selection signal and controls the tuner 310 to change and search all channels in order, and controls the switch 330 to A / A. The digital signal output from the D converter 320 is input to the single carrier processing unit 340, which is the default predefined processor, and modulates the corresponding channel signal according to the indication signal 1 output from the first indicating unit 360. It is determined whether the mode is single carrier modulation, and the modulation mode information of the corresponding channel is stored in the channel table preset in the memory 510. Subsequently, the central processing unit 500 outputs a switch control signal and controls the switch 330 to switch to the multi-carrier processing unit 350 which is another processor, outputs a channel selection signal, and controls the tuner 310 to control all channels. Are searched in order, and according to the indication signal 2 output from the second indicator 370, it is determined whether the modulation mode of the corresponding channel signal is multi-carrier modulation, and the modulation mode information of the corresponding channel is stored in the memory 510. Store in the preset channel table. Accordingly, the channel table is generated.

When the user selects a channel, the central processing unit 500 outputs a channel selection signal to control the tuner 310 and selects a corresponding channel, searches for a modulation mode corresponding to the currently selected channel in the channel table, and switches The control signal is output to control the switch 330 to switch to the processing unit corresponding to the modulation mode of the selected channel according to the search result.

The memory 510 stores a channel table and may be various types of rewritable devices capable of storing data without a power supply such as a flash memory or a nonvolatile memory.

6A, 6B, and 6C are diagrams for describing a channel table generation process in the memory of FIG. 5.

3, 6A, 6B, and 6C, it is assumed that the digital multimedia signal receiver receives a total of six channels. As shown in FIG. 6A, initially, information about a channel and a corresponding modulation mode do not exist.

When a user inputs a channel pre-search command, the controller 380 controls the tuner 310 to search all channels, and controls the switch 330 so that the digital signal output from the A / D converter 320 is single. It is input to the carrier processing unit 340, it is determined whether the channel of the single carrier modulation mode in accordance with the indication signal (1), and the determined channel and modulation mode, for example, determine a single carrier mode and stores in the channel table. Here, the generated channel table is as shown in FIG. 6B.

Subsequently, the controller 380 controls the switch 330 to switch to the multi-carrier processing unit 350, controls the tuner 310 to search all channels again, and controls the switch 330 to control the A / D converter ( The digital signal output from 320 is input to the multicarrier processing unit 350, and it is determined whether the channel is the multicarrier modulation mode according to the indication signal 2, and the determined channel and the modulation mode are, for example, the multicarrier mode. Determine and save to channel table. Here, the generated channel table is as shown in FIG. 6C.

7A and 7B are diagrams each showing an example of the structure of a data frame of a single carrier modulated signal with a PN sequence inserted therein and a data frame of a multicarrier modulated signal.

7A shows the structure of a data frame of a single carrier modulated signal. 7B shows the structure of a data frame of a multicarrier modulated signal. Here, the PN sequence inserted into the single carrier modulated signal and the PN sequence inserted into the multicarrier modulated signal are different from each other.

8 is a block diagram illustrating a digital multimedia signal receiver according to a second embodiment of the present invention. Referring to FIG. 8, the digital multimedia signal receiver includes a tuner 810, an A / D converter 820, a switch 830, a single carrier processor 840, a multicarrier processor 850, and a controller 860. do. Here, the tuner 810, the A / D converter 820, the switch 830, the single carrier processing unit 840, and the multi-carrier processing unit 850 are the same as the corresponding components of FIG. Omit.

The controller 860 receives a digital signal from the A / D converter 820. The controller 860 detects a modulation mode of the signal according to the PN sequence shown in FIGS. 7A and 7B. The PN sequence is used to detect the modulation mode of the signal, and the controller 860 extracts the PN sequence from the data frame header of the digital signal output from the A / D converter 820. Subsequently, the controller 860 compares the PN sequence extracted from the data frame of the signal with the PN sequence corresponding to the multi-carrier modulated signal and the single-carrier modulated signal stored in the controller 860, and then the controller 860 It is determined which PN sequence among the preset PN sequences stored in the. In this embodiment, the channel table is generated after being searched once for all channels.

Other types of identification information, such as pilot, together with the PN sequence may be used to determine the modulation mode of the channel. In the case of a pilot, the power difference between the pilot maximum power value and the average power value of the output signal of the A / D converter 820 is calculated, and the calculated power difference is a predetermined range or a single carrier modulated signal for the multicarrier modulated signal. The controller 860 detects the modulation mode of the signal based on which of the predetermined ranges of? One or more pilots may be used.

The above two kinds of identification information may be used individually or together.

9A and 9B are flowcharts illustrating a process of generating a channel table according to the present invention, respectively.

9A, a user inputs a specific channel dictionary search command (S900). The controller 380 or 860 controls the tuner 310 or 810 to search all channels and determines the modulation mode of all channels according to the indication signal (S910). Subsequently, the controller 380 or 860 stores the information in the channel table preset in the memory (S920).

9B, the user selects a channel (S930). The controller 380 or 860 searches for a modulation mode corresponding to the selected channel in the predetermined channel table (S940). Here, the predetermined channel table is preferably the channel table generated in step S920. Finally, the controller 380 or 860 controls the switch 330 or 830 to switch to the appropriate processing unit according to the search result.

Hereinafter, a process of generating a channel table by the digital multimedia signal receiver of FIG. 3 will be described in detail with reference to FIG. 10.

FIG. 10 is a flowchart illustrating a process of generating a channel table by the digital multimedia signal receiver of FIG. 3.

Referring to FIG. 10, a user inputs a command for searching for a specific channel dictionary (S1000). The controller 380 controls the tuner 310 to search for one channel (S1005). Subsequently, the controller 380 determines whether the instruction signal 1 output from the first indicator 360 is "1" (S1010). In this case, the indication signal may be represented in a different format.

If the control unit 380 determines that the indication signal 1 is "1" in step S1010, it is determined that the modulation mode of the current channel is a single carrier modulation mode (S1015), and the current channel and its modulation mode information are stored in a channel table. It is stored in (S1020). If it is determined in step S1010 that the indication signal 1 is not "1", no information is stored in the channel table. The controller 380 determines whether the search for all the channels is completed (S1025). If the controller 380 determines that the search for all channels is not completed in step S1025, the controller 380 controls the tuner 310 to search for another channel (S1030), and repeats steps S1010 to S1025. . If it is determined in step S1025 that the controller 380 completes the search for all channels, the controller 380 controls the switch 330 to switch to the multi-carrier processing unit 350 (S1035).

The controller 380 controls the tuner 310 to search for one channel (S1040). Subsequently, the controller 380 determines whether the instruction signal 2 output from the second indicator 370 is "1" (S1045). If the control unit 380 determines that the indication signal 2 is "1" in step S1045, it is determined that the modulation mode of the current channel is a multi-carrier modulation mode (S1050), and the current channel and its modulation mode information are stored in the channel table. It is stored in (S1055). If it is determined in step S1045 that the indication signal 2 is not "1", no information is stored in the channel table. The controller 380 determines whether the search for all channels is completed (S1060). If the controller 380 determines that the search for all channels is not completed in step S1060, the controller 380 controls the tuner 310 to search for another channel (S1065), and repeats steps S1045 to S1060. . If it is determined in step S1060 that the control unit 380 completes the search for all channels, the process ends.

In this case, the indication signal is generated according to one of a signal on which FEC is performed, a synchronization signal, an signal on which equalization is performed, and an MPEG stream extracted from a single carrier processing unit or a multicarrier processing unit or a combination of these signals.

As described above, according to the present invention, the digital multimedia signal receiver according to the present invention can process both a single carrier modulated signal and a multicarrier modulated signal.

In addition, the digital multimedia signal receiver according to the present invention can store all channels and their modulation mode information in a channel table by a channel pre-search operation.

Further, according to the channel pre-search method according to the present invention, when the user selects a channel, the digital multimedia signal receiver according to the present invention searches for a modulation mode corresponding to the channel selected in the channel table, and automatically selects the appropriate processing unit. This allows the user to watch programs according to different modulation modes and to switch between the various modulation mode processing units with great efficiency.

In addition, the modulation mode of the channel can be automatically detected by referring to the channel table.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (7)

A digital multimedia signal receiver capable of processing a single carrier modulated signal and a multicarrier modulated signal, A tuner for receiving a multimedia signal in any one of a single carrier modulation mode and a multiple carrier modulation mode; An A / D converter converting the signal output from the tuner into a digital signal; A switch for switching the digital signal output from the A / D converter; A single carrier processing unit processing a single carrier modulated signal output from the switch; A multicarrier processor for processing a multicarrier modulated signal output from the switch; And And a controller configured to generate a switch control signal for controlling the switch with reference to a previously stored channel table. The switch is switched to apply the digital signal to any one of the single carrier processing unit and the multicarrier processing unit according to the switch control signal output from the control unit. And the channel table includes channels and modulation modes of each channel. The method of claim 1, The single carrier processing unit, A demodulator for demodulating the digital signal output from the switch if the multimedia signal is a single carrier modulated signal; A synchronization unit for synchronizing the demodulator by using a demodulation signal output from the demodulator; An equalizer which equalizes the demodulated signal output from the demodulator; An FEC unit performing forward error correction (FEC) on the equalized signal output from the equalizer; And And a descrambler for descrambling the FEC signal output from the FEC unit to generate an MPEG stream. The multicarrier processing unit, A demodulator for demodulating the digital signal output from the switch if the multimedia signal is a multi-carrier modulated signal; An FFT unit performing a fast fourier transform (FFT) on the digital signal output from the demodulator; A synchronization unit for synchronizing the demodulator by using the demodulation signal output from the demodulator or the FFT signal output from the FFT unit; An equalizer for equalizing the FFT signal output from the FFT unit; An FEC unit which performs FEC on the equalization signal output from the equalization unit; And And a descrambler for descrambling the FEC signal output from the FEC unit to generate an MPEG stream. The method of claim 2, The control unit, And a memory for storing the channel table. The method of claim 3, wherein The memory, Digital multimedia signal receiver, characterized in that the flash memory or non-volatile memory. In the channel modulation mode automatic detection method of a digital multimedia signal receiver capable of processing a single carrier modulated signal and a multi-carrier modulated signal, Receiving a multimedia signal selected by a user; Determining a modulation mode of the selected multimedia signal with reference to a channel table; And automatically processing the selected multimedia signal according to the determined modulation mode. The method of claim 5, And a channel and modulation modes of each channel are included in the channel table. The method of claim 6, The channel table is pre-stored in a predetermined memory, characterized in that the channel modulation mode automatic search method.

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