KR101444464B1 - Apparatus and method for controlling receiving channel in broadcasting receiver - Google Patents

Abstract

The present invention relates to an apparatus and method for controlling a reception channel of a broadcast signal receiver capable of receiving a broadcast signal of a channel having an offset frequency at a high speed. When a channel on which a broadcast signal is received is scanned, A PLL (Phase Locked Loop) is controlled to sequentially receive broadcast signals of a plurality of channels, information on a channel on which a broadcast signal is received and an offset frequency of the channel are stored in the memory, and when a broadcast signal of a predetermined channel is received The channel manager reads the information of the corresponding channel and the offset frequency of the corresponding channel in the memory and sets the frequency of the PLL according to the read information of the corresponding channel and the offset frequency to receive the broadcast signal of the corresponding channel at a high speed.

DVB-T, Offset, Channel Switching, Channel Scan, OFDM, COFDM, Channel Switching, DVB-SI

Description

[0001] Apparatus and method for controlling a receiving channel of a broadcast signal receiver [0002]

The present invention relates to an apparatus and method for controlling a reception channel of a broadcast signal receiver. More particularly, the present invention relates to a broadcast signal receiver, such as a digital television receiver and a set top box, which uses a DVB-T (Digital Video Broadcasting-Terrestrial) technology, in which, when a channel on which a broadcast signal is received is automatically scanned, And the offset frequency of the corresponding channel are stored together, and when the receiving channel is switched, the broadcasting signal of the corresponding channel can be received at a high speed using the stored channel information and the offset frequency of the corresponding channel And more particularly, to a receiver channel control apparatus and method for a broadcast signal receiver.

Many countries are now broadcasting digital television. Most of these digital television broadcasts are based on DVB-T. That is, the ATSC (Advanced Television Systems Committee) scheme used in North America and Korea, the Integrated Service Digital Broadcasting-Terrestrial (ISDB-T) scheme used in Japan and Brazil, and the Digital Terrestrial Multimedia Broadcast), and digital television broadcasting of each country are based on the DVB-T system.

The radio waves used to transmit broadcasting signals in digital television broadcasting are controlled by countries. Generally, frequencies of VHF (Very High Frequency) and UHF (Ultra High Frequency) are used for digital television broadcasting.

However, prior to digital television broadcasting, analog TV broadcasting was being performed first. Therefore, digital television broadcasting should not affect existing analog television broadcasting.

In Europe, a range of offset frequencies is set in advance, and broadcasting stations broadcasting a broadcasting signal of a predetermined channel set a center frequency of a corresponding channel within a preset offset frequency range. So that the broadcasting signal can be broadcasted.

The offset frequency is set to ± 1/6 MHz in one step. In the UK, the offset frequency is set in a range of about ± 166.67 kHz, which is one step. In France, offset frequency is set to about ± 166.67 kHz It is regulated to be able to set the frequency, but in some areas including the Crocica region in France, it is regulated to set the offset frequency in the range of ± 500 kHz in three steps, including Denmark, Finland, Iceland, Norway and Sweden Nordic (Nordig) specifies that the offset frequency can be set in the range of 50 kHz.

In this way, in broadcasting a broadcasting signal of a predetermined channel in the broadcasting station, the center frequency can be shifted within a predetermined offset frequency range, so that when a broadcasting signal receiver receives a broadcasting signal of a predetermined channel, It is necessary to detect the offset frequency and to receive the broadcast signal by shifting the center frequency by the detected offset frequency.

To achieve this, conventionally, when a broadcast signal of a predetermined channel is received, a broadcast signal is received by setting a frequency of a PLL (Phase Locked Loop) of the tuner unit according to a center frequency of the channel, The offset frequency is detected from the received broadcast signal.

When the offset frequency is detected, a frequency of a PLL (Phase Locked Loop) of the tuner unit is set according to a center frequency reflecting the offset frequency, and a broadcast signal of the channel is received.

However, when receiving a broadcast signal of a channel having an offset frequency, the conventional technique described above sets the frequency of the PLL according to the center frequency of the channel, detects the offset frequency, Since it is necessary to receive the broadcast signal of the corresponding channel by setting the frequency, it took a long time to receive the broadcast signal of the channel having the offset frequency.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a receiver channel control method and apparatus for a broadcast signal receiver capable of receiving a broadcast signal of a channel having an offset frequency.

Also, the present invention automatically scans a channel on which a broadcast signal is received, stores the information of the channel and the offset frequency in a memory together with an offset frequency, and when a reception command of a predetermined channel is generated, The present invention also provides a receiver channel control apparatus and method for a broadcast signal receiver that can receive a broadcast signal of a corresponding channel at a high speed using information of a corresponding channel and an offset frequency.

According to an apparatus and method for controlling a reception channel of a broadcast signal receiver of the present invention, when a scan command for a channel on which a broadcast signal is received is generated, the controller sequentially selects channels one by one to determine whether a broadcast signal is received, It is determined whether or not there is an offset frequency.

If the offset frequency is present in the broadcast signal, a predetermined offset detection algorithm is performed to detect the first offset frequency.

Then, a center frequency is extracted from a DVB-SI (Digital Video Broadcasting-Service Information) table included in the broadcast signal, and the second offset frequency of the corresponding channel is calculated by subtracting the extracted center frequency from the original center frequency of the channel do.

If the calculated second offset frequency is within a predetermined frequency range, for example, within a range of ± 550 kHz including a margin of 10% at ± 500 kHz which is allowed in some areas including the Croisic region of France, And stores the second offset frequency as an offset frequency of the corresponding channel. If the calculated second offset frequency is out of a preset frequency range, And stores the information capable of receiving a broadcast signal of the channel and the first offset frequency as an offset frequency of the corresponding channel.

When a reception command of a predetermined channel is generated, the broadcasting signal receiver reads the information and the offset frequency that can receive the broadcasting signal of the corresponding channel from the memory, And sets a frequency of a PLL (Phase Locked Loop) of a tuner section according to information capable of receiving a broadcast signal of a channel and an offset frequency, thereby receiving a broadcast signal of the corresponding channel.

Therefore, the reception channel control apparatus of the broadcast signal receiver of the present invention includes a tuner unit for setting a frequency of a PLL (Phase Locked Loop) according to a channel to be received and receiving a broadcast signal of the channel, A demultiplexer for demultiplexing the demodulated signal of the demodulator to extract an AV (Audio and Video) signal and program information; an AV signal decoder for decoding the AV signal; And a user interface unit for controlling the tuner unit, the demodulator unit, the demultiplexer unit, the AV signal decoder, and the program information processor according to a user command input from the outside to receive a broadcast signal of a predetermined channel , The control unit controls the PLL when a user command for channel scanning is input, Information of a channel on which a broadcast signal is received and an offset frequency of the channel are stored in the memory, and when a user command for reception of a predetermined channel is inputted, information of the corresponding channel and an offset And controls the frequency of the PLL to be set by reading the frequency.

The controller detects a first offset frequency of the corresponding channel using an offset frequency detection algorithm and detects a center frequency of a corresponding channel included in a DVB-SI (Digital Video Broadcasting-System Information) table received together with the broadcast signal And calculates a second offset frequency as a difference value from the original center frequency of the corresponding channel. If the calculated second offset frequency is within a predetermined frequency range, the second offset frequency is offset And controlling the first offset frequency to be stored as an offset frequency of the corresponding channel if the second offset frequency range is not within a preset frequency range.

In addition, according to the present invention, a channel manager controls a PLL of a tuner unit according to a user command of a channel scan to sequentially receive broadcast signals of a plurality of channels, A channel scanning step of storing the offset frequency of the channel in the memory; and a channel manager reading the information of the corresponding channel and the offset frequency of the corresponding channel in the memory according to a user command of receiving a predetermined channel to set the frequency of the PLL And a broadcast signal receiving step.

The channel scanning step may include determining whether a broadcast signal is received while setting a frequency of the PLL according to a channel of a broadcast signal to be received, and if the channel is a channel through which the broadcast signal is received, Extracting an offset frequency of the channel and storing the information of the channel and the extracted offset frequency in the memory.

The offset frequency may be stored by detecting a first offset frequency using an offset frequency detection algorithm, and determining a center frequency of the channel broadcast in a DVB-SI (Digital Video Broadcasting-System Information) table included in the received broadcast signal Calculating a second offset frequency that is a difference between a center frequency of the channel broadcast extracted and extracted and an original center frequency of the channel, and a second offset frequency when the calculated range of the second offset frequency is within a predetermined range, Storing the frequency as an offset frequency of the corresponding channel and storing the first offset frequency as an offset frequency of the channel when the second offset frequency is not within a predetermined range.

The determination of whether or not the broadcast signal is received may be made by setting a frequency of the PLL and then RF (Radio Frequency) AGC (Automatic Gain Control) provided in the tuner unit is locked, the modulated signal is detected, When the received data is detected in the modulated signal, it is determined that the channel is the one on which the broadcast signal is received.

Wherein the step of receiving the broadcast signal comprises the steps of: when the user command for receiving a predetermined channel is input, the channel manager reads information of the corresponding channel and an offset frequency of the corresponding channel from the memory; And setting a frequency of the PLL according to an offset frequency of the PLL to receive a broadcast signal of the corresponding channel.

Determining whether the received data is detected in the received broadcast signal after setting the frequency of the PLL, and fixing the frequency of the PLL when the received data is detected.

According to an apparatus and method for controlling a reception channel of a broadcast signal receiver of the present invention, when an automatic scan command for scanning a channel on which a broadcast signal is received is generated, the broadcast signal receiver sequentially scans all channels one by one, And detects an offset frequency when the broadcast signal is received and the offset frequency is present. After detecting the offset frequency, information that can receive the broadcast signal of the corresponding channel and an offset frequency are combined together And stores it in the memory.

When a reception command of a predetermined channel is generated, the broadcast signal receiver reads the information capable of receiving the corresponding channel and the offset frequency of the corresponding channel in the memory, The frequency of the PLL of the tuner unit is set according to the offset frequency of the corresponding channel so that the broadcast signal of the corresponding channel can be received at a high speed.

Therefore, according to the present invention, there is no need to separately detect an offset frequency of a corresponding channel when receiving a broadcast signal of a predetermined channel in which an offset frequency exists, and thereby, even for a broadcast signal of a channel in which an offset frequency exists, The broadcasting signal of the corresponding channel can be received at a high speed by setting the frequency of the PLL of the tuner unit.

The following detailed description is merely illustrative, and is merely an example of the present invention. Further, the principles and concepts of the present invention are provided for the purpose of being most useful and readily explaining.

Accordingly, it is not intended to provide a more detailed structure than is necessary for a basic understanding of the present invention, but it should be understood by those skilled in the art that various forms that can be practiced in the present invention are illustrated in the drawings.

1 is a signal flow diagram illustrating an operation of scanning a channel through which a broadcast signal is received in a broadcast signal receiver. Referring to FIG. 1, when a user command to automatically scan a channel on which a broadcast signal is received is generated, a channel manager of the broadcast signal receiver stores the lowest channel number in the channel variable N (S100) (S102), the PLL (Phase Locked Loop) of the tuner unit is set so that the tuner unit scans the channel N (S104), and waits for a predetermined period of time until the channel N broadcast signal is received.

In this state, the channel manager determines whether the RF (Radio Frequency) AGC (Automatic Gain Control) provided in the tuner unit is locked due to the existence of a broadcast signal in the corresponding channel (S106).

If the RF AGC is not locked because there is no broadcast signal received on the corresponding channel, the channel manager determines whether the channel N is equal to or greater than a maximum channel number that can be received by the broadcast signal receiver in step S108.

If it is determined in step S108 that the channel N is not equal to or greater than the maximum channel number that can be received by the broadcast signal receiver, 1 is added to the channel variable N in step S110, and the process returns to step S102, The mobile station repeats the scan operation to determine whether a broadcast signal is received

If it is determined in step S108 that the N channel is equal to or greater than the maximum channel number that can be received by the broadcast signal receiver, the channel manager terminates the operation of scanning the channel on which the broadcast signal is received.

If it is determined in step S106 that a predetermined broadcast signal is received on the corresponding channel N and the RF AGC is locked, the channel manager determines whether a modulation signal is detected in the received broadcast signal (S112).

For example, digital television broadcasting modulates predetermined data to be broadcast with OFDM (Orthogonal Frequency Division Multiplexing) or COFDM (Coded Orthogonal Frequency Division Multiplexing) signals, and the channel manager of the broadcast signal receiver transmits It is determined whether a COFDM or OFDM modulation signal is detected.

If no COFDM or OFDM modulation signal is detected as a result of the determination, the channel manager determines whether a preset predetermined time has elapsed (S114). If the preset time has not elapsed, the channel manager returns to step S112, An operation of determining whether or not an OFDM modulated signal is detected is repeated.

If a modulation signal is detected before the set time elapses in this state, the channel manager determines whether an offset frequency exists in the broadcast signal of the currently received channel N (S116). Here, the operation of determining whether or not an offset frequency exists is generally widely used, and a detailed operation for determining whether or not an offset frequency exists is omitted.

As a result of the determination, if the offset frequency exists, the channel manager detects the offset frequency using a normal offset frequency detection algorithm (S118), and returns to step S104 to transmit the broadcast signal of the channel N including the offset frequency The PLL is set so as to be able to receive the signal, the RF AGC is locked after waiting for reception of the broadcast signal, the modulation signal is detected, and the operation of determining whether or not the offset frequency is present is repeated.

If it is determined that the offset frequency does not exist, it is determined whether the received data is detected in the modulated signal (S120).

As a result of the determination, when the received data is not detected, the corresponding channel is not normally received, and the channel manager determines whether the channel N is equal to or greater than a maximum channel number that the broadcast signal receiver can receive (S108) If it is determined that the N channel is not equal to or greater than the maximum channel number that can be received by the broadcast signal receiver (S110), the flow returns to step S102 to receive a broadcast signal of the next channel .

If the received data is detected as a result of the determination, the broadcast signal is normally received on the corresponding channel, and the channel manager stores information on the channel N as a channel on which the broadcast signal is received (S122). After storing the information of the channel N, the channel manager determines whether the channel N is equal to or greater than a maximum channel number that can be received by the broadcast signal receiver (S108) If the channel number is not equal to or greater than the maximum channel number that can be received, 1 is added to the channel N (S110), and the process returns to step S102 to repeat the operation of receiving the broadcast signal of the next channel.

That is, when a user command to automatically scan a channel on which a broadcast signal is received is generated, the broadcast signal receiver sequentially selects all channels and determines whether or not a broadcast signal is received. If the broadcast signal is a channel on which a broadcast signal is received Only the information of the corresponding channel is stored as a channel on which the broadcast signal is received.

2 is a signal flow diagram illustrating an operation of receiving a broadcast signal of a predetermined channel selected in a broadcast signal receiver. Referring to FIG. 2, the channel manager of the broadcast signal receiver determines whether a channel N tuning command is input from the user (S200).

When the tuning command of the channel N is input as a result of the determination, the channel manager reads the information of the channel N (S202), sets the PLL of the tuner unit according to the information of the read channel N, (S204)

In this state, the channel manager determines whether the RF (Radio Frequency) AGC (Automatic Gain Control) provided in the tuner unit is received on the channel N (S206).

If it is determined that the broadcast signal is received and the RF AGC is locked, the channel manager determines whether a modulation signal is detected in the received broadcast signal (S208).

If it is determined that the modulation signal has not been detected, the channel manager determines whether a predetermined time has elapsed (S210). If the predetermined time has not elapsed, the channel manager returns to step S208 to determine whether the modulation signal is detected Is repeatedly performed.

If a modulation signal is detected before the set time elapses in this state, the channel manager determines whether an offset frequency exists in the broadcast signal of the currently received channel (S212).

If it is determined that the offset frequency exists, the channel manager detects the offset frequency using a normal offset frequency detection algorithm (S214), and returns to step S204 to receive the broadcast signal of the channel N including the offset frequency Then, the PLL is set so that RF AGC is locked after reception is waited, a modulation signal is detected, and an operation of determining whether or not an offset frequency exists is repeated.

If it is determined that the offset frequency does not exist, it is determined whether the received data is detected in the modulated signal (S216).

As a result of the determination, when the received data is detected, the channel manager fixes the frequency of the corresponding channel so that it can continuously receive the broadcast signal (S218).

The receiving of the broadcast signal of the predetermined channel can receive the broadcast signal of the corresponding channel at a high speed when the offset frequency does not exist in the corresponding channel.

However, if there is an offset frequency in the channel to be received, the broadcast signal of the corresponding channel is received to detect the offset frequency, and the PLL is set again according to the detected offset frequency to receive the broadcast signal of the corresponding channel. It takes a long time to receive the broadcast signal of the mobile station.

3 is a block diagram illustrating a configuration of a preferred embodiment of a broadcast signal receiver according to the present invention. Here, reference numeral 300 denotes a tuner unit. The tuner unit 300 includes a PLL (Phase Locked Loop) and an RF AGC, and receives a broadcast signal of a predetermined channel as the frequency of the PLL is set.

Reference numeral 310 denotes a demodulation unit. The demodulation unit 310 demodulates the broadcast signal received by the tuner unit 300. For example, digital television broadcasting modulates a predetermined transport stream into an OFDM signal and transmits the OFDM signal. The demodulator 310 demodulates the OFDM signal to extract a transport stream.

Reference numeral 320 denotes a demultiplexer. The demultiplexer 320 demultiplexes the transport stream demodulated by the demodulator 310 and extracts predetermined program information including an AV signal and a DVB-SI (Digital Video Broadcasting-System Information) table.

Reference numeral 330 denotes an AV decoder. The AV decoder 330 decodes the demultiplexed AV signal in the demultiplexer 320 and outputs the decoded AV signal to the outside so that the user can view the AV signal.

Reference numeral 340 denotes a program information processing unit. The program information processing unit 340 processes predetermined program information including the DVB-SI table demultiplexed by the demultiplexing unit 320. [

Reference numeral 350 denotes a user interface unit. The user interface unit 350 performs a predetermined operation according to a user command input from the outside.

The user interface unit 350 includes a channel manager 352. When a user command input from the outside is a channel scan command, the channel controller 352 sets a frequency of the PLL built in the tuner unit 300, and the broadcast signal receiver sequentially receives broadcast signals of all channels . The channel manager 352 receives the output signals of the tuner unit 300, the demodulator 310, the demultiplexer 320 or the AV signal decoder 330 and the program information processed by the program information processor 340 Information on the channel on which the broadcast signal is received and the offset frequency of the channel are stored in the memory 360. [

When the channel manager 352 of the user interface unit 350 receives the user command to scan the channel on which the broadcast signal is received, the reception channel controller of the present invention having the above- To the center frequency of each channel so that the tuner unit 300 sequentially receives broadcast signals of the respective channels.

The broadcast signals of the respective channels received by the tuner unit 300 are demodulated by the demodulator 310. The program information including the AV signal and the DVB-SI table is demultiplexed by the demultiplexer 320, Is decoded and output by the AV signal decoder 330. [

The program information including the DVB-SI table demultiplexed by the demultiplexer 320 is input to the program information processor 340 and processed.

In this state, the channel manager 352 outputs the output signals of the tuner unit 300, the demodulator 310, the demultiplexer 320, or the AV signal decoder 330 and the output signals of the program information processor 340 Program information, and the like, and determines whether or not a broadcast signal is received and whether an offset frequency is present. The information on a channel through which the broadcast signal is received is stored in the memory 360 according to the reception of the determined broadcast signal and existence of the offset frequency, Store the offset frequency of the channel.

When a user command to receive a broadcast signal of a predetermined channel is input while the channel on which the broadcast signal is received is scanned and the information of the channel and the offset frequency of the broadcast signal are stored in the memory 360, (352) reads the information of the corresponding channel and the offset frequency in the memory (360).

The channel manager 352 sets the frequency of the PLL of the tuner unit 300 according to the read information of the corresponding channel and the offset frequency, and receives the broadcast signal of the desired channel desired by the user.

4 is a signal flow diagram illustrating an operation of scanning a channel on which a broadcast signal is received in the receive channel control method of the present invention. 4, when a user command to scan a channel on which a broadcast signal is received is generated, the channel manager 352 of the user interface unit 350 stores the lowest channel number in the channel variable N (S400) (S402), sets a frequency of a PLL (Phase Locked Loop) provided in the tuner unit 300, and waits for a predetermined time until a broadcast signal is received (S404). Here, the frequency set of the PLL is set according to the center frequency of the channel N.

In this state, the channel manager 352 determines whether the RF (Radio Frequency) AGC (Automatic Gain Control) provided in the tuner unit 300 is received on the channel N or not (S406). As a result of the determination, if the RF AGC is not locked, the channel manager 352 determines that there is no broadcast signal received on the channel N, and determines whether the channel N is equal to or greater than the maximum channel number that can be received by the broadcast signal receiver S408).

If the N channel is not equal to or greater than the maximum channel number that can be received by the broadcast signal receiver, the channel manager 352 adds 1 to N (S410), returns to step S402, Repeating from the operation of receiving the broadcast signal.

If it is determined in step S406 that the broadcast signal is received on the channel N and the RF AGC is locked, the channel manager 352 determines whether a modulation signal is detected in the received broadcast signal (step S412).

If it is determined that the modulation signal is not detected, the channel manager 352 determines whether a predetermined time has elapsed (S414). If the predetermined time has not elapsed, the channel manager 352 returns to step S412, Is repeatedly performed.

If the modulation signal is not detected even if the set time elapses in such a state, the broadcast signal is not received on the corresponding channel, and the channel manager determines whether the channel N is equal to or greater than the maximum channel number that can be received by the broadcast signal receiver If it is determined in step S108 that the channel N is not equal to or greater than the maximum channel number that can be received by the broadcast signal receiver in step S410, the process returns to step S402 to return to step S402, Repeating from the operation of receiving the signal.

If a modulation signal is detected before the set time elapses, the channel manager 352 determines whether an offset frequency exists in the broadcast signal of the currently received channel N (S416).

If it is determined that the offset frequency exists, the channel manager 352 detects the first offset frequency using the offset frequency detection algorithm (S418). The channel manager 352 determines whether the received data is detected in the modulated signal (S420).

As a result of the determination, if the received data is detected, the broadcast signal is normally received on the corresponding channel, and the channel manager 352 detects the center frequency of the corresponding channel in the DVB-SI table processed by the program information processing unit 340 S422), and calculates a second offset frequency that is a difference between a center frequency of the corresponding channel broadcasting the detected current broadcasting signal and an original center frequency of the corresponding channel (S424).

The channel manager 352 determines whether the calculated range of the second offset frequency is within a preset frequency range (S426). For example, the channel manager 352 may determine that the range of the second offset frequency is within ± 500 kHz considering a margin of about 10% at ± 500 kHz, which is the range of offset frequencies allowed in the Corsica region of France It is judged whether or not it is.

As a result of the determination, when the range of the second offset frequency is within a predetermined frequency range, the channel manager 352 determines that the second offset frequency is the accurate offset frequency for the channel, The offset frequency is stored in the memory 300 as the offset frequency of the corresponding channel (S428).

As a result of the determination, when the range of the second offset frequency is out of the preset frequency range, the channel manager 352 determines that the second offset frequency is not accurate, And stores the offset frequency of the channel in the memory 300 (S430).

After storing the N-channel information and the offset frequency of the corresponding channel, the channel manager 352 determines whether the N-channel is greater than or equal to a maximum channel number that the broadcast signal receiver can receive (S408) If it is determined that the N channel is equal to or larger than the maximum channel number that can be received by the broadcast signal receiver, 1 is added to the N channel (S410), and the flow returns to step S402 to repeat the operation of receiving the N channel broadcast signal do.

5 is a signal flow diagram illustrating an operation of receiving a broadcast signal of a predetermined channel selected in the receive channel control method of the present invention. Referring to FIG. 5, the channel manager 352 included in the broadcast signal receiver determines whether an N-channel tuning command is input from the user (S500).

As a result of the determination, when the tuning command of the N channel is input, the channel manager 352 reads the information of the N channel and the offset frequency of the N channel together (S502), and outputs the read N channel information and offset frequency to the tuner unit 300) and then waits for a predetermined time for receiving a broadcast signal of the corresponding channel (S504)

In this state, the channel manager 352 determines whether or not the received data is detected from the output signal of the tuner unit 300 (S506), fixes the frequency of the PLL when the received data is detected, (S508).

That is, when a scan command for a channel on which a broadcast signal is received is generated, the channel manager 352 sequentially selects all channels and determines whether a broadcast signal is received and whether an offset frequency exists, In the case of a channel on which a signal is received, the information of the channel and the offset frequency are stored together in the memory 360.

When receiving a broadcast signal of a predetermined channel, the channel manager 352 reads the information of the corresponding channel and the offset frequency from the memory 360, and outputs the frequency of the PLL, which is provided in the tuner unit 300, It is possible to receive a broadcast signal of a predetermined channel at a high speed by setting it according to the offset frequency.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, I will understand.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

In the present invention, when a channel on which a broadcast signal is received is scanned, the channel in which the broadcast signal is received and the offset frequency information of the channel are stored together. When the user instructs reception of a predetermined channel, Information and offset frequency are read out and the broadcasting signal is received, so that it is possible to switch at a high speed when the receiving channel is switched.

1 is a signal flow diagram illustrating an operation of scanning a channel through which a broadcast signal is received in a broadcast signal receiver,

2 is a signal flow diagram illustrating an operation of receiving a broadcast signal of a predetermined channel selected by a broadcast signal receiver,

3 is a block diagram illustrating a configuration of a preferred embodiment of a broadcast signal receiver according to the present invention.

4 is a signal flow diagram illustrating an operation of scanning a channel on which a broadcast signal is received in the receive channel control method of the present invention, and Fig.

5 is a signal flow diagram illustrating an operation of receiving a broadcast signal of a predetermined channel selected in the receive channel control method of the present invention.

Claims (8)

A tuner unit for setting a frequency of a PLL (Phase Locked Loop) according to a channel to be received and receiving a broadcast signal of the channel; A demodulator for demodulating the broadcast signal received by the tuner; A demultiplexer for demultiplexing the demodulated signal of the demodulator to extract an AV (Audio and Video) signal and program information; An AV signal decoder for decoding the AV signal; A program information processing unit for processing the program information; And And a user interface unit for controlling the tuner unit, the demodulator, the demultiplexer, the AV signal decoder, and the program information processor according to a user command input from the outside to receive a broadcast signal of a predetermined channel, Wherein the user interface unit comprises: When a user command for channel scanning is inputted, the controller controls the PLL to sequentially receive broadcast signals of all channels, store information of a channel on which a broadcast signal is received and an offset frequency of the channel in a memory, When a user command is input, controls the frequency of the PLL to be set by reading the information of the corresponding channel and the offset frequency of the corresponding channel in the memory, The user interface unit detects a first offset frequency of the corresponding channel using an offset frequency detection algorithm and detects a center frequency of a corresponding channel included in a DVB-SI (Digital Video Broadcasting-System Information) table received together with the broadcast signal And calculates a second offset frequency as a difference value from the original center frequency of the corresponding channel. If the calculated second offset frequency is within a predetermined frequency range, the second offset frequency is offset And stores the first offset frequency as an offset frequency of the corresponding channel when the second offset frequency is not within a predetermined frequency range. delete A channel scanning step of controlling the PLL of the tuner unit according to a user command of the channel scan to sequentially receive broadcast signals of a plurality of channels and storing information of a channel on which a broadcast signal is received and an offset frequency of the channel in a memory; And And a broadcast signal receiving step of causing the channel manager to read the information of the corresponding channel and the offset frequency of the corresponding channel in the memory according to a user command for receiving a predetermined channel, thereby setting the frequency of the PLL, Wherein the channel scanning step comprises: Determining whether a broadcast signal is received while setting a frequency of the PLL according to a channel of a broadcast signal to be received; Extracting an offset frequency of a corresponding channel when the broadcast signal is received, and storing information on the channel and the extracted offset frequency in the memory, Storing said offset frequency; Detecting a first offset frequency with an offset frequency detection algorithm; Which is a difference value between a center frequency of the corresponding channel broadcast and an original center frequency of the corresponding channel extracted and extracted from a DVB-SI (Digital Video Broadcasting-System Information) table included in the received broadcast signal, 2 calculating an offset frequency; And stores the second offset frequency as an offset frequency of the corresponding channel if the calculated range of the second offset frequency is within a predetermined range, and when the range of the second offset frequency is not within the predetermined range, And storing the offset frequency as an offset frequency of the corresponding channel. delete delete The method of claim 3, wherein the determining whether the broadcast signal is a channel includes: After setting the frequency of the PLL, an RF (Radio Frequency) AGC (Automatic Gain Control) provided in the tuner unit is locked, a modulated signal is detected, and when received data is detected in the detected modulated signal, And determining that the received signal is a received channel. 4. The method of claim 3, wherein the broadcasting signal reception step comprises: When the user command for receiving a predetermined channel is inputted, the channel manager reads the information of the corresponding channel and the offset frequency of the corresponding channel in the memory; And setting a frequency of the PLL according to the information of the read channel and the offset frequency of the corresponding channel to receive a broadcast signal of the corresponding channel. 8. The method of claim 7, further comprising: after setting the frequency of the PLL; Determining whether the received data is detected in the received broadcast signal, and fixing the frequency of the PLL when the received data is detected.

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