JP3141922B2 - Digital broadcast receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for digital broadcasting corresponding to communication satellite broadcasting and TV (Television) broadcasting, and more particularly to an MPEG (Moving Picture Expert).
Group) proposes a digital broadcast receiver that can automatically check the program contents, select a broadcast channel, and easily and reliably select a channel in the MPEG multiplexing system, which is one standard for moving picture compression.

[0002]

2. Description of the Related Art Conventionally, a digital broadcast receiver of this type, for example, when receiving a CS (Communications Satellite) satellite broadcast, receives a 12 GHz band radio wave for a satellite broadcast and receives a first intermediate frequency signal of a 1 GHz band. Since the converter for converting to has a different first local oscillation frequency depending on the model, even if the frequency of the first intermediate frequency signal output by the converter differs from the frequency preset in the receiver, There has been proposed a technology capable of selecting a channel from a broadcast wave received by automatic adjustment.

[0003] First, FIG.
This will be described with reference to FIG.

A 12 GHz band radio wave for satellite broadcasting is converted into a first intermediate frequency signal having a frequency of 1 GHz band by a converter 2 in an antenna 1, and the first intermediate frequency signal is converted by a frequency converter 22 into a second local signal. The second local oscillation frequency is received from the oscillation unit 28 and converted into a second intermediate frequency signal. The second local oscillator 28 sets a second local oscillation frequency corresponding to the channel to a PLL (Phase-Locked Loop) for each channel selection.
It is generated by a synthesizer or the like.

[0005] The first local oscillation frequency generated by the converter for receiving satellite broadcasts is mainly 11.3G.
Hz, 11.2 GHz, 11.3 GHz, etc., and the first local oscillation frequency differs depending on the type of converter.

The first intermediate frequency signal is output from the converter 2 at a frequency obtained by subtracting the first local oscillation frequency from the radio wave of the 12 GHz band, so that a different first local oscillation frequency is output even in the same channel of the same satellite. The frequency becomes completely different corresponding to the converter 2.

Therefore, when installing a digital broadcast receiver, the second local oscillation frequency is adjusted according to the first local oscillation frequency of the converter 2.

A technique for solving this problem is described in, for example, Japanese Patent Application Laid-Open No. Hei 6-22234. This broadcast receiver will be described with reference to FIG.

A broadcast wave received via the antenna 1 and the converter 2 is supplied to a first intermediate frequency amplifying section 21 and a frequency converting section 2.
2. The signal is converted into a baseband signal by the second intermediate frequency amplifier 23 and the demodulator 24 and output.

On the other hand, for the combination of the first local oscillation frequency and each of all the channels, the frequency offset detector 25 detects the offset frequency and the signal presence / absence determiner 26 from the second intermediate frequency signal via the demodulator 24. The presence or absence of each signal is detected, and the information is sent to the control unit 27.
Are stored in the storage unit 28 and are created in a table. The control unit 27 determines the correct first local oscillation frequency from this table, writes the first local oscillation frequency into a register, and stores the array of the second local oscillation frequency corresponding to the determined first local oscillation frequency in the storage unit. 28. Thereafter, the channel selection operation is performed at the second local oscillation frequency.

More specifically, first, three types of first local oscillation frequency data and one type of channel data are stored, and the deviation of the first local oscillation frequency is finely tuned in all patterns obtained by combining them. Store as data. Next, the first local oscillation frequency that can be received with fine tuning with the same deviation from the stored fine tuning data and that can receive more channels is adopted and determined to be correct. Thereafter, a channel selection operation is performed based on the second local oscillation frequency data separately stored corresponding to the first local oscillation frequency.

On the other hand, another technique is disclosed in, for example,
No. 15895. In the receiver disclosed herein, for the purpose of simplifying fine tuning, 1
When a broadcast frequency of one channel is received, a fine tuning frequency is stored, and this fine tuning frequency is added to frequency data when a next channel is selected.

Further, another technique is disclosed in, for example, Japanese Patent Laid-Open No. 5-1.
No. 99526. In the receiver disclosed herein, for the purpose of automatically recognizing the first local oscillation frequency of the converter, the first intermediate frequency data corresponding to the five types of first local oscillation frequencies and the broadcast frequencies of a plurality of satellites are transmitted. All the combined patterns are stored, and reception is performed for all of the patterns. As a result, the first local oscillation frequency that can be received within a specified fine tuning frequency range is automatically adopted.

[0014]

The above-mentioned conventional digital broadcasting receiver has the following problems.

The first problem is that there is an opportunity to receive an erroneous broadcast channel at a fine tuning frequency due to a frequency offset or the like.

The reason is, for example, that although the program being broadcast is the first channel, there is an opportunity to select the second channel from the second local oscillation frequency table, and in this case, there is no confirmation of the program. is there.

The second problem is that automatic recognition by fine tuning cannot be performed, and there is a chance that manual adjustment is required when receiving broadcast waves.

The reason is that the reception is attempted at a frequency registered in advance, and the fine tuning frequency is selected based on the possibility of reception and the amount of correction, but it has a first local oscillation frequency not registered in the receiver. This is because, when connected to a converter, this frequency cannot be received because the frequency is not registered, and it is determined that there is no corresponding channel.

A third problem is that an erroneous table is selected, and there is an opportunity to manually take trouble when receiving a broadcast channel.

[0020] The reason is that the reception is attempted at a frequency registered in advance, and the fine tuning frequency is selected based on the possibility of reception and the amount of correction, but the first local oscillation frequency is connected to a converter having a deviation. This is because, in such a case, a converter having a near first local oscillation frequency is erroneously recognized, a correct table is not selected, and a broadcast channel that cannot be received occurs.

The fourth problem is that the storage unit has channel data that is not used when the device is installed, and the storage area is wasted. This is because the versatility has been promoted so as to be able to cope with the automatic recognition of a converter having a plurality of different first local oscillation frequencies, and the data having the first local oscillation frequency other than those used is provided.

It is an object of the present invention to automatically create a correspondence table of broadcast channels and program information for the first local oscillation frequency even if the first local oscillation frequency of the converter is unknown, and to create the table. Another object of the present invention is to provide a digital broadcast receiver capable of deleting data for a first local oscillation frequency other than the above from a correspondence table.

[0023]

SUMMARY OF THE INVENTION A digital broadcast receiver according to the present invention comprises: a PLL synthesizer; a local oscillation frequency of the PLL synthesizer is changed to sequentially sweep a broadcast wave received via an antenna within the local frequency band. Broadcast wave detecting means for detecting broadcast waves, and combining broadcast frequency information and program information read from the detected broadcast waves, and local oscillation frequency information of the PLL synthesizer when the broadcast waves are received.
And a correspondence table creating means for creating and storing a reception frequency list including at least broadcast frequency and program information and the local oscillation frequency as a correspondence table.

Further, the digital broadcast receiver according to the present invention, upon receiving a program selection designation, reads the corresponding local oscillation frequency by comparing it with the stored program information in the correspondence table, and reads out the corresponding local oscillation frequency. There is provided channel selection means for instructing the PLL synthesizer to select a broadcast channel.

The digital broadcast receiver embodying the above receives the sweep instruction, changes the frequency of the broadcast wave band, oscillates and outputs the signal, and also performs AFT (Automatic Frequency Tuning).
ng) a PLL synthesizer unit that stops changing the oscillation frequency when receiving the signal and outputs oscillation frequency information; and a first intermediate frequency signal of a broadcast wave received via an antenna and a converter. And a frequency converter that outputs a second intermediate frequency signal when the frequency matches the oscillation frequency received from the PLL synthesizer, and demodulates the second intermediate frequency signal that is output from the frequency converter.
A transmission path decoding unit that outputs and decodes an FT signal and outputs a transport stream, a digital multiplex decoding unit that extracts and outputs a control signal for selecting reception from the transport stream, and a sweep unit that sweeps the PLL synthesizer unit. While sending the instruction, when the AFT signal is received, the sweep instruction is stopped, the control signal is received, and the oscillation frequency information received from the PLL synthesizer unit is combined with the program information and broadcast frequency information included in the control signal. A control unit that creates and stores a correspondence table of broadcast frequencies, program information, and oscillation frequencies of broadcast channels.

Further, when the control unit receives a program selection designation, the control unit compares the program information with the stored program information in the correspondence table, reads out the oscillation frequency from the corresponding oscillation frequency information, and uses the oscillation frequency to generate the PLL synthesizer. Unit is instructed to output the oscillation frequency.

That is, when the above-mentioned means is connected to any type of converter, it obtains program information for each broadcast channel swept over all reception bands corresponding to that converter, Is automatically created and stored in a correspondence table between the local oscillation frequency and the program information for selecting.

Therefore, the above means does not receive an erroneous broadcast channel in which a program is switched according to a correspondence table including a program, and has no relation to the local oscillation frequency of the connected converter, so that the local oscillation frequency of the converter is registered in advance. No, in particular, it does not have a table for multiple types of converters, and sweeps over all the corresponding reception bands so that unreceivable broadcast channels do not occur, and when connected, only for the connected converter. Since the correspondence table is created automatically, the data of the broadcast channels that are not used are not stored.

[0029]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. In the digital broadcasting receiver shown in FIG. 1, in addition to a frequency conversion unit 3 which receives a broadcast wave from an antenna 1 via a converter 2 by a first intermediate frequency signal (hereinafter referred to as an IF signal), a transmission path decoding It is assumed that the digital multiplex decoding unit 5 includes a unit 4, a digital multiplex decoding unit 5, a control unit 6, a PLL synthesizer unit 7, and a storage unit 8, and a video stream and an audio stream are output from the digital multiplex decoding unit 5.

Further, the transmission path decoding unit 4 is provided with an IQ (In-phase)
/ Quarter-phase) demodulator 11, QPSK (Quaternary)
Phase-Shift Keying) demodulator 12, Viterb decoding (Viterb decoding)
i decoding) unit 13 and Reed-Solomon decoding (Reed
-Solomon decoding) unit 14, and the storage unit 8 stores the correspondence table 1
It is assumed that there are five storage areas.

The difference from the prior art is that in a digital broadcasting receiver using the MPEG multiplexing system, a PLL synthesizer section 7 for supplying a local oscillation frequency to a frequency conversion section 3 for receiving broadcast waves controls a control section 6. Receiving and sweeping from one end to the end of the reception band of the broadcast wave, and when a reception frequency equal to or higher than the predetermined level is obtained in accordance with the frequency of the broadcast wave, the second intermediate frequency signal output from the frequency conversion unit 3 is used. The control unit 7 sequentially stops by the obtained AFT (Automatic Frequency Tuning) signal, obtains program information and the like from the reception selection control signal included in the second IF signal, and adds local oscillation frequency information at that time to the correspondence table. 15.

The AFT signal is an IQ for inputting the second IF signal.
Obtained from the demodulation unit 11.

On the other hand, in digital broadcasting using the MPEG multiplexing method, in a broadcast wave signal, in addition to a video signal and an audio signal, a PSI (Programme Spec) of a reception selection control signal is included.
ificInformation) signal is multiplexed.

The PSI signal is frequency-converted from a first IF signal received from the antenna 1 to a second IF signal using a PLL synthesizer, and is converted into an IQ demodulation unit 11 of the transmission path decoding unit 4.
A transport stream defined by the MPEG multiplexing method obtained via the QPSK demodulation unit 12, the Viterbi decoding unit 13, and the Reed-Solomon decoding unit 14 is obtained from a signal decoded by the digital multiplex decoding unit 5.

The PSI signal includes a satellite selection signal and a program selection signal. Upon receiving any broadcast wave, it is possible to search for a selection signal of another broadcast wave.

As the satellite selection signal, there is NIT information shown in FIG. 2A, and the NIT information includes the satellite frequency and the polarization plane for each broadcasting station (broadcast channel). The PAT information shown in FIG. 2B and the PAT information shown in FIG.
There is PMT information shown in FIG.
The PAT information includes the program number set by the broadcasting station for the NIT number for each piece of NIT information, and the PM for each program.
A list of individual numbers of T information is included, and PAT information is
It contains program information on video and audio for each piece of information.

The correspondence table 15 stored in the storage unit 8 is shown in FIG.
As shown in FIG. 2, the PSI signal shown in FIG.
The local oscillation frequency of the synthesizer unit 7 is added as PLL data, and for each broadcast station (broadcast channel, broadcast frequency),
It is assumed that it is created sequentially for each program.

Next, referring to FIGS. 1 to 3 together with FIG. 4, a procedure for automatically creating a correspondence table centered on the control unit 6 will be described.

First, the control unit 6 instructs the PLL synthesizer unit 7 to start sweeping (step S101), and waits for an AFT signal received from the transmission line decoding unit 4 (step S102). Upon receiving the sweep start instruction, the PLL synthesizer unit 7 starts sweeping from one end of the broadcast wave reception band.

On the other hand, the frequency conversion unit 3 determines the frequency of the broadcast wave received via the antenna 1 and the converter 2,
When the local oscillation frequency received from the PLL synthesizer unit 7 matches, the broadcast wave is converted into a second IF signal and sent to the transmission path decoding unit 4. The transmission path decoding unit 4 generates an AFT signal when the IQ demodulation unit 11 automatically tunes and receives a broadcast wave, and sends it to the control unit 6 and the PLL synthesizer unit 7.

The control unit 6 converts the AFT signal into an IQ demodulation unit 11
(YES in step S102), the CPU 11 instructs the PLL synthesizer unit 7 to stop the sweep (step S103). P
Since the LL synthesizer unit 7 receives the AFT signal from the IQ demodulation unit 11 and receives the instruction to stop the sweep from the control unit 6, the LL synthesizer unit 7 stops the sweep of the local oscillation frequency and sends frequency information including the local oscillation frequency to the control unit.

The control section 6 stores the frequency information received from the PLL synthesizer section 7 (step S104).

On the other hand, the second IF signal is output as a transport stream to the digital multiplex decoding section 5 via the transmission path decoding section 4, and the digital multiplex decoding section 5 extracts the PSI signal from the transport stream and sends it to the control section 6. send.

The control section 6 sends the P
NIT information, PAT information, and P included in the SI signal
The MT information is received (step S105), a correspondence table of the program information and the reception frequency as shown in FIG. 3 is created (step S106), and the local oscillation frequency during oscillation received from the PLL synthesizer unit 7 in step S104. Is recorded in the correspondence table as PLL data (step S107).

Next, the control section 6 stores the correspondence table 15 created and stored in the storage section 8 (step S108).
Instruct the PLL synthesizer unit 7 to restart the sweep (step S109), and return to the step S102 for receiving the AFT signal from the IQ demodulation unit 11.

If the control unit 6 receives from the PLL synthesizer unit 7 as frequency information that the reception band to be swept has reached the end while the procedure S102 is "NO" and waits for the reception of the AFT signal (step S110). YES), the procedure for creating the correspondence table ends.

The correspondence table 15 automatically created and stored in the storage unit 8 is referred to by the control unit 6 when the control unit 6 receives a program selection instruction from the operator. The control unit 6 determines the PL from the correspondence table 15 based on the received program number.
A broadcast wave (broadcast channel) in which the L data and the program information are indexed, a local oscillation frequency based on the PLL data is instructed to the PLL synthesizer section 7, and the frequency conversion section 3 obtains the broadcast wave.
Is selected, and program information related to video and audio is sent to the digital multiplex decoding unit 5. The digital multiplex decoding section 5 selects a video stream and an audio signal from the transport stream input from the transmission path decoding section 4.

In the above description, the configuration corresponding to the MPEG multiplexing system is illustrated as the transmission path decoding unit and the digital multiplexing decoding unit. However, in other systems, an AFT signal is generated and a broadcast wave including necessary program information is included. Is used, the necessary information can be extracted from the broadcast wave automatically, and the correspondence table can be automatically created and stored, so that this function can be exhibited.

In the above description, PAT information is received after receiving frequency information in the procedure.
Other orders may be used.

As described above, the present invention has been illustrated and described. However, the separation, merging, distribution, and the like of functions, or the exchange of procedures before and after, parallel operation, and the like are free as long as the above functions are satisfied. It is not limited.

[0052]

As described above, according to the present invention, the following effects can be obtained.

The first effect is that even if the broadcast frequency of a program is switched, it will not be erroneously received.

The reason is that the reception frequency is created in the correspondence table in combination with the program information, and the program is selected and instructed based on the correspondence table, and the station is selected by selecting the broadcast wave.

A second effect is that a broadcast channel can be automatically set by connecting to any type of converter.

The reason is that the data of the first local oscillation frequency included in the converter is not necessary because the entire reception band of the broadcast wave is swept and searched to create the reception data of the broadcast wave in the correspondence table. is there.

A third effect is that no unreceivable broadcast channel is generated even when the broadcast channel is automatically set. Therefore, troublesome manual reception can be avoided.

The reason is that since broadcast waves are searched over the entire reception band without preparing a frequency table in advance, no omission occurs in a set broadcast channel.

A fourth effect is that the storage area of the storage unit can be used effectively by setting only the necessary amount of broadcast channel data to be stored.

The reason is that, when the apparatus is installed, a correspondence table of program information and the like with respect to a reception frequency is created from a received broadcast wave. Is unnecessary, and data is automatically generated only from received broadcast waves, so that data of an unused broadcast channel is not generated.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of program information showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a correspondence table showing an embodiment of the present invention.

FIG. 4 is a flowchart showing one embodiment of a correspondence table creation procedure of the present invention.

FIG. 5 is a functional block diagram showing an example of the related art.

[Explanation of symbols]

 Reference Signs List 1 antenna 2 converter 3 frequency conversion unit 4 transmission line decoding unit 5 digital multiplex decoding unit 6 control unit 7 PLL synthesizer unit 8 storage unit 11 IQ demodulation unit 12 QPSK demodulation unit 13 Viterbi decoding unit 14 Reed-Solomon decoding unit 15

Claims (4)

(57) [Claims] 1. A PLL (Phase-Locked Loop) synthesizer, and a broadcast for detecting a broadcast wave by changing a local oscillation frequency of the PLL synthesizer and sequentially sweeping a broadcast wave received via an antenna within the local frequency band. Wave detecting means, broadcast frequency information and program information read from the detected broadcast wave, and the PLL when the broadcast wave is received
And a correspondence table creating means for creating and storing at least broadcast frequency and program information for all broadcast channels, and a reception frequency list including the local oscillation frequency as a correspondence table by combining local oscillation frequency information of the synthesizer. Digital broadcast receiver. 2. The method according to claim 1, further comprising, upon receiving a program selection designation, comparing the stored program information in the correspondence table with a stored local oscillation frequency, and instructing the PLL synthesizer based on the local oscillation frequency. A digital broadcast receiver comprising channel selection means for selecting a broadcast channel by performing a selection. 3. Receiving a sweep instruction, changing the frequency of the broadcast wave band, oscillating and outputting the signal, and performing AFT (Automatic Freq).
and a PLL synthesizer unit that stops changing the oscillation frequency when receiving the signal and outputs oscillation frequency information, and a first intermediate frequency signal of a broadcast wave received via an antenna and a converter. A frequency converter that outputs a second intermediate frequency signal when the frequency of the signal matches the oscillation frequency received from the PLL synthesizer;
A transmission path decoder for demodulating the second intermediate frequency signal output from the frequency converter, outputting and decoding the AFT signal and outputting a transport stream, and a control signal for selecting reception from the transport stream A digital multiplexing decoding unit for extracting and outputting a sweep instruction to the PLL synthesizer unit, while stopping the sweep instruction when receiving the AFT signal, receiving the control signal, and receiving program information included in the control signal. In the broadcast frequency information, the PLL
A digital broadcast receiver, comprising: a control unit that creates and stores a correspondence table of broadcast frequency, program information, and oscillation frequency of a broadcast channel by combining oscillation frequency information received from a synthesizer unit. 4. The control unit according to claim 3, wherein the control unit, upon receiving a program selection designation, checks the program information in the stored correspondence table and reads out the oscillation frequency from the corresponding oscillation frequency information. A digital broadcast receiver for instructing the PLL synthesizer unit to output the oscillation frequency based on a frequency.