JP2004349758A - Receiver for digital broadcast - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable proper reception in a receiver of a DAB system. <P>SOLUTION: In the receiver in a DAB (digital audio broadcasting) system, the data about ensemble and service are stored in a RAM (random access memory) 43. When countries represented by country identification codes or extended country codes change, the data about the ensemble and service stored in the RAM 43 are collectively deleted. After this deletion, the storage of data about of the ensemble and service into the RAM 43 is resumed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a digital audio broadcasting receiver.
[0002]
[Prior art]
In Europe, broadcasting according to the Eureka 147 standard is carried out as digital audio broadcasting. This digital audio broadcast is generally called DAB. This DAB is
Transmission bandwidth: 1.5MHz
Modulation method: OFDM
Data compression method of audio signal: Layer II of MPEG audio is adopted.
[0003]
As described above, one transmission channel uses a transmission bandwidth of 1.5 MHz. This transmission channel is called an “ensemble”, and the ensemble is tuned to the center frequency of the ensemble. Is selected. Further, the ensemble is divided into a plurality of channels called "services". Although the number of the services is 64 channels at the maximum, each of the services corresponds to, for example, one FM broadcasting station, and digital data such as digital audio data is broadcast by each of the services.
[0004]
Therefore, when listening to a DAB program, an ensemble (frequency) is selected, and a target service is selected from a plurality of services (programs) included in the ensemble. Since the ensemble and the service are given identification codes called “ensemble ID” and “service ID”, respectively, the target service can be selected or specified by the ensemble ID and the service ID.
[0005]
FIG. 4A shows a configuration of a transmission frame in DAB. Each frame has a synchronization channel SC, a high-speed information channel FIC, and a main service channel MSC. In this case, the synchronization channel SC is used for processing such as frame synchronization and AFC, and is composed of a null symbol NULL and a phase reference symbol TFPR as shown in FIG. 4B.
[0006]
The high-speed information channel FIC is configured as described below, and is for indicating information such as what services are being sent at what transfer rate and how many to the main service channel MSC. Further, the main service channel MSC is for providing an original service, and digital audio data and various digital data are arranged therein.
[0007]
The configuration of the high-speed information channel FIC is composed of a plurality of blocks FIB as shown in FIG. 4C, and each block FIB is composed of a plurality of groups FIG and other data as shown in FIG. 4D. It is composed of Note that the number of block FIBs per one high-speed information channel FIC and the number of group FIGs per one block FIB differ depending on the frame transmission mode.
[0008]
Then, the group FIG is one of the configurations shown in FIGS. 4E to 4H corresponding to the configuration of the main service channel MSC. 4E and 4H have a header, a country identification code (Country ID) CID, and other data. Here, the country identification code CID is 4 bits, and takes any one of hexadecimal values "1" to "F", as shown in FIG. Have been assigned. For example, in France, CID = “F”, and in the UK, CID = “C”.
[0009]
4F and 4G have an extended country code (Extended Country Code) ECC in addition to the country identification code CID. This extended country code ECC is used when the country identification code CID alone does not sufficiently correspond to each country. As shown in FIG. 5, an 8-bit hexadecimal value "E0" to "E4" is used. Take one of the values
[0010]
Further, the high-speed information channel FIC also provides data such as a service name and its identification code, an ensemble name and its identification code transmitted by the main service channel MSC.
[0011]
6A and 6B show examples of data that could be obtained when DABs were actually received in France and the United Kingdom. In the reception example in France (FIG. 6A), since the country identification code CID is “F” in France, the head of the ensemble ID and the service ID is “F”. In the UK reception example (FIG. 6B), since the country identification code CID and extended country code ECC of the United Kingdom are “C” and “E1”, the service ID starts with “C” or “E1”.
[0012]
Therefore, in the DAB receiver, by registering the ensemble ID and the service ID in the receiver in advance, a desired service can be selected and received with one touch.
[0013]
Further, even when the FM broadcasting provides the RDS service, when the program is broadcast, the data related to the program and the broadcasting station are transmitted together with the program. Program to be performed can be selected (for example, see Patent Document 1).
[0014]
[Patent Document 1]
JP-A-7-79135
[0015]
[Problems to be solved by the invention]
By the way, the conventional baseband chip for DAB reception consumes large power, and therefore, it has been difficult to develop a portable DAB receiver.
[0016]
However, recent advances in semiconductor processes have made it possible to reduce the power consumption of baseband chips for DAB reception. As a result, portable DAB receivers or DABs that can be driven by dry batteries or secondary batteries have been received. Machine became feasible. Therefore, the user can enjoy digital audio broadcasting even while traveling by long-distance train.
[0017]
However, since various countries are close to each other in Europe, there are many opportunities to move to each country for work or play, and it is possible to move easily. And DAB is served by country. For this reason, when the user moves from one country to another country, the user cannot receive the service he or she was listening to until then.
[0018]
For example, when traveling from France to the United Kingdom by boarding the Eurostar, first, in France, the service shown in FIG. 6A can be received, but when Eurostar enters the Eurotunnel, the previous service cannot be received. Then, after 20 to 30 minutes have passed and the train enters the mainland of England, DAB can be received. However, at this time, the service cannot be received because the frequency position of the ensemble is generally different in the UK.
[0019]
Therefore, the user performs an ensemble search and receives a new ensemble service. That is, when moving from one country to another, data such as ensemble and service remaining in the DAB receiver becomes meaningless. Rather, the display of the DAB receiver displays an ensemble or service name that cannot be received due to the meaningless data.
[0020]
Even if the ensemble is broadcast on the same frequency as the source (France) in the destination (UK), the ensemble ID and the service ID change, and the service configuration in the ensemble also changes. Machine needs to rebuild the service. Otherwise, the DAB receiver will try to receive the source service at the destination, and will continue to do so.
[0021]
The present invention is intended to solve the above problems.
[0022]
[Means for Solving the Problems]
In the present invention,
A receiver for receiving a digital broadcast in which a set of digital data of a plurality of programs, data of information on each of the plurality of programs, and an identification code indicating a country to which the broadcast is directed,
When the digital broadcast is received, the data of the information is stored in a RAM,
When the identification code changes, the data of the information stored in the RAM is erased collectively,
After the erasure, the storage of the information data in the RAM is restarted.
The digital broadcasting receiver is configured as described above.
Therefore, when the receiving country changes, various data are cleared and then updated
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
(1) First embodiment
In this example, when the receiving country of the DAB changes due to the movement of the user, meaningless display is not displayed and ensemble and service can be appropriately reconstructed.
[0024]
In FIG. 1, reference numeral 10 denotes an example of a DAB receiver according to the present invention. In the DAB receiver 10, a broadcast wave signal of DAB is received by an antenna 11, and the received signal is supplied to a front-end circuit 12 configured in a superheterodyne format and down-converted into an intermediate frequency signal of a predetermined frequency. The intermediate frequency signal is supplied to the A / D converter circuit 13 and A / D converted into a digital signal.
[0025]
The digital signal is supplied to the quadrature demodulation circuit 14 to demodulate data of the in-phase component (I component) and the quadrature component (Q component) of the baseband. Output data in the frequency domain. The data in the frequency domain is deinterleaved by a deinterleave circuit 16 and then supplied to a Viterbi decoder circuit 17 where error correction is performed, and a service (program) is selected to obtain digital audio data of a target service. (MPEG data) is extracted.
[0026]
Subsequently, the extracted MPEG data is supplied to a decoder circuit 18 to decode digital audio data of a target service, and the decoded digital audio data is supplied to a D / A converter circuit 19 to be supplied with an analog audio signal. The signal is supplied to the speaker 22 through the amplifier 21.
[0027]
At this time, of the data in the frequency domain obtained by the FFT circuit 15, data of the symbol TFPR for phase reference (see FIG. 4) is supplied to the DSP 31, and the AFC of the front end circuit 12 is performed. 15 and a process such as synchronization in the Viterbi decoder circuit 17 are executed.
[0028]
Further, a microcomputer 40 is provided for system control, and predetermined signals are accessed between the DSP 31 and the circuits 17 and 18 to select an ensemble and a service.
[0029]
In this case, the microcomputer 40 has a CPU 41 that executes various processing routines, a ROM 42 in which those processing routines are written, and a RAM 43 for a work area. Further, the microcomputer 40 has a nonvolatile memory 44 for storing various data, and an input / output circuit 45 for a user interface. The key 52 is connected.
[0030]
The LCD 51 is used to display information about services being received during DAB reception and to display setting items and contents when various settings are made. The key 52 is used to select an ensemble or a service or to perform various settings when executing the setting, and includes, for example, a program key for receiving a preset.
[0031]
Further, the memory 44 has a preset table for receiving presets. In the preset table, when a service is registered in the program key of the keys 52, data for receiving the service is stored. When one of the program keys is operated, data corresponding to the operated program key is taken out of the data stored in the preset table and supplied to the front-end circuit 12 and the Viterbi decoder circuit 17, and the operation is performed. The service registered in the registered program key is received.
[0032]
When an arbitrary service is received, various data obtained during the reception, for example, data such as an ensemble ID, a service ID, an ensemble label, and a service label are accumulated in the RAM 43.
[0033]
The stored data is used when receiving a service corresponding to the data. That is, when a certain service is being received, data relating to another service simultaneously broadcast by the same ensemble is also obtained. Yes, or switch reception to another service.
[0034]
When the service being received is switched to another service, the data necessary for receiving the switched service, that is, the ensemble ID and the service ID are stored in the last channel (until immediately before the power is turned off last time). The received service is stored in the memory 44 as data. Then, when the power is turned on next time, the service received until immediately before the power was last turned off is received according to the data of the last channel.
[0035]
In addition to the above configuration, especially in the present invention, a routine 100 as shown in FIG. The details of the routine 100 will be described later, but in FIG. 2, the routine 100 only shows a portion related to the present invention. The routine 100 is repeatedly executed by the CPU 41, for example, every one minute while the power of the DAB receiver 10 is turned on. When the last channel data is stored in the memory 44, the country identification code CID and the extended country code ECC are also stored.
[0036]
Then, the processing of the CPU 41 for the routine 100 starts from step 101 of the routine 100. Next, in step 102, when the ensemble is not received, the ensemble is received, for example, by scanning a DAB broadcast frequency band. Subsequently, the process proceeds to step 103, in which the country identification code CID and the extended country code ECC are extracted from the ensemble being received.
[0037]
Next, in step 104, the country identification code CID obtained in step 103 is compared with the country identification code CID stored in the memory 44. The country identification code CID (and the extended country code ECC) stored in the memory 44 is stored in the memory 44 when the service received as described above is changed or when step 113 described later is executed. It is saved in.
[0038]
Then, as a result of the comparison of the country identification codes CID in step 104, if the two are equal, the process proceeds from step 104 to step 105, where the extended country code ECC acquired in step 103 and the memory 44 are stored in the memory 44. The stored extended country code ECC is compared.
[0039]
As a result of the comparison of the extended country codes ECC, if the two are equal, it is the same as the current receiving country when the country identification code CID and the country extended code ECC are received and stored in the memory 44. That is, the current receiving country is the same as the receiving country of the last channel. Therefore, the process proceeds from step 105 to step 114, and ends the routine 100. In this manner, even if the routine 100 is executed, if the country receiving the DAB does not change, all data stored in the RAM 43 and the memory 44 is left as it is.
[0040]
However, as a result of the comparison of the country identification codes CID in step 104, if the two are different, it means that the current receiving country is different from the receiving country when the country identification code CID was received and stored in the memory 44. And the service is changing. Therefore, in this case, the process proceeds from step 104 to step 111, and in this step 111, data such as ensemble and service stored in the RAM 43 are collectively erased.
[0041]
Subsequently, the process proceeds to step 112, in which data on the currently received ensemble or service is stored and accumulated in the RAM 43, and subsequently, in step 113, the data stored in the memory 44 is stored in the memory 44. The identification code CID and the extended country code ECC are updated with the data obtained in step 103. After that, the routine 100 ends at step 114.
[0042]
Therefore, when the country receiving the DAB changes, the identification codes CID and ECC stored in the memory 44 and the data stored in the RAM 43 are updated to the data in the receiving country.
[0043]
Further, as a result of the comparison of the extended country codes ECC in step 105, if the two are different, the current receiving country is different from the receiving country when the country identification code CID and the extended country code ECC are received and stored in the memory 44. If the ensemble and services are changing. Therefore, in this case, the process proceeds from step 105 to step 111. Thereafter, steps 111 to 113 are executed as described above, and the identification codes CID and ECC stored in the memory 44 are stored in the RAM 43. Existing data is updated to the data in the receiving country.
[0044]
Thus, according to the routine 100, when the receiving country changes due to the movement of the DAB receiver 10, various data stored in the RAM 43 is deleted once, and then data such as ensemble and service in the receiving country is renewed. It accumulates. Therefore, for example, when the user travels from France to the United Kingdom on a Eurostar, information on ensembles and services that cannot be received on the LCD 51 based on meaningless data is not displayed.
[0045]
Also, since the receiving country has changed, when reassembling the ensemble and the service in the RAM 43, the data used for the restructuring is distributed over a plurality of frames. It takes time. However, in the routine 100, when the receiving country changes, the data in the RAM 43 is collectively erased in step 111 and then updated to new data in step 112, so that old data and new data may be mixed. There is no. Therefore, the ensemble and the service can be appropriately reconstructed, and it is possible to prevent the destination from trying to receive the source service or maintaining the state.
[0046]
In the above description, for example, when data is deleted in step 111, the fact that the country indicated by the country identification code CID and the extended country code ECC has changed can be displayed on the LCD 51. Further, it is also possible to enable or disable these functions for each country or collectively for all countries. Alternatively, the routine 100 may be executed only when the power is turned on.
[0047]
(2) Second embodiment
In this example, the preset table for preset reception is updated when the DAB receiving country changes.
[0048]
Also in this example, the hardware of the DAB receiver 10 is configured as shown in FIG. In the ROM 42, for each country indicated by the country identification code CID and the extended country code ECC, a preset table of ensembles and services that can be received in that country is prepared.
[0049]
Further, a routine 200 shown in FIG. 3 is provided in the ROM 42 instead of the routine 100 shown in FIG. 2, and this routine 200 is executed by the CPU 41, for example, every one minute while the DAB receiver 10 is powered on. It is executed repeatedly.
[0050]
Then, the processing of the CPU 41 for the routine 200 starts from step 201 of the routine 200, steps 202 to 205 similar to steps 102 to 105 of the routine 100 are executed, and the DAB is received by the country identification code CID and the extended country code ECC. It is determined whether the country has changed.
[0051]
If the receiving country has not changed, the process proceeds from step 205 to step 214, and the routine 200 ends. Thus, even if the routine 200 is executed, if the country receiving the DAB does not change, the preset table in the memory 44 is left as it is.
[0052]
However, if the receiving country has changed, the process proceeds from step 204 or 205 to step 211, where it is determined whether the ROM 42 has a preset table corresponding to the current receiving country. Is done. If a preset table corresponding to the current receiving country is prepared in the ROM 42, the process proceeds from step 211 to step 212. In this step 212, the preset table corresponding to the current receiving country is extracted from the ROM 42. Is written to the memory 44.
[0053]
Subsequently, the process proceeds to step 213. In this step 213, the fact that the preset table has been updated to the content corresponding to the current receiving country is displayed on the LCD 51, and then the routine 200 is ended in step 214.
[0054]
If the preset table corresponding to the current receiving country is not prepared in the ROM 42 in step 211, the process proceeds from step 211 to step 215. In this step 215, although the receiving country has changed, the preset table is updated. The inability to do so is displayed on the LCD 51, and then the routine 200 is terminated in step 214.
[0055]
Thus, according to the routine 200, when the receiving country changes with the movement of the DAB receiver 10, the preset table for preset reception is automatically updated, so that even in the destination country, the DAB can be received with one touch. can do.
[0056]
It is also possible to enable or disable automatic updating of the preset table for each country or collectively for all countries.
[0057]
(3) Third embodiment
In this example, when the receiving country of DAB changes, the preset table for preset reception is updated according to the contents based on the past reception history.
[0058]
Also in this example, the hardware of the DAB receiver 10 is configured as shown in FIG. Further, when the service is received, the ensemble and service data obtained at that time are classified by country indicated by the country identification code CID and the extended country code ECC, and are processed into a preset table format for each country. Stored in the memory 44.
[0059]
Further, a routine 200 shown in FIG. 3 is provided in the ROM 42, and this routine 200 is repeatedly executed by the CPU 41, for example, every one minute while the power of the DAB receiver 10 is turned on. However, in the case of this example, in step 211, it is determined whether a preset table corresponding to the current receiving country (a preset table processed from the reception history) is created in the memory 44. Then, when a preset table corresponding to the current receiving country is created in the memory 44, the process proceeds from step 211 to step 212. In this step 212, a preset table corresponding to the current receiving country is selected. The data is written to the original preset table in the memory 44.
[0060]
Therefore, in the case of this example, when the receiving country changes, the contents of the preset table are updated according to the receiving history in the receiving country, so that services with a high receiving frequency can be appropriately received.
[0061]
Also in this example, the user can select whether to enable / disable automatic updating of the preset table for each country or collectively for all countries.
[0062]
(4) Fourth embodiment
In the above description, the case where only reception of DAB is considered is considered. However, in the case of a receiver capable of receiving AM broadcast and FM broadcast in addition to DAB, the above item (2) or (3) is applied to DAB. When implementing, the same processing can be performed for AM broadcasting or FM broadcasting.
[0063]
In this case, the preset table is automatically updated according to the receiving country for not only DAB but also AM broadcasting and FM broadcasting. Therefore, it is possible to appropriately receive AM broadcasting and FM broadcasting even in the destination country. Can be.
[0064]
Also in this example, the user can select whether to enable / disable automatic updating of the preset table for each country or collectively for all countries.
[0065]
[List of abbreviations used in this specification]
A / D: Analog to Digital
AFC: Automatic Frequency Control
AM: Amplitude Modulation
CPU: Central Processing Unit
D / A: Digital to Analog
DAB: Digital Audio Broadcasting
DSP: Digital Signal Processor
Eureka: European Research Coordinating Agency
FFT: Fast Fourier Transform
FM: Frequency Modulation
LCD: Liquid Crystal Display
MPEG: Motion Picture Image Coding Experts Group
OFDM: Orthogonal Frequency Division Multiplex
RAM: Random Access Memory
RDS: Radio Data System
ROM: Read Only Memory
[0066]
【The invention's effect】
According to the present invention, when the receiving country changes due to the movement of the receiver, various data stored in the RAM is deleted once, and then the data in the receiving country is stored again. Information on broadcasts that cannot be displayed is not displayed.
[0067]
Also, when the receiving country changes and the data in the RAM is reconstructed, the old data and the new data are not mixed, so that the data can be properly reconstructed. It is possible to prevent the user from trying to receive the broadcast of the moving source or continuing the state. Further, when the receiving country changes, the preset table for receiving the preset is automatically updated, so that even in the destination country, the broadcast can be received with one touch.
[Brief description of the drawings]
FIG. 1 is a system diagram illustrating one embodiment of the present invention.
FIG. 2 is a flowchart illustrating one embodiment of the present invention.
FIG. 3 is a flowchart showing another embodiment of the present invention.
FIG. 4 is a diagram for explaining the present invention.
FIG. 5 is a diagram for explaining the present invention.
FIG. 6 is a diagram for explaining the present invention.
[Explanation of symbols]
Reference Signs List 10 DAB receiver, 11 Antenna, 12 Front end circuit, 13 A / D converter circuit, 14 Quadrature demodulation circuit, 15 FFT circuit, 16 Deinterleave circuit, 17 Viterbi decoder circuit, 18 Decoder Circuit, 19 D / A converter circuit, 21 amplifier, 22 speaker, 31 DSP, 40 microcomputer, 41 CPU, 42 ROM, 43 RAM, 44 nonvolatile memory, 45 input / output circuit , 51… LCD, 52… Key

Claims (4)

A receiver for receiving a digital broadcast in which a set of digital data of a plurality of programs, data of information on each of the plurality of programs, and an identification code indicating a country to which the broadcast is directed,
When the digital broadcast is received, the data of the information is stored in a RAM,
When the identification code changes, the data of the information stored in the RAM is erased collectively,
After the erasure, the digital broadcast receiver resumes storing the information data in the RAM. A receiver for receiving a digital broadcast in which a set of digital data of a plurality of programs, data of information on each of the plurality of programs, and an identification code indicating a country to which the broadcast is directed,
A digital broadcast receiver wherein, when the identification code changes, a preset reception preset table prepared for each country is changed to a preset table corresponding to the country indicated by the changed identification code. A receiver for receiving a digital broadcast in which a set of digital data of a plurality of programs, data of information on each of the plurality of programs, and an identification code indicating a country to which the broadcast is directed,
Data for selecting received programs is stored by country,
A digital broadcast receiver configured to set, as data for program selection, data corresponding to a country indicated by the changed identification code among data stored for each country when the identification code changes. In the digital broadcast receiver according to claim 2 or 3,
It has an AM broadcast or FM broadcast receiving circuit,
A digital broadcast receiver wherein when the identification code changes, data for receiving the AM broadcast or the FM broadcast is also changed at the same time.

Images