JPH0779170A - Rds data processing unit - Google Patents

Abstract

PURPOSE:To provide a RDS data processing unit in which synchronization is detected in a short time even when an error of reception data takes place and out-of-synchronism hardly takes place when the synchronization is once attained. CONSTITUTION:The processing unit is provided with an error rate detection section 11 receiving success/failure information for error correction outputted from an error correction processing section 5 and detecting an error rate of past reception data, a synchronization state discrimination section 12 receiving a data error rate outputted from the detection section 11 to discriminate whether the state is in the synchronization state or in the out of synchronism state, an RDS data initializing section 7 receiving the discrimination information to initialize RDS data being received in the case of out of synchronism, an RDS data storage section receiving and storing data received from the data error detection section 4 or the error correction processing section 5 when no error is in the received data or error correction is successful, and an RDS data output section 8 outputting the data stored in the RDS data storage section 6 to an external device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RDS data processor, and more particularly, it is mainly used in Europe.
DS (Radio Data System: hereinafter abbreviated as RDS)
The present invention relates to an RDS data processing device used in a receiver.

[0002]

2. Description of the Related Art In Europe, when a general broadcasting station broadcasts a program, information relating to the program (broadcasting station name, broadcasting station frequency broadcasting the same program, traffic information identification signal, etc.) is multiplexed as data. It is transmitted by modulation. There is a radio data system that allows the receiving side to demodulate this and select the desired program content based on that data, and to provide that service to radio listeners. , RDS.

An example of an RDS data processing device conventionally used in this RDS is shown in the block diagram of FIG. As shown in FIG. 4, this conventional example corresponds to the RDS demodulator 10 and an RDS data fetching unit 1 that fetches data from the RDS demodulator 10 bit by bit via an RDS input terminal 9. A syndrome exchange unit 2 for demodulating the captured data,
The data demodulation and the demodulated data are received, and the data demodulation synchronization signal detection unit 3 for determining whether the transmission data and the RDS receiver are in synchronization and the determination result by the data demodulation synchronization signal detection unit 3 are received. A data error detection unit 4 for detecting an error in the received data, and an error correction process for receiving the data error detection information output from the data error detection unit 4 and correcting the error in the received data and determining whether the correction is successful or unsuccessful. RDS data initialization for receiving the error correction failure information output from the error correction processing unit 5 and initializing the RDS data being received when the error correction processing unit 5 cannot correct the error The data input from the data error detection unit 4 or the error correction processing unit 5 when the unit 7 and the received data have no error or when the error correction is successful. And RDS data storage section 6 for storing received, in order to use the received demodulated data, RD
An RDS data output unit 8 that outputs the data stored in the S data storage unit 6 to the outside is configured. When demodulating RDS data, the received reception data is subjected to syndrome conversion, data demodulation, and synchronization signals are detected. If the synchronization signal cannot be detected, error correction processing is performed. If the error correction processing cannot be performed, data initialization including RDS data being captured is performed and data is captured again bit by bit. Done.

The radio data signal in RDS is repeatedly multiplexed and broadcast with 104 bits as one group, as shown in FIG. One group consists of four blocks each having 26 bits, and each block consists of a 16-bit information word and a 10-bit check word. Block 1 is a program identification (PI: Program Identification, hereinafter referred to as PI) code, and block 2 is a traffic information program identification (TP: T).
raffic-Program Identification (hereinafter referred to as TP)
Code, program announcement identification (TA: Traffic ー Announceme
nt Identification, hereinafter referred to as TA) code, program type (PTY: Program Type, hereinafter referred to as PTV) code, and the like. Block 3 shows the station frequency (AF: Alternative) of the network station broadcasting the same program. Frequencie
s, hereinafter referred to as AF) data, and block 4 is provided with program service name information (PS: Program Service Name, hereinafter referred to as PS) data such as a broadcasting station name and a network name.

By using this RDS digital data, in a car radio, even when the reception state changes due to movement, the AF code is used to continuously find broadcasting stations having the same broadcasting content one after another. Automatic tracking to receive,
There are various uses such as displaying a station name of a broadcasting station received using a PS code and searching for a traffic information station using a TP or TA code to search for a traffic information station. In car radios that utilize these, how quickly data is taken in is important. Especially, automatic tracking (AF operation)
In the case of performing, it is required to receive frequencies of a plurality of broadcasting stations, quickly find a broadcasting station having the best reception condition, and instantaneously switch the frequencies.

In this RDS receiver, the received RD
When there is a data error in one block of S data and the error correction is impossible, in the data processing device of the RDS receiver shown in FIG. 4, all the data (4 Block) and initialize 1 again
Data is re-acquired bit by bit. That is,
As shown in FIG. 6, when data is fetched from the block 1, if there is an uncorrectable error in the data of the block 4, the data of the blocks 1 to 3 that have been fetched up to that point are invalidated, The data is read again. For example, when processing is performed using the data of the block 2 (TP, TA, PTY, etc.), when the error in the data of the block 4 is detected, the synchronization is lost, and the block 1 fetched up to that point The data from to block 3 are invalidated. Therefore, the data of the required block 2 cannot be obtained until the data of the next group is fetched. Therefore, if a data error of several bits that cannot be corrected occurs, the synchronization is lost and the data is delayed.

As shown in FIG. 6, in the RDS data, the sync state and the out-of-sync state are A, B, C (or C ^′) as offset words for blocks 1 to 4, respectively. ) And D are assigned. That is, the block 1 is A, the block 2 is B, the block 3 is C (C ^' ), and the block 4 is D. In the RDS receiver, data errors, sync signals, etc. are detected based on this order.
For example, when the offset word of the data next to the offset word A is C (C ^' ) or D, it is determined that the data contains an error. Basically, a state in which received data is captured in the order of A → B → C (C ^′ ) → D is called a synchronization state, and a state in which the received data is not captured in order is called out of synchronization.

As a conventional solution to such a loss of synchronization, as shown in FIG. 7, every time one block of data is fetched, a data error from the present time to five blocks is checked to check for five blocks. When there is an uncorrectable error of 3 blocks or more (in FIG. 7,
For B, D, and A) shown as NG, it is determined that the synchronization is lost, and the method of reacquiring data bit by bit is performed.

As another conventional measure, a DRS receiver detects multipath interference (when multipath interference occurs, an error occurs in RDS data), and an error occurs depending on the occurrence status of the multipath interference. Correction ability of correction (0 to
A method of controlling 5-bit error correction (Japanese Patent Laid-Open No. 64-44645) has been proposed.

[0010]

DISCLOSURE OF THE INVENTION The conventional RDS described above
In the data processing device, as a measure against the above-mentioned out-of-sync, the data error of up to 5 blocks or less is checked every time one block of data is taken in, and if there is an uncorrectable error of 3 blocks or more, the out-of-sync is lost. In the case of the method of re-capturing data bit by bit, it is determined to be the synchronization state in the case of data error of 1 block and 2 blocks in a relatively good reception state, It can be used without clearing the previously fetched data, but when the reception status is poor, it becomes apparent that the synchronization status will be maintained, so the determination of loss of synchronization will be delayed, and the next synchronization recovery will occur. The result is that it takes time to clear the data, re-acquire the data, and perform synchronization detection. Further, since the synchronization state is set in spite of the state in which many data errors occur, there is a disadvantage that the error correction probability becomes high when performing error correction.

As another conventional measure, a method in which a multipath is detected by a DRS receiver and the error correction capability is controlled according to the occurrence status of the multipath is a method in which the received electric field strength is a weak electric field and There is a drawback in that it is not possible to cope with a situation where a data error occurs in a state where no path occurs.

[0012]

The RDS data processing device of the present invention is a block demodulator that demodulates data contained in a received broadcast wave and a predetermined number of data of demodulated data by the data demodulating unit as one block. In a data processing device in an RDS receiver, which comprises at least a block synchronization signal detecting means, an error correction processing means for performing error correction on the demodulated data, and an error correction control means for controlling error correction in the error correction means. ,
Error rate detection means for receiving data indicating success / failure of error correction by the error correction processing means and detecting a data error rate of received data of several past blocks before the present time;
And a synchronization state determination means for determining the synchronization state of the received data based on the data error rate obtained by the error rate detection means. The determination result by the synchronization state determination means includes past data. In the state where there are few errors, even if there is an uncorrectable error in the currently received data, the received data is continuously taken in as the synchronization state, and in the above judgment result, when the past data has many errors, the currently received data is received. If there is an uncorrectable error in the stored data, it is determined that the data is out of synchronization, the RDS data is initialized, and the received data is fetched bit by bit again.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. As shown in FIG. 1, the present embodiment corresponds to the RDS demodulator 10, and an RDS data capturing unit 1 that captures data from the RDS demodulator 10 via an RDS input terminal 9 bit by bit. Syndrome exchange unit 2 for demodulating the captured data
And a data demodulation synchronization signal detection unit 3 for receiving the data demodulation and the demodulated data to determine whether the transmission data and the RDS receiver are in synchronization, and the determination result by the data demodulation synchronization signal detection unit 3. In response to the received data, the data error detection unit 4 for detecting an error in the received data, and the data error detection information output from the data error detection unit 4 for error correction of the received data and error for judging success / failure of the correction. The error processing unit 5 and the error rate detection unit 1 that receives the error correction success / failure information output from the error correction processing unit 5 and detects and outputs the error rate from the error state of the past received data.
1 and the past data error rate output from the error rate detection unit 11 to determine whether the synchronization state or the out-of-synchronization state is entered, and the synchronization state determination unit 12 Upon receiving the determination information, the RDS data initialization unit 7 that initializes the RDS data being received in the case of loss of synchronization, and the data error detection when the received data has no error or when the error correction is successful, respectively. RDS data storage unit 6 which receives and stores the data input from the unit 4 or the error correction processing unit 5, and the data stored in the RDS data storage unit 6 in order to use the received and demodulated data. , RDS data output section 8 for external output
And is configured. As is clear from comparison with FIG. 4, the difference from the conventional example of the present invention is that the error rate detection unit 11 and the synchronization state determination unit 12 are newly provided.

Next, the operation of this embodiment will be described.

The RDS data input from the RDS demodulator 10 to the RDS data processing device via the RDS data input terminal is input to the RDS data capturing section 1 and is captured bit by bit in synchronization with the clock.
In the syndrome exchange section 2, the data input from the RDS data acquisition section 1 is syndrome-converted and demodulated, and the demodulated output data is input to the data demodulation synchronization signal detection section 3. In the data demodulation synchronization signal detection unit 3, receiving the demodulated data that has undergone the syndrome conversion,
The sync signal of each block (offset check word) is detected and output. The data detection unit 4 determines whether or not there is an error in the received data based on whether or not the synchronization signal is detected. If there is no error, the RDS data storage unit 6 is checked. The data is transferred, and if there is an error, the data is transferred to the error correction processing unit 5. The error correction processing unit 5 receives the erroneous data, performs error correction on the erroneous data, and when the data can be corrected, the data is transferred to the RDS data storage unit 6. The information indicating that the correction is successful is output to the error rate detection unit 11 while being stored. If the error correction processing unit 5 cannot correct the error,
Information indicating the unsuccessful correction is output from the error correction processing unit 5 and input to the error rate detection unit 11. Error rate detection unit 11
In the above, in response to the information indicating the error correction success / error correction failure output from the error correction processing unit 5, these pieces of information are accumulated and the data error rate of the RDS data in several blocks in the past is calculated and output. And is sent to the synchronization state determination unit 12. In the synchronization state determination unit 12, the data error rate is input, and the RDS data signal is initialized through the determination process of whether the RDS reception data is in the synchronization state or out of synchronization. It is determined whether or not the RDS data should be continuously fetched, and if the state is out of synchronization, the determination information instructing the initialization of the RDS data signal is output to the RDS data initialization unit 7. Sent. The RDS data initialization unit 7 receives the judgment information and initializes the RDS data being received.

That is, in the reception state in which the past data has few errors, even if there is an error that cannot be corrected in the currently received one block of data, the data is continuously taken in as the synchronization state, and the past data is taken in again. If there is an error that cannot be corrected in the data that is currently being received in a state where there are many errors in the data, the RDS data is initialized, it is determined that the data is out of synchronization, and the data is rewritten for each bit. The data is taken in.
In the RDS data initialization unit 7, the synchronization state determination unit 1
The information indicating the initialization, which is output from 2, initializes the data being received or the stored data, and various information necessary for capturing the data. In the RDS data storage unit 6, the data after error correction or the data without error is stored for each block. In the RDS data output section 8, the RDS
The data stored in the data storage unit 6 is output or transferred to the outside as needed.

2, 3 (a) and 3 (b) are diagrams comparing the results of the synchronization determination according to the present invention and the synchronization determination due to an error in 3 blocks out of the past 5 blocks.

FIG. 2 shows an example in which the synchronization state is judged by the error of 3 blocks out of the past 5 blocks, and there are uncorrectable errors in the offset words B, D and A (N.
In the case of G), it is determined that synchronization is lost at the point a in FIG. 2, and at the point b, there is no data error in the offset words B, D and A (OK), and the synchronization is in progress. It is judged to be one.

FIG. 3A shows an example of the case where the error rate is 50% or more and it is determined that the synchronization is lost.
FIG. 3B is an example of a case where the error rate is 50% or less and it is determined to be in the synchronization state. In FIG. 3 (a), in the case of similar data, it is judged to be out of synchronization at the point of a ^' , and therefore, when the data error is relatively large, the data is cleared quickly, and the reliability of the data to be taken in is high. Is improved and erroneous correction is reduced. Further, in FIG. 3B, since it is determined that the data is in the synchronous state at b ^" , it is possible to quickly capture the correct data even in the state where the data error is relatively large.

[0021]

As described above, according to the present invention, the synchronization status is determined based on the data error rate of the received RDS data. Therefore, once the synchronization status is reached, some data error occurs. Since it is difficult to lose synchronization, the acquired data can be validated, and even if synchronization is lost, synchronization can be quickly recovered.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration example of a block of RDS data in the present embodiment.

FIG. 3 is a diagram showing a configuration example of a block of RDS data in the present embodiment.

FIG. 4 is a block diagram showing a conventional example.

FIG. 5 is a diagram showing a baseband coding structure in an RDS system.

FIG. 6 is a diagram showing a configuration example of a block of RDS data in a conventional example.

FIG. 7 is a diagram showing a configuration example of a block of RDS data in a conventional example.

[Explanation of symbols]

 1 RDS data importing unit 2 syndrome exchange unit 3 data demodulation synchronization signal detecting unit 4 data error detecting unit 5 error correction processing unit 6 RDS data storing unit 7 RDS data initializing unit 8 RDS data output unit 9 RDS data input terminal 10 RDS data Modulator 11 Error rate detection unit 12 Synchronization state determination unit

Claims (1)

[Claims] 1. A data demodulation means for demodulating data contained in a received broadcast wave, a block synchronization signal detection means for performing block synchronization with a predetermined number of data of the demodulated data by the data demodulation means as one block, and the demodulated data. In a data processing device in an RDS receiver having at least error correction processing means for performing error correction and error correction control means for controlling error correction in the error correction means, a success / failure of error correction by the error correction processing means is provided. Upon receiving information indicating success, error rate detection means for detecting a data error rate of received data of several past blocks before the present time, and synchronization of the received data based on the data error rate obtained by the error rate detection means. And a synchronization state determination means for determining the state, and the determination result by the synchronization state determination means. As a result, when there are few errors in the past data, even if there is an uncorrectable error in the currently received data, the received data is continuously taken in as the synchronization state, and the judgment result shows that there are many errors in the past data. In this state, when there is an uncorrectable error in the currently received data, it is determined that the data is out of synchronization, the RDS data is initialized, and the received data is fetched bit by bit again.
Data processing device.