JP3181430B2 - Receiver for digital data multiplex system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital data multiplexing system.
Relates to a digital data multiplexing system receiver for receiving a broadcast station of the same broadcast content using a frequency code systems out, in particular read all frequency codes of the same network, it relates to a receiver for digital data multiplexing system for the automatic follow-up.

[0002]

2. Description of the Related Art In Europe, a digital data multiplexing system for multiplexing and transmitting various digital data (data that can be used for automatic selection of a best receiving station, traffic information identification, display of a broadcasting station name, and the like) to an FM radio broadcast is used. I have. Such a digital data multiplexing system is called an RDS (Radio Data System), and uses a frequency code (AF code), which is one of transmission data, for example, to successively receive broadcast stations (AF stations) of the same broadcast content. Automatic tracking can be performed.

[0003] Such a frequency code transmission method includes a method of transmitting a unique frequency code for each receiving station (method A:
Method-A) and a method of repeatedly transmitting a frequency code for every broadcasting station in a network (for example, a specific country) at a constant period (Method-B). According to Method A, a frequency code uniquely created by each broadcasting station is transmitted. According to Method B, a common frequency code classified for each station is transmitted from all broadcasting stations in the network. Therefore, there is no need to create a frequency code for each station.

[0004]

However, in the above-described transmission system, an identification signal for identifying Method A and Method B is not transmitted, and the identification of the transmission system and the frequency code of the frequency code are not transmitted to the receiver side. It leaves the detection method. Further, the conventional RDS receiver reads only the frequency code paired with the frequency code of the receiving station in method B, and does not read the frequency code of another same network.
Therefore, a frequency code required for automatic tracking by a broadcasting station may not be superimposed on transmission data in some cases, and there is a problem that automatic tracking cannot be performed due to a shortage of frequency codes.

FIG. 5 is an explanatory diagram for explaining automatic tracking of a conventional RDS receiver. Referring to FIG. 5, at a point A, a first broadcast station (broadcast frequency: 92.3 MHz,
While receiving AF: 96.1 MHz, 96.7 MHz), the user moves from point A to point B, and the second broadcast station (broadcast frequency: 93.5 MHz,
AF: 96.1 MHz), the broadcast frequency of the second broadcast station is not in the frequency code of the first broadcast station,
Once the third broadcast station (broadcast frequency: 96.1 MHz, AF: 93.5 MHz) at point C, which is the AF station of the first broadcast station, is not received, automatic tracking cannot be performed, and the user must select a channel again. There is a problem that.

[0006] Accordingly, it is an object of the present invention, de being received
Digital transmitted is superimposed from digital multiplex broadcast station
A digital data multiplexing system that reads all frequency codes of the same network consisting of method B included in the multiplexed data and can smoothly follow automatically based on the frequency codes.
It is to provide a non-receiver.

[0007]

According to the present invention, the above object is superimposed on a digital multiplex broadcast signal and transmitted.
In a digital data multiplexing system receiver that demodulates digital multiplexed data and receives a broadcast station having the same broadcast content based on a frequency code included in the digital multiplexed data, a transmission method identification unit that identifies a frequency code transmission method, A storage unit for storing a frequency code, and when the receiving station frequency code is detected based on the method B identified by the transmission method identifying unit, the receiving unit frequency code and the paired frequency code are stored in the storage unit. In addition, when detecting the same other-station frequency code as the pair of frequency codes, a code detection unit that stores the other-station frequency code and the paired frequency code in the storage unit, and a frequency code stored in the storage unit. This is achieved by an automatic tracking control unit that performs automatic tracking based on the automatic tracking.

[0008]

In the above configuration, a frequency code transmission method such as method B is identified, and when a receiving station frequency code is detected based on the identified method B, the receiving station frequency code and the paired frequency code are stored in the storage unit. Along with storing, when the same other station frequency code as the paired frequency code is detected, the other station frequency code and the paired frequency code are stored in the storage unit, and the automatic tracking is performed based on the stored frequency code. Do.

[0009]

FIG. 1 is a block diagram of a main part of an RDS receiver according to the present invention. Reference numeral 1 denotes a PLL circuit which outputs a predetermined voltage signal corresponding to a station to be received to the FM front end 2. The FM front end 2 receives an FM broadcast signal input from the antenna ANT based on a voltage signal, and generates a predetermined intermediate frequency signal (IF). Reference numeral 3 denotes an intermediate frequency detection amplifier that amplifies the intermediate frequency signal converted by the FM front end 2 to a predetermined level and detects the signal.

Reference numeral 4 denotes MPX, which is an intermediate frequency detection amplifier 3
Demodulated into a stereo signal. 5
Denotes an amplifier (AMP), which amplifies a stereo signal in accordance with a volume setting value (not shown). A speaker 6 is driven by the amplifier 5 and outputs an audio signal based on the stereo signal. Reference numeral 7 denotes an RDS decoder, which outputs an RDS such as a frequency code transmitted at a predetermined transmission timing.
Demodulate the DS data. 8 is an error correction circuit;
RD such as frequency code demodulated by DS decoder 7
An error in S data is detected while synchronizing each group, and the error is corrected.

Reference numeral 9 denotes a signal meter, which detects the level of the reception state of the receiving station (including the AF station) by monitoring the signal strength (for example, electric field strength) of the intermediate frequency signal output from the intermediate frequency detection amplifier 3. I do.

Reference numeral 10 denotes a control unit for controlling the overall operation of the RDS receiver.
Or a transmission method identification unit 10a for identifying a method B, a first storage unit 10b for storing a frequency code of a pair with a frequency code of a receiving station, and a first storage unit 10b for storing a frequency code of a pair with a frequency code of another station. The second storage unit 10c reads a frequency code of a pair with the frequency code of the receiving station when detecting the frequency code of the receiving station based on the method B among the identified frequency code transmission methods, and avoids duplication to avoid the first frequency code. When a frequency code of another station that matches the frequency code of the pair is detected, the frequency code of the other station and the frequency code of the pair are read and stored in the second storage section while avoiding duplication. A code detection unit 10d
An automatic tracking control unit 10 that performs automatic tracking based on the frequency codes stored in the first storage unit 10b and the second storage unit 10c
e etc.

FIGS. 2 and 3 are examples of frequency codes for explaining the transmission method. FIG. 2 is an example of a frequency code of method A, and FIG. 3 is an example of a frequency code of method B. In the method A shown in FIG. 2, it is assumed that, for example, a station having a frequency of 92.0 MHz is currently being received. According to Method A, the frequency code transmitted by being superimposed on the received broadcast signal is first a number code (5 stations) indicating the total number of frequency codes to be transmitted and a frequency code (92.0
MHz) are sent in pairs. Subsequently, 93.5 and 1
The frequency codes of 00.4 MHz, 94.1 and 101.8 MHz are transmitted in pairs, and a total of five frequency codes including the current receiving station are transmitted. As described above, in the method A, the same code as the frequency code of the receiving station immediately following the number code is not included in the subsequent frequency codes.

In the method B shown in FIG. 3, it is assumed that, for example, a station having a frequency of 92.3 MHz is currently being received.
(See FIG. 3A). According to Method B, the frequency code transmitted by being superimposed on the received broadcast signal is, first,
A number code (5) indicating the total number of transmitted frequency codes
Station) and the frequency code of the receiving station (92.3 MHz) are sent in pairs. Subsequently, 92.3 and 96.1 MH
The frequency codes of z, 92.3 and 96.7 MHz are transmitted in pairs, and a total of five frequency codes including the current receiving station are transmitted. Thus, in Method B,
The same code as the frequency code of the receiving station immediately following the number code is included in the subsequent frequency codes, and the frequency code of the same broadcast content is always paired with the frequency code of the receiving station.

Further, in the method B, the frequency codes of all broadcasting stations belonging to the same specific network, such as in the former West Germany, are transmitted according to the above-mentioned transmission method. That is, the frequency code for the 95.9 MHz frequency broadcasting station shown in FIG.
A frequency code for a 96.1 MHz broadcast station shown in FIG. 3C, a frequency code for a 98.5 MHz broadcast station shown in FIG. 3D, and a 96.7 MHz broadcast station frequency shown in FIG. Code, Figure 3
A frequency code for a broadcast station having a frequency of 93.4 MHz shown in (f) is repeatedly transmitted at a constant cycle. Therefore, the reception frequencies 92.
Frequency code 96.1, 9 transmitted as a pair with 3 MHz
6.7 MHz, on the other hand, in FIGS. 3 (c) and (e)
It indicates that it is transmitted as a pair with a number code. The number code and the frequency code described above are digital transmission data.

FIG. 4 is a flowchart of data processing of the control unit 10 according to the present invention. The operation of the RDS receiver of FIG. 1 will be described with reference to FIG. First, the control unit 10 receives RDS data such as a frequency code, which is superimposed on the FM broadcast signal of the current receiving station, via the RDS decoder 7 and the error detection and correction circuit 8 (step 101). Next, the transmission method identification unit 10a of the control unit 10 determines whether the transmission method of the frequency code is method A or method B (step 102). The identification of such transmission method is
This is performed by checking whether or not the same code as the frequency code of the receiving station immediately following the number code is included in the subsequent frequency codes.

If the transmission method is method B, the code detector 10 determines whether or not the frequency code immediately after the transmitted number code is the frequency code of the current receiving station as shown in FIG.
If the frequency code is detected by d and is the frequency code of the receiving station (step 103), the frequency code in the same program broadcasting paired with the receiving station is sequentially read (step 104), and the frequency code is first stored so as not to be duplicated. The information is stored in the unit 10b (steps 105 and 106).

Next, the code detector 10b of the controller 10
Detects whether the frequency code of the pair with the receiving station is in the frequency code of the other station (step 107), and if so, sequentially reads the frequency code in the same program broadcast paired with the frequency code of the other station (step 107). 108), the frequency code is stored in the second storage unit 10c as a spare code for automatic tracking so as not to overlap (step 10).
9, 110).

On the other hand, if the transmission method is method A in the process of step 102, the control unit 10 converts the frequency code in the same program broadcast transmitted superimposed on the received broadcast signal as shown in FIG. The frequency code is sequentially detected by the detection unit 10d (step 111), and the frequency code is stored in the first storage unit 10b so as not to be duplicated (step 112,
113). In this embodiment, the storage unit is divided into the first storage unit 10b and the second storage unit 10c, but may be one.

As described above, based on the frequency code stored in the first storage unit 10b, the automatic tracking control unit 10e of the control unit 10 outputs a frequency control signal to the PLL circuit 1, and the same broadcast with good reception condition Follow stations automatically. Here, when the automatic tracking cannot be performed with the frequency code stored in the first storage unit 10b, the automatic tracking is performed based on the spare frequency code stored in the second storage unit 10c. . Further, the present invention is also applicable to other radio data systems such as RBDS (Radio Broadcast Data System) in the United States.

[0021]

As described above, according to the present invention, when the frequency code transmission system is identified and the receiving station frequency code is detected based on the identified method B, the receiving station frequency code and the paired frequency code are stored in the storage unit. And when the same other-station frequency code is detected, the other-station frequency code and the paired frequency code are stored in the storage unit, and the automatic tracking is performed based on the stored frequency code. Therefore, all the frequency codes of the same network can be read, and automatic follow-up can be smoothly performed based on the frequency codes.

[Brief description of the drawings]

FIG. 1 is a main block diagram of an RDS receiver according to the present invention.

FIG. 2 is an example of a frequency code of a method A;

FIG. 3 is an example of a frequency code of a method B;

FIG. 4 is a flowchart of data processing of a control unit 10 according to the present invention.

FIG. 5 is an explanatory diagram for explaining automatic tracking of a conventional RDS receiver.

[Explanation of symbols]

 Reference Signs List 1 PLL circuit 2 FM front end 3 Intermediate frequency detection amplifier 7 RDS decoder 8 Error detection and correction circuit 9 Signal meter 10 Control unit 10a Transmission method identification unit 10b First storage unit 10c Second storage unit 10d Code detection unit 10e Automatic tracking control unit

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03J ⁷ /00-7/18 H04B 1/16

Claims (1)

(57) [Claims] 1. A demodulated digital multiplex data transmitted is superimposed on a digital multiplex broadcast signal, receiving a broadcasting station of the same broadcasting contents based on the frequency code included in the digital multiplex <br/> data digital In a data multiplexing system receiver, a transmission method identification unit for identifying a frequency code transmission method, a storage unit for storing a frequency code, and a receiving station frequency code based on a method B identified by the transmission method identification unit. Upon detection, the receiving station frequency code and the paired frequency code are stored in the storage unit, and when the same other station frequency code as the paired frequency code is detected, the other station frequency code and the paired frequency code are detected. A code detection unit that stores the following in the storage unit, and an automatic tracking control unit that performs automatic tracking based on the frequency code stored in the storage unit. Digital data multiplexing system <br/> receiver, characterized in that there was e.