JP3065442B2 - Receiver for digital data multiplex system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is digital data that receive the same program broadcast station by an automatic tracking using digital data multiplexing system, such as RDS (Radio Data System)
It relates to a receiver for data multiplexing system, the digital data multiplexing system, in particular it is possible to prevent erroneous reception of the automatic follow-up
The present invention relates to a system receiver.

[0002]

2. Description of the Related Art In a car radio, a driver usually operates the radio, and when a car travels a long distance and leaves the service area of a receiving station, it is necessary to reselect the station every time. There has been a demand for advanced station functions. This demand was particularly strong in Europe, where FM broadcasts with a relatively narrow service area are the main body of radio broadcast services and the broadcast reception ratio on car radio is high. A digital data multiplexing system standardized by the European Broadcasting Union to satisfy this requirement is RDS (Radio Data System).

[0003] RDS is a system for multiplexing and transmitting various digital data (data that can be used for automatically selecting the best receiving station, identifying traffic information, displaying the name of a broadcasting station, etc.) to FM radio broadcasting. Automatic follow-up for sequentially selecting the same program broadcasting station having a good reception condition by utilizing the PID data and the PI data.

[0004] The AF list is also called an alternative frequency list, and corresponds to a frequency list of a broadcasting station (referred to as an AF station) broadcasting the same program in the same or an adjacent reception area. All the frequencies of the program broadcasting stations can be known. The PI data is also called program identification data and is unique data given to the same broadcast program (program). Even if the broadcast station is different, the same PI program has the same PI data. .

Conventionally, for example, in a receiver having one tuner configuration, automatic tracking of the same broadcast program station is performed by checking the reception electric field strength of each AF station on the demodulated AF list at predetermined time intervals (referred to as an AF search). )), And receives a broadcast from the AF station having the maximum reception electric field strength which is larger than the reception electric field strength of the receiving station up to that time, and thereafter, when PI data of the maximum AF station is detected, It is determined whether the PI data matches the PI data of the original receiving station. If the detected PI data matches the PI data of the original receiving station, the maximum A
If reception from the F station is continued and PI data is not detected, or if the detected PI data does not match the PI data of the original receiving station, the AF having the next highest received electric field strength
Station is regarded as the maximum AF station, the tuning is shifted to the maximum AF station,
Thereafter, the identity of the PI data is confirmed. If they do not match, the same processing is continued, and if they match, the maximum AF station is received.

[0006]

Normally, the broadcasting station on the AF list broadcasts the same program as the current receiving station, and confirms the identity of PI data after moving to the maximum AF station as in the conventional method. Is performed, there is no problem, and the confirmation of the identity of the PI data is a deep color, just to make sure. However, near the border, in countries such as France and Italy, there are many broadcasting stations with the same frequency, so that the PI data is often different. Conventionally, after confirming the identity of PI data after moving to the AF station and receiving the broadcast,
If the I data is different, the user tunes to the wrong station until the identity is completed, and a different program from the previous program is broadcasted, giving the user discomfort.

Accordingly, an object of the present invention is to provide an RDS radio receiver capable of preventing a different broadcast program from being received again during tracking.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the receiving electric field strength of a receiving broadcasting station is controlled by using an AF list or PI data which is superimposed on a digital data multiplex broadcasting signal and transmitted. When the signal level falls below the level, the reception electric field strength of each AF station on the AF list is checked, and the AF station having the maximum reception electric field strength is an AF station larger than the reception electric field strength of the reception broadcast station up to that time. The broadcast from the station is received, and thereafter, it is determined whether or not the PI data of the AF station matches the PI data of the original receiving broadcast station. If they match, reception from the AF station is cascaded. Next, update the broadcast from the AF station with the largest received electric field strength,
In the digital data multiplexing system receiver having an automatic tracking function of receiving the desired AF station by repeating the same processing, when the received erroneously AF station PI data is different at the same frequency which are on the AF list , At least the misunderstanding
The frequency of the received AF station, the received frequency of the original receiving station,
A memory for storing the PI data as AF search prohibited conditions, have listed from the current received broadcast station AF list
When automatically following an AF station,
Refers to the specified AF search prohibition condition and meets the condition.
AF search forbidden to search for AF stations
Means are achieved.

[0009]

[Function] Digital data using digital multiplex data
In a multiplex system receiver, a P over a predetermined electric field strength level broadcasting at a frequency listed in the AF list
The condition when a broadcast station having a different I code is erroneously received is stored in a memory so that the broadcast station is not received again.

[0010]

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

Reference numeral 4 denotes an MPX, which is an intermediate frequency amplification detector 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). Reference numeral 6 denotes a speaker which is driven by the amplifier 5 and outputs an audio signal.
An RDS decoder 7 demodulates an AF list, PI data, and the like transmitted at a predetermined transmission timing. Reference numeral 8 denotes an error correction circuit, which detects errors in the RDS data such as the AF list and PI data demodulated by the RDS decoder 7 while synchronizing each group, and corrects the errors.

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

Reference numeral 10 denotes a first memory for storing RDS data (AF list, PI data, etc.) read from a broadcast station currently being received, and 11 stores conditions for erroneous reception with automatic tracking. This is a second memory that stores the following conditions. That is, in the automatic tracking in the RDS receiver, the electric field intensity level of the receiving station that is currently listening is lowered, and when the same program on the AF list is to be automatically followed to the AF station that is broadcasting, the electric field intensity level that can be received well. In some cases, a program having the same frequency as the frequency in the above list and having different contents being broadcast is erroneously received. However, it checks the PI data and returns to the original receiving station immediately if the PI data is incorrect. At this time, the three frequencies of the original receiving station, the PI data, and the frequency of the erroneously received AF station are stored.

Reference numeral 12 denotes a control unit for controlling the overall operation of the RDS receiver, and based on the detection level of the signal meter 9, the signal strength of the current receiving station and the signal strength of the selected AF station are determined during automatic tracking. AF search means for searching for an AF station having a good reception state, and determining whether or not the AF search is an AF search for a broadcast station which has been previously erroneously received.
Has an AF search prohibiting means for performing a check based on the above data, and prohibiting the AF search if the broadcast station has been erroneously received before. The prohibition of the AF search is performed under the above three AND conditions. That is, even if any of the three conditions is missing, the following algorithm causes an error and the normal AF
This is because no search is performed. FIG. 2 is a flowchart of the present invention, and the RD shown in FIG.
The automatic tracking process of the S radio receiver will be described. In FIG. 2, the control unit 12 performs the following automatic tracking processing in a state where a broadcast program from a predetermined RDS station is being received by the radio receiver. First, an AF list, PI data, etc., which are superimposed and transmitted on the FM broadcast of the current receiving station, are received via the RDS decoder 7 and the error correction circuit 8 (step 1).
01), the data is read (step 102), and the first
It is stored in the memory 10 (step 103).

In order to maintain the signal strength level of the current receiving station in a good receiving state, the signal strength of the receiving station is monitored by the signal meter 9 (step 104). Reference numeral 12 determines an AF station frequency from the AF list, outputs a frequency control signal for each AF station to the PLL circuit 1, and starts each AF search (step 105). When the AF station having the highest signal strength is received (step 106), the signal strength level is compared with the signal strength level of the original receiving station (step 107). If the signal strength level is not higher than the signal strength level of the original receiving station, the signal is returned to the original receiving station (step 106). Step 10
8) Thereafter, the flow returns to step 104 to repeat the same processing.

On the other hand, if the signal strength level of the received AF station is higher than the signal strength level of the original receiving station in step 107, the data of the AF station is read (step 1).
09), check PI data (step 110),
If the PI data do not match, the condition at that time is stored in the second memory 11 (step 112), the condition is returned to the original receiving station (step 113), and the next strongest AF station is received (step 114). Thereafter, the flow returns to step 107 to repeat the same processing.

If the PI codes match at step 110, the reception is determined as the AF station as the receiving station (step 110), and the previous data in the first memory is updated to store the data at the receiving station. Then, the signal strength of the receiving station is monitored by the signal meter 9 (Step 116), and if the signal strength is confirmed to be equal to or lower than the predetermined level, the control unit 12 obtains the AF station frequency from the AF list. Then, the search of each AF station except the AF search under the condition stored in the second memory is started (step 11).
7). Thereafter, the flow returns to step 106 to repeat the same processing.

[0018]

As described above, according to the present invention, digital data
AF list and P sent to be superimposed on the multiplex broadcast signal
When the received electric field strength of the receiving broadcasting station falls below a predetermined level using the I data and the like, the receiving electric field strength of each AF station listed in the AF list is checked, and the receiving broadcasting station reception up to that time is checked. A broadcast from an AF station having an electric field strength larger than the electric field strength and having the highest received electric field strength is received, and thereafter, it is determined whether or not the PI data of the AF station matches the PI data of the original receiving broadcast station. If this is the case, the reception from the AF station is cascaded, and if they do not match, the broadcast from the AF station with the next highest received electric field strength is updated successively, and the same processing is repeated to receive the desired AF station. Digital with
In a receiver for multi-data multiplexing system, when an erroneous reception of an AF station having the same PI frequency but different PI data from the AF list , at least the frequency of the erroneously received AF station is obtained.
Number, the receiving frequency of the original receiving station and its PI data
The memory that stores the F-search prohibition condition and the current reception
Automatically follow the AF stations listed on the AF list from the broadcasting station
To perform an AF search stored in the memory in advance.
Refer to the prohibited condition and search for the AF station corresponding to the condition.
Since it is provided with an AF search prohibiting means for prohibiting , when searching for an AF station on the AF list ,
Not just the frequency of the AF station that received the error, but also the error
Multiple data including the frequency of the AF station are set as prohibition conditions.
More accurate selection of AF stations receiving erroneous reception
To improve the accuracy of the automatic tracking function for the desired AF station.
This has the effect of increasing the number of layers.

[Brief description of the drawings]

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

FIG. 2 is a flowchart of an automatic tracking process according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 PLL circuit 2 FM front end 3 Intermediate frequency amplification detector 7 RDS decoder 8 Error detection and correction circuit 9 Signal meter 10 First memory 11 Second memory 12 Control unit

Claims (1)

(57) [Claims] 1. An AF list or PI data transmitted by being superimposed on a digital data multiplex broadcast signal is used. When the received electric field intensity of a receiving broadcast station falls below a predetermined level, the received information is listed on the AF list. Check the received electric field strength of each AF station, and check if the received electric field strength of the AF station is larger than the received electric field strength of the received broadcast station so far.
The broadcast from the station is received, and thereafter, it is determined whether or not the PI data of the AF station matches the PI data of the original receiving broadcast station. If they match, reception from the AF station is cascaded. Next, in a receiver for a digital data multiplexing system having an automatic tracking function of updating a broadcast from an AF station having a large received electric field strength and repeating a similar process to receive a desired AF station, When an erroneous reception of an AF station with the same frequency as that on the list but different PI data occurs ,
Also the frequency of the erroneously received AF station and the reception of the original receiving station
A memory for storing the frequency and its PI data as AF search prohibition conditions ,
When automatically following the AF station on the
Refer to the AF search prohibition condition stored in
AF support that prohibits search to the corresponding AF station
Digital prohibition means ,
Data multiplex system receiver.