JPH04137811A - Automatic channel selection controller for rds receiver - Google Patents

Abstract

PURPOSE:To prevent malfunction of automatic channel selection without decreasing the possibility of changeover based on an AF data by setting an inhibit only when dissidence of data of network recognition code of frequency information code AF station is confirmed. CONSTITUTION:A controller 10 reads an AF data without an inhibit flag from an AF memory 11 to set a frequency division ratio to a PLL circuit 6, a front end 2 makes channel selection based on the frequency division ratio to receive an AF station. Only when it is detected that a network recognition code stored in the AF memory 11 and a network recognition code of the AF station are different, an inhibit flag provided independently in the AF memory 11 is set and the decision of the received electric field level of the reception station with the inhibit flag set thereto is not implemented from the succeeding time. Thus, malfunction of automatic channel selection is prevented without reducing the probability of changeover based on the AF data.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is applicable to RDS (
The present invention relates to an automatic tuning control device for an RDS receiver that performs automatic tuning for reception of data of a radio data system.

[Conventional technology]

When a broadcast station broadcasts, information related to the program content is multiplex-modulated and transmitted as data, and the receiving side can select the desired program content based on the demodulated data, making it possible to listen to radio. There is an RDS that can provide this service to users.

This RDS data includes a network identification code (hereinafter referred to as PI), a traffic information bureau selection code (hereinafter referred to as TP).
), traffic announcement recognition code (hereinafter referred to as TA), program service name information code such as broadcasting station name or network name (hereinafter referred to as PS), frequency information code for a group of network stations broadcasting the same program (hereinafter referred to as (referred to as AF), etc.

By the way, in the case of an on-vehicle receiver, the reception condition of the broadcast wave being received may deteriorate as the vehicle travels.

However, in the case of RDS broadcasting, as mentioned above, it is possible to obtain the AF data of a group of network stations broadcasting the same program, so by storing this AF data in memory, the received signal level It is possible to select other same network stations with large (different strengths).

[Problem to be solved by the invention]

However, if the vehicle travels long distances or along the borders of European countries, there may be a broadcasting station on a different network that has the same frequency as the AF data, outside of the same network that is currently being received. There was an issue with the channel selection malfunctioning.

Also, during RDS data demodulation, for some reason, an incorrect A
F data may be accumulated in the memory, and as mentioned above, there is a problem in that the automatic channel selection malfunctions.

Note that as a near-value technique, there is Japanese Patent Application Laid-Open No. 2i0413.1.

This invention was made in order to solve the above-mentioned problems, and it is an automatic tuning I! of an RDS receiver that can prevent automatic tuning malfunctions without reducing the possibility of switching based on AF data. II? The purpose is to obtain an I device.

[Means to solve the problem]

The automatic tuning control device for an RDS receiver according to the present invention has a built-in frequency information code memory storing at least one frequency information code, and the level of the received signal of the frequency information code station is the same as the original frequency information. If the network recognition code of the frequency information code station is determined to be detectable when the signal level received by the code station is higher than that of the code station, the network recognition code of the frequency information code station is compared with the network recognition code stored in the frequency information code memory to confirm that the two match. This system is equipped with a controller that allows the frequency information code station to continue receiving when the station is present.

[For production]

The controller in this invention checks the network recognition code of the frequency information code station when automatically tuning from the receiving station to the frequency information code station, and only when it detects that the network recognition code is different, stores the frequency information code in the frequency information code memory. An independently provided prohibition flag is set for each station, and from the next time on, the received electric field level determination operation of the receiving station for which the prohibition flag is set will not be performed.

〔Example〕

Embodiments of an automatic channel selection control device for an RDS receiver according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment.

In FIG. 1, 1 is an antenna, and the FM multiplex broadcast waves received by this antenna 1 are so arranged that a desired reception station is selected by a front end 2. The received signal has an intermediate frequency (I
After being converted into F), it is supplied to the FM detection section 3.

Further, the front end 2 is configured to perform channel selection control by a phase-locked loop (hereinafter referred to as PLL) circuit 6 including a programmable frequency divider. This PLL
The frequency division ratio of the circuit 6 is set by a controller 10, which will be described later.

By setting the frequency division ratio by the controller 10, the front end 2 performs the channel selection operation as described above.

Furthermore, the detection output of the FM detection section 3 is transmitted through a multi-plex (hereinafter referred to as MPX) via an NK (noise canceller) 4.
) is supplied to a demodulation circuit 5.

In this case, in the case of stereo broadcasting, the left (L) channel and right (R) channel audio signals are separated and output.

Further, the detection output of the FM detection unit 3 is inputted to the RDS decoder 9 via a 57 KHz band pass filter 8, and the output of this RDS decoder 9 is converted into distinguishable data by the controller 10. Ru.

The controller 10 has a built-in AF memory 11, and the information of the receiving station taken in by the controller 10,
That is, the above-mentioned PI and AF.

Each piece of information such as PS, TP, TA, etc. is configured to store AF data in the AP memory 11.

Further, a level detection section 7 is provided which detects a received signal level (' is different intensity) based on the IF signal level in the FM detection section 3, and the received signal level detected by the level detection section 7 is sent to the controller 10. It is now being supplied.

Next, the operation will be explained. F received by antenna 1
A desired station of the M multiplex broadcast waves is selected by the front end 2, converted to an intermediate frequency, and then supplied to the FM detection section 3.

The detection output of the FM detection section 3 is supplied to the MPX demodulation circuit 5 via the NK4, where it is demodulated, and in the case of stereo broadcasting, it is separated into L and R channel audio signals and output.

Further, the output of the FM detection unit 3 is inputted to the RDS decoder 9 via the bandpass filter 8, and the output of the RDS decoder 9 is converted by the controller 10 into discriminable data.

The controller 10 receives the above information PIAF and PS of the receiving station.
, TP, TA, etc., and store the AF in the AF memory 11.
Store data.

Further, the received signal level (field strength) is detected by the level detector 7 based on the level of the intermediate frequency signal in the FM detector 3, and the detection result is output to the controller 10.

Next, the operation of automatic channel selection control, which is a feature of the present invention and is executed by the controller 10, will be explained according to the flowchart shown in FIG.

Note that the following Table 1 shows data stored in the AF memory 11.

In Table 1, f, ft, . And AF memory 11
It is assumed that one or more stations already exist in the AF frequency data storage area shown in Table 1.

First, in step S1, the PI data (network recognition code) of the broadcasting station currently being received is sent to the controller 1 via a 57KHz bandpass filter and an RDS decoder.
At the same time, the detection output of the FM detection section 3 detects the received signal level in the level detection section 7, and is held in the AF memory 11 of the controller 10.

Next, the process advances to step S2, where one piece of AF data without a prohibition flag is selected and read out from the AF memory 11, and the AF data without a prohibition flag is read out.
A frequency division ratio is set in the L circuit 6, and the front end 2 performs a tuning operation according to the set frequency division ratio and receives an AF station.

The received signal level of this AF station is compared with the received signal level of the original receiving station in step S3, and if the comparison result exceeds the received signal level of the optical receiving station, the process proceeds to step S4, and if there is After waiting for a certain period of time, it is determined whether the PI code of the AF station can be detected or not.

As a result of this determination, if the PI code can be detected, the PI code data held in the AF memory 11 in step Sl is compared with the data of the PI code in step S5.

If it is confirmed that they match as a result of this comparison, the process advances from step S5 to step S8 and continues receiving the AF station. In this case, a switch has been made to the AF station.

In addition, in the process of step S3 above, if it is determined that the received signal level of the AF station is lower than the received signal level of the original receiving station, or in step S4, the AF station's P
If it is determined that the I code data cannot be received, the process moves to step S7 and returns to the original receiving station without setting the prohibition flag. That means waiting for the next opportunity.

Further, in step S5, if the PI code data held in the AF memory 11 and the PI code of the AF station do not match, the process moves from step S5 to step S6, and the prohibition corresponding to the AF memory 11 is Set the prohibition flag in the flag storage area (see Table 1) and return to the original receiving station.

In other words, in this case, AF data from the next time onwards will not be selected in step S2, making it possible to prevent automatic channel selection malfunctions.

In the above embodiment, the case where the AF station is compared with the received signal level of the receiving station one by one was explained, but the AF memory 1
Continuously check all or some frequencies within 1,
Similar effects can be obtained even when switching to the best station.

[Effects of the Invention] As described above, according to the present invention, a prohibition flag is provided only when a mismatch in data of the PI code of an AF station is recognized, and the prohibition flag is set when the PI code of the AF station cannot be received. Since it is not provided, there is an effect that automatic channel selection malfunction can be prevented without reducing the possibility of switching based on AF data.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an automatic channel selection control device for an RDS receiver according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the execution procedure of the controller in the embodiment. 1... antenna, 2... front end, 3...
FM detection section, 4...NK, 5...MPX demodulation circuit,
6... PLL circuit, 7... Level detection section, 8...
Bandpass filter, 9... RDS decoder, 10.
...Controller, 11...AF memory.

Claims (1)

[Claims] A front end capable of receiving RDS broadcast waves including frequency information, codes, and network recognition codes of the same network stations, and having a function of selecting the same network stations, and outputting an intermediate frequency signal; A phase-locked loop circuit in which a frequency division ratio is set in order to perform a tuning operation, an FM detection section that performs FM detection on the intermediate frequency signal, and a multiplex that demodulates the output of this FM detection section and outputs an audio signal. a demodulation circuit, a level detection section that inputs the output of the FM detection section and detects the received signal level, an RDS decoder that converts the output of the FM detection section into predetermined distinguishable data, and a broadcast of the current reception frequency. a frequency information code memory that holds the network recognition code obtained by demodulating the wave; and determines whether or not the network recognition code can be received from the output of the level detection section; If possible, return to the original receiving frequency station without setting the prohibition flag to prevent switching to the same network station frequency again, and if the above network recognition code can be received, the network recognition of the current receiving frequency station is performed. If the code does not match, the above prohibition flag is set and the reception is returned to the original current reception frequency station, and the above phase is set so that the reception frequency will not be switched to the same network station that has the above prohibition flag in the same network station switching operation again. An automatic tuning control device for an RDS receiver, comprising a controller for controlling a lock loop circuit.