JP2012142647A - Broadcasting receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcasting receiver suitable for receive switching using data on previously received alternative frequency (AF) station, which has been discarded.SOLUTION: The broadcasting receiver comprising: a tuner for receiving a broadcast signal transmitted in a signal format of RDS system; storage means which decodes the broadcast signal received by the tuner into AF station data and stores the AF station data; and identification information adding means which makes reference to multiplex data included in broadcast frequencies when a signal level which enables successful decode of a broadcast signal is obtained in frequency following-up using the AF station data, and adds given identification information to the AF station data stored in the storage means. The broadcasting receiver determines the order of broadcast frequencies to follow up based on the identification information, and executes the frequency follow-up.

Description

  The present invention relates to a broadcast receiver, and more particularly, to a broadcast receiver that is designed to be compatible with multiplex broadcasting based on the RDS system and configured to receive and process broadcast signals based on the signal format of the system.

  Radio broadcasts that multiplex and transmit related data related to broadcast programs on audio broadcast signals have been standardized and put into practical use. For example, RDS (Radio Data System) standardized by, for example, the European Broadcasting Union is known. In the RDS system, digital data is multiplexed on an analog FM broadcast signal. The RDS multiplexed data (hereinafter referred to as “RDS data”) includes a PI (Programme Identification) code, an AF (Alternative Frequencies) list, and the like. The PI code is a program identification code including a country name code and a program code. The AF list is a frequency list of broadcasting stations that broadcast the same or related programs. A broadcast receiver designed in conformity with the RDS system, for example, when moving outside the service area of a selected station while moving by car, refers to the AF list and broadcasts another broadcast station (hereinafter referred to as “AF”). The reception is automatically switched to “Station”. A specific configuration example of this type of broadcast receiver is described in Patent Document 1.

  By the way, it is difficult to receive all RDS data broadcasted by the selected station without loss under a situation where the reception state is deteriorated. For example, when a reception error occurs, there is a possibility that part or all of the AF list cannot be decoded. Even if the reception state is good, not all AF stations that can be physically received are included in the AF list because of the coverage area.

  Therefore, the broadcast receiver stores a list of AFs received in the past (hereinafter referred to as “actual AF” for convenience of explanation) in the memory. When the reception state of the selected station deteriorates, the broadcast receiver preferentially checks the actual AF list in the memory, follows the actual AF station, and tries to determine whether or not reception is possible. If the reception state of the track record AF station is not good, the reception AF station is tracked with reference to the AF list of the program that has been received before tracking (hereinafter referred to as “reception AF” for convenience of explanation) Try receiving or not.

  The actual AF list may include AF station data that cannot be acquired from the program being listened to due to a reception error or the like. The achievement AF list is useful information in that it compensates for missing AF stations in the reception AF list. However, if the storage of actual AF station data is allowed without limitation, the actual AF station data that cannot be received will be stored in the memory. For this reason, the check time of the result AF station becomes long, and there is a problem that reception switching is not performed promptly. Therefore, an upper limit is set for the number of recordable AF station data that can be stored. When storing past AF station data exceeding the limit number, old past AF station data is sequentially discarded. Even if the limit number is not exceeded, the result AF station data that failed in the reception attempt is discarded.

JP-A-9-107320

  In this field at the time of filing this patent application, it is common knowledge to effectively limit the number of recordable AF station data that can be stored as described above. However, considering the possibility that receivable AF station data is included in the past AF station data that has been the target of discarding, the present inventor makes the past AF station data valid. I focused on what to use.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a broadcast receiver suitable for switching reception using the actual AF station data that has been the target of discarding. It is to be.

  A broadcast receiver according to an embodiment of the present invention that solves the above-described problems is a tuner that receives a broadcast signal transmitted in the RDS signal format, and decodes and stores AF station data from the broadcast signal received by the tuner. With reference to the multiplex data included in the storage means and the broadcast frequency at which a signal level capable of normally decoding the broadcast signal by frequency tracking using the AF station data is obtained, the AF station data stored in the storage means is predetermined. And an identification information adding unit for adding the identification information, determining the order of the broadcast frequencies to be followed based on the identification information, and performing frequency tracking.

  In this way, if the AF station data in the storage means is attached with identification information without being discarded, the tracking target can be extended to AF stations that have been discarded in the past, and the efficiency based on the identification information can be increased. Frequency tracking can be performed. Since the follow-up omission of the receivable AF station is reduced, the user can listen to the high-quality broadcasting service more continuously.

  The identification information adding means is included in the PI code on the tracking target side included in the broadcast frequency at which a signal level capable of normally decoding the broadcast signal by frequency tracking and the oldest AF station data stored in the storage means. The PI code on the storage means side may be compared, and identification information may be attached to the oldest AF station data according to the comparison result.

  For example, the storage unit may include a first storage area that stores AF station data and a second storage area that is different from the first storage area. In this case, the identification information adding means performs comparison processing when AF station data exceeding the storage capacity of the first storage area is stored, and the AF station data with the identification information is stored in the first storage area. To the second storage area.

  The broadcast receiver according to the present invention stores AF station data received before execution of frequency tracking in the first storage area after moving the AF station data with identification information to the second storage area. It is good.

  The identification information adding means is stored in the PI code on the tracking target side included in the broadcast frequency from which the signal level capable of normally decoding the broadcast signal by frequency tracking and the storage means that failed in the frequency tracking attempt. The storage unit side PI code included in the AF station data may be compared, and identification information may be added to the AF station data that has failed to follow in accordance with the comparison result.

  The broadcast receiver according to the present invention may be a device mounted on a moving body such as a general passenger car.

  ADVANTAGE OF THE INVENTION According to this invention, the broadcast receiver suitable for performing reception switching using the performance AF station data used as the object of cancellation is provided.

It is a block diagram which shows the structure of the broadcast receiver of embodiment of this invention. It is a figure which shows the flowchart of the process performed in embodiment of this invention. It is a figure which shows the flowchart of the process performed in embodiment of this invention. It is a figure which shows the flowchart of the process performed in embodiment of this invention.

  Hereinafter, a broadcast receiver according to an embodiment of the present invention will be described with reference to the drawings. The broadcast receiver of this embodiment is a radio suitable for receiving multiple broadcasts by the RDS method.

  FIG. 1 is a block diagram showing the configuration of the broadcast receiver 1 of the present embodiment. The broadcast receiver 1 is an in-vehicle broadcast receiver and is installed in a general passenger car or the like. The broadcast receiver 1 is designed to be compatible with multiplex broadcasting by the RDS method, and is configured to receive and process a broadcast signal according to the signal format of the method.

  As shown in FIG. 1, a broadcast receiver 1 includes an antenna 101, a tuner 102, an analog signal processing circuit 103, an audio signal processing circuit 104, a power amplifier 105, a speaker 106, an RDS demodulator 107, and a PLL (Phase Locked Loop). A circuit 108, a microcomputer 109, an input interface 110, and a display 111 are provided.

  The broadcast receiver 1 receives broadcast radio waves with the antenna 101 and outputs them to the tuner 102. The tuner 102 extracts an RF (Radio Frequency) signal of the selected station from the received radio wave under the control of the microcomputer 109 via the PLL circuit 108. The extracted RF signal is frequency-converted to an intermediate frequency suitable for signal processing such as filtering. The tuner 102 outputs an IF (Intermediate Frequency) signal obtained by frequency conversion to the analog signal processing circuit 103.

  The selected station is designated by a user operation on the input interface 110, for example. The designation information of the selected station is stored in a built-in RAM (Random Access Memory) of the microcomputer 109. For example, immediately after the broadcast receiver 1 is turned on, the microcomputer 109 controls the channel selection operation of the tuner 102 via the PLL circuit 108 according to the information stored in the built-in RAM.

  The analog signal processing circuit 103 has an IF detection (IF-Detection) circuit, a noise canceller (Noise Canceller), and a weak electric field processing (Multiplex) circuit. The IF signal input to the analog signal processing circuit 103 is detected as an audio signal by the IF detection circuit, and then noise is removed by a noise canceller. The audio signal is processed by the weak electric field processing circuit according to the reception state of the selected station such as mute, high cut, and separation control, and is output to the audio signal processing circuit 104.

  The audio signal input to the audio signal processing circuit 104 is output and reproduced as sound from the speaker 106 after predetermined audio signal processing and after gain adjustment according to the volume by the power amplifier 105.

  The analog signal processing circuit 103 has a built-in S meter, for example. The S meter measures the value of the detection voltage at the time of demodulating the analog audio signal at a predetermined sampling period and outputs it to the microcomputer 109. The detected voltage value is a DC voltage proportional to the received radio wave, and is correlated with the CN ratio of the received radio wave. The microcomputer 109 monitors the detection voltage value and estimates the CN ratio of the received radio wave.

  The signal detected by the analog signal processing circuit 103 is also output to the RDS demodulator 107. The detection signal is demodulated by the RDS demodulator 107, decoded into RDS data by the RDS decoder of the microcomputer 109, and stored in the built-in RAM.

  The RDS data includes PS (Program Service), RT (Radio Text), AF list, PI code, and the like. The microcomputer 109 displays, for example, PS and RT on the display screen of the display 111, and controls the tuning operation of the tuner 102 via the PLL circuit 108 according to the information of the AF list and PI code.

  Actual AF station data is stored in the built-in RAM. The actual AF station data includes broadcast station information such as PI code and broadcast frequency. An upper limit is set for the number of track record AF station data that can be stored in the built-in RAM. FIG. 2 shows a flowchart of processing executed when storing past AF station data exceeding the limit number. For convenience of explanation, the processing step is abbreviated as “S” in the description and drawings in this specification.

  For example, when frequency tracking is performed as the reception state of the selected station deteriorates, the process of the flowchart in FIG. In frequency tracking, AF stations are tested in a predetermined order to check whether a sufficient signal level (a signal level at which a broadcast signal can be normally decoded) is obtained. A specific description of frequency tracking will be described later.

  As shown in FIG. 2, in the process of S1, it is determined whether or not the actual AF station data number stored in the built-in RAM has reached the limit number. If the number of track record AF station data has not reached the limit (S1: NO), information such as the PI code and broadcast frequency of the program received before frequency tracking is stored in the internal RAM as the latest track record AF station data. Stored (S7). After the actual AF station data is stored, the process of this flowchart ends.

  When the number of track record AF station data in the built-in RAM has reached the limit (S1: YES), the PI of the oldest track record AF station data in the built-in RAM (hereinafter referred to as “oldest track record AF station data”). A code and a PI code superimposed on a broadcast frequency at which a sufficient signal level is obtained by frequency tracking (that is, a PI code desired to be received, hereinafter referred to as “tracking target PI code”) are all digits. It is determined whether or not they match (S2).

  When it is determined that the PI code of the oldest track record AF station data and the tracking target PI code match all digits (S2: YES), the oldest track record AF station data moves to the reception AF storage area in the built-in RAM. (S6). Therefore, a space for one data is made in the storage area for the actual AF station data. The reception AF storage area is an area for storing reception AF station data allocated separately from the area for storing actual AF station data. For convenience of explanation, the oldest track record AF station data moved to the reception AF storage area is referred to as “oldest received AF station data”. In the process of S7, information such as the PI code and broadcast frequency of the program received before frequency tracking is stored in the built-in RAM as the latest actual AF station data, and the process of this flowchart ends.

  When it is determined that the PI code of the oldest track record AF station data and the tracking target PI code do not match (S2: NO), it is determined whether only the Area code of both PI codes is different (S3). . Here, the PI code has a 2-byte structure, and the lower 4 bits in the upper 1 byte are defined as an Area code.

  When the PI code of the oldest track record AF station data and the area code of the tracking target PI code match (in other words, only the Area code does not match) (S3: YES), the reverse flag of the oldest track record AF station data is turned on. (S4). The inversion flag is a flag indicating that only the actual AF station data in the built-in RAM is different from the Area code. In the process of S6, the oldest track record AF station data for which the reverse flag is turned on moves to the reception AF storage area. Therefore, a space for one data is made in the storage area for the actual AF station data. In the process of S7, information such as the PI code and broadcast frequency of the program received before frequency tracking is stored in the built-in RAM as the latest actual AF station data, and the process of this flowchart ends.

  Except when the PI code of the oldest track record AF station data and the tracking target PI code differ only in the Area code (S3: NO), the oldest track record AF station data is discarded (S5). Therefore, a space for one data is made in the storage area for the actual AF station data. In the process of S7, information such as the PI code and broadcast frequency of the program received before frequency tracking is stored in the built-in RAM as the latest actual AF station data, and the process of this flowchart ends.

  FIG. 3 shows a flowchart of another form of processing. When the reception state of the selected station deteriorates, the actual AF station is tracked with reference to the actual AF station data in the built-in RAM. As shown in FIG. 3, when the reception state of the track record AF station is poor and tracking to the track record AF station fails (S11), it is determined whether or not the cause of the tracking failure is a PI code error (S12). Specifically, it is determined whether or not the PI code of the track record AF station (hereinafter referred to as “tracking track record AF station”) data in the built-in RAM in which tracking is attempted and the tracking target PI code all match. The If both PI codes match in all digits (S12: NO), the processing of this flowchart ends. If the two PI codes do not match (S12: YES), the process proceeds to S13.

  In the process of S13, the content of mismatch between the PI code of the tracking failure achievement AF station data and the tracking target PI code is detected. If both PI codes differ only in the Area code (S13: YES), the inversion flag of the tracking failure achievement AF station data is turned on (S14). In the process of S15, the tracking failure result AF station data in which the reverse flag is turned on moves to the reception AF storage area. For convenience of explanation, the tracking failure record AF station data moved to the reception AF storage area is referred to as “tracking failure reception AF station data”. After the tracking failure reception AF station data is moved, the process of this flowchart is terminated.

  Unless the PI code of the tracking failure track record AF station data and the tracking target PI code differ only in the Area code (S13: NO), the PI code of the AF that has attempted to follow cannot be decoded normally due to the influence of interference waves, etc. Probability is high. Therefore, the PI error flag of the tracking failure result AF station data is turned on (S16). In the process of S15, the tracking failure result AF station data in which the PI error flag is turned on moves to the reception AF storage area. After the tracking failure reception AF station data is moved, the process of this flowchart is terminated.

  FIG. 4 shows a flowchart of processing for performing frequency tracking and trying to switch reception of the AF station according to a predetermined priority when the reception state of the selected station deteriorates. The process of the flowchart of FIG. 4 is repeatedly executed during the operation of the broadcast receiver 1.

  As shown in FIG. 4, in the process of S31, it is monitored whether or not a predetermined AF station switching start condition is satisfied. For example, when the reception intensity of the selected station falls below a predetermined threshold, it is necessary to switch the reception of the AF station accompanying the deterioration of the reception state, and the predetermined AF station switching start condition is satisfied. When the predetermined AF station switching start condition is not satisfied (S31: NO), the processing of this flowchart ends. If the predetermined AF station switching start condition is satisfied (S31: YES), the process proceeds to S32.

  In the processing of S32, the count of the built-in timer A of the microcomputer 109 is started. In the process of S33, the result AF station is tracked with reference to the result AF station data in the built-in RAM. Follow-up is tried in order from the new performance AF station in the built-in RAM. If a trackable track record AF station is detected (S34: YES), the reception frequency is switched to the track record AF station. Next, the built-in timer A is cleared (S45), and the processing of this flowchart ends.

  If no trackable AF station that can be followed is detected (S34: NO), it is determined whether or not the count value of the built-in timer A exceeds the count value B (S35). When the count value B is not exceeded (S35: NO), the reception AF station is tracked with reference to the reception AF station data in which the confirmation flag in the reception AF storage area is turned on (S36, S42). In the tracking, the best reception station is searched from the reception AF station data in which the confirmation flag is turned on. When the best reception station is detected (S43: YES), the reception frequency is switched to the reception AF station. Next, the built-in timer A is cleared (S45), and the processing of this flowchart ends.

  If no followable receiving AF station is detected from the receiving AF stations with the confirmation flag turned on (S43: NO), it is checked again whether a predetermined AF station switching start condition is satisfied (S44). If the predetermined AF station switching start condition is not satisfied (S44: NO), the built-in timer A is cleared (S45), and the process of this flowchart ends. If the predetermined AF station switching start condition is satisfied (S44: YES), the process returns to S33, and the process of this flowchart is continued.

  The count value C is defined as a value larger than the count value B. When the count value of the built-in timer A exceeds the count value B but is not less than the count value C (S35: YES, S37: NO), the received AF station is referred to the flagless received AF station data in the received AF storage area. Is followed (S38, S42). In tracking, the best receiving station is searched from the received AF station data without a flag. When the best reception station is detected (S43: YES), the reception frequency is switched to the reception AF station. Next, the built-in timer A is cleared (S45), and the processing of this flowchart ends. Note that the confirmation flag is turned off under certain conditions. As an example, when the reception frequency is changed by manual tuning, seeking, etc., if the AF of the RDS data of the newly received station is stored in the built-in RAM as the actual AF station data, the actual AF station data is determined as a confirmation flag. Is moved to the reception AF storage area in a state where is turned off (no flag).

  If no followable receiving AF station is detected from the receiving AF stations without a flag (S43: NO), it is checked again whether a predetermined AF station switching start condition is satisfied (S44). If the predetermined AF station switching start condition is not satisfied (S44: NO), the built-in timer A is cleared (S45), and the process of this flowchart ends. If the predetermined AF station switching start condition is satisfied (S44: YES), the process returns to S33, and the process of this flowchart is continued.

  The count value D is defined as a value larger than the count value C. When the count value of the built-in timer A exceeds the count value C but is not less than the count value D (S35: YES, S37: YES, S39: NO), the received AF station data with the inversion flag in the reception AF storage area turned on Referring to (2), the follow-up to the reception AF station is performed (S40, S42). In tracking, the best received station is searched from the received AF station data with the inversion flag turned on. When the best reception station is detected (S43: YES), the reception frequency is switched to the reception AF station. Next, the built-in timer A is cleared (S45), and the processing of this flowchart ends.

  If no followable receiving AF station is detected from the receiving AF stations whose inversion flag is turned on (S43: NO), it is checked again whether or not a predetermined AF station switching start condition is satisfied (S44). If the predetermined AF station switching start condition is not satisfied (S44: NO), the built-in timer A is cleared (S45), and the process of this flowchart ends. If the predetermined AF station switching start condition is satisfied (S44: YES), the process returns to S33, and the process of this flowchart is continued.

  When the count value of the built-in timer A exceeds the count value D (S35: YES, S37: YES, S39: YES), the received AF station data is referred to the received AF station data in which the PI error flag in the received AF storage area is turned on. Following the station is performed (S41, S42). In tracking, the best received station is searched from received AF station data in which the PI error flag is turned on. When the best reception station is detected (S43: YES), the reception frequency is switched to the reception AF station. Next, the built-in timer A is cleared (S45), and the processing of this flowchart ends.

  If no followable receiving AF station is detected from the receiving AF stations with the PI error flag turned on (S43: NO), it is checked again whether a predetermined AF station switching start condition is satisfied (S44). . If the predetermined AF station switching start condition is not satisfied (S44: NO), the built-in timer A is cleared (S45), and the process of this flowchart ends. If the predetermined AF station switching start condition is satisfied (S44: YES), the process returns to S33, and the process of this flowchart is continued.

  In this way, when the past AF station data that was previously discarded is conditionally retained and given a predetermined priority, the tracked AF station data that was subject to discarding is used while efficiently suppressing the frequency tracking time. The received switching is preferably achieved. Since the follow-up omission of the receivable AF station is reduced, the user can listen to the high-quality broadcasting service more continuously. The AF with a confirmation flag is an AF included in data obtained from a normal decoding result and has high reliability, and therefore has a high priority for follow-up trials. An AF with a PI error flag has been determined to be a different station in the past. However, the AF with the PI error flag may be determined as the same station as a result of moving the area and improving the reception environment. However, since the possibility of being determined as the same station is low, the priority of follow-up trials is low. There is a possibility that the AF with the reverse flag is broadcasting the same contents only in different broadcast areas. Therefore, the priority of the follow-up trial is higher than that of the AF with the PI error flag.

  The above is the description of the embodiment of the present invention. The present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the technical idea of the present invention.

101 antenna 102 tuner 103 analog signal processing circuit 104 audio signal processing circuit 105 power amplifier 106 speaker 107 RDS demodulator 108 PLL circuit 109 microcomputer 110 input interface 111 display

Claims (6)

A tuner for receiving a broadcast signal transmitted in a signal format of RDS (Radio Data System) system;
Storage means for decoding and storing AF (Alternative Frequencies) station data from the broadcast signal received by the tuner;
With reference to the multiplexed data included in the broadcast frequency at which a signal level capable of normally decoding the broadcast signal by frequency tracking using the AF station data is obtained, the AF station data stored in the storage means is assigned a predetermined identification Identification information giving means for attaching information;
Have
A broadcast receiver characterized by determining the order of broadcast frequencies to be tracked based on the identification information and performing frequency tracking.   The identification information adding means includes a PI (Programme Identification) code on the tracking target side included in the broadcast frequency at which the signal level is obtained, and the storage means included in the oldest AF station data stored in the storage means 2. The broadcast receiver according to claim 1, wherein the identification information is added to the oldest AF station data in accordance with a comparison result. The storage means
A first storage area for storing the AF station data;
A second storage area different from the first storage area;
Have
The identification information giving means executes the comparison process when AF station data exceeding the storage capacity of the first storage area is stored, and the AF station data with the identification information is stored in the first storage area. The broadcast receiver according to claim 2, wherein the broadcast receiver moves to the second storage area.   The AF station data received before the execution of frequency tracking is stored in the first storage area after the AF station data with the identification information is moved to the second storage area. Item 4. The broadcast receiver according to item 3.   The identification information adding unit includes the PI code on the tracking target side included in the broadcast frequency from which the signal level was obtained, and the AF station data stored in the storage unit that failed in the frequency tracking attempt. 2. The broadcast receiver according to claim 1, wherein a PI code on the storage means side is compared, and the identification information is attached to the AF station data that has failed to follow in accordance with the comparison result.   The broadcast receiver according to any one of claims 1 to 5, wherein the broadcast receiver is mounted on a mobile body.

Images