EP2627017A1

EP2627017A1 - Radio receiver that avoids updating stored frequency lists in tunnels

Info

Publication number: EP2627017A1
Application number: EP13153048.7A
Authority: EP
Inventors: Shizuto Arita; Tomoya Hamaguchi; Takanobu NAGASHIMA; Satoru Nagayama
Original assignee: Alpine Electronics Inc
Current assignee: Alpine Electronics Inc
Priority date: 2012-02-07
Filing date: 2013-01-29
Publication date: 2013-08-14
Anticipated expiration: 2033-01-29
Also published as: JP2013162383A; EP2627017B1; JP5808035B2

Abstract

A radio receiver includes a broadcasting station list creating unit (42) that creates a broadcasting station list, an entry determining unit (43) that determines whether the radio receiver has entered a tunnel, an exit determining unit (44) that determines whether the radio receiver has exited from the tunnel, a list holding unit (45) that holds the contents of the list when the radio receiver has entered a tunnel, a seek processing unit (46) that sweeps a receive frequency in one direction when a frequency sweeping instruction is issued and that stops the sweeping of the frequency when a broadcasting signal is detected, a mute processing unit (47) that keeps output sound in a non-sound state, and a list holding determining unit (48) that determines, on the basis of a result by the exit determining unit (44), whether or not the contents of the list should continue to be held.

Description

The present invention relates to a radio receiver such as a radio data system (RDS).
Receivers that create a list of receivable broadcasting stations have been known (for example, JP 2010-268333 A ). In the case of such receivers, a movable body in which a receiver is mounted determines, with the use of a position detector such as a global positioning system (GPS), whether or not the movable body has entered an area where reception is difficult, such as an underground facility. When the movable body enters the area where reception is difficult, the broadcasting station list is not updated. Accordingly, a situation in which the number of broadcasting stations registered in the broadcasting station list is reduced when the movable body enters the area where reception is difficult can be avoided.
Receivers that automatically update preset contents have also been known (for example, see JP 6 334 490 A ). When the reception levels of a plurality of preset broadcasting stations (broadcasting station list) fall below a reference value, the receivers update the preset contents by replacing the preset plurality of broadcasting stations with broadcasting stations whose reception levels are equal to or greater than the reference value. With the use of a second configuration, which is provided for searching for a broadcasting station and is arranged separately from a first configuration provided for listening to broadcasts, such receivers detect the reception levels of the plurality of preset broadcasting stations. When many broadcasting stations whose reception levels fall below the reference value exist, the preset contents are not updated. Accordingly, updating of the preset contents is avoided in the case of entry to a tunnel or the like.
In the receiver disclosed in JP 2010-268333 A , a navigation system or the like for determining whether or not the position detected by the position detector such as a GPS is located within the area where reception is difficult is required. Thus, the configuration of the receiver is complicated. In the receiver disclosed in JP 6 334 490 A , with the use of the second configuration, no influence is exerted on sound output of a program being received. However, since two sets of configurations for receiving broadcasting signals are required, the configuration of the receiver is complicated. Furthermore, when the configuration becomes more complicated as described above, the cost increases and the product price also increases.
Therefore, it may be an object of the present invention to provide a radio receiver that has a simple configuration and that is capable of avoiding updating of a broadcasting station list during traveling in a tunnel or the like.
The afore-discussed problem is solved by the features of the independent claims. Further embodiments and developments are defined in the corresponding dependent claims. Further examples are provides for facilitating the understanding of the invention.
For example, a radio receiver according to an aspect of the present invention includes a broadcasting signal receiving unit that receives a broadcasting signal; a sound output unit that outputs sound corresponding to the broadcasting signal; a broadcasting station list creating unit that creates a broadcasting station list representing broadcasting signals receivable by the broadcasting signal receiving unit; an entry determining unit that determines, on the basis of a reception state of the broadcasting signal, whether or not the radio receiver has entered an area where it is difficult to receive the broadcasting signal; an exit determining unit that determines, on the basis of the reception state of the broadcasting signal, whether or not the radio receiver has exited from the area where it is difficult to receive the broadcasting signal; a list holding unit that holds contents of the broadcasting station list when the entry determining unit determines that the radio receiver has entered the area where it is difficult to receive the broadcasting signal; an operating unit that receives a frequency sweeping instruction by a user; a frequency sweep processing unit that sweeps a receive frequency of the broadcasting signal receiving unit in one direction when the frequency sweeping instruction is issued using the operating unit by the user and that stops the sweeping of the receive frequency when a broadcasting signal is detected; a mute processing unit that performs, concurrently with the frequency sweep operation by the frequency sweep processing unit, an operation for keeping output from the sound output unit in a non-sound state; and a list holding determining unit that performs, concurrently with the frequency sweep operation by the frequency sweep processing unit, an operation for determining, on the basis of a result of the determination by the exit determining unit, whether the contents of the broadcasting station list should continue to be held by the list holding unit or holding of the contents of the broadcasting station list by the list holding unit should be ceased.
Specifically, the list holding determining unit determines that the contents of the broadcasting station list should continue to be held when the exit determining unit determines that the radio receiver has not exited from the area where it is difficult to receive the broadcasting signal, and determines that holding of the contents of the broadcasting station list should be ceased when the exit determining unit determines that the radio receiver has exited from the area where it is difficult to receive the broadcasting signal. In particular, preferably, the broadcasting signal receiving unit has a single-tuner configuration that receives one broadcasting signal. Furthermore, preferably, the area where it is difficult to receive the broadcasting signal, the area being used for the determinations by the entry determining unit and the exit determining unit, is an area inside a tunnel or inside a building.
Since the reception states of individual broadcasting signals are detected when a frequency sweep operation is performed in accordance with an instruction by a user, the individual broadcasting signals can be examined without affecting a normal operation for receiving a broadcasting signal (sound output). In addition, there is no need to add a different configuration for detecting a reception state and to use a navigation system or the like. Thus, a simpler configuration can be achieved. Furthermore, since a determination as to whether the contents of a broadcasting station list should continue to be held or holding of the contents of the broadcasting station list should be ceased is performed in accordance with whether or not the radio receiver has exited from a tunnel or the like, updating of the contents of the broadcasting station list during traveling inside the tunnel or the like can be avoided.
Furthermore, preferably, the list holding determining unit determines that the contents of the broadcasting station list should continue to be held or that holding of the contents of the broadcasting station list should be ceased before the frequency sweep processing unit starts the frequency sweeping or after the frequency sweep processing unit ends the frequency sweeping. Thus, the determination as to whether the contents of the broadcasting station list should continue to be held or that holding of the contents of the broadcasting station list should be ceased can be made without giving an unnatural feeling to a user.
Furthermore, preferably, the exit determining unit detects reception states of the broadcasting signals in the broadcasting station list. Alternatively, preferably, the exit determining unit detects reception states of all the broadcasting signals within a receive frequency band. Since the number of receivable broadcasting signals is reduced when the radio receiver enters a tunnel or a building, detection of entry to the tunnel or the building can be ensured on the basis of a detection result regarding the reception state.
Furthermore, preferably, the mute processing unit keeps the output in the non-sound state during the operation of the list holding determining unit. Thus, the determination as to whether the contents of a broadcasting station list should continue to be held or holding of the contents of the broadcasting station list should be ceased can be performed using a non-sound state at the time of the frequency sweep operation, and a situation in which an unnatural feeling is given to a user can be avoided.
Furthermore, preferably, the radio receiver further includes a tuning processing unit that instructs the broadcasting signal receiving unit to perform switching of a broadcasting signal; and a broadcasting station list updating unit that updates the contents of the broadcasting station list on the basis of a reception state of the broadcasting signal switched by the tuning processing unit. Preferably, the broadcasting station list updating unit holds the contents of the broadcasting station list, irrespective of the reception state of the broadcasting signal, when the list holding determining unit determines that the contents of the broadcasting station list should continue to be held. Furthermore, preferably, the tuning processing unit issues an instruction to perform switching to a broadcasting signal in the broadcasting station list. Thus, even in the case where the reception state of the broadcasting signal of the broadcasting station tuned in is bad, if the reason for the bad reception state is entry to a tunnel or the like, the contents of the broadcasting station list can be maintained. Accordingly, a situation in which the contents of the broadcasting station list are updated because of the temporary deterioration in the reception station can be avoided.
Furthermore, preferably, the entry determining unit determines, on the basis of a reception state of a broadcasting signal being received by the broadcasting signal receiving unit, whether or not the radio receiver has entered the area where it is difficult to receive the broadcasting signal. Unlike the case where the radio receiver moves away from a receivable area, the reception state of a broadcasting signal suddenly changes (deteriorates) when the radio receiver enters a tunnel. Thus, by examining the reception state, detection of entry to a tunnel or a building can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates the configuration of a radio receiver according to an embodiment;
Fig. 2 is an explanatory diagram of a basic baseband coding structure of RDS data;
Fig. 3 is a flowchart illustrating a process for performing switching of the holding state of the contents of a created broadcasting station list in accordance with entry or non-entry to a tunnel or the like;
Fig. 4 is a flowchart illustrating the process of a tuning operation which reflects the result of a determination as to whether or not the broadcasting station list should be held; and
Fig. 5 is an explanatory diagram of the tuning operation performed when the broadcasting station list continues to be held after entry to a tunnel during traveling.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a radio receiver according to an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 illustrates the configuration of a radio receiver according to an embodiment of the present invention. The radio receiver illustrated in Fig. 1 is mounted in a vehicle and receives RDS broadcasts. The radio receiver includes an antenna 10, a front end (F/E) 12, an intermediate frequency amplifier (IFA) 14, an S meter (signal meter) 16, a demodulator 20, an amplifier 22, a speaker 24, an RDS decoder 30, a controller 40, a broadcasting station list storing unit 50, a display unit 60, and an operation unit 62. The radio receiver has a single-tuner configuration that receives one broadcasting signal.
Radio data system (RDS) is a communications protocol standard, e.g. defined in IEC RDS standard version IEC 62106, for embedding small amounts of digital information in conventional FM radio broadcast signals. Radio Broadcast Data System (RBDS), defined in NRSC-4-B, "United States RBDS Standard -- Specification of the Radio Broadcast Data System (RBDS)", is the official name used for the U.S. version of RDS; the two standards are only slightly different and the NRSC-4-B standard includes only those sections that differ from the European version of the Standard, IEC 62106, Specification of the Radio Data System (RDS) for VHF/FM sound broadcasting in the frequency range from 87.5 to 108.0MHz.
In RDS broadcasting, the amplitude of a subcarrier at 57 kHz, which is a third harmonic of a stereo pilot signal at 19 kHz, is modulated using a data signal representing data, such as filtered and two-phase coded program related information and traffic information, to obtain radio data (RDS data), and the amplitude-modulated subcarrier is frequency-modulated into a main carrier and is broadcasted.
Fig. 2 is an explanatory diagram of the basic baseband coding configuration of RDS data. As illustrated in Fig. 2, RDS data is configured in units of groups each including 104 bits. Each group includes four blocks (A, B, C, and D). One block includes an information word (m0 to m15) of 16 bits and a test word and an offset word (C'0 to C'9) of 10 bits.
In the block A, program identification data (program identification code (PI code)) representing a network including country name data and program data is arranged. In the block B, traffic information broadcasting station identification data (traffic program identification code (TP code)) representing a traffic information broadcasting station that broadcasts traffic information programs and program contents identification data (program type code (PTY code)) representing the type of a program are arranged. In the block C, data relating to frequencies of individual stations in a network station group that broadcast the same program, that is, alternative frequency data (alternative frequency code (AF code)), is arranged. In the block D, broadcasting station name data (program service code (PS code)) such as a broadcasting station name and a network name is arranged.
The front end 12 extracts a desired broadcasting signal from among broadcasting signals received via the antenna 10, and performs frequency conversion to generate an intermediate frequency signal (IF signal) corresponding to the broadcasting wave. The intermediate frequency amplifier 14 amplifies the IF signal output from the front end 12. The S meter 16 detects the signal intensity of the IF signal output from the intermediate frequency amplifier 14, that is, the field intensity of the broadcasting signal received by the front end 12.
The demodulator 20 performs FM demodulation processing and stereo demodulation processing on the basis of the IF signal input from the intermediate frequency amplifier 14. RDS data including program identification data (PI code) and program contents identification data (PTY code) is superimposed on FM-demodulated data. An audio signal that is stereo-demodulated by the demodulator 20 is amplified by the amplifier 22, and audio sound is output from the speaker 24.
The RDS decoder 30 performs specific decoding processing for the data that is FM-demodulated by the demodulator 20 to restore RDS data. The RDS decoder 30 also performs an operation for detecting an error of the RDS data while achieving block synchronization and for correcting the error. Normally, the operation for error detection and error correction of RDS data is performed independently of decoding processing for RDS data, and a unit for detecting and correcting an error is provided separately.
The controller 40 controls the entire radio receiver. The controller 40 includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and the like and performs various operations by executing a specific program. For example, a tuning operation for selecting a program and receiving the program, a seek operation for performing frequency sweeping in one direction to search for a receivable broadcasting signal, an operation for creating a broadcasting station list representing receivable broadcasting signals, and the like are performed under the control of the controller 40. To this end, the controller 40 includes a tuning processing unit 41, a broadcasting station list creating unit 42, an entry determining unit 43, an exit determining unit 44, a list holding unit 45, a seek processing unit 46, a mute processing unit 47, a list holding determining unit 48, and a broadcasting station list updating unit 49.
When a tuning instruction (instruction to perform switching of a program to be received) is issued using the operation unit 62 by a user, the tuning processing unit 41 performs, for the front end 12, setting of a receive frequency corresponding to a program to be received after switching. The broadcasting station list creating unit 42 creates a broadcasting station list representing receivable broadcasting signals. The broadcasting station list includes at least program identification data (PI code) and receive frequencies corresponding to broadcasting signals of individual broadcasting stations. The broadcasting station list may be created at various times. For example, the broadcasting station list may be created at the time when a user issues an instruction using the operation unit 62, at the time when the radio receiver is activated, or at specific time intervals. The created broadcasting station list is stored in the broadcasting station list storing unit 50, which is a semiconductor memory, a hard disk device, or the like.
The entry determining unit 43 determines, on the basis of the reception state of a broadcasting signal, whether or not the vehicle has entered an area where it is difficult to receive the broadcasting signal. Specifically, the entry determining unit 43 determines, on the basis of the degree of a change in the reception state of a broadcasting signal being received (output level of the S meter 16), whether or not the vehicle has entered the area where it is difficult to receive the broadcasting signal. When a traveling vehicle moves away from a reception area of a broadcasting station, the output level of the S meter 16 gradually declines. However, when the vehicle enters a tunnel or a car park inside a building, the output level of the S meter 16 suddenly declines. Thus, when the rate of decline in the output level of the S meter 16 reaches a specific reference value or more, it is determined that the vehicle has entered a tunnel or the like.
The exit determining unit 44 determines, on the basis of the reception state of a broadcasting signal, whether or not the vehicle has exited from the area where it is difficult to receive the broadcasting signal. The "area where it is difficult to receive a broadcasting signal", which is used for the determinations performed by the exit determining unit 44 and the entry determining unit 43, is assumed to be an area inside a tunnel or inside a building. Specifically, the exit determining unit 44 determines, on the basis of the reception states of individual broadcasting signals included in a broadcasting station list (output level of the S meter 16), whether or not the vehicle has entered the area where it is difficult to receive the broadcasting signals. For example, when the reception states of all the (or a specific number or more of) broadcasting signals included in a broadcasting station list are good and all the (or the specific number or more of) broadcasting signals are receivable, it is determined that the vehicle has exited from a tunnel or the like.
When it is determined by the entry determining unit 43 that the vehicle has entered a tunnel or the like, the list holding unit 45 holds the contents of the broadcasting station list stored in the broadcasting station list storing unit 50. When a frequency sweeping instruction (seek instruction) is issued using the operation unit 62 by a user, the seek processing unit 46 sweeps a receive frequency of the front end 12 in one direction. When the output level of the S meter 16 reaches a specific value or more and a broadcasting signal is detected, the seek processing unit 46 stop the sweeping of the receive frequency. Concurrently with the frequency sweep operation (seek operation) by the seek processing unit 46, the mute processing unit 47 issues an instruction to the demodulator 20, and causes audio sound output from the speaker 24 to enter a non-sound state.
When it is determined by the exit determining unit 44 that the vehicle has not exited from a tunnel or the like, the list holding determining unit 48 determines that the list holding unit 45 should continue to hold the broadcasting station list. In the other case (in the case where it is determined that the vehicle has exited from a tunnel or the like), the list holding determining unit 48 determines that list holding unit 45 should cease holding the broadcasting station list.
The broadcasting station list updating unit 49 detects the reception state of a received broadcasting signal (output level of the S meter 16) in a tuning operation or the like using a broadcasting station list, and updates the contents of the broadcasting station list stored in the broadcasting station list storing unit 50, on the basis of the result of the detection.
When RDS data includes data to be displayed, the display unit 60 displays the data, and displays tuning information, the contents of a broadcasting station list, and the like necessary for control by the controller 40. The operation unit 62 receives instructions from a user. The operation unit 62 includes various input keys, operation tabs, and the like.
The antenna 10 and the front end 12 correspond to broadcasting signal receiving means, the intermediate frequency amplifier 14, the demodulator 20, the amplifier 22, and the speaker 24 correspond to sound output means, the broadcasting station list creating unit 42 corresponds to broadcasting station list creating means, the entry determining unit 43 corresponds to entry determining means, the exit determining unit 44 corresponds to exit determining means, the list holding unit 45 corresponds to list holding means, the operation unit 62 corresponds to operating means, the seek processing unit 46 corresponds to frequency sweep processing means, the mute processing unit 47 corresponds to mute processing means, the list holding determining unit 48 corresponds to list holding determining means, the tuning processing unit 41 corresponds to tuning processing means, and the broadcasting station list updating unit 49 corresponds to broadcasting station list updating means.
The radio receiver according to this embodiment has the configuration described above. The operation of the radio receiver according to this embodiment will now be explained. Fig. 3 is a flowchart illustrating a process for performing switching of the holding state of the contents of a created broadcasting station list in accordance with whether or not the vehicle has exited from a tunnel or the like. In the description provided below, both a tunnel and an area inside a building are referred to as a "tunnel".
When the radio receiver is receiving a broadcasting signal while the vehicle in which the radio receiver is mounted is traveling (step 100), the entry determining unit 43 determines whether or not the vehicle has entered a tunnel (step 102). When the vehicle has not entered a tunnel, a negative determination is made and the determination in step 102 is repeated. When the vehicle has entered a tunnel, an affirmative determination is made in step 102. Then, the seek processing unit 46 determines whether or not a seek instruction has been issued by a user (step 106). When a seek instruction has not been issued, a negative determination is made, and the determination in step 106 is repeated.
When a seek instruction has been issued by a user, an affirmative determination is made in step 106. Then, the mute processing unit 47 issues a mute instruction to the demodulator 20, and causes audio sound output from the speaker 24 to enter a non-sound state (step 108). The seek processing unit 46 issues an instruction to the front end 12, and starts a seek operation for sweeping a frequency in one direction from the current receive frequency (step 110).
Then, the seek processing unit 46 monitors the output level of the S meter 16, and determines whether or not a broadcasting signal whose reception state is good (output level is equal to or greater than a specific value) exists (step 112). When no broadcasting signal is detected, a negative determination is made. Then, the seek processing unit 46 determines whether or not all the frequencies have been swept through (for example, when a swept frequency reaches the upper limit (or lower limit) of a reception band, the frequency is switched to the lower limit (or upper limit) to continue frequency sweeping) (step 114). A negative determination is made and the process returns to step 112 to perform the determination as to whether or not all the frequencies have been swept through until all the frequencies have been swept through.
When a broadcasting signal is detected during the frequency sweep operation, an affirmative determination is made in step 112. After the affirmative determination is made in step 112 or after all the frequencies have been swept through and an affirmative determination is made in step 114, the seek processing unit 46 terminates the seek operation (step 116). In this state, a broadcasting signal corresponding to a new receive frequency after the seek operation is performed (the same receive frequency as that before the seek operation is performed in the case where all the frequencies have been swept through) is received, and corresponding audio sound is output.
Then, the exit determining unit 44 detects the reception states of individual broadcasting signals of a plurality of broadcasting stations in the broadcasting station list (output level of the S meter 16) in a specific order (for example, in a registered order in the broadcasting station list or in ascending or descending order of receive frequencies) (step 118). The exit determining unit 44 also determines whether or not the vehicle has exited from the tunnel (step 120). When the vehicle is traveling inside the tunnel and has not exited from the tunnel, a negative determination is made. Then, the list holding determining unit 48 determines that the broadcasting station list should continue to be held (step 122). Meanwhile, when the vehicle has exited from the tunnel, an affirmative determination is made in step 120. Then, the list holding determining unit 48 determines that holding of the broadcasting station list should be ceased (step 124).
Then, a broadcasting signal detected in step 112 or the original broadcasting signal at the time of start of the seek operation when it is determined in step 114 that all the frequencies have been swept through starts to be received (step 126), and the mute processing unit 47 terminates the mute processing (step 128). Then, the process returns to step 106 to repeat the determination as to whether or not a seek instruction has been issued.
In the case where it is determined in step 122 that the broadcasting station list should continue to be held, when a tuning instruction for performing switching to a broadcasting station in the broadcasting station list is issued after the determination in step 122 is made and switching to a broadcasting signal of the broadcasting station is actually performed, even if the reception state of the broadcasting signal is bad, the contents of the broadcasting station list are maintained without deleting the broadcasting station from the broadcasting station list.
In the case where it is determined in step 124 that holding of the broadcasting station list should be ceased, when a tuning instruction for performing switching to a broadcasting station in the broadcasting station list is issued after the determination in step 124 is made and switching to a broadcasting signal of the broadcasting station is actually performed, if the reception state of the broadcasting signal is bad, the contents of the broadcasting station list are updated by deleting the broadcasting station from the broadcasting station list.
Fig. 4 is a flowchart illustrating the process of a tuning operation which reflects the result of a determination as to whether or not the broadcasting station list should be held. When a broadcasting signal is being received (step 200), the tuning processing unit 41 determines whether or not a tuning instruction has been issued (step 202). When a tuning instruction is not issued, a negative determination is made. Then, the process returns to step 200 and the current broadcasting signal continues to be received. When a tuning instruction is issued, an affirmative determination is made in step 202. Then, the tuning processing unit 41 performs switching of a broadcasting station (broadcasting signal) (step 204). Specifically, the tuning instruction is issued by selecting a broadcasting station registered in the broadcasting station list. The tuning processing unit 41 performs switching of a broadcasting signal by performing setting of a receive frequency corresponding to the selected broadcasting station (broadcasting signal) for the front end 12.
Then, the broadcasting station list updating unit 49 detects the reception state of the broadcasting signal after switching is performed (output level of the S meter 16), and determines whether or not the detected reception state is good (step 206). When the reception state is good, an affirmative determination is made. Then, the process returns to step 200 and the broadcasting signal after switching is performed continues to be received.
When the reception state is bad, a negative determination is made in step 206. Then, the broadcasting station list updating unit 49 determines whether or not the list holding determining unit 48 has determined that the broadcasting station list should continue to be held (step 208). When the determination that the broadcasting station list should continue to be held is made in step 122 of Fig. 3, an affirmative determination is made. Then, the process returns to step 200 and the broadcasting signal after switching is performed continues to be received. Meanwhile, when the determination that holding of the broadcasting station list should be ceased is made in step 124 of Fig. 3, a negative determination is made in step 208. Then, the broadcasting station list updating unit 49 deletes the broadcasting signal (broadcasting station) in the bad reception state after switching is performed from the broadcasting station list (step 210). Then, the process returns to step 200 to continue to receive a broadcasting signal. Since the reception state of the broadcasting signal is bad, a tuning instruction or the like for performing switching to a different broadcasting station is normally issued.
Fig. 5 is an explanatory diagram of a tuning operation performed in the case where the vehicle enters a tunnel while being traveling and a broadcasting station list continues to be held. In the example illustrated in Fig. 5, the broadcasting station list includes three broadcasting stations, that is, a station A, a station B, and a station C. Apart from the stations A, B, and C, a broadcasting station for broadcasting inside a tunnel, which is separately represented as station D, exists.
When the vehicle enters a tunnel while being receiving a broadcasting signal of the broadcasting station A, the contents of a broadcasting station list created and stored in advance in the broadcasting station list storing unit 50 are held (step 104 of Fig. 3). Then, when a seek operation is performed and the broadcasting station D for broadcasting inside a tunnel is detected, a determination as to whether or not the vehicle has exited from the tunnel is performed (step 120 of Fig. 3). When the vehicle has not exited from the tunnel, the determination that the broadcasting station list should continue to be held is made (step 122). Then, a tuning operation for each of the broadcasting stations A, B, and C in the broadcasting station list is performed (since the vehicle is located inside the tunnel, the reception states of broadcasting signals of the broadcasting stations A, B, C are bad). Since the determination that the broadcasting station list should continue to be held is made, the broadcasting stations A, B, C are not deleted from the broadcasting station list. Accordingly, the contents of the broadcasting station list are held. When the vehicle has exited from the tunnel, since the determination that holding of the broadcasting station list should be ceased is made (step 124), tuning for each of the broadcasting stations A, B, and C is performed. If the reception state of a broadcasting signal for a broadcasting station is bad, the broadcasting station is deleted from the broadcasting station list.
As described above, since the radio receiver according to this embodiment detects the reception states of individual broadcasting signals when a seek operation is performed in accordance with an instruction by a user, the details of the individual broadcasting signals can be examined without affecting a normal operation for receiving a broadcasting signal (audio sound output). In addition, there is no need to add a different configuration for detecting a reception state and to use a navigation system or the like. Thus, a simpler configuration can be achieved. Furthermore, since a determination as to whether the contents of a broadcasting station list should continue to be held or holding of the contents of the broadcasting station list should be ceased is performed in accordance with whether or not the vehicle has exited from a tunnel or the like, updating of the contents of the broadcasting station list during traveling inside the tunnel or the like can be avoided.
By determining that the contents of a broadcasting station list should continue to be held or that holding of the contents of the broadcasting station list should be ceased is made after a seek operation finishes and before audio sound output starts, the determination as to whether the contents of a broadcasting station list should continue to be held or that holding of the contents of the broadcasting station list should be ceased can be performed without giving an unnatural feeling to a user.
Furthermore, by detecting the reception state of a broadcasting signal in a broadcasting station list and determining whether or not the vehicle has exited from an area such as a tunnel where it is difficult to receive the broadcasting signal, detection of exit from a tunnel or building can be ensured. Furthermore, by determining whether the contents of a broadcasting station list should continue to be held or holding of the contents of the broadcasting station list should be ceased by using a non-sound state (mute state) at the time of a seek operation, a situation in which an unnatural feeling is given to a user can be avoided.
The present invention is not limited to the embodiment described above. Various variations can be made to the present invention within the scope of the present invention as defined in the claims.
For example, although the reception states of broadcasting signals of broadcasting stations in a broadcasting station list are detected in step 118 of Fig. 3 in the embodiment described above, the reception states of all the broadcasting signals within a receive frequency band may be detected.
Furthermore, although the reception state of a broadcasting signal is detected after a seek operation finishes and the determination that the contents of a broadcasting station list should continue to be held or that holding of the contents of the broadcasting station list should be ceased is made ( steps 120, 122, and 124 of Fig. 3) in the embodiment described above, these operations may be performed before the seek operation starts (between step 108 and step 110 of Fig. 3).
Furthermore, although a radio receiver that receives RDS broadcasts has been explained in the embodiment described above, the present invention may also be applied to various radio receivers, such as digital audio broadcasting (DAB) receivers, AM receivers, and FM receivers.
As described above, since a radio receiver according to an embodiment of the present invention detects the reception states of individual broadcasting signals when a frequency sweep operation is performed in accordance with an instruction by a user, the details of the individual broadcasting signals can be examined without affecting a normal operation for receiving a broadcasting signal (sound output). In addition, there is no need to add a different configuration for detecting a reception state and to use a navigation system or the like. Thus, a simpler configuration can be achieved. Furthermore, since a determination as to whether the contents of a broadcasting station list should continue to be held or holding of the contents of the broadcasting station list should be ceased is performed in accordance with exit or non-exit from a tunnel or the like, updating of the contents of the broadcasting station list during traveling inside the tunnel or the like can be avoided.

Claims

A radio receiver comprising:
broadcasting signal receiving means (10, 12) configured for receiving a broadcasting signal;

sound output means (14, 20, 22, 24) configured for outputting sound corresponding to the broadcasting signal;

broadcasting station list creating means (42) configured for creating a broadcasting station list representing broadcasting signals receivable by the broadcasting signal receiving means (10, 12);

entry determining means (43) configured for determining, on the basis of a reception state of the broadcasting signal, whether or not the radio receiver has entered an area where it is difficult to receive the broadcasting signal;

exit determining means (44) configured for determining, on the basis of the reception state of the broadcasting signal, whether or not the radio receiver has exited from the area where it is difficult to receive the broadcasting signal;

list holding means (45) configured for holding contents of the broadcasting station list when the entry determining means (43) determines that the radio receiver has entered the area where it is difficult to receive the broadcasting signal;

operating means (62) configured for receiving a frequency sweeping instruction by a user;

frequency sweep processing means (46) configured for sweeping a receive frequency of the broadcasting signal receiving means (10, 12) in one direction when the frequency sweeping instruction is issued using the operating means (62) by an user and stopping the sweeping of the receive frequency when a broadcasting signal is detected;

mute processing means (47) for performing, concurrently with the frequency sweep operation by the frequency sweep processing means (46), an operation for keeping output from the sound output means (14, 20, 22, 24) in a non-sound state; and

list holding determining means (48) for performing, concurrently with the frequency sweep operation by the frequency sweep processing means (46), an operation for determining, on the basis of a result of the determination by the exit determining means (44), whether the contents of the broadcasting station list should continue to be held by the list holding means (45) or holding of the contents of the broadcasting station list by the list holding means (45) should be ceased.
The radio receiver according to Claim 1, wherein the list holding determining means (48) is configured to determine that the contents of the broadcasting station list should continue to be held when the exit determining means (44) determines that the radio receiver has not exited from the area where it is difficult to receive the broadcasting signal, and to determine that holding of the contents of the broadcasting station list should be ceased when the exit determining means (44) determines that the radio receiver has exited from the area where it is difficult to receive the broadcasting signal.
The radio receiver according to Claim 1 or 2, wherein the broadcasting signal receiving means (10, 12) has a single-tuner configuration that receives one broadcasting signal.
The radio receiver according to any one of Claims 1 to 3, wherein the area where it is difficult to receive the broadcasting signal, the area being used for the determinations by the entry determining means (43) and the exit determining means (44), is an area inside a tunnel or inside a building.
The radio receiver according to any one of Claims 1 to 4, wherein the list holding determining means (48) determines that the contents of the broadcasting station list should continue to be held or that holding of the contents of the broadcasting station list should be ceased before the frequency sweep processing means (46) starts the frequency sweeping or after the frequency sweep processing means (46) ends the frequency sweeping.
The radio receiver according to any one of Claims 1 to 5, wherein the exit determining means (44) is configured to detect reception states of the broadcasting signals in the broadcasting station list.
The radio receiver according to any one of Claims 1 to 5, wherein the exit determining means (44) is configured to detect reception states of all the broadcasting signals within a receive frequency band.
The radio receiver according to any one of Claims 1 to 7, wherein the mute processing means (47) is configured to keep the output in the non-sound state during the operation of the list holding determining means (48).
The radio receiver according to any one of Claims 1 to 8, further comprising:
tuning processing means (41) configured for instructing the broadcasting signal receiving means (10, 12) to perform switching of a broadcasting signal; and

broadcasting station list updating means (49) configured for updating the contents of the broadcasting station list on the basis of a reception state of the broadcasting signal switched by the tuning processing means (41),

wherein the broadcasting station list updating means (49) is configured to hold the contents of the broadcasting station list, irrespective of the reception state of the broadcasting signal, when the list holding determining means (48) determines that the contents of the broadcasting station list should continue to be held.
The radio receiver according to Claim 9, wherein the tuning processing means (41) is configured to issue an instruction to perform switching to a broadcasting signal in the broadcasting station list.
The radio receiver according to any one of Claims 1 to 10, wherein the entry determining means (43) is configured to determine, on the basis of a reception state of a broadcasting signal being received by the broadcasting signal receiving means (10, 12), whether or not the radio receiver has entered the area where it is difficult to receive the broadcasting signal.