JP3481150B2 - Radio receiver - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, DAB.
(Digital Audio Broadcast
ng) and RDS (Radio Data System)
The present invention relates to a radio receiver compatible with both digital audio broadcasting and analog audio broadcasting with data service such as m), and more particularly to a radio receiver capable of improving switching between digital audio broadcasting and analog audio broadcasting with data service. .

[0002]

2. Description of the Related Art The same radio program may be simultaneously broadcast in both DAB as a digital audio broadcast and RDS as an analog audio broadcast with a data service. Further, the DAB radio wave coverage area is usually smaller than that of RDS. DA
In the B / RDS shared car radio, the reception status such as the electric field strength of the radio waves changes as the car moves, but DAB / RD
On the S-shared car radio, DAB is received preferentially and DA
When the reception state of B deteriorates, the DAB is switched to the RDS, the same radio program of the RDS is output, and D
When the AB reception condition becomes good again, the RDS sends DAB
Is switched to and the DAB radio program is output again.

In a conventional DAB / RDS shared car radio, as soon as the reception status falls below a reference level, DAB is switched to RDS for the same radio program, and reception is performed after switching to RDS. When the state recovers above the reference level, the same radio program is restored to DAB again.

[0004]

When the automobile moves along the boundary line of the DAB radio wave coverage area, the reception state of the DAB radio wave may fall below or exceed the reference level. Frequent, conventional DA
In the B / RDS shared car radio, DAB and RDS switching for the same radio program is likely to occur frequently. DAB is about 1 second behind RDS for the same radio program, and mute (silence) is applied when DAB and RDS are switched, so that DAB and RDS are frequently switched for the same radio program. Causes the sound output from the speaker to be interrupted or discontinuous, which gives the user an unpleasant feeling.

Therefore, Japanese Patent Application No. 9-366 filed by the present applicant.
In part of the disclosure of No. 847, a hold time is set when switching from DAB to RDS or vice versa, and when the DAB reception state is below a reference level or above the switch hold time, the DAB changes to RDS. Is switched to or vice versa.

An object of the present invention is to automatically switch between a digital audio broadcast and an analog audio broadcast with a data service for the same radio program in accordance with a change in the reception state of the digital audio broadcast, and a switching hold time for suppressing frequent switching. The problem is to find a new problem in a radio receiver that is set to and further improve it.

[0007]

A radio receiver according to the present invention
According to (10), when the receiving condition of the digital audio broadcast deteriorates while the digital audio broadcast is being selected,
If there is an analog audio broadcast with a data service that is broadcasting the same radio program as a digital audio broadcast radio program, it is automatically switched to the analog audio broadcast with a data service radio program. . In this radio receiver (10), when switching from digital audio broadcasting for the same radio program to analog audio broadcasting with data service when the reception condition of digital audio broadcasting deteriorates, a first switching hold time is set, It is assumed that the digital audio broadcasting is switched from the digital audio broadcasting to the analog audio broadcasting with the data service when the reception state of the digital audio broadcasting is kept below the first reference level for the first switching hold time or more. The first switching hold time is set shorter when the level of the reception state of the digital audio broadcast is lower than when it is higher.

The radio receiver (10) is not limited to the DAB / RDS shared car radio (10). Includes DAB / RDS shared radio receivers that are used in homes, etc. without being installed in automobiles. Digital audio broadcasting and analog audio broadcasting with data service are, for example, D
AB and RDS. DAB radio waves are DQP
Transmitted by SK OFDM (Orthogonal Frequency Division Multiplexing), R
Radio waves of DS are transmitted by FM.

It is assumed that the first switching hold time set when the level of the reception state of the digital audio broadcast is lower than that when the level is higher (first switching hold time ≧ 0). The level of the reception state of digital audio broadcasting can be detected based on, for example, the electric field strength of the received radio wave and the error rate of the decoded code. The reception level of digital audio broadcasting rises as the electric field strength of the received radio wave rises. Further, it decreases as the error rate increases. The value of the first switching hold time is set to two, large and small, by dividing the level of the reception state of the digital audio broadcast when switching from the digital audio broadcast to the analog audio broadcast with data service into two levels above and below a predetermined value. May be done 3
It may be set to three or more different values divided into more than two stages, or may be set to have almost continuous values divided into no steps.

The reception status of digital audio broadcasting is
When it deteriorates significantly, the same radio program can be quickly switched to analog audio broadcasting with data service. Even if the level of the reception status of the digital audio broadcast is less than the first reference level, if the level is not extremely low, the first switching hold time is set to be long, and it is necessary to see whether the reception status of the digital audio broadcast is improved for a while. As will be seen, if improved, switching from digital audio broadcasting to analog audio broadcasting with data service is abolished, thereby eliminating unnecessary switching from digital audio broadcasting to analog audio broadcasting with data service.

According to the radio receiver (10) of the present invention, the level of the reception condition of the digital audio broadcast is changed after the same radio program is switched from the digital audio broadcast to the analog audio broadcast with data service. When the price rises, analog audio broadcasting with data service relating to the same radio program is automatically switched to digital audio broadcasting. This radio receiver (10) sets a second switching hold time when switching from analog audio broadcasting with data service to digital audio broadcasting for the same radio program when the level of digital audio broadcasting rises, It is assumed that the analog audio broadcast with a data service is switched to the digital audio broadcast when the reception state of the audio broadcast is kept at the second reference level or more for the second switching hold time or more. The second switching hold time is set shorter when the level of the reception state of the digital audio broadcast is higher than when it is lower.

According to the radio receiver (10) of the present invention, the same radio program is broadcast in both digital audio broadcasting and analog audio broadcasting with data service, and while selecting analog audio broadcasting with data service, When the reception status of digital audio broadcasting related to the same radio program is improved, analog audio broadcasting with data service is automatically switched to digital audio broadcasting. In this radio receiver (10), a second switching hold time is set when switching from analog audio broadcasting with data service to digital audio broadcasting for the same radio program when the level of digital audio broadcasting rises,
It is assumed that the analog audio broadcast with data service is switched to the digital audio broadcast when the reception state of the digital audio broadcast is maintained at the second reference level or higher for the second switching hold time or longer. The second switching hold time is set shorter when the level of the reception state of the digital audio broadcast is higher than when it is lower.

The second reference level is usually higher than the first reference level, but it may be equal to the first reference level (second reference level ≧ first reference level).

The second switching hold time, which is set when the level of the reception state of the digital audio broadcast is higher than when the level is lower, includes 0 (second switching hold time ≧ 0). The value of the second switching hold time is set to two, large and small, by dividing the level of the reception state of the digital audio broadcast when the analog audio broadcast with data service is switched to the digital audio broadcast into two levels below and above a predetermined value. The value may be set in three or more steps and set to three or more different values, or may be set in a non-step manner to be a substantially continuous value.

The reception status of the digital audio broadcast is
When there is a significant improvement, it will be quickly switched to digital audio broadcasting. Even if the level of the reception state of the digital audio broadcast is higher than or equal to the second reference level, if the level is not significantly improved, the second switching hold time is set long, and the reception state of the digital audio broadcast is not deteriorated again. After a while, the situation will be seen, and if it deteriorates again, the switch from analog audio broadcasting with data service to digital audio broadcasting will be canceled,
This eliminates unnecessary switching from analog audio broadcasting with data service to digital audio broadcasting.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a car audio 10 with a DAB / RDS shared car radio. C
Media player 12, R such as D player or MD player
The outputs of the DS tuner unit 14 and the DAB tuner unit 16 are sent to the switch 18. The microcomputer 20 controls the volume 22 and the media player 12, R via the switch 18.
The connection with the DS tuner unit 14 and the DAB tuner unit 16 is controlled, and one selected from the outputs of the media player 12, the RDS tuner unit 14, and the DAB tuner unit 16 is sent to the volume 22. The volume 22 adjusts the volume of the sound emitted from the speaker 24, and the output of the volume 22 is the amplifier.
After being amplified by 26, it is output from the left and right speakers 24. The user's instruction to the car audio 10 is given by the key 28, the input of the key 28 is sent to the microcomputer 20, and the user operates the key 28 to make a predetermined input to the microcomputer 20. Is
Various information is displayed on the display unit 30 to inform the user.
The memory 32 includes a RAM and the like, and is a microcomputer.
Data is read and written by 20.

FIG. 2 is a detailed diagram of the RDS tuner unit 14 of FIG. The FM composite signal of RDS from the antenna is PL
It is sent to the L receiving circuit 36. A predetermined FM composite signal is selected in the PLL receiving circuit 36, amplified, detected, and sent to the muting circuit 38. The RDS data demodulation circuit 40 extracts and demodulates a data portion from the FM composite signal selected by the PLL reception circuit 36, and outputs the demodulated data portion to the microcomputer 20. Microcomputer 20
Decodes the input from the RDS data demodulation circuit 40, stores the decoded data in the memory 32, and displays the data such as the reception frequency and the radio program name related to the RDS being received on the display 30 as appropriate. The reception sensitivity detection circuit 42 detects the reception sensitivity (= the electric field strength of the received radio wave) of the FM reception signal selected by the PLL reception circuit 36, and outputs the detection result to the microcomputer 20. Based on the input from the reception sensitivity detection circuit 42, the microcomputer 20 determines whether or not the electric field strength of the reception signal is, for example, 20 dBμV or more at the S meter output and the noise level at the IF output is 5 V or less. When the conditions are satisfied, the muting circuit 38 is deactivated, and the demodulated RDS audio signal is output to the switch 18. If the above-mentioned reception condition is not satisfied, the muting circuit 38 is activated and the output of the RDS audio signal to the switch 18 is stopped.

FIG. 3 is a system configuration diagram of the DAB tuner unit 16. The system microcomputer unit 52 and the control microcomputer unit 54 are included in the microcomputer 20 and have memory units 56 and 58 as the memory 32, respectively. The system microcomputer unit 52 uses a plurality of ensembles (each ensemble is transmitted by a radio broadcast wave modulated by DQPSK-OFDM, and one ensemble has a bandwidth of 5M.
Hz, and usually contains 6 ensembles, or broadcast programs. One of the ensemble is designated, and the reception frequency data related to the designated ensemble is sent to the RF block 60. The RF block 60 is an RF (R) of the ensemble designated by the system microcomputer unit 52.
Adio Frequency) is extracted and sent to the demodulation block 62. In the demodulation block 62, the system microcomputer section
RF block 60 based on demodulation start data information from 52
Demodulates the RF signal from the channel and outputs it to the channel decoding block 64. The channel decoding block 64 decodes the demodulated signal from the demodulation block 62 on the basis of the reception mode data from the system microcomputer unit 52 and the decoded channel separation data to obtain an FIC (Fast Information).
Data other than audio data such as channel data and error rate data (representing a bit error rate) is output to the system microcomputer section 52, and the decoded audio information is output to the audio decoding block 66. The audio decoding block 66 is a system microcomputer unit.
52 to MPEG header data, MPEG error data,
And PAD (Program Associate)
The audio information of a predetermined service is selected from the input from the channel decoding block 64 based on d Data) and is output as a sound.

FIG. 4 shows F contained in the DAB transmission frame.
It is a structure diagram of the type 0 area | region of IG0 / 21. 0 is FI
G indicates the type, and 21 indicates the extension.
Communication protocols for various DAB elements such as DAB transmission frames are well known, and the details are described in European Telecommunications Standards Institute (European Tel).
communication Standards
European Telecom standard issued by Institute.
nications Standard). The extension type 0 area further includes a plurality of pieces of frequency information (Frequency information).
section). The main part of each frequency information will be described. The Regionid indicates the area to which this frequency information is applied, and is followed by a plurality of FIlists (FI list: frequency information list). DAB is included in the frequency list (Freq list).
Information of an alternative frequency (alternative frequency) that is broadcasting the same program as the service of the above service is written, and the header (Hea of each FIlist)
When R & M of der) = 100, it indicates that the alternative frequency written in the frequency list is the frequency of RDS in particular. When R & M = 101, the alternative frequency written in the frequency list is A
Indicates that it is for M broadcasting. In this way,
It is possible to acquire the frequency information of the RDS broadcasting the same radio program as the radio program currently being broadcast by the predetermined service of DAB from the information of 21.

FIG. 5 is a flow chart of a program for switching from DAB to RDS for the same radio program.
This program and the program shown in FIG. 6 below have a predetermined cycle (this cycle is S73 or S8) while the car audio 10 is on.
3 corresponds to the increment cycle of the timer value. ) Every time. In S69, the car audio 10 is DA
It is determined whether or not B is selected, and if the determination is YES, S
Proceed to 70, and if NO, execute this program. S
At 70 and S71, it is determined whether or not the reception state of the DAB at the time of the previous and current execution of this program is less than the first reference level R1, and if the determinations at both S70 and S71 are YES, the process proceeds to S72. If either determination is NO, the process proceeds to S76. The reception status of DAB is D
This can be done by measuring the electric field sensitivity of the received radio wave of AB and calculating the error rate at the time of code error check performed when the received signal of DAB is decoded. As the electric field strength of the received radio wave increases, the reception state improves. Further, the reception state deteriorates as the error rate increases. In S72, the current reception state is significantly lower than the first reference level R1, that is, Ra (R
It is determined whether or not less than a <R1). If the determination is YES, S73 and S74 are skipped, and the process proceeds to S75. If NO, the process proceeds to S73. In S73, the value of the timer is incremented by 1, and in S74, it is determined whether or not the timer value has reached the predetermined value C1 or more, that is, the reception state of the RDS is less than the first reference level R1 and the level Ra.
It is determined whether or not the above is held for a predetermined time T1 or more. If the determination is YES, the process proceeds to S75, and if the determination is NO, this program is terminated. In S75, DAB is switched to RDS for the same radio program. In S76, the timer is reset.

Thus, while DAB is being selected, (a) DAB
When the reception state of <1> falls below the level Ra, it is immediately switched to RDS for the same radio program. When the reception state of the DAB is lower than the first reference level R1 and is equal to or higher than the level Ra, the elapsed time of each state is measured, and (b) the state is the predetermined time T1 corresponding to the timer value C1. When held, (c) when the DAB reception state becomes less than Ra before the elapse of the predetermined time T1,
(D) It is divided when the reception state of the DAB returns to the first reference level R1 or higher before the elapse of the predetermined time T1. In (b), the RDS is switched to the same radio program. In (c), when the reception state of DAB becomes less than Ra, the mode is switched to RDS for the same radio program. In (d), switching to RDS has been canceled,
DAB continues.

FIG. 6 is a flow chart of a program for switching from RDS to DAB for the same radio program.
This program is intended to be executed only when switching to RDS by the program of FIG.
It may be executed during the selection of RDS regardless of the switching of DAB to RDS by the program of. In S79, it is determined whether or not the car audio 10 is selecting RDS. If the determination is YES, the process proceeds to S80, and if NO, this program is executed. In S80 and S81, the DAB at the time of previous and current execution of this program (this DAB is a DAB that is currently broadcasting the same radio program as the RDS radio program output from the car audio 10). The reception state of both is the second reference level R
It is determined whether or not it is 2 or more, and if the determinations in both S80 and S81 are YES, the process proceeds to S82, and if one of the determinations is NO, the process proceeds to S86. In S82, the current reception state is significantly higher than the second reference level R2,
Rb as a very good level (Rb> R2 ≧ R1> R
a) It is determined whether or not it is the above, and if the determination is YES, S83 and S84 are skipped, and the process proceeds to S85.
If NO, the process proceeds to S83. In S83, the value of the timer is incremented by 1, and in S84, it is determined whether or not the timer value reaches a predetermined value C2 or more, that is, the reception state of DAB is the second reference level R2 or more and less than the level Rb. It is determined whether or not it is held for a predetermined time T2 or more, and the determination is Y
If ES, the process proceeds to S85, and if NO, this program ends. In S85, the service of RDS is switched to the service of DAB for the same radio program. In S86, the timer is reset.

In this way, while the RDS is being selected, the DAB broadcasting the same radio program is immediately returned to the DAB for the same radio program when (a) the reception state reaches the level Rb or higher. When the reception state of the DAB is a level that is equal to or higher than the second reference level R2 and lower than the level Rb, the elapsed time of each state is measured, and (b) the state is a predetermined time corresponding to the timer value C2. When T2 is held, (c) DAB before the predetermined time T2 elapses.
When the reception state of R becomes equal to or higher than Rb, (d) a predetermined time T
Before the elapse of 2, the DAB reception status is split when it becomes worst than the second reference level R2. In (b), the return to DAB for the same radio program is performed. In (c), when the reception state of the DAB becomes Rb or higher, the DAB is switched to the same radio program. In (d), switching to DAB is canceled and RDS
Is continued.

[Brief description of drawings]

FIG. 1 is a block diagram of a car audio with a DAB / RDS shared car radio.

FIG. 2 is a detailed view of an RDS tuner unit of FIG.

FIG. 3 is a system configuration diagram of a DAB tuner unit.

FIG. 4 includes FIG0 / 2 included in a DAB transmission frame.
FIG. 3 is a structural diagram of a Type 0 area of No.

FIG. 5 is a flowchart of a program for switching from DAB to RDS for the same radio program.

FIG. 6 is a flowchart of a program for switching from RDS to DAB for the same radio program.

[Explanation of symbols]

10 Car audio (radio receiver, DAB / RD
S shared radio receiver)

Continuation of front page (56) References JP-A-9-219654 (JP, A) JP-A-10-224246 (JP, A) JP-A-1-55919 (JP, A) JP-A-5-48396 (JP , A) JP 1-236738 (JP, A) JP 1-264320 (JP, A) JP 11-196009 (JP, A) Actual flat 4-57930 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 1/16 H04J 11/00 H03J 7/18 H04B 7/00 H04H 1/00 H04L 1/02

Claims (3)

(57) [Claims] 1. When selecting a digital audio broadcast and the reception condition of the digital audio broadcast deteriorates,
If there is an analog audio broadcast with a data service that is broadcasting the same radio program as a digital audio broadcast radio program, it is automatically switched to the analog audio broadcast with a data service radio program. In the radio receiver (10), when switching from digital audio broadcasting for the same radio program to analog audio broadcasting with data service when the reception status of digital audio broadcasting deteriorates, the first switching hold time is set to If the reception status of the audio broadcasting is less than the first reference level, the first
The digital audio broadcasting is switched to the analog audio broadcasting with the data service when it is held for more than the switching holding time, and the first switching holding time is higher when the reception level of the digital audio broadcasting is lower. A radio receiver characterized by being set shorter than time. 2. A data service related to the same radio program when the reception level of the digital audio broadcast rises after the same radio program is switched from the digital audio broadcast to the analog audio broadcast with data service. In a radio receiver (10) designed to automatically switch from analog audio broadcasting with digital audio broadcasting to digital audio broadcasting, digital audio broadcasting with data service for the same radio program when the level of digital audio broadcasting rises When switching to audio broadcasting, a second switching hold time is set, and when the reception status of the digital audio broadcasting is kept above the second reference level for the second switching holding time or longer, it is switched from the analog audio broadcasting with data service. The digital audio broadcasting is switched, and the second switching hold time is set to be shorter when the level of the reception state of the digital audio broadcasting is higher than when it is lower. The radio receiver according to item 1. 3. The same radio program is broadcast in both a digital audio broadcast format and an analog audio broadcast format with a data service, and while the analog audio broadcast format with a data service is selected, the digital audio broadcast related to the same radio program is received. When the condition improves,
In a radio receiver (10) that automatically switches from analog audio broadcasting with data service to digital audio broadcasting, analog audio broadcasting with data service for the same radio program when the level of digital audio broadcasting rises From the analog audio broadcast with data service when the second switching hold time is set when switching from the digital audio broadcast to the digital audio broadcast, and the reception state of the digital audio broadcast holds the second reference level or more for the second switching hold time or more. The radio is characterized in that the digital audio broadcast is switched, and the second switching hold time is set shorter when the level of the reception state of the digital audio broadcast is higher than when it is lower. Receiving machine.