EP0788251A2

EP0788251A2 - Digital audio broadcasting receiver

Info

Publication number: EP0788251A2
Application number: EP97101651A
Authority: EP
Inventors: Kijuro Obata; Hiroyuki Nemoto
Original assignee: Alpine Electronics Inc
Current assignee: Alpine Electronics Inc
Priority date: 1996-02-05
Filing date: 1997-02-03
Publication date: 1997-08-06
Also published as: JPH09214379A; EP0788251A3

Abstract

A digital audio broadcasting receiver designed to prevent interruption of the flow of received data when the receiver is changed to receive a program on a frequency carrier different from the frequency carrier on which the data is being received. Means for this prevention can be realized at a low cost. The receiver has a data reception detection section (50) for detecting a state where a predetermined kind of data is being received, and a warning section (70, 80) for giving warning when an instruction is input to perform reception on a frequency different from the frequency of the signal presently received.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital audio broadcasting (DAB) receiver for receiving a digital audio broadcast and, more particularly, to a DAB receiver which warns a user when the user instructs the receiver to receive on a frequency different from the frequency of a signal which the receiver is presently receiving.

2. Description of the Related Art

It has generally been recognized that digital audio systems are easy to use and have excellent characteristics, and rapid progress has therefore been made in the development of digital audio systems. From this background, the movement toward digitization of audio broadcasting has been promoted and digital audio broadcasting is now being put to practical use in Europe.
If DAB signals are transmitted, six to eight programs can be sent on one frequency carrier (ensemble). As a plurality of programs sent in this manner, data can be sent as well as ordinary music programs or the like. Accordingly, while music received on one frequency carrier is being heard, data can be received if the data is received on the same frequency carrier. Also, it is possible to start hearing a music program during reception of data.
Fig. 3 shows the relationship between two frequency carriers and a plurality of programs in DAB.
In the broadcasting shown in Fig. 3, music programs PM11, PM12, PM13, ... and data PD11 can be received on frequency carrier f1 while music programs PM21, PM22, PM23, ... and data PD21 can be received on frequency carrier f2. In this case, when music program PM12 on the frequency carrier f1 is being heard, data PD11 can be received. Also, during reception of data PD11, it is possible to start hearing music program PM13 without stopping the operation of receiving data PD11.
However, if the receiver is changed to start receiving music program PM21 (or data PD23) on the frequency carrier f2 during reception of data PD11 on the frequency carrier f1, then the flow of data PD11 received till the change is interrupted. That is, if, during reception of data on a frequency carrier, a user changes the receiver to receive a program on a different frequency carrier, the flow of data received till the change is interrupted. Moreover, the user is liable to be unaware of the interruption of the received data caused by the change to the program on the different frequency carrier.
To solve this problem, two receivers may be provided. However, this solution is disadvantageous in terms of cost.

SUMMARY OF THE INVENTION

In view of the above-described problems, an object of the present invention is to provide a DAB receiver in which during reception of data on a frequency carrier the flow of received data can be prevented from being interrupted when the receiver is changed to receive a program on a frequency carrier different from the frequency carrier on which the data is being received, the receiver being designed to achieve this function at a low cost.
To achieve the above-described object, according to the present invention, there is provided a digital audio broadcasting receiver comprising data reception detection means for detecting a state where a predetermined kind of data is being received, and warning means for giving warning when an instruction is input to perform reception on a frequency different from the frequency of the signal presently received.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a block diagram of a DAB receiver R1 which represents an embodiment of the present invention;
Fig. 2 is a flowchart of the operation of the embodiment shown in Fig. 1; and
Fig. 3 is a diagram showing the relationship between two frequency carriers and a plurality of programs in DAB.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to Fig. 1, a DAB receiver R1 which represents an embodiment of the present invention has a DAB tuner section 10, a DAB signal processing section 20, an MPEG decoder 30, a D/A converter 40, a control section 50, keys 60, a buzzer 70, a display 80 and a connector C. An apparatus 90 using data, e.g., a personal computer or the like is connected to the DAB receiver R1 through the connector C.
The DAB tuner section 10 tunes in a predetermined frequency of a received signal on the basis of a frequency setting signal from the control section 50, and outputs the received signal.
The DAB signal processing section 20 outputs a sync signal and information on the composition of a program contained in the received signal to the control section 50, outputs an audio signal to the MPEG decoder 30 and also outputs received data.
Keys 60 include a key for instructing the receiver to change a received program, and a receiving frequency change key for receiving on a frequency different from the frequency on which the receiver is presently receiving (a key for instructing the receiver to receive on a frequency different from the frequency of a signal presently received).
The control section 50 operates for overall control of the DAB receiver R1, and determines completion of reception of a predetermined kind of data when it receives a data reception completion signal from the apparatus 90 after the start of reception of the data. If the receiving frequency change key in the keys 60 is operated before the control section 50 receives data reception completion signal from the apparatus 90 after the start of reception of the predetermined kind of data, the control section 50 sounds the buzzer 70 and makes on the display 80 a warning display for warning a user that reception of the data is uncompleted. The control section 50 also comprises an example of means for giving warning about a start of reception of the predetermined kind of data when it detects the start of reception of the data.
The control section 50 detects the strength of a signal which is being received by the DAB tuner section 10. If the detected signal strength becomes small, the control section 50 calculates the error rate of the received data. If the error rate becomes equal to or lower than a predetermined rate, the control section 50 displays a received data error message "RECEIVED DATA ERROR" on the display 80 or both displays the received data error message and sounds the buzzer 70.
The operation of the above-described embodiment will next be described with reference to the flowchart of Fig. 2.
First, if the control section 50 has received no data reception completion signal from the apparatus 90 during reception of data (S1), it displays on the display 80 a message "THERE IS A POSSIBILITY OF THE CONTENTS OF PRESENTLY RECEIVED DATA BEING LOST IF RECEPTION OF A PROGRAM ON A DIFFERENT FREQUENCY CARRIER IS STARTED DURING RECEPTION OF THE DATA" (S2), thereby provoking user's attention. If at this time the key in keys 60 for inputting the instruction to change the received program is operated (S3) and if the reception of data is completed (S4), the receiver receives a new program selected by the user (S5). The control section 50 informs the user of a start or completion of the reception of data by, for example, sounding the buzzer 70 when the reception of data is started or completed.
If the key for inputting an instruction to change the received program is operated and if the reception of data is uncompleted (S3, S4), a determination is made as to whether reception of the program that the user wishes to receive necessitates a change of the frequency carrier (S11). If reception of the program that the user wishes to receive necessitates no change of the frequency carrier, there is no possibility of the data being lost and reception of the new program selected by the user is started (S12).
In the situation where the key for inputting an instruction to change the received program has been operated and where reception of data is uncompleted (S3, S4), if reception of the program that the user wishes to receive necessitates a change of the frequency carrier (S11), the control section 50 displays on the display 80 a message "DO YOU WANT TO CHANGE THE PROGRAM KNOWING THAT PRESENTLY RECEIVED DATA WILL BE LOST BY THE CHANGE ?" and sounds the buzzer 70 to warn the user (S13).
After this warning, if a key in keys 60 with which a case where there is no need for continuing the reception of data is designated (a key for instructing the receiver to receive on a frequency different from the frequency of the signal which is presently being received) is operated (S21), the reception of data presently performed is forcibly terminated (S22) and the receiving frequency is changed to a new frequency carrier to receive the new program selected by the user (S5).
After warning in step 13, if a key in keys 60 with which a case where there is a need for continuing the reception of data is designated is operated (S21), the operation of changing the frequency carrier is inhibited (S23). Then the contents of service thereafter available are limited to those receivable on the present receiving frequency. When the reception of data presently performed is completed (S24), the inhibition of change of the frequency carrier is canceled, a message "PROGRAM CHANGE OK" is displayed and buzzer sound is generated (S25).
The above-described inhibition of change of the frequency carrier may be canceled if the signal strength of the station to which the receiver is presently tuned becomes small. That is, if the signal strength of the station which is broadcasting the presently received data becomes small, then an error can occur in the received data and there is a possibility of failure to receive the correct data. In such a situation, the error rate of the data presently received is detected and the inhibition of change of the frequency carrier is canceled if the error rate is equal to or lower than a predetermined rate. Simultaneously, a message "RECEIVED DATA ERROR", for example, is displayed on the display 80 and the buzzer 70 is energized to generate warning sound.
The receiver of the present invention may be also capable of receiving frequency-modulated (FM) broadcasts or amplitude-modulated broadcasts. Then the user may wants to make a forced change into FM receiving mode or AM receiving mode even during reception of data. In such a case, reception in FM receiving mode or AM receiving mode is started while reception of data by the DAB receiver is continued. Also, a message "DATA IS BEING RECEIVED" is displayed on the display 80 and the buzzer 70 is energized to generate warning sound.
In the above-described embodiment of the present invention, the control section 50 comprises an example of data reception detection means for detecting a state where the predetermined kind of data is being received, keys 60 comprise an example of receiving frequency changing means for inputting an instruction to perform reception on a frequency different from the frequency of a signal which is presently being received, and the buzzer 70 and the display 80 comprise an example of means for warning about an uncompleted state of reception of data when an instruction is input to perform reception on a frequency different from the frequency of a signal presently received.
Also, keys 60 comprise an example of data reception continuation confirmation means for confirming a user's intention of continuing reception of data before the completion of reception of data and after this warning, and the control section 50 comprises an example of receiving frequency change inhibition means for inhibiting change of the receiving frequency if a user's intention of continuing reception of data is confirmed before the completion of reception of data and after the warning. The control section 50 also comprises an example of receiving frequency change inhibition cancellation means for canceling the inhibition of change of the receiving frequency when the continued reception of data is completed after the warning.
In the above-described embodiment of the present invention, when the control section 50 detects a start or completion of reception of the predetermined kind of data, the buzzer 70 generates buzzer sound as a sign of the start or completion of reception of the data. However, the arrangement may alternatively be such that a message expressing the start or completion is displayed on the display 80 or both the buzzer 70 and the display 80 are used.
To indicate the state of continuing reception of data, a portion of the display 80 or an indicator such as a light emitting diode may be used by being lighted continuously or by being turned on and off.
When warning or cancellation of the inhibition of change of the frequency carrier is made, only the buzzer 70 or only the display 80 may be operated. Alternatively, both the buzzer 70 and the display 80 may be used.
Further, keys 60 may include a frequency change inhibition key for inhibiting change of the frequency carrier during reception of data, and the operation of changing the frequency carrier may be inhibited during reception of data by operating this key.
According to the present invention, as described above, during reception of data on a frequency carrier, the flow of received data can be prevented from being interrupted when the receiver is changed to receive a program on a frequency carrier different from the frequency carrier on which the data is being received, and means for this prevention can be realized at a low cost.

Claims

A digital audio broadcasting receiver comprising:
data reception detection means (50) for detecting a state where a predetermined kind of data is being received;

receiving frequency changing means (60) for inputting an instruction to perform reception on a frequency different from the frequency of the signal received by the reception detected by said data reception detection means; and

first warning means (70, 80) for giving warning about incompletion of reception of data when an instruction is input to perform reception on a frequency different from the frequency of the signal received by the reception detected by said data reception detection means.
A digital audio broadcasting receiver according to Claim 1, wherein said first warning means comprises at least one of means (80) for displaying a data reception incompletion warning message and means (70, 80) for displaying the data reception incompletion warning message and for generating warning sound.
A digital audio broadcasting receiver according to Claim 1 or 2, wherein said data reception detection means (50) detects at least one of a start and completion of reception of the predetermined kind of data, and outputs through said first warning means (70, 80) at least one of a predetermined display and a predetermined warning sound indicating the start or completion of the reception of data
A digital audio broadcasting receiver according to Claim 2 or 3, wherein said first warning means continuously outputs at least one of a predetermined display and a predetermined warning sound during reception of data.
A digital audio broadcasting receiver according to any of Claims 1 to 4, further comprising:
data reception continuation confirmation means (60) for confirming an intention of continuing the reception of data before the completion of the reception of data and after the data reception incompletion warning; and

receiving frequency change inhibition means (50) for inhibiting change of the receiving frequency if an intention of continuing the reception of data is confirmed before the completion of the reception of data and after the data reception incompletion warning.
A digital audio broadcasting receiver according to any of Claims 1 to 5, further comprising receiving frequency change inhibition cancellation means for canceling the inhibition of change of the receiving frequency when the continued reception of data is completed after the data reception incompletion warning.
A digital audio broadcasting receiver according to any of Claims 1 to 6, further comprising:
data reception detection means (50) for detecting a start of reception of the predetermined kind of data; and

second warning means (70, 80) for giving warning about a start of reception of data when a start of reception or the predetermined kind of data is detected.
A digital audio broadcasting receiver according to Claim 7, wherein said second warning means comprises at least one of means (80) for displaying a data reception incompletion warning message and means (80, 70) for displaying the data reception incompletion warning message and for generating warning sound.
A digital audio broadcasting receiver according to any of Claims 1 to 8, wherein said data reception detection means (50) detects the signal strength during reception, calculates an error rate of the received data if the detected signal strength becomes small, and outputs a predetermined error signal when the error rate is equal to or lower than a predetermined rate.
A digital audio broadcasting receiver according to Claim 9, further comprising at least one of means (80) for displaying a data reception error message by being supplied with the predetermined error signal, and means (80, 70) for displaying the data reception error message and for generating a warning sound.