Receiver for receiving digital broadcast programmes comprising information about a plurality of programmes

Abstract

 A digital broadcast receiver for receiving a digital audio broadcast which transmits digital signals indicating information about a plurality of services which constitute an ensemble such that the digital signals are transmitted together with audio information of the plural services, the digital broadcast receiver incorporating: a storage portion which is capable of storing information relating to the services in a quantity corresponding to the plural services; and determining means for determining information about the service which must be stored in the storage portion in accordance with information about the plural services obtained from the ensemble which is being received, wherein the determining means determines information about the service which must be stored in the storage portion in accordance with at least information about the service which is being selected.

Description

[0001] The present invention relates to a digital broadcast receiver, and more particularly to a receiver for receiving a digital audio broadcast (hereinafter called "DAB") which is at the practical phase in Europe.

[0002] As a system for transmitting broadcasting waves including data signals including digital audio signals and formed into a predetermined format and receiving the broadcasting waves, the DAB system abided by the Europe Standard (Eureka 147) is available. In the foregoing system, one ensemble is composed of a plurality of services. Each service is composed of a plurality of components, such as English and German. Therefore, a user receives a certain ensemble to obtain information about a plurality of services and components included in the ensemble. Moreover, instantaneous switching to a different service or a component is permitted.

[0003] As a method of switching the service, a method (hereinafter called a "first method") may be employed with which the order of the services is determined in the service receiving order. When an operation for changing the service has been performed, a service which must be selected next is determined in accordance with the determined order. Another method (hereinafter called a "second method") may be employed with which a rule for determining the order is previously provided to determine, in the receiver, the order of information about the received service so as to determine the service which must next be selected in accordance with the determined order.

[0004] An assumption is made that information about four SId (Service Identifiers) consisting of B313, B413, B211 and B315 and the service (hereinafter called a "current service") which is being selected at present is B413. When the first method is employed and up-and-down switching of the service has been instructed, the upward switching causes control to be performed to select the service B211. When downward switching is performed, the control is performed to select the service B313.

[0005] A case in which the second method is employed will now be described. For example, the predetermined order determining rule is arranged such that the cover code (the third digit) is ignored and one uppermost digit and two lower digits are employed to determine the order. If the first digit and the second digit coincide with each other, an example process for determining the order by using all of the four digits results in the order of received data being determined as B211, B313, B413 and B315. Assuming that the service (the current service) which is being selected is B413 similarly to the foregoing example and up-and-down switching is instructed, control is performed to select the service B315 in a case of upward switching. Similarly, downward switching causes the control to be performed to select the service B313.

[0006] If the capacity of a memory provided for the receiver is too small with respect to the quantity of transmitted information, there arises a problem in that all of the information items cannot be stored in the receiver. If the receiver has a memory capacity corresponding to three services in the above-mentioned case, information in a quantity corresponding to one service cannot be stored, that is, information is lost.

[0007] If information about the service is stored regardless of the current service in the above-mentioned state, there arises a problem in switching the service. If the first method is employed and the current service is B211, downward switching can be performed without any problem. However, information about the service B315 cannot be stored in the upward switching operation. Therefore, there arises a problem in that the foregoing available service cannot be selected (or another service is undesirably selected).

[0008] Accordingly, an object of the present invention is to provide a digital broadcast receiver which is capable of storing information which is important to control the receiver without a loss even if information in a quantity larger than the capacity of the memory provided for the receiver is supplied.

[0009] According to one aspect of the present invention, there is provided a digital broadcast receiver for receiving a digital audio broadcast which transmits digital signals indicating information about a plurality of services which constitute an ensemble such that the digital signals are transmitted together with audio information of the plural services, the digital broadcast receiver comprising: a storage portion which is capable of storing information relating to the services in a quantity corresponding to the plural services; and determining means for determining information about the service which must be stored in the storage portion in accordance with information about the plural services obtained from the ensemble which is being received, wherein the determining means determines information about the service which must be stored in the storage portion in accordance with at least information about the service which is being selected.

[0010] According to another aspect of the present invention, there is provided a digital broadcast receiver having a structure according to the first aspect of the invention, wherein the determining means determines information about the service which must be stored in the storage portion also in accordance with information about the services stored in the storage portion.

[0011] According to still another aspect of the present invention, there is provided a digital broadcast receiver having a structure according to the second aspect of the invention, wherein information about the services includes identifying information for identifying the services, and the determining means determines the order of the plural services obtained from the ensemble which is being received in accordance with a predetermined rule for determining the order and identifying information and stores, in the storage portion, at least information about the services having the orders across the service which is being selected.

[0012] In the drawings:

Fig. 1 is a block diagram showing a DAB receiver according to the present invention;

Fig. 2 is a flow chart of the operation which is executed by a DAB control unit; and

Figs. 3A to 3D are diagrams showing an order of storing data of services.

[0013] An embodiment of the present invention will now be described with reference to the drawings. In the present invention, the foregoing first method is not considered because of its unsatisfactory ease of use. Therefore, a digital broadcast receiver adapted to the second method which can easily be operated by a user will now be described. Fig. 1 is a block diagram showing a DAB receiver according to an embodiment of the present invention. The DAB receiver incorporates a DAB receiving portion 1, a DAB control unit 2, a system control unit 3, a display unit 4, a key input portion 5, an amplifier 6, a speaker unit 7 and a storage portion 8.

[0014] The DAB receiving portion 1 includes an FFT (Fast Fourier Transform) portion for demodulating a transmitted OFDM wave, a Viterbi decoding portion for correcting an error and an audio decoder for restoring compressed audio data to original audio data. Since the above-mentioned structure is a known fact disclosed in documents, the foregoing structure is omitted from description.

[0015] The DAB control unit 2 controls the DAB receiving portion 1 and reads a variety of information data items included in FIC (Fast Information Channel) which is demodulated by the DAB receiving portion 1 so as to store information data for each service in the storage portion 8. Information above includes SId information for use in the present invention, PTY (Program Type) codes indicating the contents of services and Asu (Announcement Support) information.

[0016] The DAB control unit 2 responds to a requirement issued from the system control unit 3 to perform required processes. The processes include a process relating to switching of the selected service.

[0017] The system control unit 3 controls the overall body of the receiver. Specifically, the system control unit 3 performs a corresponding control in cooperation with the DAB control unit 2 in accordance with information supplied from the key input portion 5. The system control unit 3 controls the display unit 4 by outputting display information to the display unit 4. The DAB receiver has the above-mentioned schematic structure.

[0018] Specific control according to the present invention will now be described. In the present invention, data relating to the services across a service selected at present is stored without exception in order to smoothly control switching of the service.

[0019] Fig. 2 is a flow chart of the operation of the DAB control unit 2 according to the present invention and arranged to perform a process for storing data.

[0020] When data of a certain service has been received, the DAB control unit 2 determines the service which is being selected (step S1). If a determination is made in step S1 that a certain service is being selected, it means that a current service (= service which is being selected) exists. Therefore, in step S2, whether or not received information about the service is information of the current service is determined. Specifically, coincidence of SId is determined.

[0021] If a determination is made that received information about the service is information about the current service (step S2: coincident), the DAB control unit 2 stores received information about the service in a storage area (hereinafter called a "storage area (C)") in the storage portion 8.

[0022] If a determination is made in step S2 that received information about the service is not information about the current service (step S2: non-coincident), the process is shifted to step S4 so that a comparison of the orders is performed. At this time, the received SId and the SId of the current service are compared with each other.

[0023] If a determination is made as a result of a comparison made in step S4 that received information about the service is information about the service which is positioned before the current service, whether or not information has been stored in a storage area (hereinafter called a "storage area (A)") provided for the inside portion of the storage portion 8 (step S5).

[0024] If a determination is made in step S5 that no information is stored in the storage area (A), information about the service received this time is stored in the storage area A (step S6). If a determination is made in step S5 that information has been stored in the storage area (A), the operation is shifted to step S7 so that the order of information and the order of information stored in the storage area (A) are compared with each other.

[0025] Also the comparison of the orders is performed similarly to that which is performed in step S4. As a result of the foregoing comparison process, information stored in the storage area (A) or received information about the service received this time which is near the current service is determined.

[0026] If a determination is made in step S7 that information of the service received this time is nearer the current service, the operation is shifted to step S6 so that information above is stored in the storage area (A). Thus, information is updated. If a determination is made in step S7 that information stored in the storage area (A) is nearer the current service, update of information is not required. Therefore, the process is completed.

[0027] If a determination is made as a result of the comparison made in step S4 that information about the service received this time is positioned after the current service, whether or not information has been stored in the storage area (hereinafter called a storage area (B)) provided for the inside portion of the storage portion 8 is determined (step S8).

[0028] If a determination is made in step S8 that no information is stored in the storage area (B), information about the service received this time is stored in the storage area (B) (step S9). If a determination is made in step S8 that information has been stored in the storage area (B), the operation is shifted to step S10 so that a comparison is made with the order of information stored in the storage area (B).

[0029] Also, the comparison of the orders is performed similarly to the comparison which is made in steps S4 and S7. As a result of the comparison process, information in the storage area (B) or information about the service received this time which is nearer the current service is determined.

[0030] If a determination is made in step S10 that information of the service received this time is nearer the current service, the operation is shifted to step S9. Thus, information above is stored in the storage area (B). As a result, information is updated. If a determination is made in step S10 that information stored in the storage area (B) is nearer the current service, update of information is not required. Therefore, the process is completed.

[0031] If a determination is made in step S1 that no service is being selected, no current service serving as a reference exists. In the foregoing case, data of the received service is stored in a data area provided for the inside portion of the storage portion 8 and arranged to make a list (step S11). The data area for making the list has a region in which data of N services can be stored. A stored data group can be displayed on the display unit 4 in the form of a list owning to the operation of the key input portion 5. Storage of data is performed such that, for example, the second method of determining the order is employed to store data for N services in the ascending order of the SId. Thus, the user is able to detect services which can be received.

[0032] A state of storage of information according to the present invention will now be described with reference to the drawings. Figs. 3A to 3D are diagrams showing a state in which data of the service is stored in the storage areas (A), (B) and (C) in the storage portion 8 as a result of the storage process. In Figs. 3A to 3D, an assumption is made that extraction of the SId in the order as B211, B413, B312 and B315 is performed. Moreover, the current service is B413.

a. If information about B211 has been obtained
When information about B211 has been received, the order is compared with the service (the current service) B413 which is being selected in step S4 shown in Fig. 2. In the foregoing case, 13 is larger than 11 and the corresponding storage area (A) has no data. Therefore, information about the received B211 is stored in the storage area (A) of the storage portion 8.

b. If information about B413 has been obtained
When information about B413 has been received, also coincidence with the current service B413 is determined in step S2 shown in Fig. 2. Therefore, information about the received B413 is stored in the storage area (C) of the storage portion 8.

c. If information about B312 has been obtained
When information about B312 has been received, also the order is compared with the current service B413 in step S4 shown in Fig. 2. In this case, 13 is larger than 12 and the storage area (A) has data. Therefore, in step S7 shown in Fig. 2, the order is compared with information (B211) stored in the storage area (A). Since 11 < 12 < 13 in the foregoing case, a determination is made that information received this time is nearer the current service. Therefore, received information about B312 is stored in place of information about B211 stored in the storage area (A).

d. If information about B315 has been obtained
When information about B315 has been obtained, also the order is compared with the current service B413 in step S4 shown in Fig. 2. Since 13 < 15 and the corresponding storage area (B) has no data in the foregoing case, received information about B315 is stored in the storage area (B) of the storage portion 8.

[0033] Another control may be performed in which when a certain service has been selected, information about the selected service is given priority to be previously stored in the storage area (C).

[0034] As described above, according to the present invention, the structure is formed such that information about the service which must be stored in the storage portion is determined in accordance with information about at least the service which is being selected. Therefore, if information in a quantity larger than the capacity of the memory provided for the receiver is supplied, information which is important to control the receiver can be stored without a lost.

[0035] In the foregoing embodiment, only information about the services having identification information across identification information of the service which is being selected is stored in the storage portion 8. The structure is not limited to the foregoing structure. If the capacity of the memory is sufficiently large, it is preferable that information about larger number of services including at least the two information items is stored in the storage portion 8.

Claims

1. A digital broadcast receiver for receiving a digital audio broadcast which transmits digital signals indicating information about a plurality of services which constitute an ensemble such that the digital signals are transmitted together with audio information of the plural services, said digital broadcast receiver comprising:

a storage portion which is capable of storing information relating to the services in a quantity corresponding to the plural services; and

determining means for determining information about the service which must be stored in said storage portion in accordance with information about the plural services obtained from the ensemble which is being received, wherein

said determining means determines information about the service which must be stored in said storage portion in accordance with at least information about the service which is being selected.

2. A digital broadcast receiver according to claim 1, wherein said determining means determines information about the service which must be stored in said storage portion also in accordance with information about the services stored in said storage portion.

3. A digital broadcast receiver according to claim 2, wherein information about the services includes identifying information for identifying the services, and said determining means determines the order of the plural services obtained from the ensemble which is being received in accordance with a predetermined rule for determining the order and identifying information and stores, in said storage portion, at least information about the services having the orders across the service which is being selected.

Drawing