JP2000209111A - Receiver for digital sound broadcasting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evade troubles when a specified service is stopped by displaying that an instructed program is not broadcasted by a display element when it is not broadcasted. SOLUTION: The data of a frequency division ratio N read from a memory are set to the variable frequency divider circuit of the PLL of a tuner circuit 12 and the tuner circuit 12 is set to a reception frequency corresponding to the frequency division ratio N. Then whether or not an ensemble can be received by the set reception frequency is discriminated. In the case that it can be received, an LCD 34 for tuning display is lighted. On the other hand, in the case of discriminating that it can not be received, the fact that it can not be received is displayed at the LCD 33. In such a manner, in the case that the service including the specified program is not broadcasted even when the ensemble can be received, since it is displayed that it is not broadcasted, a user recognizes a reason for the fact that sound is not outputted even though broadcasting is received and is not bewildered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital audio broadcasting receiver.

[0002]

2. Description of the Related Art DAB (Eur
digital audio broadcasting according to the Eka 147 standard). This DAB is a system that simultaneously broadcasts up to 64 sets of digital audio signals and digital data by employing a transmission bandwidth: 1.5 MHz modulation method: OFDM audio signal data compression method: MPEG audio layer II. .

For this reason, in the DAB, the broadcast of a program has a hierarchical structure, for example, as shown in FIG. That is, DAB is, as described above, 1.
Although using a transmission band of 5 MHz, this transmission channel is called an “ensemble”, and the ensemble is selected by tuning to the center frequency of the ensemble.

[0004] The ensemble is divided into groups called "services". In the case of FIG. 3, the service is divided into four services. The service is further divided into several "service components", each of which is a digital audio signal or digital data constituting one program.

[0005] In this case, the service is one of the general broadcasting stations.
For example, the first service component of the fourth service 4 broadcasts soccer (program 4A) at the first venue, and the second service component broadcasts soccer (program 4B) at the second venue. Used to broadcast.

[0006] Further, a service and a service component have a "service ID" for identifying them.
And an identification code called "sub-channel ID", which are also transmitted at the same time. FIG. 3 shows that service IDs are SID01 to SID04,
This is the case where D is SCID01 to SCID15.

Therefore, when listening to a DAB program, an ensemble (frequency) is selected, one of a plurality of services in the ensemble is selected, and a target is selected from the selected services. The service component (program) will be selected.

[0008]

The configuration of the above-mentioned services can be arbitrarily changed by a broadcasting station. For example, only when there is a soccer game, a service 4 is prepared to broadcast soccer at each venue. Usage methods such as stopping the service 4 (not included in the ensemble) when there is no match are permitted.

For this reason, when trying to listen to a program, the corresponding service may be stopped and the program may not be able to be heard. In particular, the last memory function (when turning on the power, the function to select the program that was being listened to the last time when the power was turned off), the preset function (when the program selection key is pressed, If you try to listen to a program with a function that speeds up the selection of a program by referring to the reception history, etc. There are times when you can't listen this time.

In addition, at this time, for example, a tuning display LED
Is lit, indicating that a broadcast (ensemble) has been received. Therefore, the user is confused as to why no sound is output even though the user can receive the broadcast.

The present invention is intended to solve such a problem.

[0012]

Therefore, according to the present invention, a digital audio broadcast receiver in which signals of a plurality of programs and data specifying each of the programs are broadcasted in one transmission band is provided. A display element, when the program is designated by the data and reception of the program is instructed, and when the program specified by the data is not broadcast, the display element indicates that the program is not broadcast. And a digital audio broadcast receiver. Therefore, when the broadcast can be received but the sound of the program cannot be heard, this is displayed by the display element.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a broadcast wave signal of DAB is received by an antenna 11, and this received signal is supplied to a tuner circuit 12. This tuner circuit 12
It is configured in a superheterodyne format with a PLL,
By changing the frequency division ratio N of the variable frequency divider circuit of the PLL, the reception frequency can be changed. Then, a DAB baseband signal is demodulated and extracted from the tuner circuit 12, and this signal is supplied to an A / D converter circuit 13 and A / D converted into a digital signal.

The digital signal is supplied to a quadrature demodulation circuit 14 to demodulate data of an in-phase component (real axis component) and a quadrature component (imaginary axis component).
The T circuit 15 performs a complex Fourier transform to output a frequency component for each symbol, and the output is supplied to a Viterbi decoder circuit 16 to perform deinterleaving and error correction, and to perform digital audio of a target program (service component). The data is selected.

Subsequently, the selected data is supplied to an audio decoder circuit 17, where decoding processing such as MPEG data expansion is performed.
Digital audio data of a target program is extracted. Then, the extracted digital audio data is supplied to a D / A converter circuit 18 and D / A converted into analog audio signals L and R.
R is the speaker 21L, 2R through the amplifier 19L, 19R.
1R.

A microcomputer 31 is provided for controlling the system.
Ensemble (reception frequency) from 1 to tuner circuit 12
Is supplied as frequency data for selecting a frequency division ratio N of the variable frequency dividing circuit in the PLL.

Further, data necessary for identifying or specifying a service and a program from the Viterbi decoder circuit 16, that is, a service ID and a sub-channel I
Data such as D is taken out and supplied to the microcomputer 31. Further, the microcomputer 31 sends a selection signal SSV to the Viterbi decoder circuit 16.
SCH is supplied, the service is selected by the signal SSV,
From the selected services, digital audio data of a target service component (program) is selected by the signal SCH.

The microcomputer 31 has, as a part of a program executed by the microcomputer 31, a routine 1 as shown in FIG.
00 is prepared. The details of this routine 100 will be described later, but FIG. 2 shows only a portion related to the present invention.

Further, the microcomputer 31 includes:
For example, various operation keys 32 constituted by push switches are connected, and a display element for displaying various information, for example, an LCD 33, and an element for displaying tuning, for example, an LED 34, are connected.

In such a configuration, for example, when the power is turned on, the data stored in the memory of the microcomputer 31 when the selection of the program was previously determined by the last memory function, that is, the dividing ratio N , Service ID and sub-channel ID data are read out. Alternatively, in the case of the preset function, when a program to be received is instructed by operating the operation key 32, data previously written from the memory of the microcomputer 31, that is, the division ratio N, the service ID, and the sub-channel The ID data is read.

Subsequently, in the microcomputer 31, the processing of the CPU is performed in step 10 of the routine 100.
1 and then at step 102, the data of the frequency division ratio N read from the memory immediately before the start of this routine 100 is stored in the PL of the tuner circuit 12.
The tuner circuit 12 is set to the reception frequency corresponding to the frequency division ratio N.

Next, in step 103, it is determined whether or not the ensemble can be received at the reception frequency set in step 102. When the ensemble can be received, the process proceeds from step 103 to step 104. The high-speed information channel FIC included in the data is analyzed. The tuning display LED 34 is turned on.

In step 105, it is determined whether or not the service indicated by the service ID read from the memory immediately before the start of the routine 100 is included in the service indicated by the analysis result in step 104. If so, the process proceeds from step 105 to step 110.

In step 110, it is determined whether the service component (program) indicated by the sub-channel ID read from the memory immediately before the start of the routine 100 is included in the service component indicated by the analysis result in step 104. Is determined.
When it is included, the selection signal SS indicating the read service ID and sub-channel ID
V and SCH are supplied to the Viterbi decoder circuit 16 to select a service and a service component.

Therefore, the user can listen to the program selected by the last memory function or the preset function. In step 110, when the service component indicated by the sub-channel ID read from the memory is not included in the service component indicated by the analysis result in step 104, the sub-channel ID is the smallest among the services, for example. The service component is selected.

On the other hand, if the broadcasting of the service specified by the last memory function, the preset function, or the like is stopped, in step 105, the service I read from the memory immediately before the start of the routine 100 is executed.
Although the service indicated by D is not included in the service indicated by the analysis result of step 104, this is determined in step 105, and the processing is performed from step 105 to step 1
Go to 20.

In step 120, a predetermined display signal is supplied from the microcomputer 31 to the LCD 33, and it is displayed on the LCD 33 that the corresponding service cannot be received because the corresponding service has not been broadcast.
The next operation is awaited.

If it is determined in step 103 that the ensemble of the reception frequency set in step 102 cannot be received, the process proceeds from step 103 to step 130. In step 130, a process performed when the specified ensemble cannot be received. For example,
The fact that the reception is not possible is displayed on LCD 33.

Thus, according to the DAB receiver of FIG.
If the service including the specified program is not broadcast even though the ensemble can be received, it is displayed that the service is not being broadcast, so the user can output audio despite receiving the broadcast. You can find out why you aren't, and don't get confused.

Further, it is possible to understand the reason why no sound is output even though the broadcast can be received. At this time, by selecting another service in the same ensemble, it is quicker than in the case of receiving another ensemble. You can select a program.

That is, just because no sound is output, when the reception frequency is changed and another ensemble is received, as in the case of an AM receiver or an FM receiver, the PLL and the like of the tuner circuit 12 are re-locked. It takes time until it becomes necessary and a program can be selected. However, if you choose another service in the same ensemble,
Only the data packet to be decoded by the Viterbi decoder circuit 16 needs to be changed, and the time required for the change is extremely short.

Therefore, when it is displayed that the sound is not output even though the broadcast can be received, the program can be quickly selected by selecting another service in the same ensemble.

In step 120, since the corresponding service is being broadcast, it is possible to indicate that the service cannot be received and to automatically select another service in the same ensemble.

[0034]

According to the present invention, when a designated service is not broadcast even though a broadcast can be received, the user can know the reason why no sound is output even though the broadcast can be received. It is possible and there is no embarrassment.

Further, it is possible to understand why no sound is output even though the broadcast is received. At this time, by selecting another service in the same ensemble, it is quicker than in the case of receiving another ensemble. You can select a program.

[Brief description of the drawings]

FIG. 1 is a system diagram illustrating one embodiment of the present invention.

FIG. 2 is a flowchart illustrating one embodiment of the present invention.

FIG. 3 is a hierarchical diagram for explaining the present invention.

[Explanation of symbols]

11 antenna, 12 tuner circuit, 13 A / D converter circuit, 14 quadrature demodulation circuit, 15 FFT circuit, 16 Viterbi decoder circuit, 17 audio decoder circuit, 18 D / A converter circuit, 21L and 21R: speaker, 31: microcomputer, 32
... operation keys, 33 ... LCD, 34 ... LED, 100 ... routine

Claims (1)

[Claims] 1. A digital audio broadcast receiver in which signals of a plurality of programs and data specifying each of the programs are broadcast in one transmission band, comprising a display element, , And when the program specified by the data is not broadcast, the receiver of the digital audio broadcast displays the non-broadcast on the display element when the program is not broadcast. .