JP3135514B2 - Digital audio broadcast receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital audio broadcast (DAB) receiving apparatus, and more particularly, to a receiving apparatus capable of easily reproducing a broadcast that has been missed.

[0002]

2. Description of the Related Art FIG. 5 is a diagram for explaining a conventional digital audio broadcast. As shown in the figure, in an apparatus for performing digital audio broadcasting, audio data and service data of audio channels 1 to 6 are transmitted collectively. MPEG (moving image compression) in the audio compression encoding means 1
Audio compression is performed by an audio system. The error correction coding means 2 performs error correction coding on the data which has been subjected to the voice compression coding by a convolution method. Similarly, the error correction coding means 3 performs error coding on the service data by a convolution method. Time interleaving means 4, 5
Performs time interleaving on the data error-correction-coded by the error correction coding means 2 and 3. The multiplexing means 6 multiplexes the data time-interleaved by the time interleaving means 4 and 5. Orthogonal frequency division multiplexing modulator (OF)
DM) 7 performs an inverse fast Fourier transform on the multiplexed data. The high frequency means (RF) 9 converts the frequency of the signal in the time domain subjected to the inverse fast Fourier transform into the transmission frequency by the oscillator 8.

The following table shows the main transmission parameters of digital audio broadcasting.

[0004]

[Table 1]

[0005] The digital audio broadcasting band is, for example, 174 to 240 MHz in band III.
The ensemble includes a plurality of ensembles having a transmission bandwidth of 5 MHz, and each ensemble includes several audio channels and audio data as audio data. FIG. 6 is a view for explaining the format of a data frame formed by the multiplexing means 7 of FIG. As shown in the figure, a frame is composed of a synchronization channel, an FIC channel, and an MSC channel. The MSC channel is a channel for transferring audio and data, and one symbol constituting the channel is composed of a guard interval and an effective symbol. The guard interval absorbs this delay if it is this time even if a delayed wave such as a multipath wave is received. The symbol data is obtained by converting a number of orthogonal subcarriers into quadrature phase modulation (QPSK), 16
Modulation is performed by a method such as quadrature phase amplitude modulation (QAM).

FIG. 7 is a diagram for explaining the orthogonal frequency division multiplexing modulator 7. As shown in FIG. 2A, the transmission data is subjected to serial-parallel conversion and inverse discrete Fourier transform. This figure (b)
As shown in the above, an inverse discrete Fourier transform is performed on 1536 subcarriers (in the case of mode I) with a transmission bandwidth of about 1.5 MHz.

[0007]

By the way, in a digital audio broadcast receiving apparatus, audio data is directly received in real time, but if it is missed, it must wait until the transmitting side broadcasts again. Although it is possible to prepare a recording device to store important broadcast contents, music that the user wants to listen to, etc., there is a problem that it is difficult to judge the contents instantaneously and save it from the beginning.

In view of the above problems, it is an object of the present invention to provide a digital audio broadcast receiving apparatus capable of easily reproducing broadcast contents that have been missed.

[0009]

According to the present invention, there is provided a receiving apparatus for receiving a digital audio broadcast and processing the audio data of a plurality of audio channels in real time. And delay control means for delaying the reception signal stored in the storage means for a predetermined time and outputting the delayed signal instead of the real-time reception. Specifically, the delay control means performs control to switch between real-time reception and delay reception, and a signal immediately after down-converting a high-frequency signal obtained by receiving the digital audio broadcast as a reception signal, by Fourier transform. The demodulated signal is stored in the storage unit as a received signal, or a signal obtained by performing time deinterleaving and error correction decoding processing is received as a received signal. By this means, the reception is switched from real-time reception to delayed reception, and the broadcast contents that have been missed can be easily reproduced.

A plurality of storage means are provided in accordance with the number of a plurality of audio channels, and the delay control means sets a delay time for each of the received signals stored in the plurality of storage means. By this means, delayed reception or the like on a plurality of audio channels becomes possible. A digital video disk is used as the storage means. By this means, long-time recording becomes possible, and it is hardly affected by magnetism or the like, and the reliability is improved.

[0011] Further, display means is provided, wherein the delay control means identifies the received signal stored in the storage means as an announcement for each audio channel and broadcast contents of a song,
Display control for the display means to select between real-time reception and delayed reception, display for selecting delay time in the case of delayed reception, and display control for menu screen for displaying audio channel selection based on a list of broadcast contents I do. By this means, the broadcast contents can be understood at a glance, and only the data desired by the user can be reproduced.

In a broadcasting band for broadcasting a plurality of ensembles with a plurality of audio channels as one ensemble, the delay control means performs the menu screen display control between ensembles. By this means, a list of broadcast contents can be obtained even between ensembles, and reception according to the user's preference becomes possible. The delay control means performs repeat control to reproduce the broadcast content when the user wants to listen to the broadcast content again or misses the broadcast content. By this means, missed broadcasts can be prevented and the information can be heard from the beginning, so that the accuracy of the information is improved.

Further, another storage means is provided, and the delay control means performs one-point save control for recording the broadcast content in the another storage means when the broadcast content is desired to be heard again or missed. By this means, desired information is securely stored, and the reliability of the information is improved. The other storage means is a mini disk. This measure simplifies the device and reduces costs.

The delay control means determines the type of music from display service data excluding audio data of a plurality of audio channels included in the digital audio broadcast, and, based on the determination, determines the type of the music. The frequency band of a digital filter provided in a digital signal processing device that performs Fourier transform on a received signal is adjusted to adjust the volume and sound quality. By this means, fine reception becomes possible.

In the case where the same broadcast is broadcast on two audio channels from the broadcast station performing the digital audio broadcast with one of the audio channels being delayed for a predetermined time, the delay control means is provided when the real-time reception is interrupted. To delay reception. By this means,
When the receiver is mounted on a vehicle, it is very effective when data is lost in a tunnel, under an overpass, or the like, and reliability is improved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an example of a digital audio broadcast receiving apparatus according to the present invention.
As shown in the figure, the received signal is down-converted by the high frequency means 11 and the phase lock loop 12 and subjected to quadrature demodulation. Then, the data is subjected to analog-to-digital conversion, converted from the time domain to the frequency domain by the fast Fourier transform means 13, and the subcarrier is demodulated to extract data. The fast Fourier transform means 13 is constituted by a digital signal processor (DSP). The digital signal processor is further provided with a digital filter, and adjusts the volume in a frequency band according to the type of music, for example, bass enhancement, bass attenuation, treble enhancement,
The sound quality can be adjusted, such as high-pitched sound attenuation.
The time deinterleaving / Viterbi decoding means 14 time-deinterleaves the time-interleaved data, and further Viterbi-decodes the error-correction-coded data by the convolution method. The audio compression / decoding means 15 decodes the audio compression-encoded data into audio data. Thereafter, digital-to-analog conversion is performed, and an audio signal is output via the amplifier 16.

Time deinterleaving / Viterbi decoding means 14
Is input to a data decoder 17 and decoded into service data, which is displayed on a display 18. In addition,
An operation unit is provided on the display 18. further,
The storage device 19 includes a plurality of storage devices 19-1, 19-2, ..., 19-6 corresponding to audio channels 1 to 6.
May be provided, for example, a DVD (digital video disk), a hard disk, a semiconductor memory, an MD (mini disk), or the like. In particular, when a DVD is used, recording can be performed for a longer time, and the recording medium is hardly affected by magnetism or the like, thereby improving reliability. The storage device 19 receives and stores, for example, an analog output signal of the high-frequency means 11 and, instead of this output signal, delays the stored signal by a predetermined time to perform fast Fourier transform means 13.
Output to Similarly, the storage device 19 inputs and stores the digital output signal of the fast Fourier transform means 13,
Instead of this output signal, the stored signal may be output to the time deinterleaving / Viterbi decoding means 14 after being delayed for a predetermined time. Further, the storage device 19 receives and stores the digital output signal of the time deinterleaving / Viterbi decoding means 14, delays the stored signal in place of this output signal for a predetermined time, and outputs it to the audio compression / decoding means 15. You may.

A microcomputer 20, which is a delay control device, is provided with a high frequency means 11, a phase locked loop 12, a fast Fourier transform means 13, a time deinterleave / Viterbi decoding means 14 in response to an external request via an operation unit of the display 18. , The audio compression / decoding means 15 and the storage device 19 to control the real-time reception and storage device 19.
To control the selection of delayed reception from.

Further, the microcomputer 20 receives the service data from the data decoder 17 and, for example, emphasizes the bass in the case of classical music and emphasizes the treble in the case of popular music from the service data. Adjust the digital filter. In this way, sound quality, volume, and the like can be changed for each broadcast content, so that detailed reception can be performed.

Further, the microcomputer 20 has a voice recognition function and a level determination function. Based on the data stored in the storage device 19, the microcomputer 20 determines whether or not the broadcast content is Anaus, music, or the like by these functions. Do. FIG. 2 is a diagram for explaining the contents displayed on the display 18 by the microcomputer 20. As shown in the figure, when the receiver operates a menu button on the display 18, a list of selection of real-time reception and reproduction, selection of delay time, and selection of each audio channel is displayed on the menu screen. The broadcast content of each audio channel is displayed on the basis of the above-described voice recognition function and level function of the microcomputer 20 based on the discrimination determination of an announcement, music, and the like. Specifically, by operating a desired button, for example, selecting delay reception, selecting a delay time of 3 minutes, and selecting one channel of audio, in this case, B of audio channel 1 is selected.
The tune enters the receiving state (see FIG. 2). In this way, the broadcast contents can be understood at a glance, and only the contents desired by the user can be reproduced.

FIG. 3 is a diagram for explaining a repeat function at the time of delayed reception. As shown in the figure, when delayed reception is performed with respect to real-time reception, if a repeat operation is performed when the user wants to listen from the beginning in the middle of the song A, the song is reproduced from the beginning. If the user wants to listen to song A from the beginning in the middle of song B, the user repeats the operation by designating song A of channel 1-1 on the menu screen shown in FIG. The same applies to announcements.

[0022] In this manner, the broadcast content that has been missed can be easily heard from the beginning, and the accuracy of the information is improved. FIG. 4 is a diagram for explaining the one-point save function at the time of delayed reception. If another storage device 19-7 (not shown) is provided in the storage device 9 and a one-point save operation is performed as shown in FIG. The data is stored in another storage device 19-7. For this reason, the data stored in another storage device 9-7 can be converted and reproduced at any time by the decoder of the receiver to reproduce and listen. An MD may be used as the other storage device 19-7. The use of the MD simplifies the apparatus and reduces the cost.

Next, on the transmitter side, 2 for important broadcasts
The same broadcast content is transmitted with delay in one audio channel. When the receiver is installed in the vehicle, the receiver uses this delayed time as the guard time, and switches to delayed reception when receiving data is lost during real-time reception, for example, in a tunnel or under an overpass. Thereby, reliability is improved.

In the display 18, for example, in the 174-240 MHz band III as described above, music selected between ensembles can be sequentially stored so that a menu screen can be displayed between ensembles and delayed reception is possible. You may do so. Even during an ensemble, the broadcast contents can be viewed and received according to the user's preference.

[0025]

As described above, according to the present invention, real-time reception and delay reception can be switched, and broadcast contents that have been missed can be easily reproduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a digital audio broadcast receiving apparatus according to the present invention.

FIG. 2 is a diagram showing a case where the microcomputer 20 is a display 18;
FIG. 7 is a diagram for explaining the content displayed in FIG.

FIG. 3 is a diagram illustrating a repeat function at the time of delayed reception.

FIG. 4 is a diagram illustrating a one-point save function at the time of delayed reception.

FIG. 5 is a diagram illustrating a conventional digital audio broadcast.

FIG. 6 is a diagram illustrating a format of a data frame formed by the multiplexing unit 7 of FIG.

FIG. 7 is a diagram illustrating an orthogonal frequency division multiplexing modulation unit 7;

[Explanation of symbols]

 11, 12 high-frequency means 13 fast Fourier transform means 14 time deinterleaving / Viterbi decoding means 15 audio compression decoding means 17 data decoder 18 display means 19 storage means 20 delay control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 1/16 H04H 1/00 H04J 11/00

Claims (9)

(57) [Claims] 1. A receiving apparatus for receiving digital audio broadcasts and processing audio data of a plurality of audio channels in real time, comprising: storage means for storing received signals; and delaying the received signals stored in the storage means for a predetermined time. Delay control means for controlling output of a delayed signal instead of the real-time reception, and a signal immediately after down-converting a high-frequency signal obtained by receiving the digital audio broadcast as a reception signal. A digital audio broadcast receiving apparatus, wherein the digital audio broadcast is stored in the storage unit. 2. A receiving apparatus for receiving a digital audio broadcast and processing audio data of a plurality of audio channels in real time, comprising: storage means for storing a received signal; and delaying the received signal stored in the storage means for a predetermined time. And delay control means for controlling output of a delayed signal instead of the real-time reception. The digital audio broadcast is received and a signal demodulated by Fourier transform is stored in the storage means as a received signal. A digital audio broadcast receiving apparatus. 3. A receiving apparatus for receiving a digital audio broadcast and processing audio data of a plurality of audio channels in real time, a storage means for storing a received signal, and a delay of a predetermined time for the received signal stored in the storage means. Delay control means for controlling output of a delayed signal in place of the real-time reception, the delay control means setting a delay time for each of the received signals stored in the plurality of storage means. A digital audio broadcast receiving device, characterized in that: 4. A receiving apparatus for receiving a digital audio broadcast and processing audio data of a plurality of audio channels in real time, comprising: storage means for storing a received signal; and delaying the received signal stored in the storage means for a predetermined time. Delay control means for controlling output of a delayed signal instead of the real-time reception, further comprising a display means, wherein the delay control means stores the received signal stored in the storage means for each audio channel. An announcement, a display for discriminating the broadcast content of the song, and a display for allowing the display means to select real-time reception or delayed reception, a display for selecting a delay time in the case of delayed reception, an audio channel based on a list of broadcast content contents Performing display control of a menu screen for performing a display for selecting Digital audio broadcast receiver. 5. The delay control means performs the menu screen display control between ensembles in a broadcast band for broadcasting a plurality of ensembles, with a plurality of audio channels as one ensemble.
A digital audio broadcast receiving apparatus according to claim 1. 6. A receiving apparatus for receiving a digital audio broadcast and processing audio data of a plurality of audio channels in real time, a storage means for storing a received signal, and a delay of a predetermined time for the received signal stored in the storage means. Delay control means for controlling output of a delayed signal instead of the real-time reception, further provided with another storage means, wherein the delay control means wants to hear again in the broadcast content, or A digital audio broadcast receiving apparatus for performing one-point save control for recording the broadcast content in the another storage means when the user misses the broadcast. 7. The digital audio broadcast receiving apparatus according to claim 6, wherein said another storage means is a mini disk. 8. A receiving apparatus for receiving a digital audio broadcast and processing audio data of a plurality of audio channels in real time, a storage means for storing a received signal, and a delay of a predetermined time for the received signal stored in the storage means. Delay control means for controlling output of a delayed signal in place of the real-time reception, the delay control means comprising a display for excluding audio data of a plurality of audio channels included in the digital audio broadcast. The type of music is determined from the service data for the digital audio broadcast, and based on the determination, the frequency band of the digital filter provided in the digital signal processing device that performs the Fourier transform on the received signal of the digital audio broadcast is adjusted, Digital audio broadcasting, characterized by adjusting sound quality Receiver. 9. A receiving apparatus for receiving a digital audio broadcast and processing audio data of a plurality of audio channels in real time, a storage means for storing a received signal, and a delay of a predetermined time for the received signal stored in the storage means. And delay control means for controlling output of a delayed signal in place of the real-time reception, wherein the same broadcasting is performed on one audio channel by two audio channels from a broadcasting station that performs the digital audio broadcasting. The digital audio broadcast receiving apparatus is characterized in that, when broadcast is delayed for a fixed time, the delay control means switches to delay reception when real-time reception is interrupted.