JPH08294098A - Broadcast system and transmitter-receiver - Google Patents

Abstract

PURPOSE: To attain efficient broadcast and reception by having simple provision for revision of a frequency or addition of service or the like. CONSTITUTION: A data encoder 104 conducts digital processing such s coding of required information among video information 101, audio information 102 and various data 103 and addition of error check codes, its encode output is given to an OFDM modulator 105, its ODFM modulation signal is given to a frequency conversion section 106, in which the signal is converted into a frequency signal actually sent and outputted. Service designation information 107, parameter designation information 108, and carrier frequency designation information 109 are digitally modulated by a frequency sent actually by a digital modulator 111 and outputted. An output signal from the frequency conversion section 106 and an output signal from the digital modulator 11 are mixed by a mixer 112 and the mixed signal is fed to an amplifier means (not shown in the figure).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, terrestrial digital television broadcasting, digital audio broadcasting, or integrated digital broadcasting (ISDB: Integrated Service) for broadcasting digital information in an integrated manner.
s Digital Broadcasting) signal transmission method and a transmitter / receiver thereof.

[0002]

2. Description of the Related Art A system for transmitting video signals and audio signals by different modulation systems has already been put to practical use in current analog television broadcasting. Audio broadcasting is also carried out by different modulation methods such as FM and AM. However, these carrier frequencies and modulation schemes were predetermined, and there was no independent channel to describe them.

Further, the video signal and the audio signal are OFDM.
(Orthogonal Frequency Div
There are many examples of broadcasting by means of ion multiplexing, and an example of broadcasting these OFDM signals by dividing them into a plurality of blocks (Japanese Patent Application No. 6-7054).
8: Signal transmission / reception system for mobile objects) and O of these
There is an example in which the FDM blocks are synchronized with each other to prevent mutual interference (Japanese Patent Application No. Hei 6-74750: transmission method of multiple orthogonal frequency division multiplexing modulation methods), but these division methods and their service contents are described. There is no example of using independent channels to do this.

[0004]

According to the above-mentioned conventional system, since there is no channel describing the transmission system for broadcasting video and audio, it is necessary to change to another frequency or broadcast at a new frequency. When starting, it is necessary to inform the receiver by separately changing the frequency by agreement with the receiver side or the receiver side or by notifying that the new frequency has started broadcasting on another medium. It was

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a broadcasting system and a transceiver which solve the above problems.

Another object of the present invention is to change the frequency, add a service, and further a new system by adding a channel for describing these transmission systems in addition to a channel for broadcasting video and audio. It is to provide a broadcasting system and a transceiver that enables the start of a new service. Still another object of the present invention is to make it possible to start from the simplest broadcasting and gradually expand the range of services, facilitate the introduction of digital broadcasting, and change from analog broadcasting to digital broadcasting. It is to provide a broadcasting system and a transceiver that facilitate frequency management during the transition period.

[0007]

In order to achieve the above object, the invention according to claim 1 comprises a signal in which at least one kind of information of video, audio and data is different from each other or is modulated by the same modulation method. The first channel,
It is characterized in that the information including the modulation method and the carrier frequency of the at least one type of information is frequency-divided and broadcast with a second channel formed of a signal modulated by a predetermined carrier frequency and modulation method.

The invention according to claim 2 is based on claim 1.
In the above, the modulation method in the first channel is orthogonal frequency division multiplexing modulation.

Further, in the invention according to claim 3, in claim 2, the first channel is frequency-divided into a plurality of blocks having a narrow bandwidth and a plurality of blocks having a wide bandwidth, and the second channel is divided. Is characterized by including the division information.

Further, in the invention according to claim 4, in claim 3, the plurality of blocks having a narrow bandwidth are applied to voice and data having a relatively small capacity, and the plurality of blocks having a wide bandwidth are subjected to video and video. It is characterized in that it is applied to data having a relatively large capacity.

Further, the invention according to claim 5 is an image,
An encoder for encoding at least one kind of information of voice and data, and a first modulation means for modulating the output of the encoder by a different or the same modulation method,
Frequency conversion means for converting the output of the first modulation means into a carrier frequency to be actually transmitted, a modulation method of the first modulation means, and a carrier frequency and a modulation method in which information including the carrier frequency in the frequency conversion means is predetermined. And a means for mixing and outputting the output of the frequency converting means and the output of the second modulating means.

Further, the invention according to claim 6 is characterized in that, in claim 5, the first modulating means performs orthogonal frequency division multiplex modulation.

Further, the invention according to claim 7 is the receiving means for receiving the signals of the first and second channels of claim 1, the first decoding means for decoding the received signal of the second channel, and And a second decoding means for decoding the received signal of the first channel according to the information decoded by the decoding means.

Further, the invention according to claim 8 is that, in claim 7, the second decoding means includes means for decoding the signal of the first channel subjected to the orthogonal frequency division multiplexing modulation of claim 2. Characterize.

Further, the invention according to claim 9 is characterized in that, in claim 7, the second decoding means is means for decoding only specific information of video, audio and data.

[0016]

【Example】

(Embodiment 1) FIG. 1 shows an example of a transmitter according to the present invention. 101, 102, and 103 are supply sources of services by broadcasting, 101 is video information (supply source), 102 is audio information (supply source), and 103 is various data (supply source). Reference numeral 104 denotes a data encoder, which is video information 1
01, voice information 102, and various data 103, necessary information is input, digital processing such as encoding and error correction code addition is performed in the baseband and output, and at the same time, what service Information (service designation information) 107 indicating whether the data has been encoded is output. The type of error correction code and the type of baseband processing such as interleaving can be included in the service designation information 107 as necessary.

The baseband encoded output from the data encoder 104 is input to the OFDM modulator 105, OFDM modulated and output. At this time, parameters used for OFDM modulation, for example, the type of modulation (QPSK, multi-level QAM, etc.) of each OFDM carrier, the length of the guard interval, etc. are output as parameter designation information 108.

The OFDM modulated signal from the OFDM modulator 105 is input to the frequency conversion unit 106, converted to a frequency to be actually transmitted, and output. At this time, parameters such as the center frequency of the converted frequency are output as carrier frequency designation information 109.

Various parameters, that is, the service designation information 107, the parameter designation information 108, and the carrier frequency designation information 109 are encoded by the data encoder 110 and are preset by the digital modulator 111 at a predetermined frequency to be actually transmitted and in advance. Digital modulation (for example, BPSK or O
(FDM etc.) and output.

The output signal from the frequency converter 106 and the output signal from the digital modulator 111 are mixed in a mixer 112.
And is supplied to well-known amplification means (not shown) for obtaining a predetermined transmission power.

After the amplifying means, for example, it is radiated (broadcast) via a transmission antenna, received by a reception antenna, a tuner, etc., and supplied to a receiver described later.

FIG. 2 shows another example of the transmitter according to the present invention. This transmitter performs OFDM modulation on each data by dividing it into a plurality of blocks. Video information 2
01, audio information 202, and various data 203 are input to different data encoders 204, and the output from each data encoder 204 is input to each block divider 205 and divided into a plurality of blocks according to a predetermined division method. The plurality of outputs from the divider 205 are different OFDM signals.
Each OFD is input to the modulator 206 and OFDM-modulated.
The output from the M modulator 206 is input to each frequency conversion unit 207 and converted into a frequency to be actually transmitted, and the mixer 21
4 is input.

Service specifying information 208, parameter specifying information 210 and carrier frequency specifying information 211 similar to those in FIG. 1 and division method specifying information 209 indicating a division method (including the number of divisions) in the block divider 205 are:
The data is encoded by the data encoder 212, digitally modulated by the digital modulator 213 at a predetermined frequency to be actually transmitted, and input to the mixer 214.

The signals from the respective frequency converters 207 and the signals from the digital modulator 213 input to the mixer 214 are mixed and supplied to the amplifying means.

Also in this transmitter, it is possible to send out only the necessary one of the video, audio and various data.

FIG. 3 shows an example of the frequency spectrum of the transmission signal from the transmitter of the present invention, and 301 is a transmission mode control channel for transmitting various parameters.
The example corresponds to the output signal from the digital modulator 111, and the example in FIG. 2 corresponds to the output signal from the digital modulator 213. Further, 302 is a channel of the OFDM block, and the center frequency position, the number of each block,
Bandwidth and the like are described in the transmission mode control channel. Thus, in the transmitter according to the present invention, each channel is frequency-divided and output. Also, OFDM
The blocks can all have the same bandwidth, but can also have a bandwidth according to the amount of information to be transmitted. For example, a narrow band OFDM block for voice and relatively low capacity data,
Wideband OFDM blocks can be used for video and relatively large volumes of data.

FIG. 4 shows an example of a receiver according to the present invention. The transmission mode control channel in the received signal is demodulated in the transmission mode control channel demodulator 401, and then the content decoder 402 decodes the service designation information, the division method designation information, the parameter designation information and the carrier frequency designation information. .

In a required number of frequency converters 403, the signal of the corresponding carrier frequency in the received signal is I based on the carrier frequency designation information from the content decoder 402.
F signal or baseband signal is converted, and then OFDM demodulated in each OFDM demodulator 404 based on the parameter designation information from the content decoder 402,
Then, in the synthesizer 405, the video, audio and various data are respectively synthesized based on the division method designation information from the content decoder 402, and these are synthesized in the video decoder 406, the audio decoder 407 and the data decoder 408.
Error correction and deinterleaving are performed based on the parameter designation information from the content decoder 402, and each decoded and output as video information, audio information and various data, and provided to the receiver. Of course, it is possible for the receiver to refer to the content of the content decoder, select one program from a plurality of video programs, and output it.

FIG. 5 shows an example of a voice-only receiver according to the present invention. In this example, it is possible to obtain only the audio information even if only the audio information is transmitted as the received signal, or if the video and various data other than the audio information are simultaneously transmitted. The transmission mode control channel in the received signal is demodulated by the transmission mode control channel demodulator 501, then the parameters relating to the voice information are decoded by the content decoder 502, and based on these parameters, each frequency conversion unit 5
In 04, the signal of the corresponding carrier frequency in the received signal is IF
Signal or baseband signal, then
Each OFDM demodulator 505 performs OFDM demodulation, then synthesizer 506 synthesizes them, then speech decoder 507 decodes them, and outputs them as speech information. As in the example of FIG. 4, the recipient refers to the content of the content decoder 502,
It is also possible to select a desired program from a plurality of audio programs and output only that program.

In each of the above embodiments, the modulation method is OF
Although the case of only the DM modulation method has been described, the present invention is not limited to this, and it goes without saying that various other digital modulation methods may be used.

[0031]

As described above, according to the present invention, a data signal modulated by a predetermined method and a plurality of signals having a modulation method and a carrier frequency described by the data signal are simultaneously broadcast. By doing so, it is possible to easily respond to changes in frequency and addition of services,
In addition, a plurality of pieces of information can be efficiently broadcast and can be received more efficiently.

Further, according to the present invention, it becomes possible to effectively receive the paging service using the FM multiplex signal.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an example of a transmitter according to the present invention.

FIG. 2 is a block diagram showing another example of a transmitter according to the present invention.

FIG. 3 is a diagram showing an example of a frequency spectrum of a transmission signal according to the present invention.

FIG. 4 is a block diagram illustrating an example of a receiver according to the present invention.

FIG. 5 is a block diagram showing another example of a receiver according to the present invention.

[Explanation of symbols]

 104, 110 Data encoder 105 OFDM modulator 106 Frequency converter 111 Digital modulator 112 Mixer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Sasaki 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the broadcasting technology research institute of Japan Broadcasting Corporation (72) Inventor Satoru Yamada 1-1-10 Kinuta, Setagaya-ku, Tokyo No. Japan Broadcasting Corporation Broadcasting Technology Research Institute

Claims (9)

[Claims] 1. At least one of video, audio and data
A first channel formed of signals obtained by modulating different types of information with the same or different modulation schemes, and a modulation scheme relating to the at least one type of information and information including the carrier frequency thereof are modulated with a predetermined carrier frequency and modulation scheme. A broadcasting system characterized in that the second channel composed of the signal is frequency-divided for broadcasting. 2. The broadcasting system according to claim 1, wherein the modulation system in the first channel is orthogonal frequency division multiplex modulation. 3. The method according to claim 2, wherein the first channel is frequency-divided into a plurality of blocks having a narrow bandwidth and a plurality of blocks having a wide bandwidth, and the second channel includes the division information. Characteristic broadcasting system. 4. The method according to claim 3, wherein the plurality of narrow bandwidth blocks are applied to voice and relatively small capacity data, and the plurality of wide bandwidth blocks are applied to video and relatively large capacity data. A broadcasting system characterized by: 5. At least one of video, audio and data
An encoder that encodes information of a type, a first modulation unit that modulates the output of the encoder with a different or the same modulation method, and a frequency conversion that converts the output of the first modulation unit into a carrier frequency that is actually transmitted. Means, second modulation means for modulating information including the modulation method of the first modulation means and the carrier frequency in the frequency conversion means by a predetermined carrier frequency and modulation method, output of the frequency conversion means and the second A transmitter for mixing and outputting the outputs of the modulation means. 6. The transmitter according to claim 5, wherein the first modulation means performs orthogonal frequency division multiplex modulation. 7. A receiving means for receiving the signals of the first and second channels according to claim 1, a first decoding means for decoding the received signal of the second channel, and information according to the information decoded by the decoding means. A second decoding means for decoding the received signal of the first channel. 8. The second decoding means according to claim 7, wherein the first frequency-division-multiplexed modulation according to claim 2 is performed.
A receiver including means for decoding a signal of a channel. 9. The receiver according to claim 7, wherein the second decoding means is means for decoding only specific information of video, audio and data.