JPH1188789A - Receiver for digital broadcast and transmitter for related information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To receive a digital broadcast with different modulation systems and using a transmission channel such as a CATV and a ground wave by a same receiver by selecting a demodulation system of an operation changeover digital demodulation means and a data oscillation processing system of an operation changeover data signal processing means in response to a digital modulation system of a broadcast service selected by the selection of a recipient. SOLUTION: An operation changeover digital demodulation circuit 107 applies OFDM demodulation when digital modulated wave is an OFDN signal or applies 64QAM demodulation when digital modulated wave is a 64QAM signal depending on the modulation system of the desired digital modulated wave in response to a control signal from a control circuit 114 for channel selection and changeover of the like. An operation changeover data signal processing circuit 108 demodulates the data signal conducted at a transmitter side depending on the data signal processing system of the modulated wave similarly. The data signal processing system of a demodulation circuit 107 and a processing circuit 108 is selected depending on the digital modulation system of the broadcast service selected by the recipient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for television broadcasting, and more particularly to a receiver capable of receiving digital broadcasting of a plurality of modulation systems such as cable television (CATV), terrestrial broadcasting, and satellite transmission. is there.

[0002]

2. Description of the Related Art Conventionally, both terrestrial broadcasting and cable television using a CATV transmission line are NTSC (National Television System).
Committee) method, the composite video signal was transmitted with the vestigial sideband amplitude modulated.
CA equipped with a tuner that can tune to the frequency range used by TV
A TV compatible TV receiver was commercialized and sold.

[0003] Television broadcasting called cable television and related terrestrial broadcasting and satellite broadcasting are described in "Introduction to Cable Television Technology", edited by the Cable Machinery Technical Committee of the Electronic Machinery Manufacturers Association issued by Corona. I have.

On the other hand, with the recent development of digital transmission technology and the like, the transmission channel of NTSC video which is an analog signal
A plurality of digitized images are about to be transmitted on one channel. Regarding the digital transmission of cable television, see the Telecommunications Society of Japan Technical Report (vol.19.No.42) published on September 21, 1995, pp. John Broadcasting Transmission Experiment ". According to this report, MPEG2
A data stream in a format called a transport stream in which digital data such as an image compressed by a digital image compression technique called (Empeg 2) is multiplexed, subjected to signal processing such as Reed-Solomon error correction, and 64QAM (Quadrature Amplitude) It is modulated by a digital modulation technique called Modulation (64-level quadrature amplitude modulation) and transmitted over a CATV transmission line. Digital transmission by satellite is also described in the CSJ Technical Report (vol.19.No.42), pp. 25-30, published on September 21, 1995.
Overview of Digital Broadcasting System "and Nikkei Electronics 19
It is described in a paper "Japan's First Digital Satellite Broadcasting Realizing Nearly 70 Multi-Channels" on September 2, 1996, page 149.

[0005] In these reports and papers, each transmission system is common until it is composed of a data stream in a format called a transport stream such as image compression technology. The modulation system is CATV, 64QAM is used, and the satellite uses QPSK (Quadrature). Phase
Shift Keying (four-phase modulation) is adopted, and the error correction method is also different. In this background,
Telecommunications Technology Council of the Ministry of Posts and Telecommunications of Japan and DVB (Digit
In examinations by standardization organizations such as al Video Broadcasting, parts that can be shared as much as possible such as information source coding and multiplexing methods such as digital image compression technology are the same for CATV, terrestrial, and satellite broadcasting. There is the idea of media crossing. In each of CATV, terrestrial broadcasting, and satellite broadcasting, transmission path coding such as a modulation method, which is a unique part due to different transmission paths, is different. With this idea, digitalization of terrestrial broadcasting has been studied and the details are undecided, but there is a strong possibility that OFDM (OFDM: orthogonal frequency multiplexing) will be adopted as the terrestrial modulation method. These terrestrial broadcasting and cable television have different transmission paths between terrestrial and CATV, but both have the same transmission bandwidth of 6 MHz.

[0006]

In the prior art, CATV
A digital cable television receiver using a transmission line and a digital satellite broadcast receiver using a satellite transmission line are different devices. Regarding terrestrial digital broadcasting receivers using terrestrial transmission lines, the detailed method is undecided and unknown, but due to differences in modulation methods, etc., reception of digital cable television broadcasting using CATV transmission lines It is presumed that the device will be different from the device.

[0007] It is an object of the present invention to provide a digital broadcast receiving apparatus capable of receiving digital broadcasts having different modulation schemes using transmission lines such as CATV and terrestrial waves with the same device.

[0008]

In order to solve the above-mentioned problems, the present invention provides a demultiplexing means for separating desired video signal data, audio signal data, and the like from digital data in a transport stream, and the demultiplexing means. A video signal format converting means for converting a desired video signal data output from the means into a signal format for displaying a video, and an analog signal for outputting audio from the desired audio signal data output from the demultiplexing means. In a digital broadcast receiving apparatus having an audio signal format converting means for converting to a format, two or more types are switched by switching in order to select and demodulate a desired digital modulated wave and output digital data in a transport stream format. Operation switching digital demodulation means capable of demodulating digital modulated waves of different demodulation methods An operation switching data signal processing means capable of executing the data signal processing method such as the above-described different error correction is provided, and a service beneficiary is provided with a demodulation method of the operation switching digital demodulation means and a data signal processing method of the operation switching data signal processing means. And control means for controlling switching to a system corresponding to the digital modulation system of the broadcast service selected by the selection of the receiver.

In these means, the control means switches the demodulation method of the operation switching digital demodulation means and the data signal processing method of the operation switching data signal processing means in accordance with the digital modulation method of the broadcast service selected by the selection of the receiver. Since the demodulation method and the data signal processing method of the digital modulated wave of the selected broadcast service can be executed, different digital broadcasts can be received by the same receiving device.

[0010]

FIG. 1 is a block diagram showing a configuration of a receiving apparatus according to an embodiment of the present invention. In FIG. 1, 101 is an input terminal of a receiving apparatus, 102 is a first frequency conversion circuit, 103 is a band limiting filter, 104 is a second frequency conversion circuit, 105 is an analog-digital conversion circuit, and 106 is a low-pass filter. , 107 is an operation switching digital demodulation circuit for 64QAM demodulation and OFDM demodulation, 108 is an operation switching data signal processing circuit, 109 is a demultiplexing circuit, 110 is a video decoder, and 111 is N
A TSC encoder, 112 is an audio decoder, 113 is a video / audio display, and 114 is a control circuit.

An input terminal 101 of the receiving apparatus receives an OFDM digital modulated wave signal which is frequency-multiplexed and transmitted when receiving terrestrial broadcasting, and a 64QAM digital signal which is frequency-multiplexed and transmitted when receiving cable television. A modulated wave signal is added. In a CATV transmission path, OFDM may be retransmitted for terrestrial waves and satellite digital broadcasts may be retransmitted or 64QAM signals may be frequency-multiplexed and transmitted for independently produced digital broadcasts. A signal may be added. A first frequency conversion circuit 102 and a band limiting filter 103 select a station so as to pass a desired digital modulated wave according to a control signal from a control circuit 114, and the digital modulated wave signal is transmitted to a second frequency conversion circuit. Ten
4. The signal is converted into a digital signal by an analog-to-digital conversion circuit 105, multiplied by characteristics such as band limitation and roll-off characteristics by a low-pass filter 106, and applied to an operation switching digital demodulation circuit 107.

In the operation switching digital demodulation circuit 107, the digital modulated wave is modulated according to the modulation method of the desired digital modulated wave according to the control signal from the control circuit 114.
The signal performs OFDM demodulation, and the 64QAM signal performs 64QAM demodulation.
Similarly, in the operation switching data signal processing circuit 108 which receives the output of the operation switching digital demodulation circuit 107 as an input, error correction and interleave processing or energy spreading according to the error correction code according to the data signal processing method of the digital modulated wave. The decoding processing of the data signal processing performed on the transmission side such as processing is performed. The output is digital data in a transport stream format, demultiplexed into compressed video data and compressed audio data by a demultiplexing circuit 109, and input to a video decoder 110 and an audio decoder 112.
The compressed video data is converted into video data by a video decoder 110, and the
Converted to a video signal. The compressed audio data is converted into an analog audio signal by an audio decoder. The NTSC video signal and the analog audio signal are input to the video / audio display 113, and the video and audio of the broadcast service selected by the viewer can be displayed. The control circuit 114 controls the first frequency conversion circuit 102 in order to select a frequency on which the program is broadcast, since the program is selected by the receiver's operation of the remote controller or the like. At that time, by comparing the selected program and the frequency band in which the program is broadcast with information stored in the control circuit 114 in advance, the digital modulation method and data signal processing of the broadcast service are performed. Understand the method. As a result, the demodulation method of the operation switching digital demodulation circuit 107 and the data signal processing method of the operation switching data signal processing circuit 108 can be switched according to the digital modulation method of the broadcast service selected by the receiver.

In the embodiment of the present invention, the operation switching digital demodulation circuit 10 is controlled by the control circuit 114 in accordance with the digital modulation scheme of the broadcast service selected by the receiver.
Since the demodulation method 7 and the data signal processing method of the operation switching data signal processing circuit 108 can be switched, different digital broadcasts can be received by the same receiver.

FIG. 2 is a block diagram showing a configuration of a transmission apparatus for digital cable television broadcasting for explaining the present invention. As an example of the transmission device related to the present invention, CATV
1 shows a configuration of a transmission apparatus for digital cable television broadcasting using a transmission path.

In FIG. 2, 201 and 202 are video encoders, 203 and 204 are audio encoders, 205 is a multiplexing circuit, 206 is a data encoding processing circuit, 207 is a digital modulation circuit, 208 is a frequency conversion circuit, and 209 is a signal Synthesis circuit, 210
Denotes another modulation circuit group, and 211 denotes a CATV transmission line.

A video encoder for converting a plurality of video and audio signals
The digital video and audio data is subjected to image compression and audio compression by the audio encoders 201 and 202 and the audio encoders 203 and 204.
The plurality of video / audio data are time-division multiplexed by the multiplexing circuit 205 to be digital data in a transport stream format, and the data encoding processing circuit 206 adds an error correction code, interleave processing, energy diffusion processing, and the like. Is encoded. The processed data is applied to a digital modulation circuit 207, modulated to a 64QAM digital modulated wave, frequency-converted to a frequency transmitted by a frequency conversion circuit 208, and applied to a signal synthesis circuit 209. In the signal synthesis circuit 209, the modulated wave such as another 64QAM digital modulated wave from another modulation circuit group 210 is frequency-multiplexed and output to the CATV transmission line 211.

The configuration of the transmitting apparatus is an example of the configuration of digital cable television broadcasting, but it is almost the same as the transmitting apparatus of satellite or terrestrial digital television broadcasting, and includes a data encoding processing circuit 206 and a digital modulation circuit 207. The coding and modulation schemes are different. The coding and modulation methods are compared.

[0018]

[Table 1]

Table 1 is a comparison table of transmission line coding and the like for explaining the present invention. As can be seen from Table 1, the information source coding and multiplexing method of all digital broadcasting of CATV, satellite and terrestrial broadcasting are unified into MPEG-2 transport stream format data. The part that differs in each broadcast is a part called channel coding, which includes an error correction code, interleave processing, energy spreading processing,
The modulation method, transmission band, and the like are partially different.

CATV and terrestrial digital broadcasting both have the same transmission band of 6 MHz, but use modulation methods of 64 QAM and OFDM.
Unlike this, the error correction code also differs in part of the data encoding processing, such as in the presence or absence of an outer code of the convolutional code. For satellites, the transmission band for digital broadcasting using communication satellites currently being implemented is 27 MHz, and for digital broadcasting using broadcasting satellites currently under consideration, the transmission band is 27 MHz to 3 MHz.
It is different from terrestrial broadcasting and CATV because it is considered between 6MHz. As for the modulation method, QPSK is used for digital broadcasting using communication satellites currently being implemented, and QPSK or 8PSK is also being considered for digital broadcasting using broadcasting satellites currently under consideration, which is different from terrestrial broadcasting and CATV. The outer code of the convolutional code is used as the error correction code, but the code form is different, and is different from the terrestrial wave and CATV in a part of the data coding processing such as the interleaving processing and the energy spreading processing.

FIG. 3 is a block diagram showing a configuration of a receiving apparatus according to another embodiment of the present invention. Reference numeral 301 denotes a digital signal processor, and those having the same reference numerals as those in FIG. 1 have the same functions. Digital signal processor
Reference numeral 301 denotes an operation switching digital demodulation circuit 107 and an operation switching data signal processing circuit 108 in FIG. 1 which are digital signal processing circuits capable of switching the digital signal processing method by switching software stored in the digital signal processor 301. It consists of. In order to change or update the software content stored in the digital signal processor 301, the information may be transmitted in a time-division multiplexed manner to digital broadcast transport stream data. Using the transmitted information, change the software content stored inside the digital signal processor 301 to the new digital signal processing method characteristics or method, or update the digital signal processing method characteristics or method to the latest method. It is also possible. In FIG. 3, the operation switching digital demodulation circuit 107 and the operation switching data signal processing circuit 108 of FIG. 1 are configured by the digital signal processor 301. However, the operation switching digital demodulation circuit 107 and the operation switching digital demodulation circuit 107 may be configured by a plurality of digital signal processors. The same operation is performed even if one of the operation switching data signal processing circuits 108 is constituted by one or a plurality of digital signal processors.

According to the present embodiment, since the software of the digital signal processor 301 can be switched, different digital broadcasts can be received by the same receiver. Further, according to the present embodiment, the software content of the digital signal processor 301 can be changed or updated, and the characteristics and method of the digital signal processing method can be changed to the new characteristics and method of the digital signal processing method. It is possible to update to the method of
Further, it is also possible to change to a new digital signal processing system corresponding to a new digital broadcast.

FIG. 4 is a block diagram showing a configuration of a receiving apparatus according to another embodiment of the present invention. Reference numeral 401 denotes a data storage circuit, and those having the same reference numerals as those in FIG. 3 have the same functions. In FIG. 3, software of a plurality of digital signal processing systems is stored inside the digital signal processor 301, and the digital signal processing system is switched under the control of the control circuit 114. The processing method is such that the software of the digital signal processor 301 is recorded in the data storage circuit 401, and the software for the processing of the digital signal processor 301 is transferred under the control of the control circuit 114, thereby conforming to the digital signal processing method. Characteristics and methods can be switched. Also, by updating the data storage circuit 401,
It is also possible to change the characteristics and method of the new digital signal processing method, and to update the characteristics and method of the digital signal processing method to the latest method. This data storage circuit
Regarding the update of 401, when the software of a plurality of digital signal processing systems is stored inside the digital signal processor 301 shown in the embodiment of FIG. 3, the content of the stored software is updated. For this purpose, the data storage circuit 401 may be used. When updating the data storage circuit 401, the data storage circuit 401
-Exchange in the form of ROM by sending by mail or other means, or change the contents by time-division multiplexing with data in the transport stream format of digital broadcasting where the data storage circuit 401 is a non-volatile memory. But you can.

According to the present embodiment, since the software of the digital signal processor 301 can be switched, different digital broadcasts can be received by the same receiver. Further, according to the present embodiment, since the data storage circuit 401 is provided, it is possible to easily change or update the software content of the digital signal processor 301, and to change the characteristics or the method of the new digital signal processing method to a new one. The characteristics and system of the digital signal processing system can be updated to the latest method, and further, it is possible to change to a new digital signal processing system corresponding to a new digital broadcast.

FIG. 5 is a block diagram showing a configuration of a receiving apparatus according to another embodiment of the present invention. Reference numeral 501 denotes a band switching band limiting filter, reference numeral 502 denotes a band switching low-pass filter, and other components having the same reference numerals as those in FIG. 1 have the same functions. In the present embodiment, an example will be described in which reception of satellite and wired digital broadcasts is realized by the same device, but the same applies to reception of satellite and terrestrial or satellite-terrestrial and wired digital broadcasts. The input terminal 101 of the receiving device is supplied with a 64QAM digital modulated wave signal transmitted in a frequency multiplexed manner when receiving cable television, and a QPSK digital signal transmitted in a frequency multiplexed manner when receiving satellite digital broadcast. A modulated wave signal is added. The first frequency conversion circuit 102 and the band switching band limiting filter 501 select a station so as to pass a desired digital modulated wave according to a control signal from the control circuit 114, and the digital modulated wave signal The signal is converted into a digital signal by a conversion circuit 104 and an analog / digital conversion circuit 105, and the band is switched to a low-pass filter 50.
Characteristics such as band limitation and roll-off characteristics are multiplied by 2 and are added to the operation switching digital demodulation circuit 107.

The band switching band limiting filter 501 includes a control circuit 1
According to the modulation method of the desired digital modulated wave according to the control signal from 14, the band of the digital modulated wave is 27 MHz.
In the case of satellite digital broadcasting, the band is switched to 27 MHz, and in the case of cable digital broadcasting, the band is switched to 6 MHz. The band-switching low-pass filter 502 has a roll-off rate of the digital modulated wave of 35 in accordance with the control method of the desired digital modulated wave in response to the control signal from the control circuit 114.
In the case of% digital satellite broadcasting, switch to the 35% route characteristic, and in the case of cable digital broadcasting, switch to the 13% route characteristic.

In the operation switching digital demodulation circuit 107, the digital modulated wave is converted to QPSK in accordance with the modulation method of the desired digital modulated wave according to the control signal from the control circuit 114.
In the case of satellite digital broadcasting, QPSK demodulation is performed, and in the case of cable digital broadcasting, 64QAM demodulation is performed. Similarly, in the operation switching data signal processing circuit 108 which receives the output of the operation switching digital demodulation circuit 107 as an input, error correction and interleave processing or energy spreading according to the error correction code according to the data signal processing method of the digital modulated wave. The decoding processing of the data signal processing performed on the transmission side such as processing is performed. In the digital satellite broadcasting by the currently implemented communication satellite and the broadcasting satellite currently under study, the transmission band is 27 MHz to 36 MHz.
, The band switching band limiting filter
In some cases, it is possible to cope with only by switching the band-switching low-pass filter 502, where 501 is a band-limited band-pass filter 104 with a broader pass band.

According to the present embodiment, since the signal band limitation can be switched by the band switching band limiting filter 501 or the band switching low-pass filter 502, digital broadcasts having different transmission bands can be transmitted by the same receiver. Can be received.

In the present embodiment, the band switching band limiting filter 501 and the band switching low-pass filter 502 are applied to the embodiment of the present invention shown in FIG. 1, but the embodiment shown in FIG. 3 or FIG. It is also possible to apply to the embodiment of the invention.

FIG. 6 is a block diagram showing a configuration of a receiving apparatus according to another embodiment of the present invention. Numerals 601 and 602 denote digital signal processors, and those having the same reference numerals as those in FIG. 1 have the same functions. In the present embodiment, the digital signal processor 601 acts as the band switching band limiting filter 501 in FIG.
02 functions as the band switching low-pass filter 502. Software having multiple band limiting and low-pass characteristics is stored inside the digital signal processors 601 and 602, and by switching the characteristics under the control of the control circuit 114, the characteristics can be switched according to the digital broadcasting system. Can be.

According to the present embodiment, since the digital signal processors 601 and 602 can switch the band limiting and low-pass characteristics, digital broadcasts having different transmission bands can be received by the same receiver. . Further, since the software contents of the digital signal processors 601 and 602 can be updated, it is also possible to update the band limiting and low-pass characteristics to the latest characteristics.

In this embodiment, a digital signal processor 60 is added to the embodiment of the present invention shown in FIG.
Although 1, 602 was applied, it is also possible to apply to the embodiment of the present invention shown in FIG. 3 or FIG. 4, or to configure the digital signal processors 601 and 602 as an integrated digital signal processor.

FIG. 7 is a block diagram showing a configuration of a receiving apparatus according to another embodiment of the present invention. Reference numeral 701 denotes a data storage circuit, and those having the same reference numerals as those in FIG. 6 have the same functions. In FIG. 6, the digital signal processors 601, 6
Although a plurality of softwares for band limiting and low-pass characteristics are stored inside the device 02 and the characteristics are switched under the control of the control circuit 114, in the present embodiment, the digital signal processing method is changed to a data storage circuit. The software of the digital signal processors 601, 602 is recorded in 701, and the digital signal processors 601, 60 are controlled by the control circuit 114.
By transferring software with the two characteristics, it is possible to switch to the characteristics according to the digital broadcasting system.

According to the present embodiment, the data storage circuit 70
Because there is one, digital signal processors 601, 60
The contents of the second software can be easily updated, and the band limiting and low-pass characteristics can be updated to the latest characteristics.

In this embodiment, a digital signal processor 60 is added to the embodiment of the present invention shown in FIG.
Although 1, 602 has been applied, it can be applied to the embodiment of the present invention shown in FIG. 3 or FIG. When applied to the embodiment of the present invention shown in FIG.
It is also possible to share 701 with the data storage circuit 401.

FIG. 8 is a block diagram showing a configuration of a digital television broadcast transmitting apparatus according to another embodiment of the present invention. Reference numeral 801 denotes a software encoder, 802 denotes a multiplexing circuit, and those having the same reference numerals as those in FIG. 2 have the same functions.

The video encoders 201 and 202, the digital video / audio data from the audio encoders 203 and 204, and the software of the digital signal processors 301, 601, and 602 which are the outputs of the software encoder 801 are time-division multiplexed by the multiplexing circuit 802. The digital data is converted into digital data in a transport stream format.
At 07, an error correction code is added, interleaving processing, data spreading processing such as energy spreading processing, modulated to 64QAM digital modulated wave, frequency-multiplexed with other modulated waves such as 64QAM digital modulated wave, and CATV. Transmission line 210
Is output to

According to the present embodiment, the data for updating the software content of the digital signal processors 301, 601, and 602 of the receiving device can be transmitted by the software encoder 801 and the multiplexing circuit 802. The latest signal processing method can be transferred.

In the present embodiment, as an example of the transmitting device, the configuration of a transmitting device for digital cable television broadcasting using a CATV transmission line is shown. Almost the same, the encoding and modulation schemes of the data encoding processing circuit 206 and the digital modulation circuit 207 are different, and software for updating the software contents of the digital signal processors 301, 601, and 602 of the receiving apparatus is used. The multiplexing method in the transport stream format to the encoder 801 and the multiplexing circuit 802 is the same.

[0040]

According to the present invention, the demodulation method of the operation switching digital demodulation means and the data signal processing of the operation switching data signal processing means according to the digital modulation method of the broadcasting service selected by the receiver by the control means. By switching the system, it is possible to execute the demodulation system of the digital modulated wave and the data signal processing system of the selected broadcasting service. It is possible to provide a digital broadcast receiving device that can be received by a device.

As described above, the present invention is an extremely effective technique which makes it possible to provide a digital television broadcast receiving apparatus having various modulation schemes.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a digital television broadcast receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a digital cable television broadcast transmitting apparatus for explaining the present invention.

FIG. 3 is a block diagram showing a configuration of a digital television broadcast receiving apparatus according to another embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a digital television broadcast receiving apparatus according to another embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a digital television broadcast receiving apparatus according to another embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a digital television broadcast receiving apparatus according to another embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a digital television broadcast receiving apparatus according to another embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a digital television broadcast transmitting apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 101: input terminal of receiving apparatus 102: first frequency conversion circuit 103: band-limiting filter 104: second frequency conversion circuit 105: analog-to-digital conversion circuit 106: low-pass filter 107: operation switching digital demodulation circuit 108: operation Switching data signal processing circuit 109 Demultiplexing circuit 110 Video decoder 111 NTSC encoder 112 Audio decoder 113 Video / audio display 114 Control circuit 301, 601, 602 Digital signal processor 401, 701 Data storage circuit

Continued on the front page (72) Inventor Morikake Akiyama 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Multimedia Systems Development Division, Hitachi, Ltd. Address Co., Ltd. Multimedia System Development Division, Hitachi, Ltd.

Claims (15)

[Claims] 1. A frequency conversion means for converting a frequency of a desired digital modulated wave from a group of modulated waves transmitted through a transmission line such as a terrestrial wave or a cable into a frequency which can be easily selected, and an output of the frequency conversion means. Band-limiting filter means for passing a desired digital modulated wave, analog-to-digital conversion means for converting a desired digital modulated wave output from the band-limiting filter means to a digital signal, and output of the analog-to-digital conversion means. Low-pass filter means for band limiting, digital demodulation means for demodulating a desired digital modulated wave output from the low-pass filter means, and transmission of a desired digital modulated wave output from the digital demodulation means. Performs data signal processing such as error correction according to the signal to output transport stream format digital data. Data signal processing means, demultiplexing means for separating desired video signal data, audio signal data, and the like from digital data in a transport stream format output from the data signal processing means, and an output of the demultiplexing means. Video signal format conversion means for converting the desired video signal data into a signal format for displaying video, and audio for converting the desired audio signal data output from the demultiplexing means into an analog signal format for outputting audio. A digital broadcast receiving apparatus having signal format conversion means, wherein the digital demodulation means is an operation switching digital demodulation means capable of demodulating digital modulated waves of two or more different demodulation systems by switching, and wherein the data signal processing is performed. The means can be switched to implement a data signal processing method such as two or more different error corrections. An operation switching data signal processing means capable of executing the operation switching digital demodulation means and a data signal processing method of the operation switching data signal processing means selected by a receiver who is a service beneficiary; A digital broadcast receiving apparatus, comprising: a control unit that controls the operation switching digital demodulation unit and the operation switching data signal processing unit to switch to a system according to the digital modulation system. 2. The digital broadcast receiving apparatus according to claim 1, wherein said operation switching digital demodulation means and said operation switching data signal processing means switch a digital signal processing system by switching software such as a computer. A digital broadcast receiving apparatus comprising software signal processing means capable of performing the following. 3. The digital broadcast receiving apparatus according to claim 2, further comprising: recording means for recording software of said operation switching digital demodulation means and software signal processing means constituting said operation switching data signal processing means. Wherein the software recorded on the recording means is transferred to the software signal processing means under the control of the control means, so that the system can be switched according to the digital signal processing method. Broadcast receiver. 4. A frequency conversion means for converting a frequency of a desired digital modulated wave from a group of modulated waves transmitted through a transmission line such as a terrestrial wave or a cable into a frequency which can be easily selected, and an output of the frequency conversion means. Band-limiting filter means for passing a desired digital modulated wave, analog-to-digital conversion means for converting a desired digital modulated wave output from the band-limiting filter means to a digital signal, and output of the analog-to-digital conversion means. Low-pass filter means for band limiting, digital demodulation means for demodulating a desired digital modulated wave output from the low-pass filter means, and transmission of a desired digital modulated wave output from the digital demodulation means. Performs data signal processing such as error correction according to the signal to output transport stream format digital data. Data signal processing means, demultiplexing means for separating desired video signal data, audio signal data, and the like from digital data in a transport stream format output from the data signal processing means, and an output of the demultiplexing means. Video signal format conversion means for converting the desired video signal data into a signal format for displaying video, and audio for converting the desired audio signal data output from the demultiplexing means into an analog signal format for outputting audio. In a digital broadcast receiving apparatus having signal format conversion means, the low-pass filter means is an operation switching low-pass filter means capable of changing two or more different pass characteristics by switching, and the digital demodulation means , 2 by switching
Operation switching digital demodulation means capable of demodulating digital modulated waves of different demodulation schemes, wherein said data signal processing means can execute two or more different data signal processing schemes such as error correction by switching. Switching data signal processing means, wherein the pass characteristics of the operation switching low-pass filter means, the demodulation method of the operation switching digital demodulation means, and the data signal processing method of the operation switching data signal processing means are service beneficiaries. Control means for controlling the operation switching low-pass filter means, the operation switching digital demodulation means, and the operation switching data signal processing means to switch to a characteristic or a method according to a digital modulation method of a broadcasting service selected by a user. A digital broadcast receiving device comprising: 5. The digital broadcast receiving apparatus according to claim 4, wherein said operation switching low-pass filter means, said operation switching digital demodulation means and said operation switching data signal processing means are implemented by software such as a computer. 5. The digital broadcast receiving apparatus according to claim 4, wherein the digital broadcast receiving apparatus is configured by software signal processing means capable of switching characteristics and systems according to the digital signal processing system by switching. 6. A digital broadcast receiving apparatus according to claim 5, wherein said operation switching low-pass filter means, said operation switching digital demodulation means, and said operation switching data signal processing means comprise software signal processing means. Recording means for recording the software of the present invention, and the software recorded in the recording means is transferred to the software signal processing means under the control of the control means, whereby characteristics and methods corresponding to the digital signal processing method are obtained. A digital broadcast receiving device characterized by being switchable. 7. A frequency conversion means for converting a frequency of a desired digital modulated wave from a group of modulated waves transmitted through a transmission line such as a terrestrial wave or a cable into a frequency which can be easily selected, and an output of the frequency conversion means. Band-limiting filter means for passing a desired digital modulated wave, analog-to-digital conversion means for converting a desired digital modulated wave output from the band-limiting filter means to a digital signal, and output of the analog-to-digital conversion means. Low-pass filter means for band limiting, digital demodulation means for demodulating a desired digital modulated wave output from the low-pass filter means, and transmission of a desired digital modulated wave output from the digital demodulation means. Performs data signal processing such as error correction according to the signal to output transport stream format digital data. Data signal processing means, demultiplexing means for separating desired video signal data, audio signal data, and the like from digital data in a transport stream format output from the data signal processing means, and an output of the demultiplexing means. Video signal format conversion means for converting the desired video signal data into a signal format for displaying video, and audio for converting the desired audio signal data output from the demultiplexing means into an analog signal format for outputting audio. In a digital broadcast receiving apparatus having a signal format conversion unit, the band-limiting filter unit is an operation switching band-pass filter unit that can change two or more different pass characteristics by switching, and the low-pass filter unit is Operation switching low-pass filter means that can change two or more different pass characteristics by switching An operation switching digital demodulation means, wherein the digital demodulation means is capable of demodulating digital modulated waves of two or more different demodulation schemes by switching;
The data signal processing means is an operation switching data signal processing means capable of executing a data signal processing method such as two or more different types of error correction by switching, and includes a pass characteristic of the operation switching band limiting filter means and the operation switching low Digital modulation of a broadcast service selected by selecting a receiver as a service beneficiary by setting a pass characteristic of a band-pass filter means, a demodulation method of the operation switching digital demodulation means, and a data signal processing method of the operation switching data signal processing means. Control means for controlling the operation switching band-pass filter means, the operation switching low-pass filter means, the operation switching digital demodulation means, and the operation switching data signal processing means for switching to a characteristic or a method according to a method. A digital broadcast receiving apparatus characterized by the above-mentioned. 8. The digital broadcast receiving apparatus according to claim 7, wherein said operation switching band-pass filter means, said operation switching low-pass filter means, said operation switching digital demodulation means, and said operation switching data signal processing means. A digital broadcast receiving apparatus characterized by comprising software signal processing means capable of switching characteristics and methods according to digital signal processing methods by switching software such as a computer. 9. The receiving apparatus for digital broadcasting according to claim 8, wherein said operation switching band-pass filter means, said operation switching low-pass filter means, said operation switching digital demodulating means, and said operation switching data signal processing means. Recording means for recording software of the software signal processing means constituting the digital signal processing means by transferring the software recorded in the recording means to the software signal processing means under the control of the control means. A digital broadcast receiving apparatus characterized by being capable of switching characteristics and methods according to the method. 10. A frequency conversion means for converting a frequency of a desired digital modulated wave from a group of modulated waves transmitted through a transmission line such as a terrestrial wave or a cable into a frequency which can be easily selected, and an output of the frequency conversion means. Band-limiting filter means for passing a desired digital modulated wave, analog-to-digital conversion means for converting a desired digital modulated wave output from the band-limiting filter means to a digital signal, and output of the analog-to-digital conversion means. Low-pass filter means for band limiting, digital demodulation means for demodulating a desired digital modulated wave output from the low-pass filter means, and transmission of a desired digital modulated wave output from the digital demodulation means. Data signal processing means for performing data signal processing such as error correction according to the signal and outputting digital data, Descrambling means for decrypting the output of the data signal processing means so that only a limited receiver can demodulate the data to obtain digital data in a transport stream format; and a transport stream format which is an output of the descrambling means. Demultiplexing means for separating desired video signal data, audio signal data, and the like from the digital data, and a video signal format for converting the desired video signal data output from the demultiplexing means into a signal format for displaying video. Conversion means, and a digital broadcast receiving apparatus having an audio signal format conversion means for converting the desired audio signal data output from the demultiplexing means into an analog signal format for audio output, wherein the digital demodulation means comprises: Switching can demodulate digital modulated waves of two or more different demodulation methods. Operation switching digital demodulation means, wherein the data signal processing means is an operation switching data signal processing means capable of executing a data signal processing method such as two or more different error corrections by switching, and the descrambling means, Operation switching descramble means capable of executing two or more different descrambling methods by switching, a demodulation method of the operation switching digital demodulation means, a data signal of the operation switching data signal processing means, and a data signal of the operation switching descramble means. The operation switching digital demodulation means, the operation switching data signal processing means, and the operation switching data so as to switch a processing method to a method according to a digital modulation method of a broadcasting service selected by a receiver who is a service beneficiary. That control means for controlling the scrambling means is provided. Receiving apparatus of digital broadcast and symptoms. 11. The digital broadcast receiving apparatus according to claim 10, wherein said operation switching digital demodulation means, said operation switching data signal processing means, and said operation switching descramble means are switched by software such as a computer. A digital broadcast receiving apparatus comprising software signal processing means capable of switching a digital signal processing method or the like. 12. A digital broadcast receiving apparatus according to claim 11, wherein said operation switching digital demodulation means, said operation switching data signal processing means, and said software signal processing means constituting said operation switching descramble means are implemented by software. Recording means for recording the software, and the software recorded in the recording means is transferred to the software signal processing means under the control of the control means, so that the method according to the digital signal processing method can be switched. A digital broadcast receiving device, characterized in that it is possible. 13. A digital broadcast receiving apparatus according to claim 3, wherein the contents of software to be recorded in said recording means are distributed to a recording medium such as a compact disk. Alternatively, a digital broadcast receiving apparatus updated by sale. 14. A digital broadcast receiving apparatus according to claim 3, wherein the contents of software recorded in said recording means are broadcast in a transport stream format. A digital broadcast receiving apparatus, which is updated by a signal in digital data of digital broadcast. 15. A signal source encoding means for generating digitized video and audio data by inputting a video signal and an audio signal, a digital data generating means for generating digital data of demodulation software of a receiving device, Multiplexing means for multiplexing the video / audio data output from the signal source coding means and the digital data output from the digital data generating means into multiplexed data in a transport stream format; Transmission side data signal processing means for adding error correction codes, interleaving processing, energy spreading processing, etc. to multiplexed data in a certain transport stream format, and digital modulation for converting the transmission side data signal processing means to a digital modulated wave signal Means for converting the output of the digital modulation means to a suitable frequency of the transmission line band. That frequency conversion means and transmitting apparatus of a digital broadcasting which is characterized in that it comprises a.