JPH02279083A - Data receiver - Google Patents

Abstract

PURPOSE:To receiver a digital data sent while being scrambled in duplicate in an excellent state by descrambling a 1st descramble data and sending the result and sending a 1st descramble data as it is when a 2nd descramble control data is inputted. CONSTITUTION:A digital data SDAD1 scrambled and sent with 1st or 1st and 2nd scramble methods is descrambled in response to the 1st scramble method to obtain a 1st descramble data DAD1. When a descramble control data DTDS in response to the 2nd scramble method is inputted through an input terminal 14, the 1st descramble data DAD1 is sent while being descrambled further. Moreover, when a 2nd descramble control data DTDS of a prescribed value is inputted through the input terminal 14, the 1st scramble data DAD1 is sent as it is. Thus, the digital data SDAD1 sent while being scrambled in duplicate is received in an excellent state.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a data receiving device, and is suitable for application to, for example, a receiving device for satellite television broadcast signals.

B. Summary of the Invention The present invention provides a data receiving device that descrambles digital data that is transmitted after being scrambled using a first or first and second scrambling method, and then descrambles the digital data that is transmitted after being scrambled using a first scrambling method. When descramble data is obtained and descramble control data according to the second scrambling method is input through the input terminal, the first descramble data is further descrambled and sent out, and second descramble data having a predetermined value is sent out. By transmitting the first descramble data as is when the first descramble control data is input, it is possible to satisfactorily receive digital data that is doubly scrambled and transmitted as required.

C. Prior Art Conventionally, satellites for relaying television broadcasts from predetermined broadcasting stations have been used to transmit, for example, CA TV (cable tel.
A system has been proposed in which programs are supplied to a central station (so-called head end) of a broadcasting company (evision).

In such cases, the transmitted television broadcast signal has horizontal scanning lines swapped (so-called line sharrafling).
Even if someone other than the subscriber receives the television broadcast signal, it is scrambled in a uniform manner so that normal images and sound cannot be viewed (Japanese Patent Application Laid-Open No. 1983-1999).
256287).

Therefore, in such a satellite television broadcasting signal transmission/reception system, a decoder with a built-in descrambler is provided to the person contracting with the broadcasting station, and this decoder is used to reproduce the scrambled television broadcasting signal in its original form. This allows users to view and listen to normal images and sounds.

D Problems to be Solved by the Invention Incidentally, whether or not to operate the decoder provided to the subscriber is generally allowed to be controlled by the broadcasting station, which is the transmitting side, based on the contract.

This allows broadcast stations to turn on and off the decoder on a per-channel or time-zone basis depending on the status of individual contracts with subscribers, allowing users to pay and watch only the programs they want. It is possible to realize a so-called pay/view type service.

In such a transmission system, if the cost of the program source is high, such as a new movie or special program, the decoder that operates under a regular contract may be operated so that it cannot be viewed without a special contract. ,
In other words, if dual pay/pay service can be realized, the usefulness of the entire system can be further improved.

The present invention has been made in consideration of the above points, and is an attempt to propose a data receiving device that has a simple configuration and can satisfactorily receive digital data that is transmitted after being doubly scrambled as required. be.

E Means for Solving Problems In order to solve these problems, in the present invention, transmission is scrambled using the first scrambling method, or scrambled using a second scrambling method in addition to the first scrambling method. The data receiving device 4 that receives the digital data 5DAllI descrambles the received digital data 5DADI according to the first scrambling method to generate first descrambled data D.
a first descrambling means 10 for sending out ADI;
Input terminal 14 to which second descramble control data D T o s according to the second scrambling method is input.
and a second descramble calculation means 13 that descrambles the first descramble data I) ant based on second descramble control data D T e s inputted via the input terminal 14. , second
When the second descramble control data DT, , corresponding to the scrambling method of When the rumble control data DTas is input, the first descramble data DA! 11 was sent as is.

The digital data 5DADl scrambled and transmitted using the first or first and second scrambling methods is
The first one is descrambled according to the scrambling method of
When the first descramble data D, ! is obtained, and the descramble control data D T o s according to the second scrambling method is input through the input terminal 14, the first descramble data D, ! 1. is further descrambled and sent out, and second descramble control data D having a predetermined value is sent through the input terminal 14.
By transmitting the first descrambled data D^o1 as is when Ttts is manually input, the digital data 5Daoz, which is doubly scrambled and transmitted as required, can be successfully received.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

In the figure, 1 generally indicates a satellite television broadcast signal transmission/reception system to which the present invention is applied, in which a satellite television broadcast signal sent from a transmitter 2 is transmitted to a receiver 4 through a satellite line 3 including a relay satellite. be done.

In the case of this transmitting device 2, the video signal SVD is input to the video scrambling circuit section 5, and the video signal SVD is input to the video scrambling circuit section 5, and the video signal SVD is inputted in units of one frame in the order of horizontal scanning lines according to the scrambled data SDA inputted from the control circuit (not shown). Line sharing is performed, and as a result, a scrambled video signal 5Dvo is sent out.

The audio signal DA11 is PCM audio data, and is manually input to the data scrambling circuit section 6 together with the scramble data SDA supplied to the video scrambling circuit section 5.

The data scrambling circuit unit 6 formats the input digital audio signal D0 and scramble data SDA based on a predetermined format, and then digitally scrambles the input digital audio signal D0 and scramble data SDA according to the key data KEY input from the control circuit. The resulting scrambled audio signal 5DAD is sent out.

In this case, the digital audio signal DAfl is formatted according to the audio format of the satellite television broadcast signal in standard sound quality mode (A mode) or high sound quality mode (B mode).

Note that the scramble data SDA is superimposed on the independent data portion defined in this audio format, and scrambled together with the digital audio signal DAD.

In this way, the scrambled audio signal 5Daa sent out from the data scrambling circuit 6 is sent to the multiplexing circuit 7.
In this step, scramble control information SIF is written which includes key data KEY input from the control circuit and decoder identification numbers DID corresponding to the plurality of receiving devices 4 that are permitted to receive the data.

Furthermore, this scrambled audio signal 5Dao+ is 4-phase PSK (pha
se 5hift keying), frequency 4
．． After being frequency multiplexed with the scrambled video signal SD0 having a frequency band up to 5 (M7), it is FM modulated at a predetermined carrier frequency and is sent to the satellite line 3 including the relay satellite as a satellite television broadcast signal. .

This satellite television broadcast signal is received by a receiving device 4 through a satellite line 3, FM demodulated, and then passed through a low-pass filter and a band-pass filter (not shown) to generate a scrambled video signal SDv.

and scrambled audio signal after being divided into 5DADI,
A video descrambling circuit section 8 and a separation circuit 9, respectively.
is input.

The scrambled video signal 5Dvo input to the video descrambling circuit section 8 is scrambled one frame at a time in the order of horizontal scanning lines according to the descrambled data DSA generated based on the scrambled data SDA given from the data descrambled circuit section 10. A descrambling process is performed on a frame-by-frame basis, and as a result, a video signal 5VI11 is obtained.

In addition, the separation circuit 9 separates the scramble control information SIF from the input scrambled audio signal 5 Daet and sends it to the authorization determination circuit 11, and also sends the other scrambled audio signal 5Das to the data descrambling circuit section 10. .

The authorization determination circuit 11 uses, for example, a contract decoder identification number RID inputted from a decoder identification number storage circuit 12 having a ROM configuration given from the transmitting device 2 at the time of contract, and scramble control information SI inputted from the separation circuit 9.
It is determined whether the decoder identification number DID matches any one of the plurality of decoder identification numbers DID in F.

As a result, when the authorization determination circuit 11 detects the decoder identification number DID that matches the contracted decoder identification number RID, it determines that it is authorized as the receiving device 4, and uses the key data KEY included in the input scramble control information SIF. is supplied to the data descrambling circuit section 10.

As a result, the data descrambling circuit unit 10 receives the key data KE input from the authorization determination circuit 11.
The scrambled audio signal 5DADx is descrambled based on Y, and the resulting audio signal DAD is sent to the subsequent exclusive OR circuit 13.

At this time, the data descramble circuit section 10 supplies the scramble data SDA included in the independent data portion of the scrambled audio signal 5DAEII to the video descramble circuit section 8.

In this embodiment, the exclusive OR circuit 13 is
An exclusive OR operation is performed between the audio signals DAI, I sent out from the data descrambling circuit section 10 and the coefficient data DT o s inputted through the input terminal 14, and the logical output obtained as a result is used as the received audio signal. Signal DAtlt
It is designed to be sent as .

Note that this input terminal 14 is connected to the output terminal a of the switch circuit 15.
It is connected to the. The first input terminal C of this switch circuit 15 is grounded, and the coefficient data D T o s outputted from the coefficient data generation circuit 16 is inputted to the second input terminal C.

This coefficient data generation circuit 16 generates, for example, an audio signal D0 on the transmitting device 2 side, in place of PCM audio data.
By inputting digital data obtained by scrambling the PCM audio data using a predetermined scrambling method to the data scrambling circuit section 6, when performing the scrambling method based on a special contract in addition to the scrambling method based on the normal contract, the PCM Coefficient data DT consisting of descrambling control data corresponding to the method of scrambling audio data is generated.

Therefore, if the first input terminal of the switch circuit 15 is selected, the audio signal DA□ sent out from the data descrambling circuit section 1o is output as it is as the received audio signal D03, and thereby If the second input terminal C of the switch circuit 15 is selected, the audio signal RI, □ sent from the data descrambling circuit section 10 can be further converted into coefficient data DTss. The resulting digital data is then descrambled based on the received audio signal. , thereby making it possible to satisfactorily receive television broadcast signals based on special contracts in addition to regular contracts.

According to the above configuration, the received scrambled audio signal 5
DAIII is descrambled in the data descrambling circuit section 10 to obtain the audio signal DAIII, and at the same time, coefficient data DT o s consisting of descrambling control data according to a scrambling method based on a special contract is inputted through the input terminal 14. When the audio signal DiDl is further descrambled and sent out, and when the coefficient data DT o s having a predetermined value is input, the audio signal DADI is sent out as is, in addition to the normal contract. It is possible to realize a data receiving device 4 that can satisfactorily receive television broadcast signals based on a special contract.

Further, according to the above configuration, the external coefficient data generation circuit 1
6, based on a special contract (coefficient data DT consisting of descrambling control data according to the scrambling method,
, and sends it through an input terminal 14 to an exclusive OR circuit 1 which executes descrambling operation processing.
3, even if the scrambling method based on the special contract is changed in various ways, it is possible to respond promptly without modifying or changing the receiving device 4 itself. Therefore, it is possible to realize a receiving device 4 whose performance can be further improved.

In addition, in the above-mentioned embodiment, when a service is provided under a special contract in addition to a regular contract, only the audio signal is
Although the double scrambling method is used for transmission, the present invention is not limited to this, and video signals may also be transmitted using the double scrambling method. Broadcast signal transmission and reception system 1
The overall usefulness can be further improved.

Further, in the above-described embodiments, the case where the present invention is applied to a receiving device for satellite television broadcast signals has been described, but the present invention is not limited to this, and can be applied to other applications such as satellite communication using video signals, terrestrial communication, etc. It is widely applicable and suitable for data receiving devices of data transmission devices.

H Effects of the Invention As described above, according to the present invention, it is possible to realize a data receiving apparatus that can satisfactorily receive digital data transmitted after being doubly scrambled as required, with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a satellite television broadcast signal transmission and reception system according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Satellite television broadcasting signal transmission and reception system, 2... Transmitting device, 3... Satellite line, 4... Receiving device, 10... ...Data descrambling circuit section, 13...Exclusive OR circuit, 14...Input terminal, 16...
...Coefficient data generation circuit.

Claims (1)

[Claims] A data receiving device that receives digital data that is transmitted after being scrambled using a first scrambling method, or after being scrambled using a second scrambling method in addition to the first scrambling method. a first descrambler that descrambles the digital data according to the first scrambling method and sends out first descrambled data; and second descramble control data according to the second scrambling method. an input terminal into which is input, and second descramble calculation means that descrambles the first descramble data based on the second descramble control data input through the input terminal. , the second scrambling method according to the second scrambling method.
When the descramble control data is input, the first descramble data is descrambled and sent, and when the second descramble control data having a predetermined value is input, the first descramble data is descrambled and sent. A data receiving device characterized in that data is transmitted as is.