JPH0870445A - Signal transmission method and record reproduction method - Google Patents

Abstract

PURPOSE: To remove possibility that a program distributed to specified viewers with charge is illegally viewed, to charge corresponding to the number of viewing times, and on the other hand, allowing viewers to freely view the sent programs whenever they like CONSTITUTION: A program distributing station 1 sents a scrambled program signal a1 and a key information requiring signal b1 for undoing this scramble to VTR2. VTR2 records the program signal as it is scrambled and records the key information requiring signal for undoing scramble at a position capable of reproducing before the program signal so as to view the program by descrambling means of a decoder at the time of reproduction. At the time of reproduction, VTR2 sends a key information requiring signal B2 for descrambling to the program delivering station 1 to obtain key information d1. The decoder 3 decodes a reproduced program signal (e) through the use of key information d1 to project on a television receiver 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting and recording / reproducing various signals, and more particularly to a signal transmitting / recording / reproducing method suitable for transmitting / recording / reproducing a scrambled signal for preventing eavesdropping. .

[0002]

2. Description of the Related Art As a conventional example of transmitting a scrambled signal for prevention of wiretap viewing, there is an addressable CATV system published in "Latest AV Equipment and Digital Technology" published by Corona and supervised by Fujio Mauri. . In such a system, the viewer sends key information for descrambling from the CATV station, descrambles it with a decoder, and views it with a television receiver.

Here, when the viewer desires to watch the sent program later or whenever he / she likes, the video signal of the descrambled decoder output is recorded on the VTR. Become. This allows the viewer to watch the recorded program later at any time, but from the viewpoint of the CATV station, the program distributed to the specified viewer for a fee can be arbitrarily selected by an unspecified number of viewers. The problem is that it may be viewed at a place without charging a fee. This means that scrambling to prevent eavesdropping does not work, so CATV
On the station side, the decoder output is protected so that it can be displayed on the television receiver but cannot be recorded on the VTR.

Further, in the pay-per-view system, which is a fee-based charge for each program viewed, the CATV station side wants to charge each time a viewer views a program, so that recording on a VTR and repeated viewing are also restricted. It will be.

[0005]

However, the CAT
If the above-mentioned measures are taken on the V station side, there arises a problem that the viewer's request to watch the sent program at a later time when he / she wants can not be satisfied. As described above, the conventional technique has a drawback that, for example, both the demand on the CATV station side and the demand on the viewer side cannot be satisfied.

As the prior art related to the present invention,
For example, JP-A-5-48996 and JP-A-6-624.
Some are disclosed in Japanese Laid-Open Patent Publication No. 02. In the former publication, the video and audio of a television or the like, along with recitation information, is scrambled and recorded in a recording device, and at the time of reproduction, only when the recitation information is coincident, descrambling is performed,
A technique has been disclosed in which recorded image information is protected by performing restoration and reproduction of a normal image or sound.

Further, in the latter publication, when dubbing a movie tape for distribution, scrambling is applied to video information for dubbing, and information for controlling a scramble key and a video theater necessary for descrambling is provided as an IC. Record it on a card and send it along with the distribution tape,
A technique has been disclosed in which the IC card is used to descramble at the time of projection to prevent an illegal dubbing action of the distribution tape.

However, all of these prior arts are intended to protect the video information in the recording device and the movie information at the time of dubbing, and the CATV station side which provides the video information for a fee and the video information. No consideration is given to the relationship with the viewer who receives the information.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, for example, from the viewpoint of a CATV station, without paying an unspecified number of charges to a program distributed to a specific viewer for a fee. Eliminates the possibility of repeated viewing,
On the other hand, it is an object of the present invention to provide a signal transmission method and a signal recording / reproducing method that allow the viewer to freely watch the transmitted program at any time. Of course, this is not limited to CATV, and the same problem can be solved for satellite broadcasting and other pay program distribution systems.

[0010]

In order to achieve the above object, the present invention is a signal transmission method for transmitting a scrambled signal for preventing wiretap viewing, which is the transmitting station side of the signal. Is a scrambled signal, transmits a key information request signal for requesting transmission of key information for descrambling, when receiving the key information request signal sent from the receiving station side, It is characterized in that the key information is transmitted again. Further, the key information request signal is characterized in that it is transmitted to the receiving station side together with the telephone number of the telephone line of the transmitting station side.

Further, the present invention is a recording / reproducing method for recording / reproducing a scrambled input signal for preventing wiretap viewing, wherein the receiving station side of the signal records the input signal in a scrambled state. And a key information request signal for requesting transmission of key information for descrambling, which is transmitted together with the scrambled input signal, prior to the signal recording area for recording the input signal while being scrambled. It is characterized in that it is recorded at a position where it can be played back, and when playing, the key information request signal is played back and output prior to playing the scrambled signal, and the scrambled signal is played back after receiving the key information. is there. Further, the recording / reproducing of the key information request signal is performed in the audio signal recording area as an audio band signal, and when requesting and receiving the key information is performed through a telephone line, the key information request signal indicates the key information. It is characterized in that it is recorded and reproduced together with the tone dial signal of the telephone number of the telephone line for requesting and receiving.

[0012]

According to the signal transmission method of the present invention, the transmitting station side is
When the key information request signal sent from the receiving station side is received, the key information is transmitted again. Therefore, if the receiving station side does not receive the key information from the transmitting station side, scrambling is performed. Unscrambled scrambled signal. Therefore, the transmitting station side can charge each time the key information request signal is received, and it is possible to prevent snooping. When the key information request signal is transmitted to the receiving station side together with the telephone number of the telephone line of the transmitting station side, the receiving station side automatically requests the transmitting station side to transmit the key information, Be able to unscramble the signal. Therefore, operability is improved.

According to the recording / reproducing method of the present invention, during reproduction, the key information request signal is reproduced and output prior to the reproduction of the scrambled signal, and the scrambled signal is reproduced and output after the key information is received. It Therefore, the receiving station side can automatically transmit the key information request signal to the transmitting station side by simply reproducing the recorded signal, and subsequently can receive the key information from the transmitting station side, which is a simple operation. , Will be able to get the unscrambled signal.
In addition, the receiving station side can obtain the descrambled signal at any time when desired. Furthermore, by recording the key information request signal as a voice band signal in the voice signal recording area, the key information request signal is automatically transmitted to the transmitting station side via the telephone line, and then the key information requesting key is transmitted from the transmitting station side. You will be able to receive information.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. Here, an example in which the present invention is applied to a helical scan type digital VTR which records and reproduces a scrambled video signal distributed through a CATV line together with key information for a fee will be described. The same applies to the system,
Note that it has a similar effect. Further, although the description will be given of the signal transmission method and the recording / reproducing method as an example of the configuration of the apparatus that realizes the present invention, there are cases where an apparatus having only a reproducing function for the program signal is configured. Even in that case, it should be noted in advance that similar effects can be obtained by the same operation and function as the operation of the reproducing part.

First, the operation of the entire system for realizing the signal transmission method and recording / reproducing method according to the present invention will be described with reference to the configuration example shown in FIG. FIG. 1 is a block diagram showing an embodiment of the configuration of a signal transmission and recording / reproducing system according to the present invention. In FIG. 1, reference numeral 1 denotes a CAT that delivers a program.
A program distribution station such as V station, 2 a VTR for a viewer to record the program signal, 3 a decoder for descrambling the program signal,
Reference numeral 4 is a TV receiver for viewing the program.

A program distribution station (CATV) that distributes programs
The station 1 transmits the program signal a1 through the CATV line a in response to a request from the viewer. The program signal a1 is scrambled to prevent snooping. In a normal program distribution system, an addressable signal which is key information for descrambling is sent by the decoder of the viewer at the time of this program distribution, and charging is performed, but in the present invention, the key information request signal b1 is the line b when the program is distributed. Sent to the viewer side through. The key information request signal b1 is composed of a program code and an address signal of a decoder, and has information indicating what kind of key information the program distribution station 1 should send to which decoder. Of course, other information can be included if necessary, and conversely, the decoder address signal can be generated from the decoder when requesting the key information. The scrambled program signal and the key information request signal for requesting the key information for descrambling are recorded in the VTR 2 of the viewer and can be reproduced when the viewer desires.

At the time of viewing a program by VTR2 reproduction, a key information request signal b2 is sent to the program distribution station 1 through a line c before reproduction and output of a scrambled program signal. Both the key information request signal and the program signal are recorded on the tape so that they can be reproduced and output from the VTR 2 at such timing. Upon receiving the key information request signal b2, the program distribution station 1 looks at the program code and the decoder address, and sends the key information d1 necessary for descrambling to the viewer's decoder 3 through the line d. Then, the viewer is charged here. Since the key information d1 can be valid only for a predetermined decoder address, it does not matter even if it is sent through a line in which the decoders of a plurality of viewers are simultaneously connected.

In this way, the decoder 3 receives the key information d1.
Is transmitted, and the reproduced scrambled program signal e is input from the VTR 2 to the decoder 3.
The decoder 3 uses the key information d1 sent to the VTR.
Descrambling the program signal e input from 2
Output to the V receiver 4. As mentioned above, the viewer is VTR
The program recorded by 2 can be reproduced at any time and enjoyed by the TV receiver 4 at any time. On the other hand, since the program distribution station 1 can charge a fee every time the key information d1 for descrambling the program is sent, it is possible to prevent snooping.

In the embodiment of FIG. 1, the transmission of the program signal a1, the transmission / reception of the key information request signals b1 and b2, and the transmission of the key information d1 are performed using different lines, respectively. , Of course, all or some of them are time-division multiplexed lines, that is, physically 1
It doesn't matter if you go with one line. Of course, there is no problem with frequency multiplexing. In addition, these are all VT
Although the expression is performed by R2, it is also possible to use a method in which a part or the whole is performed via the decoder 3. In another embodiment described below, the reproduction of the key information request signal and the reception of the key information are performed between the VTR and the program distribution station via a telephone line, but the audio output from the VTR is input to the decoder 3. It is also possible to request and receive the key information by the telephone line connected to the decoder 3. However, it is considered that such a variation in the system configuration is only where the range of the VTR and the range of the decoder are divided, and therefore detailed description will be omitted.

Next, a second embodiment of the present invention will be described. In the first embodiment, after the VTR 2 outputs the key information request signal b2 to the program distribution station 1, the program distribution station 1 sends the key information d1 to the decoder 3 until the decoder 3 is ready to descramble. During this period, if the scrambled program signal e is reproduced from the VTR 2, the scramble during that time becomes undecipherable. In order to avoid this, the recording position of the key information request signal and the recording position of the program signal may be adjusted so that the scrambled program signal e is not reproduced early. However, if the time from when the key information request signal b2 is reproduced to when the key information e is sent is indefinite, this measure cannot be said to be sufficient. Therefore, the second embodiment is adapted to cope with such a case.

FIG. 2 is a block diagram showing the configuration of the signal transmission and recording / reproducing system of the second embodiment. In FIG. 2, 5 is a CATV station for distributing a program, 6 is a VTR for a viewer to record a program signal, 3 is a decoder for descrambling the program signal, 4 is a TV receiver for viewing the program, 3 4 is the same as the embodiment of FIG. In this embodiment, the program signal a1 and the key information request signal b1 sent from the program distribution station 5 are on the CATV line f, and the key information request signal b2 from the VTR 6 on the viewer side to the program distribution station 5.
The key information d1 from the program distribution station 5 uses the telephone line g. The key information request signal b1 may use the telephone line g instead of the CATV line f.

Next, the operation of this embodiment will be described. First,
The program distribution station 5 receives the scrambled program signal a1.
And a key information request signal b1 for requesting key information for descrambling the program, to the viewer side. However, in this embodiment, the program signal a1 is sent to the VTR 6 on the viewer side through the CATV line f, but the key information request signal b1 is the same as the CAT prior to the transmission of the program signal a1.
It is transmitted from the program distribution station 5 to the VTR 6 through the V line f. Thus, in this embodiment, the transmission of the key information request signal b1 and the transmission of the program signal a1 are the same CATV line f.
Through time sharing. In this way, both the key information request signal b1 and the scrambled program signal a1 sent from the program distribution station 5 are recorded on the tape by the VTR 6.

When the tape is reproduced by the VTR 6, the key information request signal b2 is first reproduced prior to the reproduction of the scrambled program signal, and the program distribution station 5 is supplied to the program distribution station 5 through the telephone line g, as in the case of the embodiment shown in FIG. Sent. When the program distribution station 5 receives the key information request signal b2 as in the case of the embodiment shown in FIG. 1, it looks at the program code and the decoder address, finds the key information d1 necessary for descrambling, and also the telephone line. VTR of the viewer through g
Return to 6. Then, as in the embodiment of FIG. 1, the viewer is charged at this point.

When the key information d1 is sent to the VTR 6 in this way, the VTR 6 outputs this key information d1 to the decoder 3 and also outputs the reproduction signal e of the scrambled program signal to the decoder 3. . Thereafter, the program signal descrambled by the decoder 3 is output to the TV receiver 4 as in the embodiment of FIG. 1, and the viewer can enjoy the program.

As described above, according to this embodiment, the key information d1 corresponding to the key request signal b2 is input to the VTR 6, so that the VTR 6 for reproducing and outputting the scrambled program signal can descramble it. It is possible to know the timing when the key information is obtained. So VTR6
When the key information request signal b2 is reproduced, it is put in a pause state, and when the key information d1 is received from the program distribution station 5 or when it is output to the decoder 3, the pause is released and the scrambled program signal is released. The output of can be started. By doing so, it is not necessary to adjust the recording positions on the tape of the key information request signal and the scrambled program signal as in the embodiment of FIG. 1, and the key information request signal is reproduced. Even if the time from when the key information is sent to when the key information is sent is indefinite, it is possible to prevent inconvenience.

In this embodiment, the transmission of the key information request signal b2 to the program distribution station 5 and the reception of the key information d1 from the program distribution station 5 are carried out by a telephone line, but of course, a line other than the telephone line is used. It doesn't matter if you use. When a telephone line is used as in this embodiment, if the telephone number of the line used for transmitting the key information of the program distribution station 5 is put in the tone dial signal at the beginning of the key information request signal b1 or b2. It is convenient. This telephone number may be added to the beginning of the key information request signal b1 at the time of program signal distribution and sent from the program distribution station 5 to the VTR 6, or a predetermined telephone number may be stored in advance in the VTR 6 on the viewer side. Alternatively, it may be added to the sent key information request signal b1 and recorded on a tape, or inserted before the key information request signal b2 during reproduction and output.

In this embodiment, since the information is exchanged using the telephone line g, the information is converted into a voice band signal and transmitted / received. Therefore, when the tape reproduction by the VTR 6 is started, first, the telephone line g connected to the VTR 6 is opened, and if the key information request signal b2 starting from the telephone number is output here, the telephone line g is automatically connected to the program distribution station 5.
And can receive the key information d1. The key information d1 can be dial tone. In this case, the received key information can be easily converted into a digital signal by the dial tone decoder. Of course, the modulation method used in general modems such as FSK may be used. The telephone line g may be released after receiving the key information d1.

In this way, the viewer can watch the program by merely putting the VTR 6 in the reproduction state without any external operation. Such an effect is that when the telephone number is stored in the VTR 6 in advance, only the telephone line can be connected in addition to the key information request signal, so that the telephone line to which the viewer subscribes can be changed. Even with a pulse dial line, the same effect can be obtained by using a pulse dialer during reproduction.

Next, a third embodiment of the present invention will be described. This embodiment relates to an apparatus for realizing the recording / reproducing method according to the present invention. As described above, an example in which the present invention is applied to a helical scan type digital VTR will be described, but it is of course also applicable to other recording / reproducing devices. In some embodiments described below, the input / output part of the key information may or may not be shown, but if the key information is directly sent to the decoder as in the embodiment of FIG. No output part is needed. On the other hand, in the case of the configuration of the embodiment of FIG. 2, a signal input circuit, a dial tone decoder or modem, an analog or digital signal output circuit, etc. are required depending on the key information transmission method and the input method to the decoder 3. However, this embodiment is compatible with both. Further, it should be noted in advance that the magnetic head for recording / reproducing on / from the helical track on the tape has the same method as that of a normal fixed head for simplifying the drawing. Further, although the recording head and the reproducing head are described separately for the sake of clarity, it does not matter even if the recording / reproducing head is used.

FIG. 3 is a block diagram showing an embodiment of a VTR used in the recording / reproducing method of the present invention, and FIG. 4 is a schematic diagram showing a signal recording pattern on the tape. In the block diagram of FIG. Input and output of signals and key information request signals
The description is made independently in correspondence with the embodiment.

In FIG. 3, 11 is a program signal input / output terminal, 12 is a program signal input circuit, 13 is a program signal recording signal processing circuit, 14 is a magnetic recording head mounted on a rotary drum, and 15 is a key information request. A signal input terminal, 16 is a data receiver for receiving a key information request signal, 17 is a recording signal processing circuit for the key information request signal, 18 is a fixed magnetic recording head, 19 is a controller for controlling each part of the VTR,
Reference numeral 20 is a magnetic tape, 21 is a magnetic reproducing head attached to a rotating drum, 22 is a reproduction signal processing circuit for program signals,
23 is a program signal output circuit, 24 is a program signal output terminal,
Reference numeral 25 is a fixed magnetic reproducing head, 26 is a reproduction signal processing circuit for the key information request signal, 27 is an output circuit for the key information request signal, and 28 is a key information request signal output terminal.

A scrambled video signal for prevention of wiretapping is input to the program signal input terminal 11 as a program signal a1 via the CATV line and sent to the signal input circuit 12. The form of this input signal is the program distribution station 1
There are some conceivable methods depending on how the interface between the decoder 3 for descrambling and the recording / reproducing apparatus to which the present invention is applied are taken. However, here, since only the part related to the essence of the invention is explained, the channel is selected. , The modulation applied for signal transmission is demodulated, and in the case of digital transmission, the signal after detection and correction of code error during transmission is input to the recording / reproducing apparatus. To do. Therefore, depending on how to interface with the decoder, the signal input circuit 12 may include a tuner, a demodulator, and an error correction circuit. Similarly, the signal output circuit 23 described later may have a configuration including an error correction code generation circuit, a modulator, an RF converter, and the like.

In this embodiment, it is assumed that the input / output of the recording / reproducing apparatus is a scrambled digital video signal. In that case, it is conceivable that the time-axis-compressed input signal is recorded at high speed and the time axis is expanded during reproduction to be an output signal. However, in the present embodiment, no particular operation is performed on the time axis. I will explain. These points are the same in other embodiments described later. Signal input circuit 12
Sends the scrambled digital video signal to the recording signal processing circuit 13 for the program signal.

On the other hand, the key information request signal input terminal 15 is used to request the program distribution station 1 to transmit the key information for canceling the scramble applied to this program by the decoder having a predetermined registered address. The key information request signal b1 is input. Key information request signal input terminal 1
The key information request signal b1 from 5 is input to the data receiver 16, received as the key information request signal, and then sent to the recording signal processing circuit 17 for the key information request signal.

The recording signal processing circuit 13 and the recording signal processing circuit 17 respectively respond to the scrambled digital video signal a1 and the key information request signal b1.
Signal processing for recording on tape, that is, signal block division, addition of error detection code and error correction code, recording modulation, and the like are performed. The timing is controlled by the controller 19, and the digital video signal a1 is recorded on the magnetic tape 20 by the rotary magnetic recording head 14 and the key information request signal b1 is recorded on the magnetic tape 20 by the fixed magnetic reproducing head 18.

Here, the controller 19 adjusts the timing at which the recording signal processing circuit 13 and the recording signal processing circuit 17 output the recording signal so that the recording signal is simulated as shown in FIG. That is, a scrambled digital video signal which is a program signal is recorded on the helical track in the order of 1, 2, 3, 4, ... Starting from the position indicated by p in FIG. 4, while the key information is It is recorded at a position where it can be reproduced before the beginning of the digital video signal shown in q of FIG. It should be noted that the positional relationship between the head p of the actual video signal and the key information q depends on the actual positional relationship between the rotary head and the fixed head and is not exactly the same as in FIG. FIG. 4 merely shows an example in a simulated manner.

At the time of reproduction, the fixed magnetic reproducing head 25 first reproduces the key information request signal of the q portion of the linear track from the magnetic tape 20 recorded as shown in FIG. Is input to the reproduction signal processing circuit 26. Then, the rotary magnetic reproducing head 21 is used to read 1, 2, and 3 in FIG.
The scrambled digital video signal is reproduced in the order of 3, 4, ... And inputted to the reproduction signal processing circuit 22 for the program signal. The reproduction signal processing circuit 22 and the reproduction signal processing circuit 26 respectively perform recording modulation applied to the scrambled digital video signal and the key information request signal reproduced from the magnetic tape 20 by the magnetic reproduction head 21 and the magnetic reproduction head 25, respectively. It demodulates, detects and corrects a code error generated during recording and reproduction, and returns the signal divided into blocks to the original continuous signal, and outputs it through the signal output circuit 23 and the key information request signal output circuit 27. From the program signal output terminal 24 and the key information request signal output terminal 28, respectively, the scrambled digital video signal e and the key information request signal b.
Outputs 2.

As described above, first, the key information output terminal 28
When the key information request signal b2 for requesting the transmission of the key information for descrambling is output and sent to the program distribution station 1 as described in the embodiment of FIG. And the key information d1 for descrambling the scrambled video signal by the decoder 3 of the viewer is sent to the decoder 3. Following this, if the signal recording position on the magnetic tape 20 is set by the controller 19 so that the timing at which the scrambled video signal e is output from the program signal output terminal 24, By connecting the output terminal 24 to the decoder 3, the viewer can watch a desired program at any time.

On the other hand, when this tape is reproduced again, the viewer is charged in the same manner, and the decoder 3 of the viewer is used to unscramble the digital video signal. The key information is sent from the program distribution station 1 to the decoder 3. Therefore, the viewer can enjoy the program at any time and any number of times, and on the other hand, the side that distributes the program can prevent the program from being viewed without paying a fee, and can prevent the wiretap viewing.

When the key information request signal b1 is a signal in the audio signal band, the area for recording the key information request signal q in FIG. 4 may be an audio signal track. In that case, the recording system of the audio signal track of the VTR 2 may be an analog system, but the recording signal processing circuit 17 and the reproduction signal processing circuit 26 for the key information request signal of FIG. 3 are analog circuits, and an equalizer or an equalizer is used. It will be composed of a bias circuit and the like. Needless to say, in this case, circuits unique to digital signal processing such as an error correction circuit are not included.

Next, a fourth embodiment of the present invention will be described. This embodiment shows a recording / reproducing apparatus for transmitting / receiving a key information request signal via a telephone line and recording a program signal and a key information request signal on an equivalent helical track. This will be described with reference to FIGS.
In the embodiment of FIG. 5, the transmission of the program signal, the key information request signal, and the key information corresponds to the embodiment of FIG. Of course, in this case, various receiving methods can be considered for the key information request signal and the key information, but here, description will be given for the case of receiving the same telephone line.

FIG. 5 is a block diagram showing the configuration of the recording / reproducing apparatus of this embodiment, and FIG. 6 is a diagram schematically showing the signal recording pattern on the tape. In FIG. 5, 30 is a signal input terminal, 31 is a signal input circuit, 32 is a telephone line connection terminal, 33 is a key information request signal input circuit, 34 is a recording signal processing circuit, and 35 is a magnetic recording head mounted on a rotary drum. , 36 is a controller, 37 is a magnetic tape, 38
Is a magnetic reproducing head mounted on a rotary drum, 39 is a reproduction signal processing circuit, 40 is a signal output circuit, 41 is a key information request signal output circuit, 42 is a modem, 43 is a signal output terminal, 44 is a key information output circuit, Reference numeral 45 is a key information output terminal.

The scrambled digital video signal a1 is input to the signal input circuit 31 through the signal input terminal 30. Prior to that, the key information request signal is sent through the telephone line connected to the telephone line connection terminal 32. b1 is input. The key information request signal b1 is a digital signal modulated into a voice band signal so that it can be transmitted and received on a telephone line, demodulated into a digital signal by the modem 42 and input to the key information request signal input circuit 33. Then, the output of the signal input circuit 31 and the output of the key information request signal input circuit 33 are both input to the recording signal processing circuit 34. The recording signal processing circuit 34 causes the controller 36 to pass the key information request signal and the scrambled digital video signal through the rotary magnetic recording head 35 so that the recording signal on the tape becomes as shown in FIG. Record at 37. Controller 36
In the recording pattern on the magnetic tape 37, the key information request signal b1 is recorded on the helical track shown by s in FIG. 6, and then the scrambled digital video signal from the helical track shown by r in FIG. 1, 2,
The recording signal processing circuit 34 is controlled in the order of 3, 4, 5, .... Here, in order to compensate for the time difference from the output of the key information request signal at the time of reproduction to the acquisition of the key information, if necessary, the helical track s in which the key information request signal of FIG. 6 is recorded and the program signal. Between the helical track r where the digital video signal is recorded,
It is also possible to adjust the timing so that an empty helical track is inserted.

During reproduction, the rotary magnetic reproducing head 38 is
First, the key information request signal of s in FIG. 6 is reproduced from the magnetic tape 37 and input to the reproduction signal processing circuit 39. Subsequently, the magnetic reproducing head 38 reproduces the digital video signal,
6 are performed in order from r to 1, 2, 3, 4, 5, ... And input to the reproduction signal processing circuit 39. Hereinafter, similar to the embodiment of FIG.
Controlled by 6, the recording modulation applied to the input key information request signal and the scrambled digital video signal is demodulated, and the code error generated during recording and reproduction is detected and corrected, and further divided into blocks. The signals are returned to the original continuous signals, and the digital video signal is sent to the signal output circuit 40 and the key information request signal is sent to the key information request signal output circuit 41.

The key information request signal output circuit 41 is provided before the signal output circuit 40 outputs the digital video signal e.
Key information request signal b through the telephone line connected from the telephone line connection terminal 32 to the program distribution station 5 via the modem 42
Send 2. In the program distribution station 5, this key information request signal b
Looking at the contents of 2, the decoder of the requested viewer returns the key information d1 for descrambling the digital video signal through the same telephone line.

The key information d1 thus obtained is
It is input to the modem 42 from the telephone line connection terminal 32. The key information demodulated into a digital signal by the modem 42 is input to the key information output circuit 44, and the key information output terminal 4
5 is output to the decoder 3. After that, the signal output circuit 40 outputs the scrambled digital video signal e to the decoder 3 via the signal output terminal 43. Here, in this embodiment, the key information d1 is sent to the VTR, so that the reproduction of the VTR is stopped until the output of the digital video signal is received and sent to the decoder 3, and the key information d1 is sent to the decoder 3. It can be controlled by the controller 36 to restart the reproduction of the digital video signal e after being sent.

As described above, also in the embodiment of FIG.
The same effect as the embodiment of FIG. 3 can be obtained. In the embodiment of FIG. 5, the output of the key information d1 and the digital video signal e is output to the decoder 3 through the separate terminals 45 and 43, but the output of the key information output circuit 44 is output. Alternatively, the controller 36 may be connected to the output circuit 40 to switch the output from the signal output terminal 43. In that case, only one signal output is connected to the decoder 3, and the key information is output first, and then the scrambled digital video signal is output.

Next, a fifth embodiment of the present invention will be described. This embodiment shows a recording / reproducing apparatus capable of recording the key information request signal on the same helical track as the digital video signal by the area division method.
In a digital VTR, an audio signal and a video signal are often recorded on the same helical track by area division. Here, the case of recording the key information request signal using the digital audio area will be described. Further, the key information request signal is output from the VTR as a signal in the audio band by using the reproduction circuit of the digital audio signal and is sent to the program distribution station through the telephone line.
Of course, the recording area and the method of reproduction and transmission are not limited to this.

FIG. 7 is a block diagram showing the configuration of the recording / reproducing apparatus of this embodiment, and FIG. 8 is a diagram schematically showing a signal recording pattern on the tape. In FIG. 7, 50 is a signal input terminal, 51 is a signal input circuit, 52 is a key information request signal extraction circuit, 53 is a recording signal processing circuit, 54 is a magnetic recording head mounted on a rotary drum, 55 is a controller, and 56 is a controller. The magnetic tape, 57 is a magnetic reproducing head mounted on a rotary drum, 58 is a reproducing signal processing circuit, 59 is a key information request signal output circuit, 60 is a key information request signal output terminal, and the other parts are the same as those in FIG.

The key information request signal b is applied to the signal input terminal 50.
1, followed by the scrambled digital video signal a1. In this embodiment, it is assumed that the key information request signal b1 includes, as information, the telephone number of the telephone line used by the program distribution station for receiving the key information request signal and transmitting the key information. Also, the telephone line to which the viewer subscribes is assumed to be a push-phone line. These input signals are input to the signal input circuit 51, where the key information request signal is separated and extracted by the key information request signal extraction circuit 52, and the telephone number included in the key information request signal is the tone dial signal A. / D
The converted signal is converted into the voice band after the other signals are also subjected to the predetermined modulation and then converted into the A / D converted signal, which is converted into the digital audio signal format used in the VTR. Can be assembled. Then, the digital video signal a1 which is still scrambled is supplied from the signal input circuit 51, and the key information extraction circuit 52 requests the key information for descrambling the digital video signal. The signal b1 is sent to the recording signal processing circuit 53 with its timing adjusted.

The recording signal processing circuit 53 is a controller 55.
The signal processing for recording the input key information request signal and the digital video signal on the tape, that is, the block division of the signal, the timing of which is controlled by
An error detection code and an error correction code are added, and the key information request signal is multiplexed as a digital audio signal with a digital video signal to perform recording modulation. Then, the rotary magnetic recording head 54 records on the magnetic tape 56 as shown in FIG. The controller 55 is u in FIG.
The key information request signal formatted in the digital audio signal is scrambled in the area shown by, and the area shown by the subsequent t is scrambled in the order of 1, 2, 3, 4, 5, .... The recording signal processing circuit 53 is controlled so as to record the digital video signal as it is. Note that, as in the case of FIG. 6, the recording position of the key information request signal is merely an example in FIG. 8, and if it is a position where it can be reproduced earlier than the digital video signal which is the program signal, for example, For example, it can be 10 tracks before, or depending on the amount of signals, it can span the corresponding areas of a plurality of tracks.

At the time of reproduction, the rotary magnetic reproducing head 57 is used to output the scrambled digital video signal of t of FIG. 8 from the magnetic tape 56 recorded as shown in FIG. 8 after the key information request signal of u of FIG. 2, 3, 4,
.. are reproduced in this order and input to the reproduction signal processing circuit 58. The reproduction signal processing circuit 58 includes the controller 5
5, the input key information request signal and the scrambled digital video signal are demodulated for recording modulation, and the code error generated during recording and reproduction is detected and corrected, and further divided into blocks. The signals are restored to the original continuous signals, the digital video signal is processed by the signal output circuit 40, and the key information request signal is processed in the same manner as the digital audio signal, and then D / A converted to a voice band signal. It is sent to the key information request signal output circuit 59.

The key information request signal output circuit 59 opens the telephone line connected to the key information request signal output terminal 60 before the signal output circuit 40 outputs the digital video signal, and outputs the key information request signal b2. Start. When the tone dial signal is output to the telephone line, the telephone line is connected to the program distribution station. When the key information request signal output circuit 59 finishes outputting the telephone number portion at the head of the key information request signal b2, it waits for the call to be connected to the program distribution station, and when the call is connected, outputs the remaining key information request signal. In this way, when the key information request signal b2 is sent to the program distribution station, the program distribution station charges the viewer and sends back the key information d1 as in the other embodiments. Although not shown in the figure, the key information is input to the decoder 3, and then the signal output circuit 40 outputs the scrambled digital video signal from the signal output terminal 43 to the decoder 3.

As described above, also in the embodiment shown in FIG. 7, the viewer can enjoy the program anytime as many times as the other embodiments, while the side delivering the program sends the key information. Since the charge can be made every time, the user cannot be viewed without paying the charge, and it is possible to prevent the wiretapping.

[0055]

As described above, according to the present invention,
From the viewpoint of the transmitting station side (for example, the program distribution side or the CATV station side), the possibility that the program distributed for a specific viewer for a fee can be viewed without charging an unspecified number of people, and one-sided viewing People will be able to freely watch the sent programs whenever they want.

Further, according to the present invention, the transmitting station can charge for the number of viewings. On the other hand, for the viewer side, if the user wants to repeat the viewing, if the received signal is recorded on a recording medium such as a tape and is stored,
Since there is no need to re-distribute, it is possible to realize a recording / reproducing method and apparatus that are convenient for both the program distributor and the viewer.

Furthermore, by inserting the telephone number in the signal for requesting the key signal, the key information for automatically descrambling can be obtained only by reproducing the VTR, which makes the operation troublesome. It has the effect of never becoming.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a signal transmission method of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the signal transmission method of the present invention.

FIG. 3 is a block diagram showing a configuration of an apparatus for carrying out a recording / reproducing method of a third embodiment of the present invention.

4 is a schematic diagram of a signal recording pattern recorded by the apparatus of FIG.

FIG. 5 is a block diagram showing a configuration of an apparatus for carrying out a recording / reproducing method according to a fourth embodiment of the present invention.

6 is a schematic diagram of a signal recording pattern recorded by the apparatus of FIG.

FIG. 7 is a block diagram showing a configuration of an apparatus for carrying out a recording / reproducing method of a fifth embodiment of the present invention.

8 is a schematic diagram of a signal recording pattern recorded by the apparatus of FIG.

[Explanation of symbols]

1, 5 ... Program distribution station, 2, 6 ... VTR, 3 ... Decoder,
4 ... TV receiver, 12, 31, 51 ... Signal input circuit, 1
3, 17, 34, 53 ... Recording signal processing circuit, 17, 3
6, 55 ... Controller, 33 ... Key information request signal input circuit, 22, 26, 39, 58 ... Reproduction signal processing circuit, 2
3, 40 ... Signal output circuit, 27, 41, 59 ... Key information request signal output circuit, 42 ... Modem, 44 ... Key information output circuit.

Claims (6)

[Claims] 1. A signal transmission method for transmitting a scrambled signal for preventing wiretap viewing, wherein the transmitting station side of the signal, together with the scrambled signal,
A key information request signal for requesting transmission of key information for descrambling is transmitted, and the key information is transmitted again when the key information request signal transmitted from the receiving station side is received. A signal transmission method characterized in that 2. The signal transmission according to claim 1, wherein the signal transmitting station side receives the key information request signal through a telephone line and transmits the key information through a telephone line. Method. 3. The signal transmission method according to claim 2, wherein the key information request signal is transmitted together with a telephone number of the telephone line. 4. A recording / reproducing method for recording / reproducing a scrambled input signal for preventing wiretap viewing, wherein a receiving station side of the signal records the input signal in a scrambled state, and A key information request signal for requesting transmission of key information for descrambling, which is transmitted together with the scrambled input signal, is placed at a position where it can be reproduced prior to the signal recording area for recording the input signal as it is scrambled. A recording / reproducing method characterized in that at the time of recording and reproducing, the key information request signal is reproduced and output prior to the reproduction of the scrambled signal, and the scrambled signal is reproduced and output after receiving the key information. . 5. The recording / reproducing method according to claim 4, wherein the recording / reproducing of the key information request signal is performed as an audio band signal in an audio signal recording area. 6. When key information is requested and received through a telephone line, the key information request signal is recorded and reproduced together with a tone dial signal of a telephone number of a telephone line which requests and receives key information. The recording / reproducing method according to claim 5, wherein