JPH08223554A - Am pass-through system - Google Patents

Abstract

PURPOSE: To obtain the AM pass-through system in which a video signal multiplexed with a VBI(vertical blanking interval) is recorded/reproduced without missing of data with a simple contrivance and giving its reproduction signal to an external input terminal of an AM terminal equipment so as to descramble the signal and to allow the user to enjoy the video image. CONSTITUTION: A copy section 16 of a head end 10 copies scramble information (VBI multiplex signal) to a succeeding signal at a horizontal period. An AM re-modulation section 14 modulates the signal again and gives the result to an input terminal 26 of an AM terminal equipment 20. Furthermore, a signal from the head end 10 is recorded on a VTR 30. The recorded signal is fed to other input terminal 27 of the AM terminal equipment 20. The signal from the head end 10 or the signal from the VTR 30 is selected by using a signal changeover device 28, the AM terminal equipment 20 descrambles and demodulates the selected signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a co-listening system or cable television (hereinafter referred to as CATV) which remodulates a pay satellite broadcasting received by an antenna and individually transmits it to a subscriber via a cable. AM pass-through system.

[0002]

2. Description of the Related Art In recent years, pay satellite broadcasting has started, and decoders for receiving and decoding the pay broadcasting are becoming popular. Further, in order to appropriately supply the satellite broadcasting to the subscribers, pay broadcasting is once received by an antenna, and this signal is remodulated and transmitted to each terminal device.
By integrating such a relay device with CATV or co-listening, a multimedia system rich in change can be constructed.

At present, an AM pass-through system in which the above-mentioned re-modulation is performed by amplitude modulation has been proposed and is in the stage of practical application. This AM pulse room system receives satellite broadcasting, multiplexes various pay-related information in the vertical blanking period of a video signal and AM-modulates it, and selects and demodulates this AM signal to separate VBI multiplexed signals. It is composed of an AM terminal for decoding and descrambling. In addition, V
BI is an abbreviation for VERTICAL BLANKING Interval,
This is the vertical blanking period.

FIG. 5 shows the configurations of the head end 10A and the AM terminal device 20A. The video signal (IF signal) received by the antenna is supplied to the scramble decoding unit 12 via the BS / CS tuner 11. The scramble decoding unit 12 separates the scramble information and the scramble video signal, and the VBI multiplexing unit 1 at the subsequent stage.
Supply to 3. The VBI multiplexing unit 13 multiplexes scramble information during the blanking period of the scrambled video signal. This VBI-multiplexed video signal is supplied to the AM remodulation unit 14. On the other hand, the audio signal is descrambled by the descramble decoding unit 12, and A
It is supplied to the M remodulation unit 14.

The AM remodulation unit 14 remodulates the audio signal and the video signal into a signal form of the NTSC system, and then sends the signal to each AM terminal device 20A via a cable. In this AM terminal device 20A, the signal from the AM modulation unit 14 is received by the CATV tuner 21, the video descramble processing unit 22 performs descrambling, and the video signal is demodulated, reproduced, and output. Similarly, the audio signal is demodulated by the audio demodulation unit 23 and output. In addition, V
The scramble information is supplied from the packet processing unit 24 and the security processing unit 25 for processing the signal multiplexed in the BI to the video descramble processing unit 22. Further, the signal output from the AM terminal device 20A is supplied to the television receiver or the VTR. With this configuration, only specific subscribers can enjoy the video.

However, the above-mentioned configuration has a problem that the scrambled video signal has to be descrambled when the back program is recorded, and the AM terminal device 20A has to be prepared for each recording channel. It was Further, if the scrambled video signal is recorded as it is, the data is attenuated by the Y / C separation circuit in the VTR, the scrambled data is not recorded correctly, and there is a problem that the scrambled data cannot be descrambled. .

[0007]

In the AM pass-through system as described above, the video signal descrambled by the AM terminal device can be recorded by the VTR, but when recording the back program, a plurality of decoders must be prepared. I had to do it.

Further, when recording a signal that is still scrambled, the VB in which the scramble information is multiplexed is recorded.
Since the I data is attenuated, the image cannot be correctly demodulated even when reproduced.

The present invention has been made in view of the above-mentioned problems, and it is possible to record / reproduce a VBI-multiplexed video signal without data loss by a simple device, and to reproduce the reproduced signal by an AM.
It is an object of the present invention to provide an AM pass-through system in which an image can be descrambled and enjoyed by inputting it to a dedicated input terminal of a terminal device.

[0010]

In the AM pass-through system according to the present invention as set forth in claim 1, a pay broadcast video signal received through an antenna is transmitted through a cable or recorded by a recording means. An AM pass-through system for recording on a medium, the decoding means for separating and outputting scrambled information and scrambled video signal from a video signal of the pay broadcast while descrambled and outputting an audio signal. And a multiplexing unit for multiplexing the scramble information in a predetermined horizontal period in the blanking period of the video signal from the decoding unit, and the scramble information from the multiplexing unit is copied and output in the subsequent horizontal period. And a video signal from the copying means, together with an audio signal from the decoding means, for amplitude modulation. It is characterized in that it has and a modulating means for outputting.

In addition to the AM pass-through system according to the present invention, the AM pass-through system according to a second aspect of the present invention reproduces video and audio signals from a recording medium in which the output signal from the modulating means is recorded in advance. And a video and audio signal supplied from the reproducing means via the first input terminal and a video and audio signal supplied from the modulating means via the second input terminal. By the selecting means for outputting and the copying means,
Descrambling means for descrambling the video signal scrambled from the output signal of the selecting means, and detecting means for obtaining scramble information from the copied information and the information of the copy source, and the output signal of the selecting means And a demodulation means for demodulating an audio signal.

In addition to the AM pass-through system according to the present invention, the AM pass-through system according to the present invention according to claim 3 removes the scramble information multiplexed during the blanking period from the video signal descrambled by the descrambling means. And a removing means for removing.

An AM pass-through system according to the present invention according to claim 4 is the same as the AM pass-through system according to claim 1, further comprising: a receiving means for receiving a video signal from the modulating means; and a video signal from the receiving means. Y / C separation means for separating a luminance signal and a chrominance signal from
Recording means for generating a recording signal for recording on a recording medium from the signal supplied from the separating means and outputting the recording signal to the recording medium, and a period during which scramble information is multiplexed on the video signal from the modulating means. And a switching means for bypassing the Y / C separating means and supplying to the recording means.

In the AM pass-through system according to the present invention as defined in claim 5, an AM for transmitting a pay-broadcast video signal received via an antenna via a cable or recording it on a recording medium using a recording means. In the pass-through system, the scrambling information and the scrambled video signal are separately output from the video signal of the pay broadcast, and the decoding means for descramble and output the audio signal, and the decoding means from the decoding means. Multiplexing means for multiplexing the scramble information in a predetermined horizontal period in a blanking period of the video signal, modulation means for amplitude-modulating and outputting the video signal together with the audio signal from the decoding means, and the modulating means. Receiving means for receiving a video signal from the means, and a luminance signal and a color signal from the video signal from the receiving means. Y / C separating means for separating the recording medium, a recording means for generating a recording signal for recording on a recording medium from a signal supplied from the Y / C separating means, and outputting the recording signal to the recording medium. Only during the period when the scramble information is multiplexed on the video signal from the modulating means, Y / C
A switching means for bypassing the separating means and supplying to the recording means is provided.

[0015]

According to the present invention described in the claims, the VBI data can be reliably transmitted without being attenuated, and the scrambled signal can be recorded as it is. Also, by switching the input terminals, the video signal can be reproduced from the recording medium in which the scrambled video signal is recorded in advance.

[0016]

EXAMPLES Examples will be described with reference to the drawings. 1 and 2 are block diagrams showing an embodiment of an AM pass-through system according to the present invention. FIG. 1A shows a head end 10, which has a copy unit 15 in addition to the head end 10A shown in FIG. Further, FIG. 1B shows an AM terminal device 20. In addition to the AM terminal device 20A of FIG. 5, in addition to the input terminal 26 to which the signal from the headend 10 is supplied, an externally connected device is also provided. There are provided an input terminal 27 to which a video signal is supplied and a signal switcher 28 serving as a selection means for selectively switching the input terminals 26, 27. Furthermore, from the descrambled video signal, V
A VBI removing unit 29 for removing the BI signal is added.

As shown in FIG. 1A, the scramble information is multiplexed by the VBI multiplexer 13 during the blanking period as in the conventional case. If the video signal of the predetermined horizontal cycle from the multiplexing unit 13 is the horizontal cycle that follows, for example, 17H, then 18
The data is output to H by being copied by the copying unit 15. In this way, the scramble information data is 2H
The signals are continuously transmitted, remodulated into the signal form of the NTSC system, and output. The signal from the head end 10 is the input terminal 2 of the AM terminal device 20 of FIG.
6 is supplied.

As shown in FIG. 1B, the head end 1
The video signal and the audio signal (AM signal) from 0 are supplied to the CATV tuner 21 via the input terminal 27 and further supplied to the signal switcher 28. The CATV tuner 21 receives a video signal of a desired channel and supplies the video signal to the signal switch 28. The audio signal from the signal switch 28 is supplied to the audio demodulation unit 23, and the video signal is supplied to the video descramble processing unit 22 and the packet processing unit 24. The packet processing unit 24 detects the scramble information multiplexed during the blanking period, and supplies the scramble information to the security processing unit 25. The packet processing section constitutes a detecting means for detecting the VBI multiplexed signal. In the security processing unit 25, the encryption key and the like are decrypted, and only the subscriber can receive the video descrambling processing unit 22.
Can be descrambled. Further, after the VBI removing unit 29 removes the VBI multiplexed signal multiplexed in the blanking period from the video signal descrambled by the video descramble processing unit 22, the video signal is output from the output terminal. Since the audio signal has already been descrambled, it is output after being demodulated into a stereo signal by the audio demodulation unit 23.

The signal from the AM remodulation unit 14 is supplied to the AM terminal device 20 and also to the input terminal of the VTR 30, and the scrambled signal is supplied to the VTR 3
It is recorded at 0. The VTR 30 is equipped with a tuner so that the signal of a desired channel can be recorded.

The AM signal supplied to the VTR is supplied to a Y / C separation section (not shown), where a luminance signal and a chrominance signal are separated. A luminance signal and a color signal are supplied to a recording / playback unit (not shown) and subjected to a process suitable for recording, and then a magnetic head (not shown) to a recording medium (not shown).
Is recorded using.

The operation of FIG. 1 will be described. In VTR30,
The modulated signal from the AM remodulation unit 14 is supplied to the recording processing unit via the YC separation unit. In the recording processing unit, 2H consecutive VBI signals are recorded in the recording medium, and together with the signal from the AM re-modulation unit 14, scramble information 2H consecutive data is recorded in the recording medium. When demodulating the recorded signal and the signal from the AM modulator 14, the data can be demodulated by delaying the data by 1H in the packet processor 24 and superimposing the data. Therefore, the attenuated data can be restored to some extent and processed.

Further, the attenuation characteristic or the like is calculated in advance from the transmission characteristic, and a threshold value is set in a detection section (not shown) in the packet processing section 24 so that 2H consecutive data can be detected with different threshold values. It can also be set and demodulated.
At this time, it is possible to prevent the erroneous detection of data by making the 2nd H for confirmation.

There is also a method of determining the binary level of the data, for example, by making the 2Hth data 1H inverted data. Specifically, it can be determined by setting the low level to highly reliable data and comparing the 1H and 2H data.

With this configuration, the scrambled signal can be recorded as it is, and the back program can be recorded without preparing a decoder. Also,
Since the VBI data is continuously transmitted for 2H, the VBI multi-reception signal can be detected more reliably.

Another embodiment of the present invention will be described. In this embodiment, an AM pass-through VTR 40 shown in FIG. 2 is connected in place of the VTR 30 constituting the AM pass-through system shown in FIGS. 1A and 1B.

Description will be made with reference to FIGS. 1 (A) and 1 (B).
The signal from the AM remodulation unit 14 is supplied to the AM terminal device 20 and also to the input terminal of the AM pass-through VTR 40, and the scrambled signal is supplied to the AM terminal device 20.
It is recorded on the pass-through VTR 40. The AM pass-through VTR 40 has a TV tuner 4 as shown in FIG.
1 is provided so that a signal of a desired channel can be recorded. Hereinafter, description will be added with reference to FIG.

The signal from the AM remodulation unit 14 is supplied to the Y / C separation unit 42 via the TV tuner 41, where the luminance signal and the chrominance signal are separated. The luminance signal and the color signal are supplied to the recording / reproducing unit 45, processed suitable for recording, and recorded on a recording medium (not shown). In this embodiment, a bypass unit for bypassing the Y / C separation unit 42 is provided in order to avoid the conventional problem of scrambling information attenuation. The bypass unit is the switch unit 4
4 and VBI detector 43, detects VBI, and supplies the signals multiplexed in the blanking period directly to the recording / reproducing unit 45 without passing through the Y / C separator 42.

The operation of the AM pass-through system of FIG. 1 will be described with reference to FIG. VB for detecting VBI multiplexed signal
The path of the video signal is switched by the switching signal of the I detector 43. Therefore, the attenuation of the scramble information data can be avoided, and the data can be transmitted more reliably.

With such a configuration, it is possible to detect that it is a VBI multiplexed signal at the 1H of 2H consecutive signals and to reliably process at the 2H. Also,
The signal from the conventional head end 10A which is not continuous for 2H can be dealt with. It should be noted that the detection of VBI data is performed by the first few bits of the data format. With such a configuration, it is possible to provide an AM pass-through system that can be used even with the conventional head end 10A in which the head end 10 does not have the copying unit 16.

FIG. 3 shows another embodiment of the present invention. FIG. 3 is a conceptual diagram in which a video delivery portion is added to the co-listening system or the CATV system. AM in Figure 1
A plurality of terminal devices 20 are connected, and the VTR 30 or 40 is connected to the input terminal of the AM terminal device 20.

The operation of FIG. 3 will be described with reference to FIG. By mounting the magnetic tape 50 in which the scrambled video signal is recorded together with the individual information on the VTR 30 or 40, the scrambled video signal can be supplied to the AM terminal device 20 through the input terminal 27. It has become. Therefore, it becomes possible to deliver the VTR tape 50 in which the individual information is recorded in advance to the subscribers in the case where the headend 10 or 10A fails or a large number of new subscribers cannot successfully deliver the individual information. Also, such a system can be applied to rental video. In addition, magnetic tape 50 to be delivered
The data format of is shown in FIG. In this way, individual information is written in the recordable portion 51, and the other portion 52
Is for playback only. In this way, only individual information can be updated, and the management of video software and subscribers can be easily performed. Note that there is a method of adding a detection signal to the cassette tape or the cassette half so that the writing portion can write only a predetermined record length of the tape. Moreover, information such as a lending period can be added to the individual information, and an encryption key or the like that can not be descrambled after a predetermined period can be set.

With the above configuration, individual information can be recorded on the magnetic tape 50 and the video software can be provided only to a specific subscriber.

[0033]

As described above, according to the present invention, it is possible to record a back program, which has been difficult until now, by slightly modifying the conventional AM pass-through system. The effect is that it can be applied to management.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an AM pass-through system according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the AM pass-through system according to the present invention.

FIG. 3 is a conceptual diagram showing another embodiment of the AM pass-through system according to the present invention.

FIG. 4 is a diagram showing a tape format of a magnetic tape to be mounted on the VTR of FIG.

FIG. 5 is a block diagram showing a conventional AM pass-through system.

[Explanation of symbols]

 10, 10A ... Head end 16 ... Copying means 20, 20A ... AM terminal device 27 ... Input terminal 28 ... Signal switcher 29 ... VBI removing unit

Claims (5)

[Claims] 1. An AM pass-through system for transmitting a video signal of a pay broadcast received via an antenna via a cable or recording the video signal on a recording medium using a recording means. Decoding means for descrambling and outputting the audio signal while outputting the scrambled information and the scrambled video signal separately from the video signal, and a predetermined interval in the blanking period of the video signal from the decoding means Multiplexing means for multiplexing the scramble information in a horizontal cycle, copying means for copying the scramble information from the multiplexing means in a subsequent horizontal cycle and outputting the same, and copying together with an audio signal from the decoding means AM pass-through, characterized in that it comprises a modulation means for amplitude-modulating and outputting a video signal from the means. system. 2. The AM pass-through system according to claim 1, further comprising a reproducing means for reproducing a video and audio signal from a recording medium in which the output signal from the modulating means is recorded in advance, and a first input terminal. Selecting means for selectively outputting the video and audio signals supplied from the reproducing means via the input means and the video and audio signals supplied from the modulating means via the second input terminal; and the copying means. Provides a detection means for obtaining scrambled information from the copied information and the original information.
An AM comprising: a descrambler for descramble a video signal scrambled from the output signal of the selector, and a demodulator for demodulating an audio signal from the output signal of the selector. Pass-through system. 3. The AM pass-through system according to claim 2, further comprising: removing means for removing scramble information multiplexed during a blanking period from the video signal descrambled by the descramble means. AM pass-through system featuring. 4. The AM pass-through system according to claim 1, further comprising: receiving means for receiving the video signal from the modulating means, and separating a luminance signal and a chrominance signal from the video signal from the receiving means. Y / C separation means, recording means for creating a recording signal for recording on a recording medium from the signal supplied from the Y / C separation means and outputting the recording signal to the recording medium, and An AM pass-through system comprising: a switching means for bypassing the Y / C separation means and supplying the same to the recording means only during a period when the scramble information of the video signal is multiplexed. 5. An AM pass-through system for transmitting a video signal of a pay broadcast received via an antenna via a cable or recording the video signal on a recording medium using a recording means, the video of the pay broadcast Decoding means for descrambling and outputting an audio signal while separating and outputting scrambled information and a scrambled video signal from the signal, and a predetermined horizontal period in the blanking period of the video signal from the decoding means A multiplexing means for multiplexing the scramble information, a modulating means for amplitude-modulating and outputting a video signal together with an audio signal from the decoding means, and a receiving means for receiving the video signal from the modulating means. Means and Y / C separating means for separating a luminance signal and a color signal from a video signal from the receiving means; Recording means for creating a recording signal for recording on a recording medium from the signal supplied from the separating means and outputting the recording signal to the recording medium, and only during a period in which the scramble information is multiplexed on the video signal from the modulating means. , A switching means for bypassing the Y / C separation means and supplying to the recording means.