JPS6156920B2 - - Google Patents

Info

Publication number
JPS6156920B2
JPS6156920B2 JP53112831A JP11283178A JPS6156920B2 JP S6156920 B2 JPS6156920 B2 JP S6156920B2 JP 53112831 A JP53112831 A JP 53112831A JP 11283178 A JP11283178 A JP 11283178A JP S6156920 B2 JPS6156920 B2 JP S6156920B2
Authority
JP
Japan
Prior art keywords
eavesdropping
signal
channels
adjacent
phase
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
JP53112831A
Other languages
Japanese (ja)
Other versions
JPS5539439A (en
Inventor
Atsushi Fukushima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pioneer Corp
Original Assignee
Pioneer Electronic Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pioneer Electronic Corp filed Critical Pioneer Electronic Corp
Priority to JP11283178A priority Critical patent/JPS5539439A/en
Publication of JPS5539439A publication Critical patent/JPS5539439A/en
Publication of JPS6156920B2 publication Critical patent/JPS6156920B2/ja
Granted legal-status Critical Current

Links

Description

【発明の詳細な説明】 本発明は、CATVシステムにおける多チヤンネ
ル通信方式において、グレイシンク又それに類す
る方式を用いた盗視防止装置について、隣接チヤ
ンネルの復調により盗視されることを防止するた
めの方式に関するものである。
DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for preventing eavesdropping due to demodulation of adjacent channels in a multi-channel communication method in a CATV system, with respect to an eavesdropping prevention device using gray sync or a similar method. It is related to the method.

CATVシステムにおいては、特別分野に対する
番組等、特定の視聴者以外の者には提供がはばか
られる又はしたくない番組を提供するチヤンネル
に盗視防止の処理、即ちスクランブル処理がほど
こされる。この盗視防止方式には、高周波テレビ
ジヨン複合信号の同期レベルを映像信号の尖頭値
以下にするグレイシンク方式やそれに類する方式
が、しばしば適用され、端末器で復調器により復
調するようにしている。CATVのチヤンネル配分
は一般のテレビジヨン受信機のチヤンネル配分
(6MHzおき)に配分され、かつ端末器(周波数
変換器)の出力は一般のテレビジヨン受信機の一
つのチヤンネルで受信されることが通例である。
そのため、端末器で隣接チヤンネル出力の抑圧を
行なつてはいるが、実際はテレビジヨン受信機は
隣接チヤンネルを、受信することができる。
In the CATV system, processing to prevent eavesdropping, that is, scrambling processing, is applied to channels that provide programs that are difficult or undesirable to viewers other than specific viewers, such as programs for special fields. To prevent eavesdropping, a gray sync method or a similar method is often applied, in which the synchronization level of the high-frequency television composite signal is lower than the peak value of the video signal. There is. CATV channels are allocated to channels of general television receivers (every 6MHz), and the output of the terminal device (frequency converter) is usually received on one channel of the general television receiver. It is.
Therefore, although the terminal device suppresses the adjacent channel output, the television receiver can actually receive the adjacent channel.

一方、端末器及びCATV放送局における諸問題
から、水平同期信号を全チヤンネル又は隣接を含
むチヤンネルに、いわゆるGEN LOOKを行なつ
て同位相する処理の行われることがある。この
GEN LOCK処理が行われたチヤンネル又は、隣
接の同期信号を同位相にすることを余儀無くされ
たチヤンネルにグレイシンク又はそれに類する方
式で盗視防止の処理を、隣接チヤンネルを含んだ
複数のチヤンネルに行なつた場合、端末器におい
て、一つのチヤンネルに同調させても、盗視防止
の復調器によつて隣接チヤンネルも同時に復調さ
れてしまう。そのため、特定のチヤンネル、例え
ば有料番組に隣接するチヤンネルを受信すること
により、その特定の有料チヤンネルを無料で盗視
することができる。本発明はこのような盗視を防
止することのできる方式を提供せんとするもので
ある。
On the other hand, due to various problems in terminal devices and CATV broadcasting stations, processing is sometimes performed to bring the horizontal synchronization signal into phase by performing so-called GEN LOOK on all channels or channels including adjacent channels. this
Apply Gray Sync or a similar method to prevent eavesdropping on channels that have undergone GEN LOCK processing or channels where adjacent synchronization signals are forced to have the same phase, and apply it to multiple channels including adjacent channels. If this is done, even if the terminal is tuned to one channel, the demodulator to prevent eavesdropping will demodulate adjacent channels at the same time. Therefore, by receiving a specific channel, for example, a channel adjacent to a pay program, it is possible to spy on that specific pay channel for free. The present invention aims to provide a system that can prevent such spying.

以下本発明の実施の一例を図面を参照して説明
する。
An example of the implementation of the present invention will be described below with reference to the drawings.

本実施例は、水平同期信号の2倍の周波数を盗
視防止の変調信号に用いたシステムである。第1
図において1は同期信号発生器、2は移相器(こ
こでは水平同期信号に対し90゜移相)で第2図a
に同期信号発生器1の出力波形、bに移相器2の
出力波形を示し、同期信号の信号の位相関係を示
している。同期信号発生器1及び移相器2の出力
はビデオ信号発生器3……3nに加えられ周波
数変換器6の出力チヤンネルが互に隣接チヤンネ
ルとなるように一つおきにそれぞれGEN LOCK
をかけている。ここで垂直同期の位相について考
えると水平同期信号にくらべて周波数が極めて低
いので、その隣接チヤンネルの位相差も小さいの
で全チヤンネルについてGEN LOCKがかかつて
いると考えてよい。4……4nは変調器でビデ
オ変調器の出力及び音声信号がIF信号に変調さ
れる。この複合信号は盗視防止のために盗視防止
変調器5〜5nで処理され複合信号をスクラン
ブルする。この装置は複合信号より、水平同期信
号を検出し、それに同期した2倍の周波数をもつ
信号で同期信号が抑圧されるようにAM変調がか
けられ、互いに隣接するチヤンネルでは第2図
c,dに示すような波形となる。周波数変換器6
〜6nでは、変換器6m,6m+1が隣接にな
るように周波数が配分されている。これらの出力
は搬送波信号加算器7で加算し、伝送ライン8で
各端未器9に分配される。10はテレビジヨン受
信機14に入力するための周波数変換部、11は
例えば掛算器のような盗視防止処理復調部であ
り、12は出力の信号と、盗視防止処理復調のた
めのKEY信号との分離回路で、分離されたKEY
信号はKEY信号復調回路13で処理されて盗視
防止処理復調部11に印加されて、スクランブル
された信号波形となるよう復調する。
This embodiment is a system in which a frequency twice as high as that of the horizontal synchronization signal is used as a modulation signal to prevent eavesdropping. 1st
In the figure, 1 is a synchronizing signal generator, and 2 is a phase shifter (90° phase shift with respect to the horizontal synchronizing signal here).
1 shows the output waveform of the synchronizing signal generator 1, and b shows the output waveform of the phase shifter 2, showing the phase relationship of the synchronizing signals. The outputs of the synchronizing signal generator 1 and the phase shifter 2 are added to the video signal generator 31 ...3n, and the output channels of the frequency converter 6 are GEN LOCKed every other channel so that they are adjacent to each other.
is being applied. Considering the phase of vertical synchronization here, the frequency is extremely low compared to the horizontal synchronization signal, and the phase difference between adjacent channels is also small, so it can be considered that GEN LOCK is applied to all channels. 4 1 . . . 4n is a modulator that modulates the output of the video modulator and the audio signal into an IF signal. To prevent eavesdropping, this composite signal is processed by anti-eavesdropping modulators 5 1 to 5n to scramble the composite signal. This device detects the horizontal synchronization signal from the composite signal, and applies AM modulation so that the synchronization signal is suppressed using a signal with twice the frequency synchronized with the horizontal synchronization signal. The waveform will be as shown in . Frequency converter 6
1 to 6n, the frequencies are distributed so that the converters 6m and 6m+1 are adjacent to each other. These outputs are added by a carrier wave signal adder 7 and distributed to each terminal 9 by a transmission line 8. 10 is a frequency conversion unit for inputting to the television receiver 14, 11 is a demodulation unit for eavesdropping prevention processing such as a multiplier, and 12 is an output signal and a KEY signal for demodulating the eavesdropping prevention processing. Separated KEY with separation circuit
The signal is processed by the KEY signal demodulation circuit 13 and applied to the eavesdropping prevention processing demodulation section 11, where it is demodulated into a scrambled signal waveform.

すなわち、盗視防止処理復調部11では第2図
cの信号波形の盗視防止変調分を抑圧するように
復調を行う。その波形が第2図eである。いま、
隣接チヤンネルの同期信号の位相が等しければ隣
接チヤンネルも同様に復調されるが同期信号が90
゜移相されているので盗視防止の変調分は位相が
180゜異ることになり、隣接チヤンネルの第2図
dの波形は第2図fに示すように盗視防止の変調
分がかえつて深くなるようになる。したがつて、
テレビジヨン受信機では、隣接チヤンネルを受信
してもみることができない。
That is, the eavesdropping prevention processing demodulation unit 11 performs demodulation so as to suppress the eavesdropping prevention modulation of the signal waveform shown in FIG. 2c. The waveform is shown in FIG. 2e. now,
If the phases of the synchronization signals of adjacent channels are equal, the adjacent channels will be demodulated in the same way, but if the synchronization signals are 90
゜Since the phase is shifted, the phase of the modulation to prevent eavesdropping is
This results in a difference of 180°, and the waveform of the adjacent channel shown in FIG. 2(d) has a deeper modulation component to prevent eavesdropping, as shown in FIG. 2(f). Therefore,
With a television receiver, you cannot watch adjacent channels even if they are received.

二つ以上はなれたチヤンネルについても同様の
盗視が考えられるが、比較的安価なフイルター等
により搬送波信号レベルを充分抑圧できるので問
題はない。
Similar eavesdropping is possible for two or more separate channels, but there is no problem because the carrier signal level can be sufficiently suppressed using a relatively inexpensive filter or the like.

以上で明かなように、本発明によれば盗視防止
処理された隣接するチヤンネルについて、希望チ
ヤンネルが復調されても、隣接チヤンネルは復調
されないで盗視防止が完全となる、又、隣接チヤ
ンネルの盗視防止処理は、それぞれの端末器でな
く、放送局側で行うので全体としてのコストが安
くつく、さらに処理が比較的簡単なため、何種類
かの位相の異なつた水平同期信号を用意すること
により、近接したチヤンネルの盗視を完全に防止
することも可能である、移相処理なのでIF信
号.RF信号でも可能である等の優れた効果を上
げることができる。
As is clear from the above, according to the present invention, even if a desired channel is demodulated for adjacent channels subjected to eavesdropping prevention processing, the adjacent channels are not demodulated and the eavesdropping prevention is completed. Since the eavesdropping prevention processing is performed on the broadcasting station side rather than on each terminal device, the overall cost is low, and since the processing is relatively simple, several types of horizontal synchronization signals with different phases are prepared. By doing so, it is possible to completely prevent eavesdropping on adjacent channels.Since it is a phase shift process, it is possible to completely prevent eavesdropping on adjacent channels. Excellent effects can be achieved, such as being possible with RF signals.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の一実施例を示すブロツクダイ
ヤグラム、第2図a〜fは第1図の主要部の出力
波形図である。 1……同期信号発生器、2……移相器、3
3n……ビデオ信号発生器、4〜4n……変調
器、5〜5n……盗視防止変調器、6……周波
数変換器、7……搬送波信号加算器、8……伝送
ライン、9……各端末器、10……周波数変換
部、11……盗視防止処理復調部、12……分離
回路、13……KEY信号復調回路、14……テ
レビジヨン受信機。
FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 a to 2 f are output waveform diagrams of the main parts of FIG. 1. 1... Synchronization signal generator, 2... Phase shifter, 3 1 ~
3n... Video signal generator, 4 1 to 4n... Modulator, 5 1 to 5n... Eavesdropping prevention modulator, 6... Frequency converter, 7... Carrier wave signal adder, 8... Transmission line, 9...Each terminal device, 10...Frequency converter, 11... Eavesdropping prevention processing demodulator, 12...Separation circuit, 13...KEY signal demodulation circuit, 14...Television receiver.

Claims (1)

【特許請求の範囲】[Claims] 1 多チヤンネルテレビジヨン通信方式におい
て、送信側で隣接チヤンネル間の水平同期信号の
位相を異らなせ、グレイシンク、又はそれに類す
る方式を用いた盗視防止装置により同期信号を抑
圧するように振幅変調し、受信側でその変調分を
抑圧するように復調を行うように構成したことを
特徴とするCATVシステムにおける盗視防止方
式。
1 In a multi-channel television communication system, the phase of the horizontal synchronization signal between adjacent channels is made different on the transmitting side, and amplitude modulation is applied to suppress the synchronization signal using a grey-sync or similar system to prevent eavesdropping. A method for preventing eavesdropping in a CATV system, characterized in that the receiving side performs demodulation to suppress the modulated amount.
JP11283178A 1978-09-13 1978-09-13 Stealthy glance preventing system for catv system Granted JPS5539439A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11283178A JPS5539439A (en) 1978-09-13 1978-09-13 Stealthy glance preventing system for catv system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11283178A JPS5539439A (en) 1978-09-13 1978-09-13 Stealthy glance preventing system for catv system

Publications (2)

Publication Number Publication Date
JPS5539439A JPS5539439A (en) 1980-03-19
JPS6156920B2 true JPS6156920B2 (en) 1986-12-04

Family

ID=14596619

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11283178A Granted JPS5539439A (en) 1978-09-13 1978-09-13 Stealthy glance preventing system for catv system

Country Status (1)

Country Link
JP (1) JPS5539439A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH071793U (en) * 1992-12-09 1995-01-13 有限会社新津興器 Thaw container

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH071793U (en) * 1992-12-09 1995-01-13 有限会社新津興器 Thaw container

Also Published As

Publication number Publication date
JPS5539439A (en) 1980-03-19

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