KR940004966Y1 - Descrambling apparatus of catv - Google Patents
Descrambling apparatus of catv Download PDFInfo
- Publication number
- KR940004966Y1 KR940004966Y1 KR2019880019142U KR880019142U KR940004966Y1 KR 940004966 Y1 KR940004966 Y1 KR 940004966Y1 KR 2019880019142 U KR2019880019142 U KR 2019880019142U KR 880019142 U KR880019142 U KR 880019142U KR 940004966 Y1 KR940004966 Y1 KR 940004966Y1
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- KR
- South Korea
- Prior art keywords
- amplifier
- filter
- output
- signal
- oscillator
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/16—Analogue secrecy systems; Analogue subscription systems
- H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/455—Demodulation-circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/10—Adaptations for transmission by electrical cable
- H04N7/102—Circuits therefor, e.g. noise reducers, equalisers, amplifiers
Abstract
내용 없음.No content.
Description
제1도는 본 고안의 블록다이어그램.1 is a block diagram of the present invention.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
2 : 제1믹서 3 : 제1발진기2: first mixer 3: first oscillator
4,6,8,11,14,16,18 : 필터 5,9,12,15 : 증폭기4,6,8,11,14,16,18: filter 5,9,12,15: amplifier
7 : 제2믹서 10 : 트랩부7: second mixer 10: trap unit
13 : 감쇄기 17 : AGC 검파기13: attenuator 17: AGC detector
21 : 제2발진기 20 : AFC 변별기21: second oscillator 20: AFC discriminator
본 고안은 유료 유선 TV 방송시스팀에 있어서 비가입자의 무료시청을 방지하기 위한 것으로 가입자측 컨버터에 방송신호를 복호화할때 적용되는 유선 TV 시스팀용 디스크램블러에 관한 것이다.The present invention relates to a descrambler for a wired TV system which is applied to decode a broadcast signal to a subscriber-side converter for preventing free subscribers from paying wired TV broadcasting systems.
일반적으로 유선 TV 방송이 유료방송인 경우 센터측에서는 TV 방송신호를 부호화하여 송출하고 가입자측에서 보유하게되는 컨버터에서는 상기 부호화된 TV 방송신호를 복호화하여 시청하도록 함으로써, 비가입자의 무료시청을 방해하기 위한 시스팀이 필요하게 된다.In general, when the cable TV is a pay TV, the center encodes and transmits the TV broadcast signal, and the converter retained by the subscriber decodes the encoded TV broadcast signal so that the subscriber can freely watch. This is necessary.
본 고안은 이와같은 점을 감안하여서 된 것으로, 위상이 일정한 사인파로 부호화된 TV 방송신호를 수평동기신호나 수직동기신호에 동조시켜 복호시킬수 있는 유선TV 시스팀용 디스크램블러를 제공하는데 있다.The present invention has been made in view of such a point, and provides a descrambler for a wired TV system that can decode a TV broadcast signal encoded by a sine wave having a constant phase in synchronization with a horizontal synchronization signal or a vertical synchronization signal.
이하 첨부한 도면에 따라 본 고안의 일실시예를 설명하면 다음과 같다.Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
사인파로 부호화된 입력신호와 제1발진기(3)의 발진주파수가 제1믹서(2)에서 혼합되어 필터(4), 증폭기(5), 필터(6)를 차례로 통하여 제2믹서(7)로 입력되게 구성한다.The input signal encoded by the sine wave and the oscillation frequency of the first oscillator 3 are mixed in the first mixer 2 and sequentially passed through the filter 4, the amplifier 5, and the filter 6 to the second mixer 7. Configure to be input.
상기 제2믹서(7)로 들어온 신호와 제2발진기(21)의 발진주파수가 혼합되어 필터(8), 트랩부(10), 증폭기(9)를 차례로 통한 후, 감쇄기(13)를 거쳐서는 복호된 출력이 나타나게구성하고, 필터(11)와 증폭기(12)를 차례로 거쳐서는 필터(14)와 AFC 변별기(20)로 각각 입력되게 구성한다.After the signal entered into the second mixer 7 and the oscillation frequency of the second oscillator 21 are mixed to pass through the filter 8, the trap unit 10, and the amplifier 9 in turn, and then through the attenuator 13. The decoded output is configured to appear, and the filter 11 and the amplifier 12 are sequentially input to the filter 14 and the AFC discriminator 20.
상기 AFC 변별기(20)를 거친 상기 증폭기(12)의 출력이 의해서는 제1발진기(3)가 제어되게 구성한다.The output of the amplifier 12 through the AFC discriminator 20 is configured such that the first oscillator 3 is controlled.
상기 필터(14)를 거친 상기 증폭기(12)의 출력은 증폭기(15), 필터(16), AGC 검파기(17), 필터(18), 증폭기(19)를 차례로 통하여 상기 증폭기(9)를 제어하게 구성한다.The output of the amplifier 12 through the filter 14 controls the amplifier 9 through the amplifier 15, the filter 16, the AGC detector 17, the filter 18, and the amplifier 19 in turn. To configure.
이와같이 된 본 고안의 일실시예에 대한 작용 및 효과를 상세히 설명하면 다음과 같다.If described in detail the operation and effect of the embodiment of the present invention as described above.
제1도에서 사인파로 부호화(스크램블링)된 입력신호는 제1믹서(2)에서 가변제1발진기(3)의 발진주파수와 혼합되어 필터(4), 증폭기(5), 상기필터(4)와 동일대역인 필터(6)를 거쳐 제2믹서(7)로 입력된다.In FIG. 1, the input signal encoded by sine wave (scrambled) is mixed with the oscillation frequency of the variable first oscillator 3 in the first mixer 2, so that the filter 4, the amplifier 5, and the filter 4 It is input to the second mixer 7 via the filter 6 which is the same band.
상기 제2믹서(7)로 입력된 신호는 제2발진기(21)의 발진주파수와 혼합된 후 필터(8), 트랩부(10)를 차례로 거쳐 증폭기(9)에서 증폭이 된다. 이때, 트랩부(10)에서는 다음채널의 영상신호가 분리제거된다.The signal input to the second mixer 7 is mixed with the oscillation frequency of the second oscillator 21 and then amplified by the amplifier 9 through the filter 8 and the trap unit 10 in order. At this time, the trap unit 10 separates and removes the video signal of the next channel.
상기 증폭기(9)의 출력은 감쇄기(13)를 거쳐 TV측으로 보내지게 된다. 여기에서 감쇄기(13)의 출력은 일반적으로 사용되지않는 2,3,4채널중 하나의 채널로 고정된다.The output of the amplifier 9 is sent to the TV side via the attenuator 13. Here the output of the attenuator 13 is fixed to one of two, three or four channels which are not normally used.
한편, 상기 증폭기(9)의 출력은 필터(11)를 거쳐 다시 증폭기(12)에서 증폭이 된후 AFC 변별기(20)에서 자동주파수조정이 되어 제1발진기(3)로 피이드백된다.On the other hand, the output of the amplifier 9 is amplified by the amplifier 12 again through the filter 11 and then the automatic frequency adjustment in the AFC discriminator 20 is fed back to the first oscillator (3).
따라서 상기 제1발진기(3)의 발진주파수가 일정하게 유지되게된다.Therefore, the oscillation frequency of the first oscillator 3 is kept constant.
또, 상기 증폭기(12)의 출력은 42. 46MHz 음성캐리어필터(14)를 거쳐 증폭기(15)에서 재차 증폭이 된 후 다시 음성캐리어필터(16)를 통하여 AGC 검파기(17)에 공급된다.In addition, the output of the amplifier 12 is amplified again by the amplifier 15 through the 42.46 MHz voice carrier filter 14, and then supplied to the AGC detector 17 through the voice carrier filter 16 again.
이때 음성캐리어가 진폭변조된다.At this time, the voice carrier is amplitude modulated.
부호화된 신호가 실려있는 AGC 검파기(17)의 출력은 필터(18)와 증폭기(19)를 통하여 상기 증폭기(9)에 이득조절신호로 피이드백된다.The output of the AGC detector 17 carrying the encoded signal is fed back to the amplifier 9 via a filter 18 and an amplifier 19 as a gain control signal.
상기 증폭기(9)로 피이드백되는 이득조절신호는 출력방송파와 반대의 위상을 가지게되며, 이에따라 증폭기(9)의 출력레벨은 증폭기(19)의 이득조절신호레벨과 같아지게된다.The gain control signal fed back to the amplifier 9 has a phase opposite to that of the output broadcast wave, whereby the output level of the amplifier 9 becomes equal to the gain control signal level of the amplifier 19.
이상에서 설명한 바와같은 본 고안은 사인파로 스크램블링된 TV 방송신호에서 본래의 순수한 TV 방송신호를 효율적으로 꺼낼수 (디스크램블링)있게되므로, 이를 가입자측 컨버터에 적용할 경우 유료유선 TV 방송의 시스팀활성화 및 관리용이화를 이룩할수가 있게된다.As described above, the present invention can efficiently extract the original pure TV broadcast signal from the sine wave scrambled TV broadcast signal (descrambling). Management can be achieved easily.
특히 이러한 시스팀을 쌍방향 유선 TV 시스팀구축에 적용할 경우 데이터통신시의 보안성을 향상시킬수 있는 효과도 가지게 된다.In particular, if the system is applied to the construction of an interactive cable TV system, the security of data communication can be improved.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019880019142U KR940004966Y1 (en) | 1988-11-26 | 1988-11-26 | Descrambling apparatus of catv |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019880019142U KR940004966Y1 (en) | 1988-11-26 | 1988-11-26 | Descrambling apparatus of catv |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR900011141U KR900011141U (en) | 1990-06-04 |
| KR940004966Y1 true KR940004966Y1 (en) | 1994-07-23 |
Family
ID=19281605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR2019880019142U KR940004966Y1 (en) | 1988-11-26 | 1988-11-26 | Descrambling apparatus of catv |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR940004966Y1 (en) |
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1988
- 1988-11-26 KR KR2019880019142U patent/KR940004966Y1/en not_active IP Right Cessation
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| Publication number | Publication date |
|---|---|
| KR900011141U (en) | 1990-06-04 |
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