CN1140378A - Cable TV signal scrambling and descrambling method - Google Patents
Cable TV signal scrambling and descrambling method Download PDFInfo
- Publication number
- CN1140378A CN1140378A CN 95110839 CN95110839A CN1140378A CN 1140378 A CN1140378 A CN 1140378A CN 95110839 CN95110839 CN 95110839 CN 95110839 A CN95110839 A CN 95110839A CN 1140378 A CN1140378 A CN 1140378A
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- decipher
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Abstract
A frequency-conversion encipher and decipher technique for cable TV signals features that under the control of encipher computer the TV carrier frequency is changed for enciphering while the information about change in TV carrier frequency, current date and dynamic key or decipher method are sent in real-time mode to user decoder by auxiliary channel of cable TV, and after user inserts an IC card provided by cable TV station, which contains recognition and control information, the computer identifies the user IC card, decodes decipher information from auxiliary channel and controls frequency converter to change frequency, attaining decipher purpose.
Description
The present invention relates to a kind of encrypt and decrypt method of cable TV signal.
In recent years, the cable TV of charge develops rapidly in the many cities and towns of China, and cable television network is in the ascendant.In order to guarantee carrying out of fee system, the corresponding means that extensively adopt are exactly the application television encryption technology at present, or claim the TV signal scrambling technique.If TV signal is by suitably scrambling, then the general user can not be only by adjusting each knob on the television set, the TV signal that button comes normal watching encrypted.The TV user of only paying the fees is used a kind of device that is called decipher (or descrambler), could normally watch.This device places between cable output end and the television set usually.Certainly, this technology also can be applicable to other fields such as video telephone, army television.
At present, in the television encryption technology, occurred many television encryption methods both at home and abroad, but generally speaking can be divided into two major types, be i.e. video amplitude processing mode and time shaft processing mode.The video amplitude processing mode comprises the polarity inversion, and disturbing wave superposes, multiplies each other synchronizing signal inhibition etc.; It is the time relationship of managing to change former image that time shaft is handled, and it comprises scan line reorganization, cutting, time shaft companding etc.These technology have been widely used in domestic and international satellite television, the cable television network.This two big class technology is because all based on changing television video frequency signal, can only be used for specific television program or channel one by one, decipher must be with TV RF signals demodulation, deciphering, modulation again, must cause that image, sound quality obviously descend, decipher is with high costs, is not suitable for China's cable TV network users and uses.
The purpose of this invention is to provide a kind of practicality, cheapness, effective TV frequency conversion encrypt and decrypt method that cable television network uses of specializing in.
The present invention is by changing the purpose that the television carrier frequency reaches the encryption and decryption TV signal.
The present invention is realized encrypting by ciphering computer control break TV programme carrier frequency.Simultaneously, carrier frequency change information is real-time transmitted to user's decipher together with current date, dynamic key or decryption method etc. by the cable TV auxiliary channel.User's decipher insert that cable TV station sells behind user's IC-card of identification and control data, the decipher computer obtains decryption information and control of conversion device frequency conversion deciphering by confirming user's IC-card and demodulation auxiliary channel, and the cable TV subscriber can watch stable TV programme.
The present invention only changes television channel (radio frequency carrier frequency), and do not relate to demodulation, conversion or the modulation of vision signal, has guaranteed the quality of TV image, sound.This method both can unify to encrypt number cover TV programme, also can encrypt one by one and respectively overlap TV programme.Encryption equipment is also extremely simple, only comprises variable-frequency carrier generator and encrypts controlling computer.Equally, the decipher decrypting process is greatly simplified, and both can a decipher deciphering one overlap TV programme, also can decipher number cover TV programme simultaneously, and the decipher cost descends significantly.Decrypting process adopts identification of microcomputer active user and control channel conversion (change carrier frequency) to realize by auxiliary channel, the scrambled TV service program that no decipher user TV is received is one or one group of erratic TV signal, can't watch that it is also very difficult to steal power.For China's cities and towns catv charge is laid a good foundation to the family.
With example in detail enforcement principle of the present invention:
Cable TV station is modulated to television channel low side (as VL, VH frequency range) with non-encrypted TV programme, all TV programme carrier frequencies that need to encrypt all are reserved in the high-end or extended channel of television channel, then, unifying control break TV programme carrier frequency by ciphering computer realizes encrypting.The method that carrier frequency changes directly affects the effect of encryption and the cost of decipher.As: by control integrated circuit frequency synthesis carrier generator coding, all encoded channel carrier frequencies are beated up or down realize encrypting.Like this, the decipher frequency converter that also only needs a cover to contain integrated circuit frequency synthesis local oscillation signal circuit promptly can be all encoded channels deciphering.The method of using this carrier frequency to change, the decipher cost is minimum, is suitable for encrypting simultaneously number cover TV programme.And for example: respectively overlap TV programme Interexchange Carrier frequency by the control of control electronic switch and realize encrypting.Like this, encryption equipment is very simple, and channel resource is not wasted, but each ciphered program must be joined a cover local oscillation signal generation circuit in the decipher, and the decipher cost slightly rises.For another example: the carrier frequency of respectively overlapping TV programme by independent control realizes encrypting (under the control of computer, a kind of carrier frequency does not appear on the two cover TV programme simultaneously), each ciphered program of decipher must be joined a cover frequency synthesis local oscillation signal generation circuit like this, cost is higher, but security performance is best.Carrier frequency change method also can have several, but the preceding two kinds of comparatively practicalities to enumerate.Carrier frequency changes amplitude information and is modulated to cable TV auxiliary channel together with information such as current date, dynamic key or decryption methods by the control computer after by secret key encryption, sends the frequency conversion amplitude information in encryption equipment and the user's decipher computer (single-chip microcomputer) simultaneously.After realizing encrypting, contain non-encrypted TV RF signals, the auxiliary channel computer control signal of television channel low side in the cable television network cable and be positioned at the TV signal that the high-end frequency conversion of television channel is encrypted.Can watch the non-encrypted program of low side when the cable TV subscriber does not pay dues, the user that pays dues both can watch high-end scrambled TV service program, also can watch the low side TV programme.The access customer IC-card can be write with data such as the decruption key of several months to several years, useful life or other identification and control data by cable TV station, in order to user's purchase of paying dues.The information that writes depends on computer Recognition and controlling schemes.Adopt rate system quarterly as wired TV station, can write in the IC-card season in season to tens keying material, write card date, last useful life, accumulative total deciphering time and software and hardware identification mark or the like.The user's decipher that uses among the present invention is the frequency converter of a band microcomputer, and by the straight-through television receiver of low channel TV programme, carry to television receiver high channel TV programme frequency conversion deciphering back by band pass filter for it.After the user inserted user's IC-card, microcomputer can obtain information materials such as user's date of acquisition, useful life, accumulative total deciphering time from IC-card, also can write back data such as adding up the deciphering time and write useless user's IC-card of copying or exceeding the time limit to limit.After having inserted user's decipher energized of user's IC-card, decipher reads in every data in the IC-card, judges the validity of IC-card, if for several times invalid continuously, writes useless IC-card.After the data of reading in is normal, according to the computer control signaling that demodulates, the key that retrieves agreement, draw the frequency conversion amplitude information by specific computing, the reverse frequency conversion of control deciphering frequency converter offers the TV programme of user's television set fixed channel of paying the fees.
The invention provides the very effective and cheap TV signal encrypt and decrypt method of a kind of cable television network.
Claims (4)
1. cable TV encrypting and decryption method is characterized in that: change the encrypt and decrypt that TV RF signals realizes TV signal.
2. by described television encryption of claim 1 and decryption method, it is characterized in that: above-mentioned TV RF signals changes the employing computer control.
3. by described television encryption of claim 1 and decryption method, it is characterized in that: above-mentioned user's decipher adopts IC-card that charge, control and identifying information are provided.
4. by described television encryption of claim 2 and decryption method, it is characterized in that: aforementioned calculation machine control signaling and other supplementary adopt auxiliary channel to transmit in real time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95110839 CN1140378A (en) | 1995-07-07 | 1995-07-07 | Cable TV signal scrambling and descrambling method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95110839 CN1140378A (en) | 1995-07-07 | 1995-07-07 | Cable TV signal scrambling and descrambling method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1140378A true CN1140378A (en) | 1997-01-15 |
Family
ID=5078182
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95110839 Pending CN1140378A (en) | 1995-07-07 | 1995-07-07 | Cable TV signal scrambling and descrambling method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1140378A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100391257C (en) * | 2001-09-28 | 2008-05-28 | 夏普公司 | Device, method and program for limited user or managing permitted use of number |
-
1995
- 1995-07-07 CN CN 95110839 patent/CN1140378A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100391257C (en) * | 2001-09-28 | 2008-05-28 | 夏普公司 | Device, method and program for limited user or managing permitted use of number |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |