| Patents for H04K 1 - Secret communication (16,771) |
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| 07/27/1990 | WO1990009067A1 Method and apparatus for preventing external detection of signal information |
| 07/18/1990 | EP0378446A2 Signal encryption |
| 07/18/1990 | EP0377687A1 Spectrally efficient method for communicating an information signal |
| 07/12/1990 | WO1990007846A1 Process for scrambling pal secam and ntsc composite video signals and decoder of resulting scrambled signals |
| 07/12/1990 | WO1990007845A1 Scrambling and unscrambling of composite video signals |
| 06/27/1990 | EP0375540A1 Method for scrambling composite PAL, SECAM and NTSC video signals, and decoder for signals scrambled by this method |
| 06/27/1990 | EP0375539A1 Method for scrambling and descrambling composite video signals, and apparatus therefor |
| 06/26/1990 | US4937867 Variable time inversion algorithm controlled system for multi-level speech security |
| 06/26/1990 | US4937866 System for decoding transmitted scrambled signals |
| 06/26/1990 | CA1270941A1 Video noise jammer |
| 06/23/1990 | CA2006459A1 Method for scrambling and unscrambling composite video signals and device using said method |
| 06/23/1990 | CA2006458A1 Method for scrambling pal, secam and ntsc composite video signals and decoder for unscrambling said signals |
| 06/15/1990 | CA2005323A1 Sequential correlator for spread spectrum communication system |
| 06/14/1990 | WO1990006656A1 Off-premises cable television channel interdiction method and apparatus |
| 06/12/1990 | US4933990 Optical privacy communication system in two-way optical transmission system |
| 06/05/1990 | US4932057 Parallel transmission to mask data radiation |
| 05/22/1990 | US4928309 Method and apparatus for descrambling a television signal |
| 05/16/1990 | CN1008049B Security arrangement for telecommunications exchange system |
| 05/09/1990 | EP0366975A2 Method and apparatus for frequency control of multiple oscillators using a single frequency-locked-loop |
| 05/08/1990 | US4924516 Method and system for a synchronized pseudo-random privacy modem |
| 05/08/1990 | US4924498 Method and apparatus for improving video scrambling and employing split snyc pulses |
| 04/24/1990 | US4920567 Secure telephone terminal |
| 04/24/1990 | US4920565 Method for connection of secure conference calls |
| 04/10/1990 | US4916736 Method and apparatus for encrypting and decrypting time domain signals |
| 04/03/1990 | US4914697 Cryptographic method and apparatus with electronically redefinable algorithm |
| 04/03/1990 | US4914696 Communications system with tandem scrambling devices |
| 04/03/1990 | US4914695 Method and apparatus for frequency control of multiple oscillators using a single frequency-locked-loop |
| 03/28/1990 | CN1040893A Cordless telephone |
| 03/27/1990 | US4912760 Off-premises cable television channel interdiction method and apparatus |
| 03/27/1990 | CA1267218A1 Video encryption system |
| 03/20/1990 | US4910771 Television signal converter |
| 03/14/1990 | CN1040476A In-band controller |
| 03/14/1990 | CN1040472A Communications system with tandem scrambling devices |
| 03/13/1990 | US4908860 System for the secret transmission of audio signals and television receiver for receiving such signals |
| 02/27/1990 | US4905278 Scrambling of analogue electrical signals |
| 02/22/1990 | DE3828269A1 Method for the coded transmission of videotelephone signals |
| 02/20/1990 | US4903298 System for providing encryption and decryption of voice and data transmissions to and from an aircraft |
| 01/25/1990 | WO1990000843A1 Cordless telephone |
| 01/17/1990 | EP0351102A2 Encryption apparatus |
| 01/17/1990 | CN1006517B Receiver for expanded frequency band signal |
| 01/09/1990 | US4893339 Secure communication system |
| 01/09/1990 | CA1264355A1 Gateway system and method for interconnecting telephone calls with a digital voice protected radio network |
| 01/03/1990 | EP0060299B1 Multiple signal transmission method and system, particularly for television |
| 01/03/1990 | CN1038561A Method and apparatus for encrypting and decrypting time domain signal |
| 12/20/1989 | CN1038195A Method and apparatus for improving video scrambling and employing split sync pulses |
| 12/19/1989 | US4888799 Scrambling of signals by inversion |
| 12/13/1989 | EP0345952A2 Method and apparatus for encrypting and decrypting time domain signals |
| 12/13/1989 | CN1038003A Method and apparatus for encoding and decoding information signal |
| 11/29/1989 | EP0343805A2 Reproduction of secure keys by using distributed key generation data |
| 11/29/1989 | CN1037626A Off-premises cable television channel interdiction method and apparatus |
| 11/28/1989 | CA1263463A1 Communications scrambler system |
| 11/21/1989 | US4882751 Secure trunked communications system |
| 11/02/1989 | WO1989010665A1 A method and apparatus for improving video scrambling and employing split sync pulses |
| 11/02/1989 | WO1989010664A1 In-band controller |
| 11/02/1989 | WO1989010661A1 Spectrally efficient method for communicating an information signal |
| 09/28/1989 | DE3703987C1 Method for coded information transmission |
| 09/26/1989 | CA1261087A1 Device for establishing a connection between a telecommunication network and a controllable system, such as a computer system, provided with an access control unit controllablevia a separate network terminal |
| 09/26/1989 | CA1260542A1 Confidential communication system |
| 09/21/1989 | WO1989008966A1 Off-premises cable television channel interdiction method and apparatus |
| 09/05/1989 | US4864615 Reproduction of secure keys by using distributed key generation data |
| 09/05/1989 | US4864614 Authorising coded signals |
| 08/29/1989 | US4862501 Communications network using IC cards |
| 08/29/1989 | CA1258884A1 Method and apparatus for transceiving cryptographically encoded digital data |
| 08/15/1989 | US4858223 Security arrangement for a telecommunications exchange system |
| 08/10/1989 | WO1989007375A1 Cryptographic method and apparatus with electronically redefinable algorithm |
| 08/08/1989 | US4856061 Method for cryptographic transmission of speech signals and a communication station for performing the method |
| 07/25/1989 | US4852166 Analogue scrambling system with dynamic band permutation |
| 07/25/1989 | US4852155 Systeme d'authentification analogique reciproque entre un terminal et une ligne de transmission |
| 07/04/1989 | US4845749 Secure teleconferencing system |
| 06/28/1989 | EP0322059A1 Sound scrambling/descrambling system and method |
| 06/27/1989 | CA1256554A1 Video signal scrambling and descrambling systems |
| 06/20/1989 | US4841571 Privacy signal transmission system |
| 06/20/1989 | CA1256178A1 Cryptographic digital signal transceiver method and apparatus |
| 06/13/1989 | US4839922 CATV scrambling and descrambling method |
| 06/06/1989 | US4837821 Signal transmission system having encoder/decoder without frame synchronization signal |
| 05/10/1989 | EP0167531B1 Packetized ensemble modem |
| 05/09/1989 | US4829540 Secure communication system for multiple remote units |
| 05/03/1989 | EP0314203A2 System for enabling descrambling on a selective-subscription basis in a subscriber communication network |
| 05/03/1989 | EP0313576A1 Gateway system and method for interconnecting telephone calls with a digital voice protected radio network. |
| 05/02/1989 | US4827513 Communications system |
| 05/02/1989 | US4827507 Duplex analog scrambler |
| 05/02/1989 | CA1253617A1 Digital signal composing circuit for cross-fade signal processing |
| 05/02/1989 | CA1253616A1 Secure coding and decoding system and method for television program signals |
| 05/02/1989 | CA1253601A1 Receiving digital sound/data information |
| 04/26/1989 | EP0313029A1 Apparatus for scrambled transmission of analog signals |
| 04/26/1989 | EP0312693A2 Method for speech encryption with simultaneous data transmission in narrow band transmission system |
| 04/25/1989 | US4825468 Video noise jammer |
| 04/18/1989 | US4823385 System for processing coded information |
| 04/04/1989 | CA1252237A1 Expanded partial response processing for analog signal enciphering and the like |
| 03/28/1989 | US4817146 Cryptographic digital signal transceiver method and apparatus |
| 03/28/1989 | US4817143 Scrambled signal receiver |
| 03/28/1989 | US4817141 Confidential communication system |
| 03/23/1989 | WO1989002682A1 Signal processing apparatus and methods |
| 03/22/1989 | EP0307545A2 Digital radiotransmission method for a cordless telephone |
| 03/21/1989 | US4815129 Video encryption system |
| 03/21/1989 | US4815128 Gateway system and method for interconnecting telephone calls with a digital voice protected radio network |
| 03/01/1989 | EP0305261A1 Method for quickly synchronizing vocoders coupled by enciphering and deciphering apparatuses |
| 02/07/1989 | US4803726 Bit synchronization method for a digital radio telephone system |
| 01/31/1989 | US4802219 Method and apparatus for distorting a speech signal |
| 01/31/1989 | US4802215 Security system for television signal encryption |