| 5056136 |
Secure video communications system |
| Oct-8-1991 |
A secure video communications system having at least one command network formed by a combination of subsystems. The combination of subsystems to include a video subsystem, an audio subsystem, a communications... |
| 5007088 |
Scrambling/descrambling method using a memory for storing initial pseudo-random bit patterns respectively for submultiframes |
| Apr-9-1991 |
In a communications system, a multiframe data signal is sent from a transmit end to a receive end of the system. The multiframe is composed of a series of submultiframes each containing a series of frames.... |
| 5003599 |
In-band framing method and apparatus |
| Mar-26-1991 |
An in-band framing encoder, for continuously operating on bit stream having external-framing data and payload data. The bit stream includes a plurality of time-division-multiplexed frames of payload data... |
| 4991207 |
One-way address transmission system of PCM music |
| Feb-5-1991 |
In one way address transmission system of a PCM music broadcasting, a plurality of the PCM signals are time divisionally multiplexed and then the multiplexed data is scrambled for transmission. An address... |
| 4964165 |
Method for the fast synchronization of vocoders coupled to one another by enciphering |
| Oct-16-1990 |
A method for the fast synchronization of vocoders, coupled to each other by means of enciphering and deciphering devices, consists in synchronizing the data frames transmitted by the vocoders with the... |
| 4953211 |
Encryption apparatus |
| Aug-28-1990 |
Encryption apparatus mainly intended for encrypting speech signals samples a signal to be encrypted at two differing rates, and reads the sampled signal into storage means at one of said rates and reads... |
| 4910777 |
Packet switching architecture providing encryption across packets |
| Mar-20-1990 |
Apparatus for preventing the unauthorized detection of the start and end of packets being communicated within a packet switching system. The packet switching system comprises a plurality of packet switching... |
| 4905278 |
Scrambling of analogue electrical signals |
| Feb-27-1990 |
In a system in which an audio signal is scrambled by being divided into blocks each comprising a plurality of segments, and the segments are re-ordered within the blocks to provide the scrambled signal,... |
| 4899383 |
Apparatus and method for secure digital communication |
| Feb-6-1990 |
The multiplexer in a multichannel, secure digital communication system repetitively embeds a sequence of byte length uniquely coded synchronizing signals in each of n successive frames of one channel of... |
| 4893340 |
Multijunction unit apparatus for use in a digital network |
| Jan-9-1990 |
Disclosed is an adaptive multijunction unit apparatus for multiplexing data streams between a master computer and a plurality of slave computers coupled through telephone system communication lines. The... |
| 4866773 |
System for interfacing a digital encryption device to a time-division multiplexed communication system |
| Sep-12-1989 |
A method and apparatus for interfacing a time division multiplexing (TDM) system to a data encryption device. A TDM data stream is processed prior to encryption to form a modified data stream having the... |
| 4817146 |
Cryptographic digital signal transceiver method and apparatus |
| Mar-28-1989 |
Hybrid subband coding and decoding (using different encloding/decoding algorithms in at least one subband channel) and subband time delay compensation at a point of maximum digital bandwidth compression... |
| 4817144 |
Secure TV scrambling system using framing code switching |
| Mar-28-1989 |
A television signal scrambling system scrambles by suppressing horizontal syncs and changing the phase of the video carrier during the horizontal intervals. Data is transmitted by using two different widths... |
| 4817142 |
Restoring framing in a communications system |
| Mar-28-1989 |
A secure communications system requires special arrangements for the establishment and maintenance of framing and synchronization. A framing word is transmitted at a fixed frequency, and a key necessary... |
| 4811394 |
Variable starting state scrambling circuit |
| Mar-7-1989 |
PN sequence generators used in the scrambling and descrambling circuits at remote locations are periodically preset to the same value in order to maintain synchronism, with the preset value being also... |
| 4794643 |
Method for developing a key signal for descrambling in television broadcasting |
| Dec-27-1988 |
A scrambling method for TV pictures avoids deterioration of the reproduced picture by level compressing only selected horizontal flyback portions according to a randomly selected pattern to prevent synchronization... |
| 4791669 |
Encryption/decryption system |
| Dec-13-1988 |
An encryption/decryption system for a communication channel increases the number of values for the encryption key variable without increasing the length of a cipher feedback register. This is done by providing... |
| 4768228 |
Data acquisition device |
| Aug-30-1988 |
An apparatus for receiving, detecting and storing a series of discrete bits of data transmitted in conjunction with a video signal wherein only a portion of the transmitted data is read and saved. |
| 4757536 |
Method and apparatus for transceiving cryptographically encoded digital data |
| Jul-12-1988 |
Method and apparatus are disclosed for transceiving digital control and cryptographically encoded data signals in a unique format. The format includes frame synchronization, cryptographic synchronization... |
| 4719624 |
Multilevel multiplexing |
| Jan-12-1988 |
A synchronous PCM digital transmission system including multilevel multiplexing wherein the higher order multiplexers interleave two or more tributary signals each of which comprises a multiplexed plurality... |
| 4689606 |
Data encoding/decoding circuit |
| Aug-25-1987 |
In a data encoding/decoding circuit, a data encoding circuit includes a first clock, a first time setting circuit, a first random number generator, and a converter for receiving transmission data and converting... |
| 4661657 |
Method and apparatus for transmitting and receiving encoded data |
| Apr-28-1987 |
Method and apparatus for transmitting encoded data from a transmitting station to a receiving station wherein the transmitting and receiving data stations contain data terminal equipment, cipher equipment... |
| 4654860 |
Spacecraft telemetry regenerator |
| Mar-31-1987 |
Individual data bit streams which have been merged into a telemetry stream are regenerated in their original format and at their original data rates by storing frames of the telemetry streams in a buffer,... |
| 4608455 |
Processing of encrypted voice signals |
| Aug-26-1986 |
The occurrence of a transmission error which produces a multibit error burst in the decrypted version of a composite speech and synchronization encrypted signal using a one-bit cipher feedback or similar... |
| 4606042 |
Method for digital transmission of messages |
| Aug-12-1986 |
The invention involves a method for digital transmission of messages in a digital radio relay system which utilizes a superframe so additional information can be transmitted with a digital signal. This... |
| 4598169 |
System for detecting a marker signal inserted in an information signal |
| Jul-1-1986 |
A system for detecting a marker signal with a predetermined pattern inserted periodically in an information signal comprises a circuit which repetitively generates window signals and successively shifts... |
| 4535355 |
Method and apparatus for scrambling and unscrambling data streams using encryption and decryption |
| Aug-13-1985 |
Methods and apparatus for scrambling and unscrambling a plurality of data streams having differing data, on a plurality of signal channels, are taught. The data streams may be television programs or other... |
| 4418425 |
Encryption using destination addresses in a TDMA satellite communications network |
| Nov-29-1983 |
An encryption system is disclosed which is based on channel destination addresses for a time division multiple access (TDMA) satellite communications network. A superframe initialization vector is transmitted... |
| 4410990 |
Processing binary data |
| Oct-18-1983 |
Frame information is recovered from a stream of binary data formed at a transmitter from a block of m.times.n information bits comprising m groups of n bits plus m parity bits, one for each said group... |
| 4366573 |
Method for synchronizing code machines which are operated within the framework of a block transmission network |
| Dec-28-1982 |
A method for synchronizing code machines, operated within a block network, provides that a connection completion block be transmitted and a connection confirmation block be received and stored by a code... |
| 4305152 |
Security communication system |
| Dec-8-1981 |
A security communication system comprises a transmission apparatus including a scrambling circuit for scrambling an information signal according to a specific code and a reception apparatus including a... |
| 4172968 |
Electrical system |
| Oct-30-1979 |
1. In a secure communication system; means for producing an analog intelligence signal; means for limiting the amplitude of said signal; means for transforming portions of said amplitude limited signal... |
| 4079188 |
Multi-mode digital enciphering system |
| Mar-14-1978 |
The specification discloses an electronic digital enciphering system which is selectively operable in a plurality of different modes. The system may be operated in an off-line mode for preparing enciphered... |
| 3950616 |
Alignment of bytes in a digital data bit stream |
| Apr-13-1976 |
A sequence of data bytes, which includes a low signaling rate control signal inserted in the framing bit position of each byte, is prepared for transmission by scrambling the information bits while maintaining... |
| 3931473 |
Digital multiplexer system |
| Jan-6-1976 |
A second level multiplexer for a PCM data system provides for fast reframing by utilizing the stuff words in the frame organization in addition to the main framing word. This provides a clear indication... |
