Abstract: A method of authenticating input data including user data and pin code data for an access control system. The method includes the steps of receiving the user data and the pin code data from a keyboard and/or a card reader, combining an offset data with the user data, making a modulo adjustment of said offset user data, obtaining one or more variables from the offset user data, calculating a matrix index by bringing certain variables into a predetermined equation, determining a constant from a matrix by the matrix index and comparing the constant with a corresponding digit value of the pin code data. If the constant matches the digit value, a validation signal is generated and the next constant is obtained from the matrix by the next matrix index obtained by use of a predetermined second equation so that the next digit value of the pin code data is compared with this constant.

Abstract: An apparatus for adaptive-power control of a spread-spectrum transmitter of a mobile station operating in a cellular-communications network using spread-spectrum modulation. A base station transmits a generic spread-spectrum signal and an APC-data signal. A mobile station has an acquisition circuit for acquiring and decoding the generic spread-spectrum signal, a detector for detecting a received power level of the generic spread-spectrum signal, a decoder for decoding the APC-data signal as a threshold, a differential amplifier for generating a comparison signal by comparing the received power level to the threshold, a transmitter for transmitting a transmitter spread-spectrum signal, an antenna, and a variable-gain device responsive to the comparison signal indicating an increase or decrease for adjusting a transmitter-power level of the transmitter spread-spectrum signal.

Abstract: A method and apparatus for password protecting a personal, laptop or single user computer. The user's password entry is compared to the value of a secondary password retained by the computer as well as the value of the user's stored primary password. The user may thus access the computer when his primary password is corrupted or forgotten by obtaining an alternate password from the computer manufacturer which matches the secondary password generated or stored by the computer. The operation of the method and the organization of the apparatus make the secondary and alternate passwords valid for a limited time, thereby preserving the overall integrity of the password protection system. The primary, secondary and alternate passwords may be encrypted for added security.

Abstract: A passive, all optical communications network is provided in which a single optical source in a central station serves many outstations (e.g. telephones in customers' premises). Time division multiplexed optical signals from a laser source are transmitted along a single optical fibre (14) from a central station (4). The signal is split between several secondary fibres at a first splitter (10) (e.g. array of passive couplers) and between further sets of fibres at a second set of splitters (12). At this stage there are 120 individual fibres to customers' premises (8). Digital speech or data is sent back to the central station by a laser in the customers' premises operating in a low duty-cycle mode. The 120 data streams are interleaved at the branching points.

Abstract: A system for the synchronization of encryption and decryption in a duplex cellular radio system in which an encrypted call may be switched from one cell to another. At the instant of handoff, a rapid first resynchronization means temporarily seizes the voice channel in one direction only and transmits synchronization information in such one direction. The first resynchronization means ceases to transmit the synchronization information and releases such one direction of the voice channel as soon as an indicator of successful resynchronization is detected in the other direction. Transmission of speech traffic in such one direction is then resumed after such detection of successful resynchronization.

Abstract: The address space of a data storage device is arbitrarily divided into a plurality of data-segments and a different data scrambling algorithm is assigned to each of the data-segments. A programmable address scrambling device is interposed between the address port of the data storing device and a system address bus. An appropriate one of many possible scrambling keys must be supplied to the programmable address scrambling device for each of the data-segments in order to retrieve a desired dataword within each of the data-segments.

Abstract: A computerized antenna mount system for continuously tracking a satellite in geosynchronous orbit that has an inclined orbit with respect to the equator. An antenna mount that automatically adjusts the declination angle of a ground station satellite antenna as a function of time after iteratively compiling the declination angle history from one complete orbit of a satellite. Different satellite orbits may be so compiled with selection of each satellite and its corresponding orbit information from memory.

Abstract: A single axis tracking system for a satellite moving in an inclined orbit. A linear antenna mount is used which is equipped for longitudinal tilt adjustment to enable an antenna to accurately track the longitudinal centerline of the figure 8 path of a satellite in an inclined orbit from any geographic location within the footprint of the satellite. The trajectory of the satellite is determined relative to the geographic location of the antenna mount. A time referenced tracking control signal moves the antenna mount. The signal from the satellite is periodically sampled and compared with stored values to verify the calculated trajectory. If a significant deviation occurs over a predetermined period, a new trajectory is automatically calculated and the time referenced trajectory signal is adjusted accordingly.

Abstract: This device allows an individual to participate in a television program as a function of remotely loaded data. It includes a device for reception of date (R), a keyboard (8), a clock (10) and a device for processing data entered at the keyboard as a function of the remotely loaded data and for producing a result which is a function of the processing. A device for certification is coupled to the clock (10) in order to measure the elapsed time between a characteristic instant of the running of a scenario in the device (1) and the establishment of a certification link with a server (S). A certified result is supplied by a device for comparison when there is equality, to within a given tolerance, between the measured time and a reference time computed by the server.

Abstract: A transmission system in which a suitably modulated speech or data signal is combined with a low bit rate (100b/s) spread spectrum signal and transmitted simultaneously on the same channel with the modulated speech lying within the bandwidth of the spread spectrum signal.At a receiver the modulated speech or data signal is demodulated and the modulated speech or data signal together with the spread spectrum signal are applied to a multiplier in which the spread spectrum signal is despread.A code synchronizing signal may be included in the modulated signal prior to transmission and when recovered in the receiver, the synchronizing signal is applied to a pseudo-random code generating means. The transmission system may include a text transmission system in which case the low bit rate signal comprises pages of data. A number of pages may be transmitted simultaneously by spreading the data associated with each page by orthogonal psuedo-random codes.

Abstract: A digital control system for a gas turbine engine comprises two identical control lanes each of which includes a digital computer, two data buses, input circuits, output circuits and an interface unit. Each interface unit is arranged to multiplex data on the buses and transmit this data serially through a connection. Each interface unit is responsive to receipt of data from the other unit to generate control signals (read, write and valid address) for the received data, so that, in addition to timing signals on a further connection data only is transferred between the lanes.

Abstract: A method of and apparatus for vector quantizaiton operates on binary signal vectors. Each signal vector contains a plurality of sample elements of a signal to be compressed. Each of the signal vectors is hashed to generate a value identifying one of at least three different subsets of code words collectively constituting a set of binary code words. Each of the signal vectors is hashed a second time to generate a value identifying one of at least three different subsets of code words collectively constituting a second different set of binary code words. Each code word is equal in length to the length of each of the signal vectors and has associated with it a unique binary code of a lesser length. The vector quantizer performs a distortion comparison search through the code words of the selected subset to identify the one code word and its uniquely associated code which has the least distortion of all of the code words of the one subset with respect to the hashed signal vector.

Abstract: A secure answering machine allows both secure and non-secure information to be recorded by incorporating a digital signal processor (DSP) and both a secure and non-secure RAM. The secure RAM is powered entirely by battery. The battery is then connected to the housing of the answering machine such that when the housing is tampered with, the power from the battery is shut off eliminating all information stored on the secure RAM. The secure RAM is only accessed using an encrypting code.

Abstract: The present invention pertains to a radiowave relay station in which image information or the like is transmitted by a helicopter from a first station to a second station. A direction finding device is provided which detects the direction of a transmitting source, i.e., a first station. The direction finding device calculates the vertical directional angle .phi. representing the direction of an incoming radiowave which is transmitted from the first station. This direction finding device allows the helicopter performing a relay function to fly rapidly to a contact point with the first station, i.e., in a vicinity of the first station. The direction finding device may also provide information to control an antenna driving portion for adjusting a receiving antenna located on the helicopter.

Abstract: A method and apparatus for granting selected access to material such as data and databases, messages and other textual information, graphs, tables, maps, facsimiles (FAX) of all manner of transmitted materials, audio such as speech and music, video, images, and photographs, provided on storage media utilizing information encoded in the storage media. The storage media are included in one or more reading devices associated with a computer. A storage accessing device, such as a smart card, is used in conjuction with the computer to determine whether access to a particular user to specific storage media is granted. The storage media can be sub-divided into a plurality of logical zones and access to all or a portion of the material on the storage media is granted based upon the logical zones to which the user is allowed access.

Abstract: An SSC device according to the SSC method using a correlator is disclosed, in which a plurality of stages of shift register is connected in series, the outputs of the stages of the shift register being given selectively to the correlator and the initial value of the shift register in the pseudo noise code generator on the receiving side are set in a mirror image relation with respect to the initial value of the transmitted signals of the pseudo noise code generator at the code synchronization.

Abstract: A system for the synchronization of encryption devices in a digital cellular communications system. Each of the encryption devices includes a multi-bit counter and generates a pseudo-random keystream which is combined with the data to be encrypted. The keystream is a function of the multi-bit counter value which is periodically incremented in response to a series of clock pulses. To allow proper decryption of the encrypted data, the system of the present invention provides continuous or very frequent updates of the transmitter counter value which may be used to reset the receiver counter and to resynchronize the system without the necessity of reinitialization and repetition of the intervening clock pulses.

Abstract: An arrangement for limiting the time an authorized viewer may view a television program on a television receiver including apparatus for sensing a value stored in a transportable magnetic medium, apparatus operating in response to the sensing of a value by the apparatus for sensing a value stored in a transportable magnetic medium for providing a signal indicative of the time remaining to the authorized viewer, apparatus responsive to an indication that time remains to the viewer to enable the transmission of television signals to a television receiver, and apparatus for reducing the signal indicating the time remaining to the viewer with the passage of time.

Abstract: The present invention discloses a method and apparatus for providing a cable TV system with the ability to issue information from a system manager, determine whether the information is intended for a set top designed to receive out-of-band information or in-band information, send the information to the appropriate circuitry. Reformatting of some information is necessary and is performed by a format translator. For in-band information, information may be sent over one or more of a plurality of data streams. Certain types of information are sent over one or more data streams based on the type of information and characteristics of the data streams. It is further disclosed that for efficiency, similar information intended for several addresses is grouped together in a database manager so that the information may be sent to plural addresses at one time. Scramblers are employed with the capability of inserting data onto nonscrambled channels.

Abstract: A technique for encrypting and decrypting information signals normally arranged as a succession of lines of active information, with each line having a line timing reference, such as color video information signals. The active video portion is time shifted with respect to the horizontal sync portion of the corresponding line using a predetermined slowly varying time shifting function. The time shifting information is conveyed to the decryption site by encoding the instantaneous vlue of the time shifting wave form for the beginning of each field in the vertical blanking portion of that field. To provide a reasonable maximum time shifting range, portions of the trailing edge of the active video in the preceding line and portions of the leading edge of the active video in the current line are discarded. During decryption, the original line timing and color burst signals are discarded and new signals are generated which are time displaced from the actie video portion by the original amount before encryption.