Did You Know...
...Chester Carlson was a patent agent who tired of having to make multiple copies of patent applications using the only duplication method available at the time: carbon paper. In 1959 he came up with a new copying system and took it to IBM for evaluation. The "experts" at IBM determined potential sales to be only 5,000 units because people wouldn't want to use a bulky machine when they had carbon paper. Carlson's invention was the xerography process, the company founded on the system is Xerox.
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| Number | Title | Issue Date |
| 5109286 | CATV reverse path manifold system A cable television reverse manifold system is coupled between first and second diplexers of off-premises subscriber service providing equipment. The diplexers separate the transmission path between a headend and a subscriber into downstream or forward and... | 04/28/1992 |
| 5099517 | Frame status encoding for communication networks A method and corresponding apparatus for encoding and decoding additional status bits into an existing frame status byte transmitted as part of a packet of information in a communication network. The described scheme provides for the encoding and decoding... | 03/24/1992 |
| 5093840 | Adaptive power control for a spread spectrum transmitter 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.... | 03/03/1992 |
| 5093649 | Bessel beam radar system using sequential spatial modulation A spatially modulated Bessel beam radar system for enhancing the resolution with which a range and an azimuth of a plurality of closely spaced targets is determined. In a Bessel beam radar system, a Bessel beam is generated by sequential spatial modulatio... | 03/03/1992 |
| 5093861 | Recognition apparatus and method for security systems 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 th... | 03/03/1992 |
| 5091939 | Method and apparatus for password protection of a computer 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 ... | 02/25/1992 |
| 5091942 | Authentication system for digital cellular communications A system for the authentication of mobile stations and base stations in a cellular communications network. The system includes an algorithm which generates not only a key dependent response to a random challenge, but also a temporary conversation key or c... | 02/25/1992 |
| 5086468 | Text modifier A method is disclosed and apparatus is described whereby plain text is modified before it is input to a binary key generator (encryptor). According to the invention, a plain text bit may be modified by a current modifying bit, which in turn, is based on a... | 02/04/1992 |
| 5086470 | Scrambling in digital communications network using a scrambled synchronization signal 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... | 02/04/1992 |
| 5081679 | Resynchronization of encryption systems upon handoff 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 vo... | 01/14/1992 |
| 5081675 | System for protection of software in memory against unauthorized use 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 addr... | 01/14/1992 |
| 5077561 | Method and apparatus for tracking satellites in inclined orbits 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 anten... | 12/31/1991 |
| 5075682 | Antenna mount and method for tracking a satellite moving in an inclined orbit 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 sat... | 12/24/1991 |
| 5073931 | System and individual device for participation in a broadcast program 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 funct... | 12/17/1991 |
| 5067080 | Digital control system 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 ... | 11/19/1991 |
| 5067152 | Method and apparatus for vector quantization 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 le... | 11/19/1991 |
| 5065428 | Secure mode answering machine 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... | 11/12/1991 |
| 5065162 | Communication system for helicopter 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 transmittin... | 11/12/1991 |
| 5065429 | Method and apparatus for protecting material on storage media 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, image... | 11/12/1991 |
| 5062121 | Spread spectrum communication device 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 v... | 10/29/1991 |
| 5060266 | Continuous cipher synchronization for cellular communication system 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 ke... | 10/22/1991 |
| 5060079 | Apparatus for controlling television monitoring 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 b... | 10/22/1991 |
| 5058160 | In-band controller 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 ... | 10/15/1991 |
| 5058157 | Method and apparatus for encrypting and decrypting time domain signals 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 shifte... | 10/15/1991 |
| 5056142 | Decryption device A decryption device, comprising a substrate, a plurality of encrypted information symbols located within a rectangular array of further symbols carried by the substrate, wherein the array is arranged in a predetermined number of rows by a further predeter... | 10/08/1991 |
| 5051754 | Optoelectronic wide bandwidth photonic beamsteering phased array A transmit/receive circuit for each of the antenna elements of a radar phased array including an optical fiber true time delay circuit responsive to an electrical RF signal for providing an optical signal having a controlled time delay, an optical fiber f... | 09/24/1991 |
| 5046096 | Windowed rotatable cover which reveals one indicia on one surface and a second indicia on a second surface corresponding to the first that encodes and decodes messages A simple and inexpensive apparatus for encoding and decoding messages is disclosed. The apparatus comprises a first surface having a first series of indicia and a second surface having a series of letters. Each of the letters correspond to a unique one of... | 09/03/1991 |
| 5046094 | Server-aided computation method and distributed information processing unit A server-aided computation method using a main unit for processing secret information and at least one auxiliary unit for supporting a computation that said main unit executes, said method comprising the steps of generating d' from a secret key d' using m... | 09/03/1991 |
| 5046095 | Digital data processor having data-unscrambling function A data processor includes a data unscrambling unit. The unit includes a memory circuit for storing data supplied thereto in a scrambled form, the data stored in the memory circuit being thereafter read out therefrom in an order which is to be the unscramb... | 09/03/1991 |
| 5043954 | Apparatus for preventing turning-in and transmitter for vehicle An apparatus for preventing a direct turning-in of the supersonic wave from the opening of the sender to the opening of the receiver in a supersonic wave device for a vehicle in which an object placed near the vehicle body id detected by the supersonic wa... | 08/27/1991 |
| 5039991 | Perturbation modeling system for use in processing direction-finding antenna outputs A system is disclosed in which a direction-finding system (12) employed on an aircraft (20) receives RF transmissions from a remote signal source (16). Amplitude and phase data concerning the transmission are used for direction finding but are perturbed b... | 08/13/1991 |
| 5038148 | Control data transfer system for phase shifters in antenna An antenna control data transfer system having antenna elements, phase shifters changing the phase of electromagnetic waves transmitted or received by the antenna elements, and phase shifter control circuits controlling the phase shifters, wherein each of... | 08/06/1991 |
| 5038376 | Block substitution based encryption by a modulo 2 addition method and apparatus Methods and apparatus for modulo 2 addition based encryption by block substitution techniques which allows use of the substitution scheme with relatively simple hardware. The block substitution, a one to one mapping of n bit binary numbers onto themselves... | 08/06/1991 |
| 5036333 | Antenna-rotation compensation apparatus and method for phased array antennas Electronic antenna-rotation compensation apparatus is provided for correcting data errors introduced into radar return signals by the rotation of phased array antennas. The apparatus includes circuitry for sampling and A-to-D converting I (in phase) and Q... | 07/30/1991 |
| 5034961 | Area communications system The radio station comprises a receiver antenna system responsive to direct transmissions from each of the other radio stations in the system with two remote transmitters operated alternately, i.e. one can be moved while the other is transmitting. The ante... | 07/23/1991 |
| 5031191 | Spread spectrum signal demodulation circuit A spread spectrum signal demodulation circuit includes a multiplier which multiplies an input spread spectrum signal by a demodulation PN code, and a demodulation PN code generator generates the demodulation PN code by utilizing an oscillation signal from... | 07/09/1991 |
| 5030958 | Coprocessor system and method An improvement in a coprocessor system for correcting for drifts in directions of navigation gyros, by means of satellite navigation information from global positioning satellites. Values of gyro navigation information from the gyros are interpolated to v... | 07/09/1991 |
| 5031163 | Method of determining position and dimensions of a subsurface structure intersecting a wellbore in the earth The growth of a hydraulic fracture increases the period of free oscillations in the well connected to the fracture. Simultaneously, the decay rate of free oscillations decreases. The properties of forced oscillations in a well also change during fracture ... | 07/09/1991 |
| 5029206 | Uniform interface for cryptographic services A security kernel of a secure processing system for providing security management, key management and kernel security functions. The secure processing system includes two parallel subsystems, a red subsystem and a black subsystem. The red subsystem may co... | 07/02/1991 |
| 5029210 | Cooperative communication system A cooperating communications system in which at least two stations and a connecting communications link form a cooperative communicating loop. Each station contains a plurality of amplification stages, which stages are selected by binary input messages. A... | 07/02/1991 |
