Abstract: An input signal for a travelling wave or distributed amplifier having input and output transmission lines is supplied to one end (1) of the input line and an output signal is derived from one end (4) of the output line. Conventionally, the other end (2, 3) of each line is terminated in a respective matched load, but three ports of the amplifier may be employed. The travelling wave amplifier may be used to replace a circulator (CIRC, FIG. 2) in an FMCW radar having a single transmitting/receiving antenna (ANT) (TWAMP1, FIG. 3), to replace a directional coupler (DC) for supplying a local oscillator signal to a mixer (MXR) (TWAMP2, FIG. 4), and in combination with a mixer diode (D) to form a mixer amplifier (TWAMP3, FIG. 3), giving the possibility of the larger-scale integration of RF circuits.

Abstract: An image display apparatus includes a conversion circuit which makes 1-bit information in display memory correspondence to a plurality of dot data on the display screen, so that more sophisticated image information than the ability of a display device is expanded into a bright/dark dot pattern. The apparatus enables an application display program oriented to a higher-graded display device to be displayed in a pseudo sense on a lower-graded display device.

Abstract: In a communication system, in which a great number of communication stations operate on the same telecommunication channel, such as a radio frequency, secret information transfer for selective calls as well as group calls is secured by cryptographic transmission of speech signals, in which enciphering and deciphering of the speech signals in transmitting and receiving stations, respectively, are performed by means of a secret binary transformation code associated selectively with the speech communication in question.

Abstract: A pulsed coherent radar altimeter is described which employs a narrow band receiver and utilizes a novel digital coherent pulse generator. A coherent pulse radar transmits a pulse comprised of the sum of at least two phase related RF signals closely spaced in frequency. The phase shift due to platform motion and return surface irregularity of the return signal is approximately the same for each carrier. The receiver produces a signal representative of the difference of the two carriers which is substantially free of decorrelation effects, and which can be processed in a narrow band receiver to produce range information.

Abstract: Input data is split by a splitting part into a plurality of block data having an equal data length to be processed through respective channels. Each channel data is subjected in a function operation part to a function operation in direct or indirect relation to all the other channel data to produce new channel data. Each channel data is subjected in a transform operation part to a transform operation to produce new channel data. All final channel data obtained after function and transform operations are combined by a combining part to obtain randomized data.

Abstract: A security system for a protected premise has a controller which receives data, over a pair of line conductors, from the addressed transponder of a series of addressable transponders located within the protected premise and connected across the line. To enhance the security of the system and to prevent compromising, the data is sent to the controller in coded form that changes from time to time in accordance with a secret code schedule. A decoding or decrypting system in the controller operates in accordance and in step with the same secret code schedule to decode the received coded data to recover the original information. The coded data may represent an encrypted signature of the addressed transponder which signature is decrypted to check the validity of the replying transponder.

Abstract: A digital computer system adapted for executing a set of instructions including at least one encrypted instruction. The system includes a main memory for storing the instructions, a cache memory for storing selected instructions with a relatively fast access time, a selectively operable decryption system for decrypting selected encrypted instructions from the main memory, and a central processing unit. The system is adapted so that the program stored in the main memory may be executed by the central processing unit. To this end, the decrypted instructions are decrypted only during execution when those instructions are transferred from the main memory to the cache memory so that plaintext versions of those encrypted instructions exist only in the cache memory in response to requests by the central processing unit while executing the program.

Abstract: A sweep frequency, continuous wave (CW) radar tank gauge (3) providing measurement of the level of tank contents or ullage (19), having greatly improved accuracy through improved methods of processing calibrate and return signals directed toward the surface of tank contents (20). Use of sweep synchronous measurement (46) of time domain calibrate/return difference signals (42) and time domain of a virtual "carrier" fundamental in the frequency domain, provide highly accurate measure of tank signal return times. The entire range of return signals is made available for processing and analysis (5), including distinguishable tank bottom reflections.

Abstract: A new type of passive trihedral corner reflector is described which rotates the polarization of a reflected microwave beam by 90.degree. and thereby permits a reflected radar beam to be more easily distinguished by the interrogating radar system from the random reflections from nearby objects, i.e., clutter. Rotation of the incident beam is provided by locating a passive polarizing or "twist" grid of closely spaced thin parallel wires spaced above one conducting surface by air or by a dielectric to give an electric spacing from the surface of about 0.25 .lambda.. The spacing of the wires is less than 0.25 .lambda. so that the wires constitute a reflecting surface for signals polarized parallel to the wires. The reflector can have triangular or square sides which are mutually orthogonal. In a preferred embodiment the reflector is tipped forward by 35.degree. from a reference horizontal plane and tilted clockwise in a vertical reference plane by 15.degree. to optimize reflections.

Abstract: Method and apparatus are provided for one-way transformation of data according to multiplication and/or exponentiation modulo a prime number. An implementation of the invention permits the one way residue transformation, useful in encryption and similar applications, to be implemented by n-bit computers substantially with no increase in difficulty or complexity over a natural transformation thereby, using a modulus which is a power of two.

Abstract: A privacy signal transmission system having a transmitter portion and a receiver portion. The transmitter portion digitizes an analog message signal and enciphers the digitized signal into a privacy signal before modulation and transmission to the receiver portion. The transmitter portion also extracts and modulates an analog error signal representative of the digitization error for transmission to the receiver portion. The receiver portion demodulates the digitized privacy signal and analog error signal, and after the privacy signal is deciphered and reconverted to an analog signal it is added to the received analog error to reconstitute the original analog message signal.

Abstract: Detection apparatus for alerting an operator of a moving vehicle to the proximity of a radio transmitter of known frequency and power, typically in a police vehicle. The detection apparatus includes a scanner radio having a selected channel set to the know frequency so that it provides a channel active signal during the time that the police vehicle transmitter is on. The detection apparatus further includes a timing circuit for generating a delay interval representative of the maximum time for the moving vehicle to pass the police vehicle and circuitry for generating a visual and/or audible operator alarm during the channel active signal and during the delay interval. The scanner radio is also utilized to monitor voice transmissions between the dispatcher and the police vehicle, thereby providing the vehicle operator with additional information regarding nearby police vehicles.

Abstract: A bit map image is stored as a two-dimensional array with z axis set arbitrarily at unity. Total rotation transform and screen projection is then treated as a lumped equation due to multiplicative associativity so long as only one variable "V" is included in each lumped equation. The z-data (stored elevation values corresponding to each bit map x/y coordinate) is re-inserted as a later operation after the image has been partially transformed and projected.Full yaw, pitch, and translations from virtually any perspective viewpoint may be projected onto a multiplicity of screen shapes (conical, spherical, flat, etc.), with z data being inserted into a final output.

Abstract: A repeater for local area networks of the MIL-STD-1553B type allows extension of the LAN to remote terminals. The repeater terminates the dual LAN buses and interfaces them with a single remote bus. Normally, the repeater is transparent to all traffic in the receive direction from both buses of the LAN to the remote terminal. In response to appropriate command words from the LAN, however, the repeater automatically switches direction at the correct time to transmit traffic from the remote terminal to the active bus of the LAN as called for by the LAN protocol, and then switches back. Safeguards are provided to reinitialize the repeater if a message failure occurs or the remote terminal fails to respond to a command word.

Abstract: An antenna tracking system tracks a primary antenna to follow a moving signal source, such as a communication satellite. A secondary antenna has a greater beam width than the primary antenna and receives the same tracking signal from the satellite. The primary antenna is tracked according to a predetermined search pattern which causes a variation in the signal amplitude depending upon the relative location of the satellite and the antenna position. The signal strength signals from the two antennas are input to a summation function which takes the difference of the two signals. The noise and signal variation component of the two signals is substantially the same and is therefore eliminated from the resulting difference signal. An antenna control unit utilizes the resulting difference signal to select the optimum signal strength for the particular step of the search pattern.

Abstract: A fiber optic doppler anemometer comprises a source of coherent light, a directional coupler formed by the combination of a pair of single-mode optical fibers, and a photoelectric transducer. The first end of the first fiber receives an incident beam of light from the source and guides it through the directional coupler to the second end of the first fiber, which is located adjacent to a body of moving particles to be measured, where both the second end of the first fiber and the moving particles reflect a portion of the incident light back into the first fiber. The reflected light, which has a frequency different from that of the incident beam entering the first fiber, is directed back through the directional coupler which couples a portion of the reflected light toward the first end of the second fiber. The photoelectric transducer receives the light emerging at the first end of the second fiber and converts it into analogous electrical signals.

Abstract: Disclosed is a radar apparatus including the circuitry for synchronizing a first and second pulse train, having the same pseudo random coding. The apparatus comprises a programmable delay responsive to a control signal for selectively advancing and retarding a pulse train by monotonic increments. A positive and negative range gate is utilized in passing the video signals in opposite senses in order to generate a command signal for bringing the pulse trains in synchronization.

Abstract: An intelligent synchronous modem and data communication systems utilizing the intelligent synchronous modem are provided. The modem comprises: at least one connector having a first and a second port for primary and secondary channels of communication with a host computer, wherein the primary communication channel is for communication of synchronous data and the secondary communication channel is for communication of asynchronous data; a microprocessor for recognizing and executing commands of the host computer, wherein the commands are in the form of asynchronous data received over the secondary communication channel and interface means for interfacing the microprocessor with telephone lines, wherein synchronous data received by the microprocessor is sent to the interface means.

Abstract: A generator for generating ciphering sequences, including plural clocked subgenerators (.GAMMA., .psi., .PSI.) which, in turn, generate binary sequences at one or several outputs. To achieve high cryptographic security of the ciphering sequence (.omega..sub.t) generated by the generator, n+1, at least three subgenerator are used in an arrangement in which the clock of n of these subgenerators (.psi., .PSI.) is controlled in each case by at least one of the outputs of the (n+1)th subgenerator (.GAMMA.) either directly or via function generators (.DELTA.f(t), .DELTA.f (t)) wherein the sequences (.mu.f(t), .mu. f(t)) generated by the n sub generators are logically combined by at least one function, which function assumes both binary states with approximately the same frequency when its arguments pass through all possible values.

Abstract: A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole.