Abstract: An apparatus is described which performs optical processing on electrical signals to calculate the triple product integral in a manner which accommodates high bandwidth signals, which processes were formerly possible only in mechanically unstable designs.

Abstract: An apparatus is described which performs acoustooptical signal processing functions with incoherent light, which procedures were formerly possible only with coherent light devices. Specific embodiments include an optical excisor, i.e., a programmable filter; a multichannel radiometer, i.e., an apparatus which estimates the power spectrum of a signal accompanied by noise; and an ambiguity processor, i.e., a time versus frequency cross correlator.

Abstract: Common path time and frequency domain optical adaptive linear predictors are disclosed, characterized by wide bandwidth operation for use in channel equalization, source redundancy removal, speech encoding, and other areas. The predictors are noninterferometric, avoiding the instability of such processors in the prior art.

Abstract: A pneumatic sweep generator for use as an audio source in tests near vocal frequency ranges. A horn, whose volume may be controlled by air pressure and whose tone may be controlled by air velocity, is connected to an air supply in a dual-circuit arrangement. Mechanical control devices, such as manual and pressure release valves, are located within the circuit to provide for tone and volume control. A reciprocating air cylinder continuously varies the air velocity within the horn to sweep the frequencies in an adjustable manner. Electromagnetic interference is totally eliminated by a complete absence of electrical devices in either the device or in necessary controls.

Abstract: A method is disclosed for eliminating group delay distortion resulting from filtering an information-carrying analog signal. The method allows an analog signal to be converted to digital form and back again with zero group delay distortion. The analog signal is first band or low pass filtered with a filter having a pass band substantially larger than that required to filter only the signal of interest. The filtered signal is then digitized at a rate appropriate to the filtered signal, digitally filtered to remove all but the signal of interest, and down sampled to the transmission rate. A substantially reversed process is described for reconverting the digital signal to analog form. The method is shown to be equally effective with a multiplexed signal.

Abstract: An electrooptic apparatus is disclosed for linear predictive adaptive filtering. The apparatus combines the desirable filtering effects of a correlation cancellation loop method of linear prediction with the parallelism and large bandwidth capabilities of optical processing.

Abstract: An information processor is described which is especially suitable for efficiently sorting large quantities of binary data. Data in a plurality of storage devices is fed to a plurality of compare-exchange modules and is then selectively passed back to the storage devices by means of multi-input switches. A programmable microprocessor controls passage of data through the various components in an iterative process.

Abstract: An apparatus for controllable propagation of magnetic domains, or bubbles, through an arrangement of closely spaced magnetic propagating elements arranged in an input stage, a strip-former stage, and a decoder stage. Binary logic circuitry results from selective control of bubble movement through alternate paths of elements, with at least one of said paths producing a domain strip extending the full height of the strip-former stage. The decoder stage includes a propagating element spaced apart from the strip-former stage a distance sufficient to prevent propagation of all domains in the strip-former stage except for the full-height strip. The asymmetric geometry of the strip former stage makes the full elongation of a bubble dependent upon which input provided the bubble.

Abstract: An improved method for serial transmission of binary data. Data words are conveyed over a communications path by means of four discrete signals. Bit value detection circuitry within the transmitter sequentially tests the untransmitted bits. Upon detection of only a single value in all of the untransmitted bits, the value being all ZEROs or all ONEs depending on the embodiment, an end of word signal is transmitted. In the receiver, a register is initialized to the predetermined single value state. Upon receipt of a signal representing the alternate state, the corresponding bit in the register is changed. Receipt of the end of word signal stops the process, at which time the register contains the word which was to be transmitted, thus accelerating the speed at which certain words may be transmitted.

Abstract: A hybrid space/time integrating optical ambiguity processor in which time-sequential segments of a spatially modulated optical signal are received in a two-dimensional optical modulator. The output of the optical modulator is periodically imaged along one axis and transformed along a perpendicular axis, and the result is detected for further use. Two embodiments of the two-dimensional optical modulator are described; one utilizing an electrical-to-optical transducer and one utilizing an optical-to-optical transducer.

Abstract: A space integrating optical ambiguity processor in which two one-dimensional modulators provide two-dimensional processing capability. Signals to be processed drive orthogonal Bragg cells oriented 40.degree. to the axes of the output detector. The resulting product is transformed in one dimension and imaged in the other, thereby creating a light intensity distribution representative of the cross ambiguity between the input signals.

Abstract: An apparatus for controllable propagation of magnetic domains, or bubbles, through an arrangement of closely spaced magnetic propagating elements arranged in an input stage, a strip-former stage, and a decoder stage. Binary logic circuitry results from selective control of bubble movement through alternate paths of elements, with at least one of said paths producing a domain strip extending the full height of the strip-former stage. The decoder stage includes a propagating element spaced apart from the strip-former stage a distance sufficient to prevent propagation of all domains in the strip-former stage except for the full-height strip.

Abstract: An apparatus for simultaneously generating identical cipher key at two remote terminals in a manner which prohibits interception of the key by unauthorized persons. A circuit comprising three separate wire lines is connected between the two terminals over geographically separated routes. The circuit is randomly completed and broken by a switch at each terminal, the switch position being determined at each terminal by an independent key generator. Cipher key is communicated by comparing the key generator output and the circuit condition.

Abstract: An optical fiber having a parabolic-index profile is etched to a taper below the cladding layer. A prism contacts the taper along its length within the etched portion of the fiber, and coherent light is transmitted through the prism into the fiber. Selective control of the light beam entry angle, entry position along the taper, and control of the etching depth allows excitation of specific modes within the fiber and maximization of coupling efficiency.

Abstract: An improved method and apparatus for laser recording of information onto a metal film by dynamically heating the film immediately prior to recording. A single track of information is recorded by directing two laser beams onto the film. An unmodulated preheat beam supplies energy to raise the temperature of the metal film to just below that required for recording. A modulated write beam then provides sufficient additional energy to selectively raise the temperature of the film to a necessary level for recording of data.

Abstract: A precision linear tuning circuit having particular utility to applications employing superconductors in a supercooled environment. Two capacitors, one fixed and one variable, are connected in parallel by an arrangement of shared, concentric electrodes. The variable capacitor includes one electrode and a movable facing dielectric which are tapered such that displacement of the dielectric results in a linear variation in tuning frequency.

Abstract: An apparatus for altering frequencies such that any one of a plurality of input frequencies automatically becomes another specified frequency. The value of the output frequency will remain constant regardless of which input frequency chosen, as long as the input frequencies have the relationship a, 2a, 4a, 8a . . . An input signal is received by a descending cascade of units composed of multipliers and filters. The multiplier portion of each unit must be in series with and receive the input stimuli before the filter portion of each unit. Each multiplier portion of the unit must also have a control input of a predetermined value. A phase lock loop inside of a feedback loop compensates for instantaneous variations of frequency in the input signal. This feedback loop is connected from the multiplier-filter unit to the control input for each multiplier portion.

Abstract: A method of position fixing an active transmitter source. At least two passive receivers are utilized to position fix at least one active transmitter source by obtaining the difference of the doppler frequencies received at the passive receivers, the receivers being tuned to the transmitter frequency. This differential doppler frequency is processed together with navigational information relative to the passive receiver positions at selected measurement intervals along a given measurement path of receiver movement, in order to fix the unknown position of the active transmitter source.

Abstract: A digital bridge for a telephone conferencing circuit which provides multiple conferencing capability. Microprocessor signals to a buffered memory control switching of parallel communications data into a time division multiplexed serial stream for transmission, with the position of data within each frame of the stream being a function of the intended destination. High speed switching capability results from the buffered memory circuit which is simultaneously filled with new data as current data is utilized.