Abstract: A reverse-phase HPLC method is disclosed which allows the separation of DPU and PTH-Trp and, therefore, the correct assignment of tryptophan residues in an amino acid sequence. The method is based on a modification of the conventional HPLC gradient commonly used to elute and separate all PTH amino acids of interest in automated and manual sequencing. In one embodiment, using automated instruments manufactured by Applied Biosystems, gradient modification is achieved by changing the manufacturer-supplied gradient program which controls the operation of the HPLC pumps in the instrument. Using the methods of the present invention, the correct and reliable assignment of tryptophan residues is possible and was reproducible over time, even with small sample sizes.

Abstract: An inertial measuring unit gyroscope wheel dynamic braking and sequence inhibiting circuit is disclosed. The circuit comprises a first counter for counting a specified time interval and digital logic circuitry for applying an in-phase signal to the phases of a multiphase electric induction motor driving a gyroscope wheel during the time interval, for example, a vertical gyroscope motor wheel. By placing in-phase signals on the inputs of a multiphase electric induction motor, the motor is brought completely to rest in a short time by dynamic braking. In a preferred embodiment, a second counter counts a second specified time interval after the first time interval has terminated, during which second time interval a second electric induction motor is dynamically braked, for example, an azimuth gyroscope wheel motor. During the time period when the motors are braking, a signal is fed back to an automatic sequencing circuit to inhibit further sequencing of the inertial measuring unit.

Abstract: An inertial measurement unit using body dithered ring laser gyroscopes in which the individual ring laser gyroscopes are firmly attached to a common dithered structure and provisions made to cancel the reaction moment from the dithered structure by a passive resonator. The stable element, to which both the dithered structure and the passive resonator are attached with torsion springs, also serves as a non-vibrating foundation for strapped down accelerometers. The resulting structure contains fewer parts, has lower fabricating cost and permits a smaller package size than a conventional inertial measurement unit with individually body dithered ring laser gyroscopes.

Abstract: A ring laser gyroscope having a triangular block configuration is dithered about its center of gravity. An optical wedge attached to the output mirror allows the center of support to include the line of symmetry of the block, thereby reducing temperature gradients, which could cause output signals in the absence of an input angular rate across the instrument. The optical wedge, a mirror and a beamsplitter form an interferometer to compensate the output signal of the ring laser to produce an output free from influence of the dither motion. The mirror and beamsplitter are adjustable to allow for small corrections necessary to exactly compensate the dither-motion and to achieve 90.degree. phase shift between the outputs from photodetectors.

Abstract: A ring laser gyroscope has at least two of its mirrors vibrated perpendicular to their reflective surfaces by equal and opposite amounts to maintain the total beam path length constant. The amplitude of vibration causes the beams to be shifted across surfaces of all of the mirrors by a distance that is at least close to a Bessel zero distance so as to reduce the intensity of back scattered radiation at the main wavelength to a value close to zero. For an equilateral triangular ring laser gyroscope, two of the mirrors are vibrated between about 0.66.lambda. and 0.74.lambda., optimally about 0.71.lambda.. For an isosceles triangle having vibrating mirrors at two vertexes having angles of about 51.65.degree., the magnitude of vibration should be about 0.91.lambda..

Abstract: An equilateral triangular ring laser gyroscope contains drivers to vibrate two of the mirrors synchronously and oppositely along paths displaced by about 4.27.degree. from the bisector of the vertex angles at which those mirrors are located. The magnitude of displacement is about 0.761 .lambda., where .lambda. is the wavelength of laser radiation. The purpose of the vibration is to reduce the lock-in effect in the ring laser gyroscope.

Abstract: Bias shift caused by distortion of a ring laser gyroscope block is corrected by bending the block. Electromechanical bending devices may be piezoelectric crystals adherently attached to the block and resposive to voltage derived from distorting influences.

Abstract: A transducer for driving a spoke of a ring laser gyroscope is fastened at a point of neutral radius on the spoke. The transducer may be a piezoelectric crystal provided with a pair of electrodes which are driven in push-pull by an AC voltage to dither the gyroscope.

Abstract: An improved ladder network for use in a converter utilizing a single ladder network with single pole double throw switches to simultaneously implement nonlinear sine and cosine functions.

Abstract: Electrical and mechanical synchronization of two or more synchronously driven gyroscopes, mounted on the same platform, to minimize cross-talk induced drift, is achieved by bringing one gyroscope to a speed which is slightly higher than the other by driving it at a slightly higher frequency. At speed, coincidence of mechanical position is established by means of signals from pick-offs on each gyro and the drive for the faster gyroscope is shifted to the lower frequency. Electrical synchronism is established by restarting the lower frequency generator to instantaneously establish a predetermined relationship between a pick-off signal and the frequency generator. Phase-lock start-up of a single gyroscope by instantaneous shift of the phase of the driving voltage, relative to the gyroscope wheel position, is also provided.

Abstract: A low cost, simple to manufacture, two axis gyro having an outer flexure assembly and an inner flexure assembly. Each flexure assembly contains two flexure hinges which represent a reduction in the number of hinges and milled cuts from those required in prior art devices. The inner flexure assembly is designed to nest within the outer flexure assembly and both are mounted centrally on a rotatable shaft for rotation about the gyro spin axis. The two flexures of the outer assemblies are separated 180.degree. from each other and adjacent to two slots also separated by 180.degree. in the rim of the outer gimbal. Likewise, the two flexures of the inner flexure assembly are separated 180.degree. from each other and 90.degree. from each of the outer flexures. The outer flexure assembly axis is offset axially by a controlled amount from the inner flexure assembly axis to achieve nominal balance on both flexure axes.

Abstract: To provide improved performance in a microwave antenna, particularly for use in a Doppler navigation system, rectangular arrays obtained from truncated slanted arrays are used to obtain beam shapes which exhibit a high degree of independence from over-water shifts.

Abstract: In order to provide an all-angle gradient magnetometer, first and second magnetic resonance cells are mounted to a common base and separated by a predetermined distance. Circularly polarized pumping light is passed through the two cells orthogonally. Mixed with the circularly polarized pumping light is readout light which is linearly polarized. At the output of the cells appropriate filters are provided to filter out the pumping light whereafter the modulated readout light is detected in push-pull manner and fed back to modulate the pumping beams and at the same time fed to signal processing means to permit detecting phase differences between the outputs of the separated cells.

Abstract: A dual speed resolver to digital conversion system with coarse and fine interlocking. The reference frequency is utilized to drive a bang-bang servo loop under priority control of the coarse mathetics when it is necessary to pass control to the coarse loop.

Abstract: A comparator network in a successive approximation synchro-to-digital converter uses two comparators to determine the quadrant of the synchro angle and then uses one of these comparators as a steering voltage comparator to determine the less significant bits of the synchro angle. Fractions of the sine and cosine analog inputs are cross-coupled to the comparators to provide inherent quantization error centering.

Abstract: A method and apparatus for receiving and correlating coded digital information with increased anti-jamming capability. The apparatus uses a receiver for each pair of frequencies at which the information is transmitted, a synchronizer for synchronizing the transmitter and receives, a correlator and a code sequence generator. The receiver is alternately operated at one of two frequencies over a predetermined period, and each correlator is provided with a number of sections equal to the maximum number of codes to be transmitted at each of the frequencies.

Abstract: In a ring laser gyroscope having a triangular optical resonator with mirrors at its corners, in order to prevent lock-in, a portion of the light from the beams that passes through the mirrors at the corners is fed back into the clockwise and counter-clockwise beams after being passed through an optical resonator containing a nonreciprocal phase shifter.

Abstract: A gyroscope which has a spinning fluid filled annulus as an inertial angle rate sensor is compensated for inertial drift by resolving an output signal from the sensor into acceleration proportional components related to the gimbal axes and the component related to the inner axis is applied to the outer axis, and the component related to the outer axis is applied to the inner axis to cancel out the effects of drift.

Abstract: A low cost, simple to manufacture, two axis gyro having an outer flexure assembly and an inner flexure assembly. Each flexure assembly contains two flexure hinges which represent a reduction in the number of hinges and milled cuts from those required in prior art devices. The inner flexure assembly is designed to nest within the outer flexure assembly and both are mounted centrally on a rotatable shaft for rotation about the gyro spin axis. The two flexures of the outer assemblies are separated 180.degree. from each other and adjacent to two slots also separated by 180.degree. in the rim of the outer gimbal. Likewise, the two flexures of the inner flexure assembly are separated 180.degree. from each other and 90.degree. from each of the outer flexures. The outer flexure assembly axis is offset axially by a controlled amount from the inner flexure assembly axis to achieve nominal balance on both flexure axes.

Abstract: An improved input system for isolating resolver or synchro outputs from inputs to demodulators or analog-to-digital converters uses current transformers rather than voltage transformers. The resistances of resistors connected in series with the primary windings of the isolation transformers are adjusted to standardize the input currents of the transformers.