Abstract: An RF signal amplifier comprising a single stage of amplification coupled through a first switch to the input of a SAW delay line and, after the SAW delay line is charged, through a second switch to the input RF amplifier for second amplification with the output of the RF amplifier being coupled through said first switch to an output terminal.
Abstract: A novel surface acoustic wave device that includes a multiple track transducer having a first portion for generating a transverse symmetrical mode acoustic wave and a second portion for receiving only a transverse nonsymmetrical surface acoustic wave such that substantially no direct coupling occurs between the first and second portions of the multiple track transducer and where reflector gratings are mode changing gratings that reflect the transverse symmetrical wave as a transverse nonsymmetrical wave that is received by the second portion of the multiple track transducer thereby substantially reducing undesired in-band surface acoustic wave transducer responses as well as spurious bulk responses and allowing a narrow passband to be obtained with a short structure when compared with the prior art structures.
Abstract: A superconducting gyroscope of the present invention includes a circuit which produces a magnetic field which is synchronous with the rate of rotation experienced by the gyroscope, a sensing circuit for converting the synchronous magnetic field into an electric signal, a first shield made of superconducting material for performing shielding of external stray fields, and a second shield disposed inside the first shield and made of superconducting material for expelling trapped residual magnetic flux. The synchronous magnetic field producing circuit includes a magnetic core shaped in a toroid with an air gap. The magnetic core may alternatively be formed in meandering shape by a plurality of separate magnetic core members with a plurality of air gaps therebetween. The sensing circuit includes at least one SQUID which can be directly coupled to the magnetic core.
Abstract: An improved surface acoustic wave grating structure that utilizes four electrodes per 3.lambda./2 or 5.lambda./2 transduction length of a reflector grating structure that produces a desired net internal distributed reflectivity in both magnitude and phase.
Abstract: A surface acoustic wave device for generating an output signal with only a symmetric or only an asymmetric vibration acoustic wave mode in a piezoelectric substrate. The device has first and second transversely spaced transducers and the device is driven from both the first and second transducers. A third transducer is between and acoustically coupled to the first two transducers. The electrodes of all three transducers are arranged with respect to each other so as to cause only a symmetrical acoustic vibration mode or only an asymmetrical acoustic vibration mode in the piezoelectric substrate.
Abstract: A sequential amplifier having at least two amplifier stages separated by a delay device such that switching means may energize either or both amplifier stages at any given time to obtain maximum gain of the input signal so long as no oscillations occur between stages, thus allowing a signal to be amplified by adjacent amplifier stages without the adverse effects of feedback associated therewith.
Abstract: A microstrip filter having a plurality of parallel resonant conductors mounted on a dielectric substrate is tuned by applying a portion of a hot-melt type glue to the filter surface. The glue is melted and then deposited on the conductors and spread across and along the conductors until the filter has a desired frequency response. The glue is then cooled until it becomes solid.
Abstract: A sequential amplifier having at least two amplifier stages separated by a delay device such that a clock may control both stages to energize one while the other is de-energized, thus allowing a signal to be amplified by adjacent amplifier stages without the adverse effects of feedback associated therewith.
Abstract: A control network operates a GaAs FET with a quiescent current closer to the maximum output current, I.sub.max, than to zero current. An output network couples the FET to the load and is characterized as having a low impedance at a fundamental frequency and a high impedance lower than an open circuit impedance at at least the second harmonic frequency. As a result, the peak voltage on the output terminal is greater than two times the supply voltage. A preamplifier raises the level of the input signal so that it has a positive voltage peak when biased by the control network and applied to the input terminal. This overdrives the FET and produces an output current that is at the maximum output current level for a longer time during each cycle than the output current is at a minimum level. This enhances the effect of the output network to produce an output voltage spike on the FET that is several times the DC voltage.
Abstract: This microstrip comb line filter includes a planar dielectric substrate, and a planar ground member positioned on one side of the dielectric substrate and extending along a first portion of the substrate. There is a second portion of the substrate along which the ground member does not extend, thereby forming a cavity filled with air. A plurality of generally parallel, electromagnetically coupled and spaced-apart, elongate microstrip conductors are positioned on the other side of the dielectric substrate. One end of each of the conductors is positioned adjacent to the first portion of the substrate and connected to the ground member. The other end of each of the conductors is electrically spaced from the ground member and positioned adjacent to the second portion of the substrate. The air cavity extends along at least half the length of the conductors.
Abstract: Novel GSPUDT structures are disclosed with 3/8.lambda. and 5/8.lambda. group sampling with 3.lambda. and 5.lambda. group responses. Reflectionless or unidirectional transducers, and broadband notch elements are all implementable with these new configurations. These GSPUDTs are similar to the conventional SPUDT and the "Hopscotch" transducers in that single level versions are reflectionless. Unidirectional characteristics are only obtainable from a two-level structure.
Abstract: An electrode structure for use with a surface acoustic wave device which has the same velocity as the transducers and the gratings forming the device but no reflections and which can be used to vary structure reflectivity.
Abstract: An analog switching circuit may be implemented with MESFETs without forward biasing the switching device, and is applicable to JFET switches in general. Switching currents are provided from a nominal input line which closely tracks the true analog input voltage, but is segregated therefrom. A current supply fed from the nominal input line provides transient charging current to the gate of the switching transistor during the switching transition from OFF to ON states. Voltage setting devices hold the gate and source of the enhancement-mode current supply at approximately the nominal supply voltage level when the switching transistor is ON, while a control section holds the gate and source of the current supply device at a negative reference voltage level when the switching transistor is OFF. In either case, the current supply device is inhibited from delivering gate current to the switching transistor during steady state operation.
Abstract: An electrode structure for use with a surface acoustic wave resonator which has the same velocity as the transducers and gratings but no reflections; a second embodiment provides an electrode structure having a velocity equal to the velocity of the transducers and gratings but that has a coefficient of reflectivity that can be predetermined by varying the width of the electrodes in the electrode structure.
Abstract: A voltage reference circuit is described which is capable of providing either an internally generated voltage having a trimming capability, or an externally generated voltage, with the use of only two pins. The internal voltage is connected through an interrupt circuit to an input/output terminal, which can also receive an externally generated voltage. A trimming terminal is used to apply trimming voltage signals to adjust the internally generated voltage. To convert from the internal to the external voltage source, an interrupt voltage is applied to the trimming terminal which is outside of the normal trimming voltage range. This interrupt voltage actuates an interrupt circuit to interrupt the connection between the internal voltage source and input/output terminal, leaving the output terminal available for the external voltage source.
Abstract: A carrier for an integrated circuit (IC) can has a plurality of low profile symmetrically distributed flexible arms extending from the carrier base with small hook projections for engaging a flange on the perimeter of the can. The low arm profile enables information to be printed on the side of the can while it is in the carrier. The symmetrical distribution of the flexible arms imparts an even load upon the can to prevent bending of the leads. The carrier base has round holes for receiving electrical leads projecting from the can to minimize the scraping of the leads during insertion and removal of the can from the carrier.
Abstract: A single-phase unidirectional surface acoustic wave transducer comprising a piezoelectric substrate and a transducer having localized symmetry and constructed for establishing a predetermined separation between the centers of acoustic wave reflection and transduction on said substrate by selectively orienting the transducer on a specific cut of said substrate to achieve a separation between said centers in a continuum of achievable phase angles of 0.degree.-360 .degree..