Westinghouse Electric Corporation

Other

United States of America As Represented by the Secretary of the Air Force

Robert A Moore

John D Adam

Michael R Daniel

Carl E Nothnick

S Visvanathan Krishnaswamy

Herbert Warren Cooper

Stuart S Horwitz

Robert N Sundelin

James T Godfrey

A zigzag sewing machine includes an oscillating hook. The transverse needle swing amplitude of the needle of the sewing machine is increased in amplitude from that of conventional free-arm domestic sewing machines with oscillating hooks, for example, from 5 mm to 9 mm. The increased amplitude is provided by a novel drive mechanism including a rack oscillating transversely between two extreme positions in response to rotation of a driving wheel and a pinion engaging the rack. The pinion is coupled to and drives the oscillating hook. The pinion may have a variable radius, may be coupled to the driving wheel through other racks and pinions, and may be coupled to the driving wheel through a multiple bar linkage. A constant rotation speed of the driving wheel causes the hook to oscillate at a rotational velocity that varies with rotational position of the hook so that swing amplitude of the needle transverse to the linear direction may be increased.

Wide needle swing oscillating hook system for sewing machines

A film bulk acoustic resonator (FBAR) configured as a coplanar transmission line structure. A film resonator formed over an opening in a substrate is connected to associated circuitry by one or more transmission lines formed on the substrate. The coplanar ground plane of this structure provides a simple mechanism for providing a true ground connection to the resonator without the need for vias passing through the substrate. The transmission line connection eliminates the need for wirebonds, thus simplifying fabrication, allowing the device to be more easily modified for computer simulation, and facilitating the operation of the device at microwave frequencies. Embodiments for standard, stacked, and 3-port FBAR's as well as a filter bank consisting of a plurality of coplanar 3-port FBAR's, are described.

Microwave film bulk acoustic resonator and manifolded filter bank

The linearity of group delay versus frequency in magnetostatic wave delay lines is improved by a linear variation of one of three discrete parameters in the region between the two delay line transducers. The parameter variation is applied to magnetostatic wave delay lines that have a ground plane, a magnetic garnet crystal film substrate that is spaced from the ground plane and has transmitting and receiving transducers engaged to it, and a magnetic bias field. The discrete parameters varied are the magnetic bias field; the distance of the substrate from the ground plane; and the thickness of the substrate. Appropriate linear variations of any one of the these parameters provides improved linearity of group delay versus frequency.

Magnetostatic wave delay line having improved group delay linearity

Electroacoustic apparatus is described incorporating a substrate having a transducer on an upper surface and a transducer on a lower surface positioned for receiving bulk acoustic waves; substrate taper along with transducer geometry are combined to provide bulk acoustic signals in the near zone or Fresnel zone which provide for phase and amplitude cancellation of a triple transit signal. The invention overcomes the problem of spurious triple transit signals in bulk mode acoustic delay lines for input signals having a wide bandwidth, such as an octave, and where the delay times are short such that the bulk acoustic wave remains in the near zone or the transition region between the near zone and far zone.

Wideband low triple transit delay line

Apparatus for providing a plurality of filtered outputs is described incorporating a substrate suitable for propagating surface acoustic waves having an input transducer, a first plurality of spaced-apart taps coupled together, a second plurality of spaced-apart taps coupled together where at least two of the second plurality of taps are positioned in spaces between the first plurality of taps. The invention overcomes the problem of providing separate substrate surface area for each plurality of taps coupled together.

Multiple co-surface acoustic wave filters

Electroacoustic apparatus is described incorporating a substrate having a plurality of transducers on an upper surface and a plurality of transducers on a lower surface each positioned for receiving bulk acoustic waves from a respective transducer on the upper surface wherein each receiving transducer has a predetermined acoustical path length from its respective transducer on the upper surface, means for coupling an input signal to the transducers on the upper surface, and means for coupling an output signal from the transducers on the lower surface. The invention further provides a plurality of bulk mode acoustic delay lines having predetermined acoustical path lengths which are coupled in parallel to suppress the triple transit signal. The invention overcomes the problem of spurious triple transit signals in bulk mode acoustic delay lines for input signals having a wide bandwith, such as an octave.

Triple transit suppression for bulk acoustic delay lines

An acoustic surface wave signal transmission device includes a medium having a surface suitable for propagating acoustic energy or waves and having a first impedance characteristic. The surface of the medium includes an array of periodic discontinuities of a second impedance characteristic. The widths of the discontinuities vary in a predetermined manner to reflect a portion of said acoustic energy in proportion to the widths of the discontinuities. A transmitting transducer on said surface converts an input electrical signal into corresponding acoustic energy or waves and launches the energy or waves on said medium toward said array of discontinuities. The acoustic energy is reflected from said array of discontinuities toward a receiving transducer which converts the reflected acoustic energy or waves into a corresponding electrical signal.

Phase weighted acoustic reflective array compressor

The disclosure relates to a novel device for performing signal convolution functions such as auto and cross correlation through the use of combined acoustic surface wave and semiconductor devices. A detector or pickup unit comprising a plurality of interdigital fingers coupled to associate semiconductor diodes is disposed on the surface of an acoustic substrate in the path of surface waves propagated along the surface of the substrate. The diodes are operatively connected to a summing bus from which an output signal indicative of some characteristics of the surface waves may be obtained.

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Arnold, MD, United States of America

Robert A Moore