Abstract: A control device includes a housing having a serpentinely disposed channel and a cover, secured to the housing, which converts the channel into an ultrasonic waveguide. One end of the waveguide is bounded by a stationary reflector and the other end of the waveguide communicates with a bore which holds a piezoelectric device matched to the waveguide so as to provide therein, when actuated, a propagating transverse wave in the ultrasonic frequency range. The cover includes three elongated slots, each of which slidably supports a different reflector unit. Each unit has a reflector extending into the waveguide and can be positioned anywhere along its corresponding slot. Actuation of the piezoelectric transducer by an electrical pulse causes an ultrasonic pulse to propagate down the waveguide and parts thereof are reflected back to the transducer where an electrical group of pulse signals are caused to appear.

Abstract: In a first embodiment, a control device includes a housing having a serpentinely disposed channel and a cover, secured to the housing, which converts the channel into an ultrasonic waveguide. One end of the waveguide is bounded by a stationary reflector and the other end of the waveguide holds a piezoelectric transducer matched to the waveguide so as to provide therein, when actuated, a propagating transverse wave in the ultrasonic frequency range. The cover includes a plurality of slots communicating with the waveguide, each slot being located at a different position along the propagation path of the waveguide; and a plurality of resiliently mounted reflectors, each reflector being associated with a different one of the slots and being insertable into the waveguide by, for example, fingertip pressure. Actuation of the transducer by an electrical pulse causes an ultrasonic pulse to propagate down the waveguide.

Abstract: A delay-line has two essentially identical distributed parameter delay-line sections that have series connected solenoidal coils and mutually parallel axes. The winding directions of the two coils are such that an external observer traveling along the series connected coils from one free coil-end to the other will observe a winding direction reversal in going from one section to the other. Thus a uniform unidirectional magnetic field having a component parallel to the section axes will produce induced voltages in the two coils that are of opposite polarity and no net induced voltage will appear between the free ends of the series connected coils.

Abstract: Two multimode optical fibers connected mutually at several locations along their lengths can act as an encoding or decoding structure depending on which terminals are used for the input/output of the data. Two multicoupled lines have one input which acts as the matched filter for another input, thus enabling easy correlation of data. The performance of such a structure was simulated and the results are discussed.