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100 GHz bandwidth equivalent-time sampler modules have been built and tested.These modules include strobe generation circuitry, sampling diodes, blow-by compensation, and IF amplification. The modules have been characterized for risetime, swept frequency response, timing jitter, linearity, dynamic range, and input referred noise. High-speed pulse response measurements yield a deconvolved 10%-90% risetime of approximately 3 ps. This corresponds to an estimated bandwidth of 113 GHz. Long-duration (100 ns) pulse measurements showed clean responses as well. Swept frequency measurements corroborate the bandwidth estimate, showing little to no change in response out to 65 GHz (limit of measurement system). Timing jitter measurements yielded a value of approximately 175 fs. Linearity measurements showed uncorrected linearity to within a few percent and corrected linearity of approximately 0.1%. This was over a dynamic range of 2 Vpp. Noise measurements gave a typical input referred noise of 2.5 mVms, approximately 0.7 % of the dynamic range, very close to the calculated quantum limit.

An interactive graphics computer program was developed to implement the design of low‐drag fairings to house components of various geometrical shapes. These low‐drag fairings are useful to reduce either hydrodynamic loads on structures or the hydrodynamic resistance of vehicle appendages. The program features four libraries: one of low‐drag airfoil section shapes; one of airfoil section fluid‐dynamic characteristics; one of various component shapes; and one of various arrangements of these components. The program operator may call up any of the library information for display on a Cathode Ray Tube (CRT), make modifications, or create and catalog new library information. The normal fitting mode proceeds as follows: After the operator L satisfied with the internal component arrangement displayed on the CRT, Section Shapes are called up from the library, modified, or created and placed interactively around the arrangement by specifying the location of the leading edge and trailing edge. The Section Shape, arrangement, or individual components, my be modified until the user is satisfied with the overall geometry. The design then may be evaluated for hydrodynamic characteristics by calling up information from the appropriate library or exercising an analysis program. The inputs to the analysis program ace Section Shape, Reynolds Number, and surface roughness. The outputs are lift, drag, moment coefficients, and pressure distribution. Thus, design and off‐design conditions may be evaluated easily and the user can drive the design in the desired direction.

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