Abstract: An isolator (26) and assembly method therefor. The isolator (26) is particularly useful for aircraft thrust reverser doors, and the like, and includes an outer member (28), and a isolator component (29). The outer member (28) has a central axis (A--A), a generally non-planar inner peripheral surface (32), and first and second axially extending slotted entryways (48, 48'). The isolator component (29) preferably includes a component axis (B--B), an inner member (30) having an external radial peripheral surface (33), and an elastomer or metal mesh member (40) surrounding said external radial peripheral surface (33). The isolator component (29) is assembled and retained within said outer member (28) by insertion endwise through said first and second slotted entryways (48, 48'), and rotating 90.degree. such that the component axis (B--B) is substantially aligned with the central axis (A--A).

Abstract: A tuned vibration absorber includes a mounting plate having at least two, and alternatively four, mounting holes in spaced relationship from a longitudinal center axis of the plate. An elastomeric spring is bonded to the mounting plate. A main tuning mass is bonded to the elastomeric spring opposite the mounting plate, and fine tuning masses are riveted directly onto the main tuning mass. The elastomeric spring and main mass both have a rectangular profile to maintain a low profile height from the mounting plate. A cover is formed of a single sheet of metal bent to form a rectangular box with one open side. The cover includes mounting flanges with holes that align with the mounting holes on the mounting plate. For mounting the vibration absorber on a stiffening ring of an aircraft frame, a spacing plate is positionable between a portion of the mounting plate and the stiffening rib of an aircraft frame, and adjacent to an overlapping secondary stiffening ring to provide a flat mounting surface.

Abstract: An artist portfolio that is worn as a backpack that includes a first storage compartment of rectilinear shape whose long axis is in the vertical plane. A plurality of webbing structures are affixed about the first compartment producing webbing loops for securing articles to the exterior of the compartment. A closure mechanism, such as a zipper, partially detaches the top lid of the first compartment permitting unobstructed access to the interior. The first compartment further includes a plurality of shoulder, anchor and waist straps for securing the portfolio to the upper body of the wearer. A second storage compartment of a predetermined shape is provided for housing additional articles. A plurality of upper cord lengths, locks, sleeves and eyelets are affixed at points as to allow the second compartment to be expanded and compressed about a predetermined volume. A plurality of closure mechanisms, such as zippers, permit unobstructed access to the interior of the second compartment.

Abstract: Accurate and reliable measurements of transmission parameters, e.g., envelope delay distortion or frequency response, of a network or facility (105) are obtained in a test system (FIG. 1) employing digital data acquisition units (121) by utilizing a unique test signal including a plurality of tones. A set of test signals is transmitted over the facility (105), a set of measurements is made of the received version for each test signal, each set of measurements is time averaged, and an ensemble of time-averaged sets of measurements is used to generate the desired measurements of the transmission parameters. System efficiency is enhanced by measuring prescribed transmission impairments, e.g., nonlinear distortion (3OID), signal-to-noise ratio (S/N) and frequency shift (FS) on the facility under evaluation and dynamically determining test system parameters in accordance with predetermined relationships with the measured impairments (FIGS.

Abstract: Accurate and reliable measurement results are obtained in a test system (FIG. 1) employing digital data acquisition units (121) when measuring frequency response or envelope delay distortion of a network or communication facility (105) by employing a unique test signal (21-tone) including a plurality of tones, each tone having amplitude, frequency, phase component values determined and assigned in accordance with prescribed criteria. The phase component values are determined in accordance with a relationship dependent on the number of tones in the test signal, and in one example, are initially assigned on a random, one-to-one basis to the tones. In a specific embodiment, a test signal is utilized having 21 tones. Further problems arising from nonlinearities on the facility under evaluation (105) are minimized by transmitting the 21-tone test signal a plurality of times and by reassigning the phase component values to the tones each time the test signal is transmitted.

Abstract: Errors in test results are minimized in a test system (FIG. 1) employing digital data acquisition units (121) when measuring intermodulation distortion of a voice frequency communication facility (105) by employing a unique 3-tone test signal. To this end, the three tones have predetermined amplitude, frequency and phase relationships to obtain a test signal having a desired optimum probability density function which is substantially Gaussian. Additionally, circuit noise components are eliminated from the test results by obtaining a measure of noise with a single tone test signal and subtracting it out from the three tone test results. In a specific embodiment, a measure of the power spectrum resulting from the three tone signal and the power spectrum of the single tone signal are obtained, combined and utilized to obtain measurements of second and third order intermodulation distortion products compensated for noise.