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In the analysis of automotive vibration signals, it is often desirable to precisely track individual tonal components of a signal over time. This kind of analysis is useful in defining root cause of cyclic vibrations, allowing the engineer to localize a vibration problem to a specific subsystem. The most commonplace analysis methods are block-oriented Fourier Transform (FT) approaches. However, these methods invariably lead to time localization uncertainty and imprecise frequency resolution. Other analysis methods are available that can estimate the precise frequency of content of a signal at every time step, given certain signal assumptions. This paper studies several of these analysis methods. Narrow Band filters, Kalman filtering, Auto-Regressive signal modeling and the Phase Locked Loop are examined as methods of signal decomposition and order extraction.

Door closing sounds are an important element of the craftsmanship image of a vehicle. This paper examines the relationship between closure sound quality and door system design. The perception of door closing sound quality is shown to be primarily related to it's loudness and sharpness. Of the two, sharpness is more important than loudness. Other factors, like ring-down may also affect closure sound quality. The door system is made up of a number of components. The most important in terms of sound quality are the door and body structure, latch, and door seals. Each of these are classified as either a sound source, a transmission path or a sound radiator. Methods for improving the design of these components for good closure sound quality are discussed in some detail.

The Scanning Laser Vibrometer can make full field, high resolution measurements of the normal surface velocity of automotive door glass and sheet metal vibrations. These properties make the vibrometer a very useful tool for locating compliant and noisy areas on the surface of a vehicle, generated by exterior wind noise. An advantage of the vibrometer is that it measures the vibration of the surface, capturing the transfer of noise through the surface, rather than simply measuring the exterior wind noise. Methods of experimental setup, testing, and problem analysis on outside rear view mirror/A-pillar/Sideglass configurations and body panel vibrations are discussed in the paper.