Gm Global Technolgoy Operations, Inc.

John J Westerkamp

Kamal N Majeed

Steven L Tracht

Reed D Hanson

In a vehicle suspension control in which the output of a vehicle body mounted absolute vertical acceleration sensor is integrated to provide an absolute vertical velocity signal, the sensor output is high pass filtered to remove DC components but pass components in the frequency range 1-2 Hz. The filter comprises a second order digital all-pass filter embodied recursively on a 16 bit, fixed point, digital signal processor (DSP). A first stage normalized lattice two-pair network reduces to a unity gain stage; and a second stage single multiplier two-pair lattice network minimizes computational time. The 32 bit internal accumulators of the 16 bit DSP are used advantageously to prevent errors due to internal overflow of the recursive variable.

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Beavercreek, OH, United States of America

John J Westerkamp