"Multi-level Simulation of a Real Time Vibration Monitoring System Component"

Bryan Robertson and DeLisa Wilkerson
NASA/Marshall Space Flight Center


This paper describes the development of a custom built Digital Signal Processing (DSP) printed circuit board designed to implement the Advanced Real Time Vibration Monitoring Subsystem proposed by MSFC Transportation Directorate1  in 2000 for the Space Shuttle Main Engine Advanced Health Management System (AHMS).  This Real Time Vibration Monitoring System (RTVMS) is being developed for ground use as part of the AHMS Health Management Computer Integrated Rack Assembly (HMC-IRA).  The HMC-IRA RTVMS design contains five DSPs which are highly interconnected through individual communication ports, shared memory, and a unique communication router that allows all the DSPs to receive digitized data from two multi-channel analog boards simultaneously.  This paper will briefly cover the overall board design but will focus primarily on the state-of-the-art simulation environment within which this board was developed.  This 16-layer board with over 1800 components and an additional mezzanine card has been an extremely challenging design. Utilization of a Mentor Graphics simulation environment provided the unique board and system level simulation capability to ascertain any timing or functional concerns before production.  By combining VHDL, Synopsys Software and Hardware Models, and the Mentor Design Capture Environment, multiple simulations were developed to verify the RTVMS design.  This multi-level simulation allowed the designers to achieve complete operability without error the first time the RTVMS printed circuit board was powered. The HMC-IRA design has completed all engineering and deliverable unit testing.


1AIAA-2000-3622, Advanced Engine Health Management Applications of the SSME Real-Time Vibration Monitoring System, Tony R. Fiorucci (NASA MSFC), David R. Lakin II (NASA MSFC), and Tracy D. Reynolds (Optical Sciences Corporation).


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