Abstract: A time stress measurement device is provided for use in diverse electronic and electromechanical system. The TSMD collects environmental data applied to a system, collects event data experienced by the system, time-stamps the environmental and event data, compares the environmental data to various preset thresholds, and stores the time-stamped environmental data and time-stamped event data. The data is stored in various data structures, including recent environmental data, historical environmental data, peak environmental data, and event signature data. The environmental data and event data can be retrieved by maintenance personnel to isolate and analyze system faults and failures. The device can further be capable of sending a test signal to the system in order to determine whether the system is operating properly.

Abstract: A device and method is provided for filtering frequency components of an electrical signal above a selectable low pass cutoff frequency which is changeable within a designated range. An input filter having a fixed low pass cutoff frequency provides aliasing protection for a first of at least three clock driven filter stages respectively having variable low pass cutoff frequencies proportional to a clock rate of a received clock signal. The overall selectable low pass filter is determined at an intermediate stage of the clock driven filter stages. Clock rates of respective clock signals applied to clock driven stages proceeding the intermediate stage having the selectable cutoff frequency are adjusted so that each provides aliasing protection for the next. Similarly, the low pass cutoff frequencies of clock driven filter stage succeeding the intermediate stage having the selectable cutoff frequency are adjusted to eliminate staircasing distortion in the output signal.