Wednesday, June 4, 2008

Filtering & Noise Removal

Matlab Signal Processing:

Real time data from accelerometer consists of some stationary noise it needs to be filtered out using second order Butterworth filter. But instead we applied simple RC-filter in hardware & taken moving average of past 16 samples in Matlab. Accuracy depends on initial calibration value which sensor gives at 0G (Generally for 10 bit ADC it is 512 i.e.Vcc/2). We implemented Discrimination window of +/- 5 relative acceleration values to minimise drift errors.

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