#$%^&*AU2013202846A120130502.pdf#####24 A METHOD OF CALIBRATING A DATA RECORDING UNIT Abstract A method of calibrating a data recording unit (1) for measuring head acceleration, including the steps of providing a data recording unit mounted to a head protector (15), mounting the head protector on a support, subjecting the head protector and support to a force or pressure, measuring acceleration of the head protector resulting from the force or pressure, measuring acceleration of the support resulting from the force or pressure, and determining a relationship between the measured acceleration of the head protector and of the support.
