TABLE OF CONTENTS This chapter describes various methods of calibrating shock and vibration transducers, commonly called vibration pickups. The objective of calibrating a transducer is to determine its sensitivity or calibration factor, as defined below. The chapter is divided into three major parts which discuss comparison methods of calibration, absolute methods of calibration, and calibration methods which employ high acceleration and shock. Field calibration techniques are described in Chap. 15.
As defined in Chap. 12, the sensitivity of a vibration pickup is the ratio of electrical output to mechanical input applied along a specified axis. [1], [2], [3] The sensitivity of all pickups is a function of frequency, containing both amplitude and phase information, as illustrated in Fig. 18.1, and therefore is usually a complex quantity. If the sensitivity is practically independent of frequency over a range of frequencies, the value of its magnitude is referred to as the calibration factor for that range, but it is specified at a discrete frequency. The phase component of the sensitivity function likewise has a constant value in that range of frequencies, usually equal to zero or 180 , but it may also be proportional to frequency, as explained in Chap. 12.
The frequency response of a pickup is shown by plotting the magnitude and phase...
