Frequency analysis
Shock metrology
Piezoelectric transducers
Signal conditioning

Precise measurement of shock phenomena

Applications where precise measurements are needed

In the present flight and missile weight have become very important large safety factors cannot be built Therefore, accurate information is nature of shock phenomena that are during the operation of the system.

The shocks which are encountered and are of interest can vary from less that one 'g' to many thousands of 'g' with durations of from a few microseconds to 100 millliseconds or more. This very wide dynamic range makes it very difficult to have a single measuring system that will cover the entire range. The transducer best suited to this requirement is the piezoelectric accelerometer because of its wide dynamic range and its high natural frequency. In order to accurately measure the shock phenomenon, a transducer, amplification and signal conditioning system, and readout device must be used.


Each component of the measuring system will in some degree distort the shock pulse being measured. The transducer, in general, is the limiting part of the system. The pizzoelectric accelerometer is many times better than other types of transducers which are presently available because of its wide dynamic range and high resonant frequency, and is often better than electronic systems chosen without due care.

A voltage amplifier should be chosen to have high input resistance and sufficiently wide frequency response to that the error introduced is held to a minimum. A charge amplifier is ideal for shock measurement because it eliminates the low frequency transfer function caused by the transducer capacity and amplifier input resistance. If a filter is used, it should be of the constant time delay type so that phase distortion is not introduced.

Finally the readout device should be chosen to give the desired type of readout.

To determine the total error which will be introduced by the system a calculation can be made to determine the error caused by each section of the system and then adding all of the errors together to get the total.

Due to the complexity of working with second order gransfer functions, wherever possible an approximation should be made using a first order function.