A calibration technique has been adapted to render complete system cal
ibrations of high-frequency acoustical instrumentation. This is based
on standard targets; specifically, precisely manufactured spheres comp
osed of tungsten carbide with 6% cobalt binder, The use of multiple sp
here sizes was found to be advantageous, both as an independent check
of the calibrations, and so that resonances in the sphere responses at
certain frequencies could be avoided, Complete system gains and beam
patterns, which include effects of bandpass filters and finite-pulse l
engths, were determined by moving the spheres individually in the tran
sducer far-fields. Use of this procedure ensures control over the acou
stical characteristics of transducers, which may change from the time
of manufacture and first testing due, for example, to platform mountin
g, It also provides a direct means of measuring the sampling volume at
relatively high and constant signal-to-noise ratios. Implementation o
f this technique is discussed using a multifrequency sonar system as a
n example.