RANDOM VIBRATION TEST FACILITY Russian patent published in 1994 - IPC

FIELD: test technology. SUBSTANCE: each shaper channel has three controlled channels and channel adder. Nonlinearity is checked by measuring coherence function of channels at input and output of vibration exciter-part path first at low-level signals and then at desired-level signal and comparing coherent functions obtained under two conditions in each subband. If they differ in subband of any subchannel of shaper, desired level is reduced in this subband at the same time increasing levels in other subbands of this shaper channel so that mean spectrum level in particular band corresponds to desired level. EFFECT: improved accuracy of random vibration desired spectrum shaping, extended class of tested parts due to reducing nonlinearity effect of vibration exciter-part path.