Description: Is rotined, that the observed scoring of a signal to noise ratio at time-space treating of a cue of an optical pickup in a condition of observation of gentle short radio pulses is not correct yardstick of an estimation of an overall performance of an optical-acoustic spectrum analyzer. For stabilization of odds of a false alert the value of a threshold in the schema of the detector is offered simultaneously with variation of width of a dimensional pulse response of the schema of treating to inflect.