{HEAD ~ Apparatus} for picking up and analyzing {TAIL ~ emitted accoustic and ultrasonic signals} by means of a piezoelectric pick up element connected to an amplifier with high input resistance, the output of the amplifier being connected for further evaluation to selective circuits and to an evaluation device 
for picking up
{ HEAD ~ Apparatus } for picking up and analyzing { TAIL ~ emitted accoustic and ultrasonic signals } by means of a piezoelectric pick up element connected to an amplifier with high input resistance , the output of the amplifier being connected for further evaluation to selective circuits and to an evaluation device
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