Investigation of a preamplifier noise in a pulse-echo mode

Abstract

Preamplifier noise, operating in a pulse-echo mode is investigated. Due to specifics of this mode, the input circuit should contain the elements protecting the operational amplifier input against high energy signals used for a transducer excitation. Those limiter circuits noise influences were analyzed, by applying the electro acoustical channel noise model. We indicate that those circuits degrade a preamplifier noise performance and are unwanted in a meaning of the signal-to-noise ratio. The experimental verification was carried out for every noise component separately. Recommendations are presented for the signal-to-noise ratio improvement.