Technique for the performance evaluation of the ultrasonic preamplifier input protection circuits

Usually, imaging and measurement using ultrasound employs the application of single pulse signals for probing. Despite low correlation sidelobes and wide bandwidth which contribute to the good temporal resolution such single pulses have low energy. If material attenuation and scattering are high, or application is air-coupled, signal losses are high and signal-to-noise ratio is low. Spread spectrum signals are used to spread the energy over time, producing long signals which can be compressed by matched filter producing the processing gain, which in turn is used for signal-to-noise ratio improvement. Long duration of the SS signals imposes specific requirement. Existing standards are dedicated for single pulse signals and low impedance equipment and are not exhaustive in full performance evaluation. New technique, aimed at SS signals application is presented. Aim of the work was to develop the technique for ultrasonic preamplifier performance under high energy probing pulses investigation. Recovery time, gain and input impedance frequency response, clamping energy consumption performance evaluation parameters and measurement procedures have been developed and presented. Preliminary investigation results are presented.