Ultrasonics Applications and Solutions for Industry and Research

Remote Module

These high performance low noise preamplifiers are fully integrated with our SIA-7 system.  Remote Modules add performance and flexibility to any set of transducers.  The Remote Modules work equally well with both capacitive and piezoelectric transducers.  The Modules even allow mixing and matching, one piezo device and one capacitive device at the same time.

The Remote Modules move the critical high gain functions from the SIA-7 out to the transducers’ location.  This provides the best possible performance while maintaining the simplicity of the SIA-7 design concept.  The Remote Modules are fully and completely controlled by the SIA-7 and they require no operator input (except of course connecting the cables in the first place).

The Remote Modules also offer a built in bias voltage needed for capacitive transducers.  Capacitive transducers require a bias voltage to operate correctly.  The Remote Modules provide the bias voltage when needed by clicking a button in one of the SIA-7 setup windows.

Although piezoelectric and capacitive devices have very different gain and operating characteristics, electrically they are the same.  Both piezoelectric and capacitive transducers operate as simple charge source devices.  The transducers actually produce a charge per unit sound pressure level.  The charge then appears across the total capacitance of the transducer (including any capacitance connected to the transducer such as coax cable).  The voltage that appears across the transducer is just the charge divided by the total capacitance. 

The best way to deal with ultrasonic transducers is to insert a low noise preamplifier close to the transducer.  A properly designed preamplifier greatly improves the dynamic range and minimizes electrical noise pickup.  Preamplifiers can then be placed an arbitrary distance from the electronics and that makes installing and using transducers much simpler.

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Copyright © 2007 VN Instruments Ltd
Last modified: April 02, 2007