The present invention improves the accuracy of waveshape measurements and transducers. Specifically, it is a method and apparatus which calibrates a system, which comprises transducers, amplifiers, filters and analog-to-digital converters, by digitally removing phase and amplitude errors over a frequency...http://www.google.de/patents/US5014229?utm_source=gb-gplus-sharePatent US5014229 - Method and apparatus for calibrating transducer/amplifier systems
