title: Improved signal processor for the ultrasonic dimension gauge.
abstract: Inexpensive modifications and additions to improve the performance of a widely used ultrasonic dimension gauge are presented in detail. These include a pulse width demodulator, averaging peak detector, and improved signal processing circuits. Benefits of the modifications are improved frequency response (to 1 kHz), lowered drift, increased sensitivity (to 128 mV/mm), rational gain calibration, calibrated zero suppression, and improved recovery from signal dropout. The modifications result in the ability to take the derivatives of ventricular wall motion with greater reliability.
mesh_terms: D004452:Echocardiography / Q000295:instrumentation*; D004582:Electronics, Medical; D006801:Humans; D014465:Ultrasonics / Q000295:instrumentation*