Rubinstein M L, Carlson C J, Rapaport E
Am J Physiol. 1977 Aug;233(2):H322-6. doi: 10.1152/ajpheart.1977.233.2.H322.
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.
详细介绍了对一种广泛使用的超声波尺寸测量仪进行改进以提高其性能的低成本改装方法和附加装置。这些包括脉宽解调器、平均峰值检测器和改进的信号处理电路。改装的好处包括改善频率响应（至1 kHz）、降低漂移、提高灵敏度（至128 mV/mm）、合理的增益校准、校准的零抑制以及改善信号丢失后的恢复。这些改装使得能够更可靠地获取心室壁运动的导数。
