Blad B, Johannesson J, Johnsson G, Bachman B, Lindström K
Radiation Physics Department, University Hospital, Lund, Sweden.
J Med Eng Technol. 1994 Sep-Oct;18(5):173-8. doi: 10.3109/03091909409030248.
This paper describes the implementation of a multiplying digital-to-analogue (D/A) converter as a programmable waveform generator to be used in an electrical impedance tomography (EIT) system. Different digital techniques of generation waveforms are considered and the advantages and disadvantages of the chosen slope-plus-pedestal technique are presented. A wire-wrapped prototype system has been designed, and from measured frequency spectra the total harmonic distortion can be calculated to values between 1.1 and 2.9% depending on frequency.
本文描述了一种乘法数模（D/A）转换器作为可编程波形发生器的实现，该波形发生器将用于电阻抗断层成像（EIT）系统。文中考虑了生成波形的不同数字技术，并阐述了所选斜坡加基座技术的优缺点。设计了一个绕线式原型系统，根据测量的频谱，可计算出总谐波失真，其值在1.1%至2.9%之间，具体取决于频率。
