把先进的雷达理论和扩谱通信理论与脉冲回波超声成像技术相结合,克服了脉冲B超系统峰值功率高,信噪比差及穿透力弱等缺点。研究了基于最优二相序列激励的医学超声成像理论基础,建立了数学模型。针对最佳二相序列采用自相关解码时,信杂比不能达到医学超声成像要求的难题,提出了基于编码的“倒谱FIR滤波器(CSIFIR)”,并给出了基于线性规划法的求解公式。仿真结果表明,当CSIFIR滤波器长度约为4倍的最佳二相序列长度时,用该滤波器对双极的最佳二相序列解码压缩,信号信杂比(SCR)能达到44.5dB;而用同样长度滤波器对单极的最佳二相序列解码压缩时,信号信杂比约为37.2dB,完全满足医学超声成像的要求。
The advanced theory of radar, spread spectrum communication theory and the technique of pulse reflection ultrasound imaging are combined, which overcome the high pulse peak power, low SNR and bad penetrating of B mode ultrasound system. This paper completely expatiates the feasibility of coded pulse compression technique applied to medical ultrasound system, and models this system mathematically. Since the signal to clutter ratio (SCR) couldn't meet the requirement of medical ultrasound imaging when adopting self-correlation decoding for optimum binary phase serial, it presents the CSIFIR decoding filter and practical and efficient solutions based on linear programming. The simulation results showed that the signal to clutter ratio(SCR) for four times length of optimum code CSIFIR filter to decode the bipolar optimum codes is 44.5 dB and the SCR was 37.2 dB for the same length of optimum code CSIFIR filter to decode the unipolar codes.