滤波求和方式实现宽带波束形成，采用的是通用的平面波展开法,用蒙特卡洛模拟的方法计算美式期权的价格以及基本描述。- Filtering summation way broadband beamforming, Using common plane wave expansion method, Monte Carlo simulation method of calculating the American option price and basic descr iption.