VHDL写的fpga程序，可产生三角波，方波据此波，正弦波，可实现任意频偏的调频，调相，调幅-Fpga write VHDL program can generate triangle wave, square wave accordingly wave, sine wave, can achieve any frequency offset of the FM, PM, AM

线性调频信号运用dds中改变k来实现信号调频的策略-Linear FM signal to change the use of k dds FM' s strategy to achieve signal