struct DPU_RangeProcHWA_FFTtuning_t{
/*! @brief Specify amount of right (divide) shift to apply
to convert HWA internal 24-bit Range FFT output to 16-bit RadarCube.
User should adjust this based on the setup where sensor is deployed and
sensors setting for Tx O/P power/RX gain and their application needs */
uint16_t fftOutputDivShift;
/*! @brief Specify number of Last butterfly stages to scale to avoid clipping within HWA FFT stages. Given the ADC data bit width of 16-bits and internal 24-bit widthof HWA, user has around 8-bits to grow Range FFT output and should not need to use butterfly scalingfor FFT sizes upto 256. Beyond that fft size, user should adjust this based on the setup where sensor is deployed and sensors setting for Tx O/P power/RX gain*/
uint16_t numLastButterflyStagesToScale;
}DPU_RangeProcHWA_FFTtuning;
这里面的butterfly 是FFT的基本技术术语吗
是的，butterfly（蝶形）是 FFT（快速傅里叶变换）算法中的核心技术术语。
在 FFT 算法中，"蝶形运算"（Butterfly Operation）是构成整个变换过程的基本单元。它得名于运算流程图的形状类似蝴蝶：两个输入数据经过复数乘法和加法 / 减法运算后，产生两个输出数据，形成类似蝴蝶翅膀的对称结构。
在你提供的结构体DPU_RangeProcHWA_FFTtuning_t中：
numLastButterflyStagesToScale参数用于指定在 FFT 计算的最后几个蝶形级中应用缩放（scaling）操作
这是为了避免在 FFT 计算过程中因数据位宽增长导致的溢出（clipping）问题
