AWR1642: SSR例程中关于exp2sp函数以及quadraticInterpLog2ShortPeakLoc（）函数的功能问题

露露鸭

Part Number: AWR1642

你好，我想咨询三个问题，

一、exp2sp（a）函数的功能是什么？按照注释是说的2的a次方,但结果不一样，尝试过exp2sp_c(a),输出正确的2的a次方。

二、在SSR的代码中有这么一个函数：

interpOffset = quadraticInterpLog2ShortPeakLoc(obj->cfarDetObjIndexBuf, obj->numDopplerBins, detIdx1, (CFARTHRESHOLD_N_BIT_FRAC + obj->log2numVirtAnt))

我想咨询一下函数的功能是什么，为什么输入的是cfarDetObjIndexBuf，因为这个空间内是3个坐标信息。

三、antilog2的计算依据是哪个公式。

2 年多前

0 Shine 2 年多前

TI__Guru**** 357097 points

已咨询产品线工程师，请关注帖子的回复。
https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1240419/awr1642-some-questions-about-srr-demo

0 Shine 2 年多前

TI__Guru**** 357097 points

抱歉回复晚了，请看下面e2e工程师的回复。

As mentioned in the previous thread, the unit functionality of the exp2sp function has been validated in the test report. Can they confirm if their usage is right?
This function uses a quadratic fit to estimate fractional bin for a more accurate estimate of the peak value. The input is cfarDetObjIndexBuf because we are trying to perform a fit on the list of detected bins only after the 1D CFAR stage.
2^(input/(2^fracBitIn)) {Basically perform a 2^x, in this case input is a fixed-point number}

0 露露鸭 2 年多前回复 Shine

Prodigy 110 points

你好，感谢你的帮助。

一、下面是我是用exp2sp的试验截图

结果为：

第二次

结果为：

请工程师帮忙检查一下问题所在。

二、仅利用坐标信息进行拟合吗？是否有拟合原理的指导文档？

三、还请工程师解释一下2^(input/(2^fracBitIn))的具体含义，如何等效为2^x，因为我们用到的都是浮点运算

0 Shine 2 年多前回复露露鸭

TI__Guru**** 357097 points

已跟进帖子，请关注帖子的回复。

0 Shine 2 年多前回复露露鸭

TI__Guru**** 357097 points

请看下面e2e工程师最新的回复。

The usage seems to be fine and straightforward. Would it be possible to share this standalone test script with me? I can try to connect with the right team to get some more info on this. Please expect a delay in support concerning this.
It uses the bin number or index for the fit. Unfortunately, there is no document explaining this and customers are requested to go through the source code and understand the algorithm.
Let's assume your fixed number has no fractional bits at all. Then 2^(input/(2^0)) = 2^input where x=input. The function here takes input as unsigned integers and returns a floating-point number based on the evaluation.