AWR6843AOP: Implementation of FFTShift on AWR6843AOP HWA

Hi,

Are you suggesting FFT shift like the Matlab function fftshift() by moving DC component to center of the indices?

This is likely possible to do this in the HWA, though it might be simpler and less effort by doing such in C code. What are you attempting to gain by rearranging indices?

Regards,

Tim

Hi

Yes you are right. it is same with fftshift() in matlab

i would like to see rearranging Range-Doppler map  by external Tool. 

(My customer requests me see RD map by using Tool)

So, Could you tell me how to do fftsshift in HWA ?

you can tell me that way using Doppler DPU in AWR6843AOP exmaple. 

Thanks

Best regards.

Hi,

This is possible using HWA, but you could also shift the data around quite easily by copying memory around with a temporary pointer. This would not take a lot of extra processing time I imagine, and would be a lot simpler to perform. Is there a reason why this is not an option?

Regards,

Tim

Hi,

i would like to implement this process by using HWA,

Like you said, it can be implemented embedded,  but i want to expand my personal knwoledge, alos i think it's simple if i use HWA

Best regards

JINHYUN JEONG

Hi,

So there are a few different options to do this in the HWA.

1) You can apply a multiplier (alternating +1, -1, +1, -1) to the Hanning Window used in the doppler DPU which will modify the time domain data - This will result in a shift in the doppler FFT information as fftshift() would in Matlab. This would be the most straightforward approach.

The changes would need to happen in DopplerProc_configParser(). The window will be nonsymmetric, twice the length, and then need to be multiplied by +1, -1... An example of what it would look like is below:

2) Another option is the EDMA out transfer of the range-doppler heatmap. You can use the Log2 Magnitude HWA paramset as a "empty" paramset that does not actually perform LOG2 operation. Then the EDMA transfer after the operation can set the correct A,B,C counts and addresses to move the data to the correct location at the destination address.

3) A third option would be to put a new HWA paramset it place where it utilizes the circular shift functionality built into HWA. This paramset would not perform any operations on the data other than to set srcShift to N/2 (to shift the doppler heatmap by N/2 doppler indices) and srcCircShiftWrap to log2(N) where N is the number of doppler indices. This would be a good way to get started

Regards,

Tim

Hi,

Thank you for sharing your knowledge.

i will try your solution, and let you know result.

Thanks

Best regards.

JINHYUN JEONG