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Explorer
Explorer
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Registered: ‎09-05-2015

IFFT of FFT is all zeros for floating point data format

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Hi, I simply connected the output of FFT to input of IFFT, expecting the output of IFFT is the original input.

Transform length is 8.

The architecture choice is pipelined, streaming IO.

Data format is floating point.

Input data width is 32, phase factor width is 24(I am not sure what this means)

Output ordering is Natural order.

 

The input of FFT is the values repeating from 0~127 changing every cycle.

I expect the output of IFFT is also 0~127 changing every cycle, but it's all zeros at the moment. Any suggestion?

 

Thanks in advance.

 

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Explorer
Explorer
483 Views
Registered: ‎03-16-2019

The FFT core optionally accepts data in IEEE-754 single-precision format with 32-bit words consisting of a 1-bit sign, 8-bit exponent, and 23-bit fraction. The construction of the word matches that of the Xilinx Floating-Point Operator core.

one thing you may have not considered is that IEEE-754 floating-point structure.

enter your data in 

https://www.h-schmidt.net/FloatConverter/IEEE754.html

than you can find out your answer.

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1 Reply
Explorer
Explorer
484 Views
Registered: ‎03-16-2019

The FFT core optionally accepts data in IEEE-754 single-precision format with 32-bit words consisting of a 1-bit sign, 8-bit exponent, and 23-bit fraction. The construction of the word matches that of the Xilinx Floating-Point Operator core.

one thing you may have not considered is that IEEE-754 floating-point structure.

enter your data in 

https://www.h-schmidt.net/FloatConverter/IEEE754.html

than you can find out your answer.

----------------------------------------------------------------------------
Don't forget to reply, kudo, and accept as solution
----------------------------------------------------------------------------

View solution in original post