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Visitor
Visitor
2,586 Views
Registered: ‎08-02-2011

Precision change effect is not visible in FFT7.1

Hi,

I am taking a 256 point FFT using FFT7.1. I am using a sine wave as input to xn_re via Gateway In block.

I am setting the binary points in gateway In block . I have used (number of bits , binary point)  [8,7] [16,15] and [34,33] number of bits in Gateway In to increase the precision.

I have plotted the db plot of output magnitude spectrum and I am not able see much difference as I change the precision.

 

I have few queries

 

Is it the right way to set precision?

What precision will be used for internal FFT computation?

Why I am unable to see the effect of precision change?

 

Regards,

Mayur D. Jain

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Xilinx Employee
Xilinx Employee
2,567 Views
Registered: ‎08-01-2007

Try changing the Twiddle Factor precision.

 

Also look at how much of the dynamic range you are using.  The FFT treats the data as 16.15.

Chris
Versal ACAP: AI Engines | Embedded SW Support

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