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Visitor
Visitor
5,271 Views
Registered: ‎05-19-2010

signed adder

Hi, all,  I met a probelm in my project, please help me.

 

In my project, many signed data ( each is 28 bit) are added.  In order to avoid overflow, the data are extended to 32-bit. Thus the result is 32-bit. But the output is only 28 bit, how to choose the 28-bit in the final result? the most siginificant 28 bits?

 

Best Regards,

 

Steven

 

 

 

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Xilinx Employee
Xilinx Employee
5,265 Views
Registered: ‎08-02-2011

Re: signed adder

That's a decision you'll have to make based on your system specifications.

 

You need to tradeoff between allowable distortion from saturation/overlow and dynamic range. It sounds like you have calculated the worst-case bit growth and that you cannot tolerate any saturation/overflow. In which case, you will need to use the MSBs.

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