Regarding the conversion from FIX31_15 to FIX16_14 for a signed decimal

[Maitry07]

Hello support team,

I am using Vivado FFT IP core with unscaled version . so my FFT IP Core output is FIX31_15. ( signed decimal ) . Now I need to convert it into FIX16_14 . what is the correct way in DSP to convert FIX31_15 to FIX16_14?

 

[FvM]

There's no "correct" way without considering spectral characteristic. You need to know how many integer result bits are actually utilized. If you don't know beforehand, you better use FFT with automatic scaling, otherwise you risk to loose significant data or get integer overflow when reducing width.