FPGA Intellectual Property
PCI Express*, Networking and Connectivity, Memory Interfaces, DSP IP, and Video IP
Announcements
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.

fixed_point_fft

Altera_Forum
Honored Contributor II
782 Views

Hi ! 

 

I am implementing fixed point FFT from the megawizard(streaming,burst or buffer burst). We can specify the data precision but I couldnt understand how I can specify how many bits will be for integer part, how many bits will be for the fraction parts. 

Could someone help me  

thanks
0 Kudos
1 Reply
Altera_Forum
Honored Contributor II
77 Views

Please note - you can only use Fixed Point representation with the Variable Streaming FFT.  

 

The FFT essentially doesn't care about your fractional part - it assumes the input is an integer, and you'll get an integer result (with some bit growth as described in the user guide), of course - due to the way these things work, you can use it with an implied fractional part. So for example, if you have an 18 bit input and that's got 10 fractional bits you'll get an output width 29 bits (with bit growth at the top end) - 10 of which are fractional.
Reply