Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Programming > VHDL > Quartus FFT IP problem

Reply
Thread Tools

Quartus FFT IP problem

 
 
patrick.melet@dmradiocom.fr
Guest
Posts: n/a
 
      02-06-2007
Hi everybody,

I'm trying to use the FFT IP core from Quartus 6.0...

I would like to know what are the representation of the mantissa (2's
complement or other ...) and where is the sign bit ?

My problem is : when I send a 1 MHz sine with 10 MHz sampling
frequency to the real part input of the FFT, I obtain peaks at 1 MHz
at the output and at 9 MHz, that's good but my peaks (if I represent
the mantissa in 2's complement) have one part positive and one part
negative !!! not a pure negative or positive peak... whats' happen...

Sure If I take FFT_real ^ 2 + FFT_imag ^2 then my peaks are all
positives...

Thanks

 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Quartus FFT IP output problem patrick.melet@dmradiocom.fr VHDL 0 02-09-2007 04:15 PM
Quartus FFT IP output problem patrick.melet@dmradiocom.fr VHDL 0 02-09-2007 04:01 PM
Quartus FFT IP problem patrick.melet@dmradiocom.fr VHDL 0 02-06-2007 03:35 PM
problem with fft periodogram aitor69gonzalez@gmail.com Python 1 10-25-2006 10:31 AM
To all FFT guru's (2048 point FFT on Virtex 2 pro) aj VHDL 3 11-24-2005 08:53 PM



Advertisments