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From: pbijoy at rediffmail.com<pbijoy@r...>
Date: Tue Sep 19 09:26:00 CEST 2006
Subject: [oc] fft on hardware??or DSP??
Hi
i am trying to use the Opencore FFT, i am first doing a simulation by
giving different inputs . but what i observe is this FFT generates lots of
unwanted frequencies or inotherwors the sidelobe rejection is poor.

is there any work around ?

bijoy

----- Original Message -----
From: Yan Zhang <yzhang@m...>
To: "'cores@o...'" <cores@o...>
Date: Fri, 21 Sep 2001 10:35:00 -0700
Subject: RE: [oc] fft on hardware??or DSP??

> Title: RE: [oc] fft on hardware??or DSP??
>
>
> > >
> > > The FFT I am designing for opencores should do around 1
> > > point
> > > every 10ns in an FPGA. This translates to 10us for 1024
> > > points.
> > > Essentially it will be 'real time', allowing a continuous
> > > stream of data
> > > to be processed.
>
>
> I also have designed a real time FFT (512 points) logic for 100M
> ASIC and verified by FPGA. About speed parameter looks like you
> used at least 8 multipler and number's adders parallel, not
> pipeline.
>
> Thanks
>
> Yan
>
> > -----Original Message-----
> > From: gsg43@r... [mailto:gsg43@r...]
> > Sent: 2001Äê9ÔÂ21ÈÕ 6:02
> > To: cores@o...
> > Subject: Re: [oc] fft on hardware??or DSP??
> >
> >
> >  
> > Hi John,
> > Are you implemeting pipelined fft?? The word real time fft is
> > giving this meaning...
> > which algorithm you are using and why?
> > Shall we get enough speed with pipeline fft on FPGA? I mean
> > routing delays may effect the design...
> > IF not so which FPGA will be suitable...
> > Is opencores giving code for free??
> >
> > I am trying to get brief idea on the fft implementation... I
> > am planning to simulate(Integer C code) pipelined fft.
> > Thank you,
> > gayathri :-)
> >
> > ----- Original Message -----
> > From: jdalton at asiaonline dot net dot au
> > To: cores at opencores dot org
> > CC: jdalton at asiaonline dot net dot au
> > Date: 17 Sep 2001 21:03:23 -0700
> > Subject: Re: [oc] fft on hardware??or DSP??
> >
> > > > Hi folks,
> > >
> > > Hello
> > >
> > > > 1. What is the speed of fastest FFT availabe in the
> > > market till now?
> > >
> > > Not sure.
> > >
> > > > 2. I have seen few xilinx FFT documents for virtex
> > > FPGAs saying 1024
> > > > FFT in arround 60us. Other DSP vendors giving much
> > > speed FFTs than
> > > > FPGAs.
> > > > So which is suitable for fastest FFT, either DSP or
> > > FPGA or dedicated
> > > > chip.
> > > > what are the limitations in both.
>
> > >
> > > > 3. Can I get faster FFTs in FPGA than DSPs?
> > >
> > > My guess is for long transforms, an FPGA will generally
> > > have a higher thoughput, as it can do more in parallel.
> > > A DSP could potentially have a shorter latency due to
> > > more highly optimised multipliers. For very short
> > > transforms
> > > a DSP with multiple ALUs might be faster than an FPGA as
> > > it can do
> > > everything in parallel with optimised multipliers.
> > >
> > > > 4. What are the advantages of FFT on FPGA than in
> > > DSP?
> > >
> > > See previous answer. > > > > > > Best wishes > > > John > > > > > -- > > To unsubscribe from cores mailing list please visit > http://www.opencores.org/mailinglists.shtml >