Re: [Discuss-gnuradio] Re: uses gr.file_sink 32 bit or 64 bit

[Eric Blossom]

On Fri, Apr 03, 2009 at 12:25:41PM +0000, feldmaus wrote:
> Patrick Strasser <patrick.strasser <at> tugraz.at> writes:
> 
> > 
> > Markus Feldmann wrote am 2009-03-30 17:54:
> > > For example, is this ONE sample ?
> > >    24 +  5i
> > 
> > Yes.
> > 
> > > The left is a 32bit I part and the right is the Q part ?
> > 
> > Yes! The I(nphase)-part is the real component of the complex number, the 
> > Q(uadrature)-part is the imaginary component of the complex number
> > 
> > > If i need more than one line for one sample, how many lines
> > > do i need for the fft ?
> > 
> > One "line" in your output is one complex sample.
> Yes but one line doesn't suffices for one FFT-Plot !
> Or do you want to say that one line as for example,
> 0+1i
> should result in one of my complete spectrum ???
> I doesn't think so. Ok the FFT-Plot uses a average algorithm so
> it is not very fatal if there are some zero lines, because they
> are not weighted because of the average algorithm, but i doens't
> believe this.
> 
> However i found a link where is more information.
> The subject is <data types and other questions>.
> The data Type changes. From Usrp to Host it is 8bit or 16bit short
> and will be converted at the Host to 32bit float, so that or apllication
> only compute with 32bit float values.
> 
> Regards Markus

Marcus,

I know that some of us are starting to sound like broken records, but
you seem to be missing some of the basics.  This is OK, we all started
out knowing nothing.

We've got many books and papers on the
http://gnuradio.org/trac/wiki/SuggestedReading page.  I particularly
recommend "Understanding Digital Signal Processing" by Richard Lyons.
He works through the basics of DSP with complete examples, including 
sampling, aliasing, DFT / FFT, filtering, digital data formats, complex
numbers, etc.  It's a great introductory book for autodidacts.

http://www.amazon.com/Understanding-Digital-Signal-Processing-2nd/dp/0131089897/ref=sr_1_1?ie=UTF8&s=books&qid=1238774302&sr=1-1

Eric