Re: fixed point to integer conversion

Hai randy ,

Sorry for the mistake pls see the following:

x1=3D 3.5 * sin(2*pi*fin1*t)
a=3D fi(x1)
a*8192
a.int


x1 =3D



         0    3.3664   -1.8425   -2.3579    3.1331    0.6431   -3.4851

a =3D


         0    3.3663   -1.8425   -2.3579    3.1331    0.6431   -3.4851

   DataTypeMode: Fixed-point: binary point scaling
                Signed: true
            WordLength: 16
        FractionLength: 13

             RoundMode: nearest
          OverflowMode: saturate
           ProductMode: FullPrecision
  MaxProductWordLength: 128
               SumMode: FullPrecision
      MaxSumWordLength: 128
         CastBeforeSum: true

ans =3D


           0       27577      -15094      -19316       25666
5268  -28550


  DataTypeMode: Fixed-point: binary point scaling
                Signed: true
            WordLength: 32
        FractionLength: 14

             RoundMode: nearest
          OverflowMode: saturate
           ProductMode: FullPrecision
  MaxProductWordLength: 128
               SumMode: FullPrecision
      MaxSumWordLength: 128
         CastBeforeSum: true


ans =3D


      0  27577 -15094 -19316  25666   5268 -28550


I think now u can able to help me...whether the above conversion is
proper?I am finding mismatch here between wordlength and fraction
length....

so 3.3663*8192=3D27,576.7296(rounded to nearest as 27577)

As it is rounding to nearest value.. it means some information is
lost..this will ultimately affect the frequency response of the
sinewave which i am trying to generate?I am i correct?can i conclude
that it is not advisable to use integers to represent a signal?But
fixed point is tedious to implement in hardware?any alternative?


regards,
raj.



On Jun 29, 1:05=A0pm, Mikolaj
<sterowanie_komputer...@[EMAIL PROTECTED]
> wrote:
> On 28-06-2008 at 23:11:42 Randy Yates <ya...@[EMAIL PROTECTED]
> wrote:
>
> > Randy Yates <ya...@[EMAIL PROTECTED]
> writes:
>
> (...)
>
> >
=A0http://www.mathworks.com/access/helpdesk/help/toolbox/fixedpoint/ind=
e...
>
> Here is a helpful websitehttp://tinyurl.com/.
>
> http://tinyurl.com/3lv43u
>
> --
> Mikolaj