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Microsoft Word - FFT_datasheet
SoftJin Technologies Pvt. Ltd.
India: 102, 1
st
Floor, Mobius Tower, SJR iPark, EPIP, White Field, BANGALORE 560 066, Karnataka,
India, Tel: 91-80-41779999, Fax: 91-80-41157070
US: 2900 Gordon Ave, Suite 100-11, Santa Clara, CA 95051, USA, Tel: (408) 773-1714, Fax: (408) 773-1745
Email:
sales@softjin.com
Web:
www.softjin.com
Page | 1

Data sheet for FFT Core




Functional Description
Fast Fourier Transform (FFT) is an efficient
algorithm
to
compute
the
discrete
Fourier
Transform (DFT) and its inverse in computational
effective
way.
It
reduces
the
number
of
computations required to compute N point DFT
from 2 N^2 to 2N log N. Therefore the ratio
between
a
DFT
computation
and
an
FFT
computation for the same N is proportional to
N/log(2) N. It takes time domain input data and
converts into frequency spectral domain data,
which would be used for spectral analysis and
which contains most of the signal information for
signal processing applications.

The FFT has many applications, all digital signal
processing applications. In fact any field of that
uses sinusoidal signals will make use of FFT. Some
of the areas are in Communications, Astronomy,
Geology and Optics.

Features:

Configurable for N point data.

Uses Radix-2 FFT for decimation in time.

Optimal area implementation

Can handle real and imaginary data.

Uses Fixed point implementation.

Deliverables:

Verilog RTL source code

Test benches

Synthesis and Simulation scripts

Detailed user documentation, including RTL
source code documentation

Block Diagram:

A
A
A
Architectural Diagram
rchitectural Diagram
rchitectural Diagram
rchitectural Diagram::::




SoftJin Technologies Pvt. Ltd.
India: 102, 1
st
Floor, Mobius Tower, SJR iPark, EPIP, White Field, BANGALORE 560 066, Karnataka,
India, Tel: 91-80-41779999, Fax: 91-80-41157070
US: 2900 Gordon Ave, Suite 100-11, Santa Clara, CA 95051, USA, Tel: (408) 773-1714, Fax: (408) 773-1745
Email:
sales@softjin.com
Web:
www.softjin.com
Page | 2





FFT Engine
FFT Engine
FFT Engine
FFT Engine





Radix
Radix
Radix
Radix----2 Butterfly:
2 Butterfly:
2 Butterfly:
2 Butterfly:
A
B
+
-
X
Y
*
Twid Memory













SoftJin Technologies Pvt. Ltd.
India: 102, 1
st
Floor, Mobius Tower, SJR iPark, EPIP, White Field, BANGALORE 560 066, Karnataka,
India, Tel: 91-80-41779999, Fax: 91-80-41157070
US: 2900 Gordon Ave, Suite 100-11, Santa Clara, CA 95051, USA, Tel: (408) 773-1714, Fax: (408) 773-1745
Email:
sales@softjin.com
Web:
www.softjin.com
Page | 3

FFT Parameter Table
FFT Parameter Table
FFT Parameter Table
FFT Parameter Table




This table describes the general FFT parameters:
Parameter
Type
Description
POINT
Integer
Number of points, must be power of
2 for forward FFT.
DATA_WIDTH
Integer
This data width which is fed into the
system
and
taken
out
after
computations. Default value is 32
bit.

Signals Defi
Signals Defi
Signals Defi
Signals Defined
ned
ned
ned
Signal definition table:
Signal
Direction
Description
datain <input_Re>
IN
Real inputs. datain is the port through which real
parts of all inputs will be fed. For N point input, it will
take N cycles to feed the entire data.
datain <input_Im>
IN
Through this port through which all imaginary parts of
inputs will be fed.
clk
IN
This FFT system is single clock system and all I/Os
and internal FFT processor is in synchronous with it.
start
IN
This signal enables the FFT process when it is
enabled. This ensures the predictability of the output
and synchronism.
reset
IN
This signal resets the system whenever it is enabled
and all counters, registers are sets to starting point.
twid_datain<Re>
IN
This is the port through which real parts of all pre-
calculated twiddle factors are fed into the twiddle
ram. This port is been mapped to the input port of
the twiddle ram. These are constant through the
procedure and have to be stored once at the staring.
twid_datain<Im>
IN
Through this port all imaginary parts of twiddle
factors will be stored in twiddle ram.
data_out
<output_re>
OUT
This is the output port through which the real parts of
the computed FFT output are taken out and it will
take N cycles to read the output for N point FFT
system.
data_out
<output_Im>
OUT
All imaginary output data will be read from this port.
completed
OUT
This signal indicates the point of completion of FFT
process and can be given as indicating signal to
output system which would be integrated to FFT to
be ready for reading.
SoftJin Technologies Pvt. Ltd.
India: 102, 1
st
Floor, Mobius Tower, SJR iPark, EPIP, White Field, BANGALORE 560 066, Karnataka,
India, Tel: 91-80-41779999, Fax: 91-80-41157070
US: 2900 Gordon Ave, Suite 100-11, Santa Clara, CA 95051, USA, Tel: (408) 773-1714, Fax: (408) 773-1745
Email:
sales@softjin.com
Web:
www.softjin.com
Page | 4


Schematic Symbol
Schematic Symbol
Schematic Symbol
Schematic Symbol
The FFT schematic symbol: