# Fdistrib; Fft; Filer; Findalarm - HP 48gII Advanced User's Reference Manual

Graphing calculator.

Input/Output:
CF, FC?, FS? FS?C, SF

## FDISTRIB

CAS:
Perform a full distribution of multiplication and division in a single step.

### FFT

Type:
Command
Description: Discrete Fourier Transform Command: Computes the one- or two-dimensional discrete Fourier
transform of an array.
If the argument is an N-vector or an N × 1 or 1 × N matrix, FFT computes the one-dimensional
transform. If the argument is an M × N matrix, FFT computes the two-dimensional transform.
M and N must be integral powers of 2.
The one-dimensional discrete Fourier transform of an N-vector X is the N-vector Y where:
for k = 0, 1, ..., N – 1.
The two dimensional discrete Fourier transform of an M × N matrix X is the M × N matrix Y
where:
for k = 0, 1, ..., M – 1 and l = 0, 1, ..., N – 1.
The discrete Fourier transform and its inverse are defined for any positive sequence length.
However, the calculation can be performed very rapidly when the sequence length is a power of
two, and the resulting algorithms are called the fast Fourier transform (FFT) and inverse fast
Fourier transform (IFFT).
The FFT command uses truncated 15-digit arithmetic and intermediate storage, then rounds the
result to 12-digit precision.
!´L
Access:
Input/Output:
IFFT

### FILER

Type:
Command
Description: Opens File Manager.
Access:
...µ
Input/Output: None

### FINDALARM

Type:
Command
3-64 Full Command and Function Reference
Level 1/Argument 1
n
flag number
N 1
Y
=
k
n
=
M 1
N
1
Y
=
kl
m
=
0
n
=
0
FFT FFT
Level 1/Argument 1
[ array ]
FILER
2 i kn
-------------- -
N
X
e
i
=
1 –
n
0
2 i ln
2 ikm
----------------- -
--------------- -
N
M
x
e
e
i
=
m n
( ´ is the left-shift of the Pkey).
1
( ¡ is the left-shift of the Gkey).
Level 1/Item 1
0/1
1 –
Level 1/Item 1
[ array ]
2