HP 83480A User Manual

General Purpose Oscilloscope Menus
FFT Menu
Aliasing
When using FFTs, it is important to avoid aliasing. Aliasing occurs when
there are insucient samples on each cycle of the input signal to recognize
the signal. Aliasing occurs whenever the frequency of the input signal is
greater than or equal to the Nyquist frequency (eective sample frequency
divided by 2).
When a signal is aliased, it shows up in the FFT spectrum as a signal of a
lower frequency. Because the frequency span goes from 0 to the Nyquist
frequency,
the best
way
to
prevent
aliasing
is
to
make
sure
that
the
frequency
span is
greater than
the frequencies
present
in
the
input
signal.
K
eep
in
mind that
most periodic
signals that
are
not
sine
waves
have
frequency
components
that
are
much
higher
than
the
frequency
of the
signal.
Presetting
FFT
parameters
The
FFT
vertical
parameters
,
Magnify
,
Magnify span,
and Center
frequency
are
set
to
the
default
values
whenever
the
operand
(or
operator
,
if
the
FFT
magnitude
operator
is
selected
from
the
Math
menu)
is
changed.
10-35

HP 83480A Specifications

General

Brand	HP
Model	83480A
Category	Measuring Instruments
Language	English