Scans by ArtekMedia © 2007
Minimum
Sampie Rate
The Effect of Sample Rate
upan Signal Reconstruction
To accurately record a waveform so that it may be reconstructed from
stored data, the input signal must be sampled often enough for its charac
teristics to be apparent from the sampled data. This is illustrated below for
a signal of frequency {(black line). The colored line shows the signal as it
would be reconstructed from data recorded at various sample rates. Clearly,
higher sampling rates improve reconstruction.
1- '
CYCLE
---!
1.5
SAMPLES/CYCLE
J SAMPLES/CYCLE
1- 1
CYCLE-
I
1-'
CYCLE
-
I
4 SAMPLES/CYCLE
10
SAMPLES/CYCLE
During a buffered recording, each buffer obtains
1000
input-signal samples
with the
TOTAL TIME.
The resulting sample rate
R
may therefore be expressed
as
R=
lOoo/TOTAL TIME
To assure data plotted from the buffers will accurately portray the recorded
signals, a minimum of
lO
samples per cycle of the maximum input
fre
Quency {mill should be obtained. Because the sample rate
R
is determined by
the
TOTAL TIME
setting according to the equation above, accurate recon
struction may be obtained by setting
TOTAL TIME
�
100/{mIU
4-6
Performing
Direct
and Buffered Recordings
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