Fourier Systems Ltd.
16 Hamelacha St., POB 11681, Rosh Ha
‘
ayin 48091,
Tel: +972-3-901-4849, Fax: +972-3-901-4999
www.FourierEdu.com
EXPERIENCE
SCIENCE!
There is no such thing as over-sampling.
For extremely smooth graphs, the
sampling rate should be about 20 times the expected frequency.
Note:
Sampling at a rate slower than the expected rate can cause
frequency
aliasing
. In such a case, the graph will show a frequency much lower than
expected. In Figure 3 below, the higher frequency sine wave was sampled at
1/3 of its frequency. Connecting the sampled points yielded a graph with a
lower, incorrect frequency.
Figure 3: Frequency Aliasing
Manual
sampling - use this mode for:
Recordings or measurements that are not related to time.
Situations in which you have to stop recording data after each sample
obtained, in order to change your location, or any other logging
parameter (
Note:
During the experiment
no changes
can be made to
the MultiLogPRO
’
s configuration).
To start an experiment using manual data logging, set the
RATE
to
manual
and
press the
Enter
button
once to start the data recording, then press the
Enter
button each time you want to collect a sample.
You can also perform manual logging via MultiLab (see page
Error! Bookmark not
defined.
).
2.
Sampling Points -
After you have chosen the sampling rate, choosing the
number of points will determine the logging period: Samples / Rate = Logging
time. You can also choose the duration of an experiment first, and then
calculate the number of samples: Samples = Logging time
Rate.
Continuous
In the Continuous mode, MultiLogPRO does not save data, and can continue logging
indefinitely.
