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Press <Sample Rate>
Use the knob to select 32 Hz.
Press <Scan Length>
Press [1] [0] [0] [ENTER]
Press <1 Shot/Loop> to select 1 Shot.
9. Press [START/CONT]
sets the amount of time the buffer will store and
the length of any sweep.
In this measurement, let's leave the trace defini-
tions equal to the defaults and just change the
sample rate and scan time.
Highlight the sample rate.
The trace data will be sampled at 32 Hz and
stored in the buffer. After each data point is
recorded, the reference frequency will be updated.
This determines the resolution of our data along
the time axis.
Highlight the scan length.
Set the scan length to 100 seconds (1:40). This
configures the data buffer to hold 3200 data points
(32 Hz sample rate x 100 second scan length).
The scan length is also the sweep time for the
internal frequency sweep. Sweeps are always
coordinated with the data acquisition. In this case,
the sweep range is 120 Hz (40 Hz to 160 Hz) and
will take 100 seconds and be updated 3200 times.
Each stored data point will represent a frequency
increment of 0.0375 Hz (120/3200).
Scans can repeat (Loop) or stop when finished (1
Shot). Let's take a single scan of data.
Now you're finally ready to start the scan.
The [START/CONT] key starts the scan and
sweep. The scan indicator at the bottom left corner
of the screen switches from STOP to Run 1 (single
scan in progress). The reference frequency read-
out at the bottom center displays the frequency
while sweeping.
As the frequency passes through 60 (50) Hz and
120 (100) Hz, the value of R should drop close to
zero as the signal sweeps through each input
notch filter.
When the scan is complete, the scan indicator
switches to DONE and the frequency should be
160 Hz.
Now let's try displaying the data in a more mean-
ingful way.
Scans and Sweeps