PPA45xx Quick User Guide
Page 11
Speed
In normal acquisition mode the window over which
the measurements are computed is adjusted to give
an integral number of cycles of the input waveform.
The results from each window are passed through a
smoothing filter. There are 5 pre set speed options
that adjust the nominal size of the window, and
therefore the update rate and time constant of the
filter. Greater stability is achieved at a slower speed at
the expense of a slower update rate
Very Slow
Update rate = 10s. Results window size will update
every 10 seconds
Slow
Update rate = 2.5s. Results window size will update
every 2.5 seconds
Medium
Update rate = 1/3s. Results window size will update 3
times per second
Fast
Update rate = 1/20s. Results window size will update
20 times per second
Very Fast
Update rate = 1/80s. Results window size will update
80 times per second
Window
The window application will allow the user to input
their own speed settings different to any of the 5 pre
set settings above
Smoothing
Smoothing filter will gather the data and average out
over a sliding window time scale. This is very useful
when gathering data which could be affected by
noise. Each speed above has its own time constant
for filtering and data updates
Normal
With Normal smoothing applied the following update
windows will apply to the relevant speed selected.
V.Fast =0.05s, Fast = 0.2s, Medium = 1.5s,
Slow = 12s, V.Slow = 48s
Slow
With Slow smoothing selected all results are X4
greater than in normal smoothing mode
None
With no smoothing to computed results the data
update will be dictated by the speed only
