PSM3750 Quick User Guide
Page 10
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. Smoothing does not affect
a single sweep as each point is a single
measurement. If Sweep is set to continuous then the
smoothing is applied to each new sweep result
Normal
With Normal smoothing applied the following update
windows will apply to the relevant speed selected.
V.Fast =0.1s, Fast = 0.4s, 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
Smoothing Response
Auto Reset
The smoothing response is by default
set to “auto
reset” where the filtering
described in “smoothing”
is
reset in response to a significant change in data. This
speeds up the response of the instrument to changing
conditions
Fixed Time
Auto reset can be disabled so that the filtering has a
fixed time constant, which would have an exponential
response to a step change
Phase Reference
In the case where there is very little signal on CH1,
the reference for the phase can be set to another
channel to give a more accurate measurement. This
does not change the phase results it only helps to
reduce the uncertainty due to noise.
Channel 1
Select to choose Channel 1 as reference
Channel 2
Select to choose Channel 2 as reference
Channel 3
Select to choose Channel 3 as reference (If fitted)
Low Frequency
When the generator is not used and so the
measurement is synchronised to the input frequency
measured on CH1, there is a low frequency option
that extends the frequency measurement down to
10μ
Hz. This low frequency option also applies a digital
filter which can be useful when measuring in low
frequency, noisy environments
Off
Select to switch this mode Off
On
Select to switch this mode On