User manual

PicoScope 6 User's Guide 93
Copyright © 2007-2013 Pico Technology Ltd. All rights reserved. psw.en r32
6.5.8.3
Sampling page
Location:
Tools > Preferences > Sampling
Purpose:
controls the sampling behaviour of the oscilloscope
Slow Sampling Transition
In normal (fast) sampling mode, PicoScope collects enough data to fill the screen and
then redraws the whole view at once. This method is suitable for fast timebases, when
the screen is redrawn many times each second, but with slow timebases it can cause a
unacceptable delay before the data appears on the screen. To avoid this delay,
PicoScope automatically switches to slow sampling mode, in which the scope trace
advances gradually across the screen as the scope captures data.
The Collection Time control lets you select the timebase at which PicoScope switches
to slow sampling mode.
Slow Sampling Display
When this box is checked, PicoScope displays the previous waveform in the buffer
while gradually redrawing the new waveform over the top of it. Thus, at any time, the
left-hand side of the view shows the beginning of the new waveform, while the right-
hand side shows the end of the previous waveform. A vertical bar separates the two
waveforms.
Sin(x)/x Interpolation
When the number of pixels across the scope view is greater than the number of
samples in the waveform buffer, PicoScope interpolates - that is, it fills the space
between the samples with estimated data. It can either draw straight lines between
the samples (linear interpolation) or connect them with smooth curves (sin(x)/x
interpolation). Linear interpolation makes it easier to see where the samples are,
which is useful for high-accuracy measurements, but results in a jagged waveform.
Sin(x)/x interpolation gives a smoother waveform but disguises the true locations of
the samples, so should be used with care when the number of samples on the screen
is low.
You can adjust the number of samples below which sin(x)/x interpolation is switched
on. Sin(x)/x interpolation is used only on the scope's fastest timebase.