Hioki PW8001-01 Instruction Manual page 104

Changing the Waveform Display and Configuring Recording
Peak-to-peak compression
Values sampled at rate of 15 MS/s
Waveform
drawn at a rate
of 500 kS/s
To compress a waveform sampled with a rate of 15 MS/s
to that composed of points with a rate of 500 kS/s by
using the peak-to-peak compression
Aliasing
Sampling interval
98
Maximum value
Even if you change the sampling frequency setting,
the instrument samples signals internally with
a sampling rate of 15 MS/s. When reducing the
sampling frequency, decimate of sampling points
from a waveform sampled with the rate of 15 MS/s
at regular intervals may decimate the maximum
and minimum values in the interval. The peak-
Minimum value
to-peak compression is the way to select and
decimate other points leaving the maximum and
minimum values in the interval.
Maximum value
In this way, you can reduce the sampling frequency
maintaining accurate waveforms that preserve the
peaks of the uncompressed waveforms.
The waveform data to be saved consists of two
values per data point, the maximum and minimum
values as illustrated in the figure on the left.
Minimum value
Actual input signal
When the change of a signal under measurement
becomes faster with respect to the sampling
frequency, a slow signal changes that do not exist
at a certain frequency are recorded.
This phenomena is called aliasing.
Observed waveform
Aliasing has occurred
because the sampling
frequency is low relative
to synchronization of the
incoming signal.
HIOKI PW8001A961-00