on the top of the backrest to measure fore-aft vibration. A singleaxis
accelerometer was placed on a plate and used to measure
the vertical acceleration of the floor. It was mounted on the
floor beneath the front edge and centreline of the seat. Signals
were acquired into the 18-channel PULSE data-acquisition and
analysis system. The signal-recording period was 60 s except
when on the suburban road, which is mentioned in Section 4.4.
According to the aforementioned standards, excitations up to
80 Hz should be counted for whole-body vibration analysis.
Therefore, the frequency span of measurements was chosen as
100 Hz in the PULSE Labshop software. The sampling frequency
was automatically adjusted to 256 Hz, according to
the Nyquist rule (2.56 multiplied by 100 Hz as the frequency
span). Signals were bandpass-filtered to be in the range of 0.5
to 80 Hz.