The scope of this paper relates to the
development of a novel microprocessorbased
tachometer using an innovative
method, here referred to as the 'rampwaveform
sampling technique', to provide
high accuracy and fast dynamic response
while maintaining relative simplicity both
in terms of the basic electronics and the
computational algorithm. The ramp
waveform is generated electronically by
means of the 'analogue integration' of the
time difference between consecutive
encoder pulses. This is achieved using a
temperature compensated linear ramp
generator which employs a transistor
switch, turning on-off at the falling and
rising edges of the train of square pulses
from the sensor, and a constant current
source to charge a capacitor.