Novel microprocessor-based tachometer using ramp-waveform sampling technique

The author looks at the development of a novel microprocessor-based tachometer using an innovative method, referred to as the `ramp-waveform 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. The speed measurement algorithm requires a small number (minimum of two) of sampling points on each ramp and employs linear regression methods to extrapolate backwards and hence determine the starting point of each pulse very accurately