Original Publication Date: 1980-Aug-01
Included in the Prior Art Database: 2005-Feb-13
The illustrated circuit converts the output signals from the two-phase optical tachometer T into a binary position count. The tachometer may be used with a stepping motor M having an underdamped characteristic when making a last step to a target position. Holding the target position can cause a marginal count up, count down indication from tachometer circuits. Such marginal decisions are prevented by this circuit by a rapid counting circuit and hysteresis tachometer. The illustrated circuit enables the use of a narrow hysteresis for enabling a more precise indication of position, particularly during the reversal of direction of motion. The two sets of signal waveforms illustrate the detailed operation of the illustrated circuit.