Evaluation arrangement for a digital incremental transmitter

Claim 1

An evaluation arrangement for a digital incremental transmitter of the type having first and second transmitter outputs for producing respective sinusoidal voltages of equal amplitude which are shifted in phase by 90° with respect to one another, the evaluation arrangement further having a converter for converting the sinusoidal voltages of the first and second transmitter outputs into a measurement signal corresponding proportionally to the count of the periods of the sinusoidal voltages produced, the evaluation arrangement further comprising; means for producing a periodic triangular voltage having a fundamental frequency which is an integral multiple of the frequency of the sinusoidal voltages in response to an interlinking of linear portions of the sinusoidal voltages; converter means for converting said triangular voltage into corresponding digital values; logic means for producing digital logic signals which are derived from the sinusoidal voltages and whose state combinations correspond one to one to the circular segments of the sinusoidal voltages within a period; and memory means for storing a plurality of corresponding absolute values of the sinusoidal voltages within a period, said memory means having an output for producing selected one of said absolute values and an input for receiving said digital values and said digital logic signals, said absolute values being selected in response to said digital values and said digital logic signals so as to establish the actual position value within a period of the sinusoidal voltages.