Apparatus for digitally representing angular displacement

Claim 1

An arrangement for digitally representing the angular position of the rotor of a goniometer having fixed windings, said arrangement comprising; a high-frequency signal source, a frequency divider comprising a first counter having an input circuit connected to said high-frequency signal source for deriving a divided low-frequency signal therefrom, means for receiving said low-frequency signal, for deriving sinusoidal voltages in phase quadrature from said signal and for supplying said voltages to the fixed windings of the goniometer, a second counter for receiving said high-frequency signal, a storage device for storing the count of said second counter, a transfer circuit connected between said second counter and said storage device and including an activating input circuit, said transfer circuit transferring the count of said second counter in response to the application of an activating pulse to said activating input circuit, phase-responsive means for receiving the output voltage of said goniometer and for generating, in response to a predetermined phase value of said output voltage of said goniometer, an activating pulse in an output circuit thereof, said output circuit being connected to said activating input circuit of said transfer circuit, means for deriving a reference voltage representative of the phase of the voltage of said goniometer, signal-adjusting means connected to said first counter for varying the number of pulses supplied to said first counter in response to a phase control signal thereto, a phase detector having a first input circuit connected to said reference-voltage-deriving means and a second input circuit connected to an output circuit of said second counter for generating a phase control signal, and means for applying said phase control signal to said signal-adjusting means.