Abstract: Disclosed is a microcontroller based Resolver-to-Digital converter in which synchronous sample-and-hold type demodulation is used with an optimum time of the sample-and-hold established by control of the phase and the magnitude of the reference voltage supplied to the resolver as a function of the resolver's electrical characteristics, thus minimizing the quadrature and the even harmonics effects which are a byproduct of the resolver. The demodulated resolver outputs are filtered and are converted to digital form with the use of an A/D converter integral or external to the microcontroller. The magnitude of the reference voltage is set to an optimum value in order to utilize the full range of the A/D converter. Using digital signal processing techniques and known trigonometric identities the shaft angle of the resolver is extracted from the A/D outputs and supplied to the output latches in continuous or bus controlled fashion.

Abstract: A DC to DC sine/cosine positioning servo system has an electro-mechanical DC to AC converter. The latter includes a DC torquer, having a rotor with respective windings for receiving two DC input signals proportional to the error signals detected. Mechanial movement of the rotor is proportional to the relative values of the two input signals. The rotor of a synchro control transmitter is mechanically coupled to the rotor of the DC torquer. A reference oscillator is provided which produces an AC output voltage at a predetermined frequency. The oscillator output is connected to the rotor of the control transmitter. The stator windings of the control transmitter are connected to the stator windings of a control transformer. The rotor of the control transformer produces an output voltage directly proportional to the relative angle between the rotor of the control transformer and the stator windings.

Abstract: The resolver input module for use in programmable controller systems is one of several modules mounted in a rack to form a programmable controller. The module's function is to provide position data from an externally located resolver which is connected to a machine's shaft to the programmable controller's processor module. This is accomplished by moving the resolver analog-to-digital conversion circuitry from an external module location to the programmable controller input/output rack and coupling this circuitry to circuits which synchronize the programmable controller's input fetch signals. Additionally, a user operable entry mechanism for digitally offsetting the resolver position by a user-selectable amount while accommodating different scale factors is provided. Synchronization and alignment circuitry are provided for synchronizing and aligning data to compensate for different resolver gear ratios in coarse-fine geared resolver decoding circuitry.

Abstract: A synchro-to-digital converter circuit is disclosed which includes memories that store digitized representations of the waveforms produced by the resolver. By matching these digitized waveforms to the specific resolver with which the circuit is to be employed, errors produced by the resolver are compensated.Two embodiments of the synchro-to-converter circuit are disclosed as well as a circuit for creating and storing the matched waveforms.

Abstract: A linear, analog, synchro control differential transmitter for implementing he common synchro CDX function whereby a scaled linear analog voltage is used as input instead of a mechanical shaft angular displacement. Alternate synchro functions of CT and CX that the invention implements are also disclosed.

Abstract: A cycle-portion encoder, an electronic circuit to dynamically measure the period of a variable electrical input signal and generate an output signal at a preselected time in the next cycle, is provided. The cycle-portion encoder locates a point in time in a recurrent signal's period of interest, based on the real-time measurement of the immediately preceding cycle period and a selected portion of the period of interest. A control output is delivered at the desired phase angle (with respect to the input signal) with a resolution limited only by the counting and gating electronics, and an error primarily related to the repeatability of the input signal from cycle to adjacent cycle.

Abstract: A compass data converter converts 180X and 90X synchro compass data to 1/6 degree step data. 180X synchro data is converted by utilizing a 360X to 1/6 degree step data converter that divides the synchro rotation into six 60.degree. sectors providing a digital step data code representative thereof. A 180X converter further sub divides the 60.degree. sectors into 30.degree. sub sectors by selecting a synchro output in accordance with the step data code from the 360X converter and comparing the selected synchro output to ground to provide an additional step data digit. The converter for 90X data further sub-divides the 30.degree. sub-sectors into 15.degree. intervals by selecting two synchro outputs in accordance with the 360X step data code and the additional step data digit and scaling one of the selected synchro outputs to equal the other selected synchro output at the 15.degree. interval boundaries.

Abstract: An apparatus for generating phase modulated angular positional signals in digital form. A phase tracking loop receives a phase modulated signal from the rotor of a resolver whose stator windings are excited in quadrature. The phase output of the resolver is proportional to the angular displacement of the rotor. Signals for exciting the stator windings of the resolver are applied in phase quadrature to a phase detector to develop an analog error signal when combined with the rotor output signal. The analog phase error signal provides an output indicative of the angular displacement of the rotor. The error signal is applied to a voltage controlled oscillator, converted to digital form, and combined with the excitation signals in a closed loop to force the error signal to a null, whereupon the indicated digital output angle is in coincidence with the angular displacement of the rotor shaft.

Abstract: A set rotation angle width related to a rotary machine, of which the rotation speed varies cyclically, is converted to a time width required for the rotary machine to rotate by the set rotation angle width from a given rotation angle position. The converted time width is corrected by a correcting coefficient so that the time width is not affected by the rotation variation of the rotary machine. The correcting coefficient is decided based on the rotation angle position and the rotation speed variation of the rotary machine related to the set rotation angle width from the rotation angle position, and by the correcting coefficient, correction is done so that an actual rotation angle width corresponding to the converted time width becomes the set rotation angle width.

Abstract: A system for producing a digital representation of the value of an angle .theta., typically a phase angle, from two analog input quantities representative of A sin .theta. and A cos .theta., where A is an amplitude factor, comprises logarithmic amplifiers (IC1-IC4) which produce analog representations of a plurality of quantities (sin .theta., cos .theta., sin (.theta.+3.pi./4), cos (.theta.+3.pi./4)) derived from the two input quantities and which are arranged to add or subtract their outputs to produce quantities (V.sub.1 -V.sub.4) which are independent of A and the value of each of which lies within a predetermined range (-C to +C) in at least one respective portion (2.pi./n) of an angular range for .theta. of 2.pi. radians. The digital representation of .theta. is the concatenation of digital representations of the angular portion (2.pi./n) in which .theta. lies and of the value of .theta. within the portion that is derived from the selected appropriate one of the quantities V.sub.1 -V.sub.

Abstract: Apparatus and methods for tracking a positioning system for antennas and other devices. Hardware of the invention contains circuitry which when given velocity information, changes its output position information at a specified rate. The hardware may also be triggered to capture a sample of such output position information to provide feedback to the firmware of the invention, which implements a position tracking algorithm. The algorithm utilizes two consecutive input position samples, the time between those samples and the feedback information corresponding to the last position input sample to calculate the velocity to be applied to the position tracking hardware until a new position input sample is available. When the new sample is available, a new velocity is calculated and applied to the hardware and the process is repeated. Between position input samples, the hardware updates the output position to correspond to the motion of the positioning system.

Abstract: A circuit can be configured to process signals from either a resolver or an encoder to derive an indication of the sensed angular position. (1) When the circuit is configured for an encoder, the output from the encoder is periodically sampled. The phase relationship of the encoder input signals controls a counter. The output of the counter is periodically sampled to provide the position indication. (2) In the resolver configuration, the counter is rest at regular intervals. An apparatus detects zero crossings from the resolver signal and in response thereto samples the counter output to provide a measurement of the time interval between the counter reset and the zero crossing. The magnitude of the time interval corresponds to the phase angle of the resolver signal and hence to the angular position.

Abstract: Two-phase voltage signals for use with a resolver-to-digital converter (RDC) are produced as a periodic function of permeance developed across an air gap between a rotor and stator wherein the permeance varies as a periodic sinusoidal function which can be related to the electrical angle of the position of the rotor. The two-phase voltage signals are developed as a function of inductive reactance and follow the form ##EQU1## wherein the phase angle between V.sub.x and V.sub.y is exactly 90.degree. and the term [A+A.sub.n +B+B.sub.n ] is completely free of second harmonics.