Resources Contact Us Home
Phase difference detection device and method for a position detector

Image Number 11 for United States Patent #6885310.

Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(.omega.t.+-.d+.theta.), sin((.omega.t.+-.d-.theta.)) are electrically synthesized which have electric phase angles (.theta.) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. ".+-.d" here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (.+-.d) appear in the same direction, while the phase differences (.theta.) corresponding to the position are shifted in opposite, positive and negative, directions. Thus, by measuring the respective phase shift amounts (.+-.d+.theta., .+-.d-.theta.) and performing appropriate operation, it is allowed to cancel out or extract the error (.+-.d) so that an accurate phase difference (.theta.) can be detected. Position detection data indicative of the detected phase difference (.theta.) is converted into a pulse-width-modulated signal and transmitted in the pulse-width-modulated form.

  Recently Added Patents
Terminal device, system and computer readable medium
Virtual image display device and manufacturing method of virtual image display device
Human activity monitoring device
Method of purifying crude acetone stream
Integrated monitoring in problem management in service desk
5-lipoxygenase-activating protein (FLAP) inhibitors
Method and device for surface scanning of a patient
  Randomly Featured Patents
Log for selective management of specific address in a shadow storage system
Automated spell analysis
Rotary cone drill bit with improved support arms
Process for treating loaded extractant from purification of phosphoric acid by extraction and recovering nutrients
Differential for a vehicle
Method and apparatus for processing blocks in a pipeline
Inflatable mailer, apparatus and method for preparing the same
Semiconductor device comprising thin film transistor comprising conductive film having tapered edge
Methods and apparatus for controlling an air inlet closure of an air conditioner