Displacement sensor
First Claim
Patent Images
1. A displacement sensor comprising:
- only one transducer comprising;
only one primary coil arranged to receive a periodic signal from a signal source;
two secondary coils spaced from said primary coil for mutual induction with said primary coil, said two secondary coils being differentially connected to provide only one periodic secondary output signal from said differentially connected secondary coils; and
only one movable magnetic core disposed between said primary coil and said secondary coils and arranged to be movable relative to said primary coil and said secondary coils;
at least one phase shift circuit coupled to said secondary coils, said at least one phase shift circuit receiving said only one periodic secondary output signal and developing at least one periodic phase-shifted signal which is a phase-shifted version of said only one periodic secondary output signal, said at least one phase shift circuit phase shifting said only one periodic secondary output signal in such a manner that a peak of said at least one periodic phase-shifted signal is located between adjacent peaks of said only one periodic secondary output signal;
first rectifying means for rectifying said only one periodic secondary output signal;
at least one second rectifying means for rectifying said at least one periodic phase-shifted signal;
combining means for combining a rectification output of said first rectifying means and a rectification output of said at least one second rectifying means for developing a combined output; and
low-pass filter to which said combined output is supplied.
1 Assignment
0 Petitions
Accused Products
Abstract
A displacement sensor includes a primary coil (2), secondary coils (4a, 4b), and a movable magnetic core (6) movable with displacement of an object to be measured to cause voltages generated in the secondary coils (4a, 4b) to vary. The secondary coils (4a, 4b) are differentially interconnected. A polyphase signal generating unit (10) generates two-phase component signals having different phases, from a differentially combined output voltage of the secondary coils (4a, 4b). Full-wave rectifying units (16, 18) rectify the polyphase component signals, the rectified polyphase component signals are combined in a combiner (22), and the combiner output is applied to a low-pass filter (24).
18 Citations
6 Claims
-
1. A displacement sensor comprising:
-
only one transducer comprising; only one primary coil arranged to receive a periodic signal from a signal source; two secondary coils spaced from said primary coil for mutual induction with said primary coil, said two secondary coils being differentially connected to provide only one periodic secondary output signal from said differentially connected secondary coils; and only one movable magnetic core disposed between said primary coil and said secondary coils and arranged to be movable relative to said primary coil and said secondary coils; at least one phase shift circuit coupled to said secondary coils, said at least one phase shift circuit receiving said only one periodic secondary output signal and developing at least one periodic phase-shifted signal which is a phase-shifted version of said only one periodic secondary output signal, said at least one phase shift circuit phase shifting said only one periodic secondary output signal in such a manner that a peak of said at least one periodic phase-shifted signal is located between adjacent peaks of said only one periodic secondary output signal; first rectifying means for rectifying said only one periodic secondary output signal; at least one second rectifying means for rectifying said at least one periodic phase-shifted signal; combining means for combining a rectification output of said first rectifying means and a rectification output of said at least one second rectifying means for developing a combined output; and low-pass filter to which said combined output is supplied. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification