Inductive angle sensor with improved common mode noise rejection and signal processing method of the same
The present invention provides an inductive angle sensor with improved common mode noise rejection and a signal processing method of the same, which can improve electromagnetic compatibility (EMC) characteristics and obtain an accurate output value by eliminating common mode noise. The signal processing method includes adding signals obtained from a pair of receiver coils by an adder, subtracting the signal obtained from one of the pair of receiver coils from the signal obtained from the other receiver coil by a subtracter, multiplying the value obtained from the adder by the value obtained from the subtracter by a first multiplier, multiplying the value obtained from the subtracter by itself by a second multiplier, and dividing the value obtained from the first multiplier by the value obtained from the second multiplier by a divider.
1. An inductive angle sensor with improved common mode noise rejection, the inductive angle sensor comprising:
an exciting coil formed with a ringshape and connected to an oscillator;
a coupler formed with a semicircular shape and spaced a predetermined distance from the exciting coil;
a pair of receiver coils disposed between the coupler and the exciting coil and disposed symmetrically on both sides of a center line; and
a signal processor connected to the pair of receiver coils to output a signal obtained by adding and subtracting signals obtained from the receiver coils and then multiplying and dividing the signals,
wherein the signal processor comprises an adder adding the signals obtained from the pair of receiver coils, a subtracter subtracting the signal obtained from one of the pair of receiver coils from the signal obtained from the other receiver coil, a first multiplier multiplying the value obtained from the adder by the value obtained from the subtracter and connected to a low pass filter, a second multiplier multiplying the value obtained from the subtracter by itself and connected to a low pass filter, and a divider dividing the value obtained from the first multiplier by the value obtained from the second multiplier.
2. A signal processing method that processes signals obtained from the inductive angle sensor with improved common mode noise rejection of claim 1 , the inductive angle sensor comprising a signal processor including an adder, a subtracter, a first multiplier, a second multiplier, and a divider, the method comprising:
adding signals obtained from a pair of receiver coils by the adder;
subtracting the signal obtained from one of the pair of receiver coils the signal obtained from the other receiver coil by the subtracter;
multiplying the value obtained from the adder by the value obtained from the subtracter by the first multiplier;
multiplying the value obtained from the subtracter by itself by the second multiplier; and
dividing the value obtained from the first multiplier by the value obtained from the second multiplier by the divider.
3. The signal processing method of claim 2 ,
wherein the value obtained by the first multiplier multiplying the value obtained from the adder by the value obtained from the subtracter is passed through a low pass filter to be filtered, and
the value obtained by the second multiplier multiplying the value obtained from the subtracter by itself is passed through a low pass filter to be filtered.