A method for etching a dielectric layer disposed below an antireflection layer is provided. The translucent portion has an inner space formed therein, and the translucent portion includes a first wall, a second wall opposite the first wall, and a third wall connected to each of the first wall and the second wall. The floating electrode includes a first floating electrode provided on the tunnel insulation film and a second floating electrode provided on one end portion of the first floating electrode, the floating electrode having an L-shaped cross section in a wiring direction of the control electrode. Each calculated difference is encoded using a Golomb code. More particularly, the invention relates to a method of recovering symbol synchronization of an OQPSK demodulator in which a reference correlation value is reset using a correlation value of a reception signal when detecting symbol synchronization in the OQPSK demodulator, preventing errors in detecting symbol synchronization due to noise, thereby increasing the accuracy in symbol synchronization.