A 3D input system and an angle encoder are disclosed. The 3D input system comprises a computing device and one or more position sensing gloves. The position sensing glove comprises a plurality of angle encoders each installed thereon at a location about a finger joint. An inertial measurement unit (IMU) is installed on the glove. A firmware uses data from the angle encoders and IMU to calculate fingertip positions in a 3D space. The firmware generates keystrokes on a virtual keyboard based on the fingertip positions. The angle encoder comprises a first and a second components rotatable with respect to each other, and an encoder pattern comprising codewords for indicating the angle between the first and second components. The encoder pattern comprises a set of base encoder channels coded with a conventional Gray code, and a set of Booster channels for improving the resolution of angle measurement.