A quadrature demodulation device effectively utilizes the result of quadrature detection in order to improve demodulation efficiency. Each of these two 180\xb0 fold lines of the fold-in panels includes first and second compressed areas extending from respective ends of the 180\xb0 fold line, and a C-shaped cut extending between the first and second compressed areas. The system page memory locations are mapped into user tasks as read-only memory locations, allowing read-only memory accesses during run-time. The illumination fixture includes a reflector having a concave reflecting surface, a socket, and an attachment.