A visual presentation apparatus includes a generally rectangular stage on which a material is placed, a video camera for obtaining an image of the material, a camera arm on which the video camera is mounted so that the video camera is located above a central portion of the stage, and an arm mount provided outside one of corners of the stage. The VLIF signal may be further downconverted to a baseband signal in the analog domain. The compression assembly is attached to at least one wall member and forms the screen assembly into a concave shape. Also, the second direction is the direction among in-plane directions of the photomask that is perpendicular to the alignment direction. The words A, B, C to be searched can be characterized by two auxiliary bits Z whose formation is exactly inverted relative to that of normal data words A, B, C. Further embodiments provide LVADs that are powered by RF energy.