Abstract: A mixer circuit is provided with a quadrature demodulator including a Gilbert cell in which a first differential amplifier and a switching circuit are vertically stacked for connection and a bypass circuit including a second differential amplifier having a pair of differential input terminals short-circuited with each other, and provided in parallel with the first differential amplifier. Correction of a DC offset is performed by inactivating the first differential amplifier and activating the second differential amplifier, and detecting the DC offset under such state.

Abstract: An information recording medium suitable for optical discs such as DVD-RAM is provided for integrated management of data as objects in different kinds of AV formats. Also apparatus is provided for data recording and playing to the medium. The medium stores management information including program chain information (PGC information) defining the playback order of the objects, and object information containing information relevant to the objects. The object information has general information of the object, attribute information and a map associating a playback time point of the object with an address on the optical disc of a component of the object to be played. The PGC information has cell information including information about type of object, identification information. The order of the cell information in the PGC information corresponds to the order in which the objects are played back.

Abstract: A profile measuring apparatus provided with an improved probe for measuring profiles throughout a wide area of the surface of an object with a high level of response and high accuracy. The probe 10 comprises an arm 3 having a stylus 1 fixedly mounted to the distal end thereof, which is coupled to a stationary part 11 of the apparatus by an arm holding member 5 made of a V-shaped leaf spring in such a way that the arm 3 is tilted in one axial direction by a contact pressure exerted thereto during measurement. Displacement of the arm 3 is thereby detected through measuring an elastic deformation of the leaf spring caused by the contact pressure exerted to the stylus 1 being pressed against the surface to be measured.