A method and apparatus for modifying the level of a speech signal is provided in which the gain parameter in the encoded speech signal is changed in a variable and cyclical manner over time. The method includes providing a stable high frequency reference signal and dividing the high frequency reference signal to provide a system clock signal having a plurality of system clock phases. An information processing device fetches the information via the communication line and executes creation of report data for recording related to inspection data of the thermal equipment and delivers the created report data to the facility site. Removal of the functional groups results in a change in the net change in the charge of the polymer which can disrupt interactions between cations and the anionic polymers and facilitate release of cations. The holding unit has a stopper which is formed of a conductive material and holds the brim of the semiconductor substrate, a stopper holder which supports the stopper at the outer circumferential portion thereof, a retaining member which retains the stopper to the support disk, and a heating unit which heats the stopper.