An audio system is disclosed and includes a semiconductor device having an analog-to-digital converter system and includes a controller and a programmable control register coupled to the controller. For each speech frame, one of four possible bit rates is used to encode the frame according to the standard. In addition, certain control techniques that take into account certain parameters, such as physical parameters of the workpiece being heated, the heating process parameters, and so forth, may be implemented. The pressure transducer is in communication with an instrument that can display the pressure detected in the pressure chamber for analysis. The mounting bracket is suitable for different types of motors.