Abstract: An audio system is constructed by a personal computer and an audio device, which are connected together by way of a serial bus such as a universal serial bus (USB), for example. The audio device such as an audio component stereo system provides at least one audio source such as the tuner and recording media, which provides first audio data representing music or else. The personal computer uses graphical user interface (GUI) for controlling operation of the audio data, wherein it provides control data and second audio data representing message sounds, which are transmitted to the audio device via the serial bus. Thus, the audio device performs mixing between the first audio data and second audio data on the basis of the control data. Then, speakers produce sounds based on mixing result. The audio device is equipped with an analog mixing circuit, which performs analog mixing between analog signals corresponding to the first and second audio data respectively.

Abstract: A frequency control apparatus controls the frequency of an output signal thereof in synchronism with an externally input timing signal. A variable frequency oscillator generates the output signal such that the output signal has a frequency thereof variable in response to a control signal input to the variable frequency oscillator. An input device receives the timing signal. A checking device checks a monitor amount variable in response to the frequency of the output signal from the variable frequency oscillator, in timing in which the timing signal is input. A calculating device calculates a difference between the checked monitor amount and a predetermined desired amount. A control device controls the control signal input to the variable frequency oscillator such that the calculated difference becomes zero.

Abstract: Disclosed is a process for the preparation of a composite metal oxide superconductor, in which a composite metal oxide composition comprising Bi, Pb, Sr, Ca and Cu and further containing an alkali metal at a specific ratio is used as the starting material, and this composite metal oxide composition is molded and fired. According to this process, precipitation of the 80 K phase and other impurities is controlled, and a superconductor containing a large quantity of the 110 K phase and a high critical temperature is obtained.