Abstract: The noise generated from a power converter is suppressed by increasing the noise frequency to a level not lower than the maximum frequency of the human audible range. To obtain the frequency of an output current harmonic component as a noise source which has exceeded the maximum frequency of the human audible range, it is adequate to determine that the frequency of a driving carrier wave for the individual converter cells in the power converter, in which the phases of the carrier wave for the converter cells are mutually shifted by a given value between the converter cells, meets the following equation.

Abstract: The noise generated from a power converter is suppressed by increasing the noise frequency to a level not lower than the maximum frequency of the human audible range. To obtain the frequency of an output current harmonic component as a noise source which has exceeded the maximum frequency of the human audible range, it is adequate to determine that the frequency of a driving carrier wave for the individual converter cells in the power converter, in which the phases of the carrier wave for the converter cells are mutually shifted by a given value between the converter cells, meets the following equation.

Abstract: An apparatus 1 for testing mixed signal electronic devices (i.e., devices, such as LSI devices, whose input/output signals include direct current signals, digital signals and analog signals, where the time relationship between the various input and output signals may be either synchronous or asynchronous) includes a master clock subsystem (MCLK-SS) 11, a subsystem group comprised of a digital master subsystem (DM-SS) 12, a digital slave subsystem (DS-SS) 13, a waveform generator subsystem (WG-SS) 14, a waveform digitizer subsystem (WD-SS) 15, a time measuring module (TMM) 16, and a direct current subsystem (DC-SS) 17, and an interfacing test head 18. The MCLK-SS 11 receives a master clock from a timing generator 21 or DSP 23 of the device under test (DUT) 186 and generates a first master clock MCLK1 and a second master clock MCLK2, each of which is synchronized with the master clock from the DUT.

Abstract: An audio amplifier which processes mainly dynamic signals and which is provided with a plurality of amplifying systems each having a preamplifier and a main amplifier. A plurality of power sources are used to separately supply electric power to the respective amplifying systems, resulting in elimination of transient crosstalk.