HIGH FREQUENCY POWER SUPPLY DEVICE

PROBLEM TO BE SOLVED: To provide a high-frequency power supply device capable of precisely carrying out control in order to achieve protection of a power amplification part by detecting only spurious components of reflected wave power which affect the amplification part. SOLUTION: From among fundamental frequency components and the spurious components contained in the reflected wave power, the fundamental frequency components and the spurious components of the reflected wave power as a detection target are converted into difference frequency signals having a constant frequency by generating a plurality of third high frequency signals S31, S32, ... of frequency having the constant difference against a plurality of respective frequencies as detection targets from a high frequency generation part 103 in time-series, and multiplying these third high-frequency signals by a reflected wave detection signal Sr by a multiplying part 121. Then, these difference frequency signals are extracted from a filter 122, and the fundamental frequency components and the spurious components of the reflected wave power are detected from the level of the extracted difference frequency signals. COPYRIGHT: (C)2010,JPO&INPIT