| 摘要 |
PURPOSE:To make the configuration of a circuit small while increasing the working efficiency by using pulse-width modulation circuits from which a servomechanism of pulse-width modulation is obtained, chopper circuits and step-up transformers which increases the output of the chopper circuits. CONSTITUTION:Sine-wave signals which are output from an oscillator 41 are first converted into two voltage signals of different phase and then are inputted into pulse-width modulation circuits 43a and 43b, which generate sine-wave signal (a), triangular-wave signal (b) and pulse-width modulation signal (c). The pulse width modulation signal (c) are converted into two drive signals of different duty ratio. The drive signal (c) are inputted into chopper circuits 44a and 44b, which, chopping a d.c. voltage which is gained by rectifying the output from an a.c. power 45 by a rectifier 46, generate sine-wave signals of the specified frequency. On the output side of the chopper circuits 44a and 44b, step-up transformers 47a and 47b are installed, which increase a voltage amplitude output from each of the chopper circuits 44a and 44b into the desired value. |
