| 摘要 |
PURPOSE:To enable digitizing processing, and to enable precise drive by forming a pulse signal at a 50% duty and shaping two-system pulses. whose phases are displaced mutually by 90 deg. from the pulse signal. CONSTITUTION:A VCO 5 transmits pulses at a 50% duty. A phase shifter 6 sends pulses, phase thereof are displaced mutually by 90 deg., from output terminals 6-2, 6-3 on the basis of the pulses. These pulses are applied to drive electrodes 1-1, 1-2 through output circuits 7, 8 and coils 10, 11. Displacement from a predetermined phase difference of a phase difference between an output signal from an electrode 1-3 for monitor and drive frequency is detected, and the displacement is fed to the VCO 5 through a low-pass filter 4. |
