| 摘要 |
PURPOSE:To secure extraction of the signal featuring the 90 deg. phase difference to the basic wave signal regardless of the phase difference between the two signals by eliminating the range for the phase control. CONSTITUTION:In case signal (a) is selected by change-over switch 4, signal (a) passes through phase control circuit 5 and wave form conversion circuit 6. Then output signal (g) is compared with signal (b) for the phase at phase comparator 7, and thus the error voltage is supplied to phase control circuit 5 to secure the control so that the phase of signal (a) may feature the 90 deg. phase difference to signal (b). The error voltage, i.e., the output voltage of integrator 8 is monitored by window comparator 9. And when the phase lock becomes impossible, change-over switch control circuit 10 switches switch 4 in sequence to select signals (c)-(e) and to secure the phase lock. |
