| 摘要 |
899,935. Automatic phase control systems. PHILIPS ELECTRICAL INDUSTRIES Ltd. Jan 6, 1960 [Jan. 9, 1959], No. 487/60. Class 40(5). In an arrangement for synchronizing an oscillator 3, Fig. 5, with a synchronizing signal 1, comprising a phase detector 2 to which the signal 1 and a sawtooth waveform 4 derived from the oscillator are applied, and which is effective over a limited range of phase difference to control through a filter 5 a reactance valve 6, an additional catching circuit including a gate 9 for gating the synchronizing signal directly to the oscillator is controlled by a separate phase detector 7 to open the gate when the phase error exceeds the catching range of the first phase detector, and to close it in conjunction with a reduced output from phase detector 2 when the phase error is brought back within the catching range. The pulses 10 from the oscillator to the second phase detector are chosen to be of great duration with respect to pulses 1. Synchronization of pulses 1 and 10 causes valve 24 to draw current and cut off gate 9. In the out of synchronizm position pulses 1 are amplified and fed via capacitor 27 for direct synchronization to the screen grid of oscillator 29. |
