| 摘要 |
A circuit for synchronizing an oscillator keyed by a pulse is provided with a low amplitude reference oscillation. A phase shift regulating loop has a phase discriminator which is fed, on one hand, with a branched component of the oscillator output and, on the other hand, with the reference oscillation. The phase discriminator compares the phases of the two oscillators and emits a resultant regulating voltage an adjustable reactance for controlling the oscillator frequency during the leading edge of the keying pulse. A phase shift device, adjustable over 180 DEG , is connected between the oscillator and the phase discriminator, the phase discriminator having a high-ohmic output which is connected, via an impedance converter, to the adjustable reactance. A sampling switch is interposed between the impedance converter and the adjustable reactance, the switch being closed at the beginning of a pulse and opened shortly before the end of a pulse, the pulses being of predetermined duration, and a holding circuit holds the regulating voltage at least to an approximate value across the adjustable reactance prior to the end of a pulse, until the closing of the sampling switch.
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