| 摘要 |
The invention relates to a device for servocontrolling an oscillator with a frequency-agile, very low phase-noise microwave frequency source. This device is associated with a phase loop comprising a voltage-controlled oscillator 10, a mixer 1 and a low-pass filter 12. It includes means for rough precentring, using a digital/analog converter 8 and a forward/backward counter 7 loaded with a code Cp associated with the new frequency of the source, and a convergence loop incorporating a circuit 1 to 5 for comparing the frequency of the oscillator with the frequency of the source and a logic circuit 6 controlling the forward or backward counting of the forward/backward counter 7 according to whether the frequency of the oscillator is less than or greater than the frequency of the source after the rough precentring. The invention applies in particular to the master synthesisers of frequency-agile Doppler radars. <IMAGE>
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