| 摘要 |
An oscillator (1) is stabilized by a frequency discriminator in order to reduce its phase noise. A microwave amplifier (4) supplies sufficient power to maintain the oscillation. The oscillator and the frequency discriminator use a common resonator or time delay unit (6). A pair of directional couplers (9, 11) deflect a little of the microwave incident upon the resonator (6) and a little of the microwave transmitted by the resonator. Resistors (12, 13) terminate the unconnected ports of the directional couplers. A fixed phase rotator (14) compensates for the longer route of one deflected microwave. A frequency discriminator signal (18) is generated by phase comparison (15), base-band amplification (16) and filtering (17) of the deflected and phase-compensated microwaves. The frequency discriminator signal controls the phase in the oscillator by means of, for example, a controllable phase rotator (2). In this connection, a control system which measures and corrects the phase error in the oscillator is obtained. |
