Microwave frequency discriminator with a cryogenic sapphire resonator for ultra-low phase noise
Abstract
Results of an X-band frequency discriminator using a cooled sapphire microwave resonator are presented. These results show a lower close-in (1 Hz to 1 kHz offset) phase noise measurement floor than any oscillator presently available. This performance is made possible by a sapphire 'Whispering gallery' mode resonator which shows the highest quality factor (with Q's up to 30 million) for any RF, microwave, or acoustic resonator at temperatures down to 77K. Performance is further increased by the use of novel phase detection circuitry. The sapphire discriminator was used to characterize the phase noise of a single crystal quartz oscillator of the highest quality, without the use of a second similar oscillator as reference.
- Publication:
-
ESA Special Publication
- Pub Date:
- June 1992
- Bibcode:
- 1992ESASP.340...35D
- Keywords:
-
- Cryogenics;
- Frequency Discriminators;
- Microwave Oscillators;
- Resonators;
- Sapphire;
- Signal To Noise Ratios;
- Whispering Gallery Modes;
- Carrier Frequencies;
- Cryogenic Equipment;
- Noise (Sound);
- Phase Detectors;
- Quartz Crystals;
- Spectrum Analysis;
- Superhigh Frequencies;
- Systems Engineering;
- Electronics and Electrical Engineering