Search

A report is presented on the measurement of a frequency synthesiser that provides round frequencies (10 GHz, 5 MHz, 100 MHz) with high spectral purity from a cryocooled sapphire oscillator in the vicinity of 10 GHz. The synthesiser and sapphire oscillator are a part of Elisa, a frequency reference that exhibits a stability of parts in 10-15 from 1 s to 1000 s integration time, designed and implemented for the European Space Agency. The synthesiser features low 1/f phase noise, -96 dBc/Hz at 1 Hz off the carrier at the 10 GHz output, and -133 dBc/Hz at 1 Hz offset at the 100 MHz output. [ABSTRACT FROM AUTHOR]

The phase noise characterisation of two 10 GHz cryogenic sapphire oscillators exhibiting frequency stability higher than 3×10-15 is reported. One of these oscillators developed for the deep space navigation ground stations of the European Space Agency, incorporates a closed cycle cryocooler as cold source. Near the carrier, the measured phase noise is limited by a flicker frequency noise: Sϕ(f)=-30log(f)-98 dBrad2/Hz. [ABSTRACT FROM AUTHOR]

The frequency stability measurement of a new kind of secondary frequency standard, the whispering gallery mode maser oscillator, is reported. Based on a very simple design the beatnote comparison with a state-of-the-art cryogenic sapphire resonator oscillator gave a preliminary result of 10-14 frequency instability at 1 s integration time. The measurement is limited by the microwave synthesis chain used to evaluate the maser stability. [ABSTRACT FROM AUTHOR]

The operation of a low phase noise 10.35 GHz microwave cryogenic sapphire resonator oscillator is demonstrated. Based on a very simple architecture, the oscillator presents phase noise performances of -104 dBrad2/Hz at f=10 Hz off the carrier (slope 1/f 3), lower than -152 dBrad2/Hz at f=1 kHz (slope 1/f), and of -160 dBrad2/Hz at f>=10 kHz (white). [ABSTRACT FROM AUTHOR]

Characterisation of a new microwave temperature compensated sapphire-rutile resonator oscillator is reported. The oscillator frequency instability performances are better than 2×10-13 for τ<1000 s, and the frequency drift is estimated at 2.5×10-12/day. These medium- and long-term results constitute, to date, the state-of-the-art for microwave temperature compensated sapphire resonator oscillators. [ABSTRACT FROM AUTHOR]

The operation of a 12.7 GHz cryogenic oscillator based on a whispering gallery mode resonator doped with Ti3+ ions is presented. The resonator operates at 34 K and exhibits a frequency stability order 2 × 10-13 for 8 s<τ<20 s. This corresponds to state-of-the-art line splitting of order 10-7. [ABSTRACT FROM AUTHOR]

The operation of a microwave cryogenic sapphire resonator oscillator presenting an exceptional frequency stability for long integration times has been demonstrated. Based on a very simple design the 11.5 GHz oscillator presents a fractional frequency instability lower than 6 × 10-14 over one day. [ABSTRACT FROM AUTHOR]

A new high-Q sapphire whispering gallery mode resonator is proposed to achieve ultra-high frequency stability. It is proposed to use the sapphire resonator without metallic walls to suppress spurious modes perturbating the main resonance. Providing the azimuthal order of the chosen whispering gallery mode is sufficiently high, Q-factors better than 2 × 10[SUP)8] have been observed, which turn out to be sufficient to reach a high frequency stability. A first oscillator prototype operating at 12 GHz shows a relative frequency instability of 3 × 10[SUP-14]. [ABSTRACT FROM AUTHOR]