Abstract :
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 off 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.
