We present the design of a novel, ultra-low phase-noise frequency synthesizer implemented with extremely low noise regenerative frequency dividers. This synthesizer generates eight outputs viz. 1.6 GHz, 320 MHz, 160 MHz, 80 MHz, 40 MHz, 20 MHz, 10 MHz and 5 MHz for an 8 GHz input frequency. The residual single sideband (SSB) phase-noise of the synthesizer at 5 MHz and 10 MHz outputs at 1 Hz offset from the carrier is -150 dBc/Hz and -145 dBc/Hz respectively, an unprecedented phase-noise. We also report the lowest values of phase-noise to date for 5 MHz and 10 MHz radio-frequency (RF) signals achieved with our synthesizer by dividing an 8 GHz signal generated from an ultra-stable optical-comb based frequency division. The absolute SSB phase-noise achieved for 5 MHz and 10 MHz signals at 1 Hz offset is -150 dBc/Hz and -143 dBc/Hz and at 100 kHz offset is -177 dBc/Hz and -174 dBc/Hz, respectively. The phase-noise of the 5 MHz signal corresponds to a frequency stability of approximately 7.6 x 10-15 at 1 s averaging time for a measurement bandwidth (BW) of 500 Hz, and the integrated timing jitter over 100 kHz BW is 20 fs.
Citation: IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control
Pub Type: Journals
frequency synthesizer, optical frequency divider, phase-noise, regenerative frequency divider