We present the design of a novel, ultralow-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 noises of the synthesizer at 5 and 10 MHz outputs at 1 Hz offset from the carrier are -150 and -145 dBc/Hz, respectively, which are unprecedented phase noise levels. We also report the lowest values of phase noise to date for 5 and 10 MHz 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 noises achieved for 5 and 10 MHz signals at 1 Hz offset are -150 and -143 dBc/Hz, respectively; at 100 kHz offset, they are -177 and -174 dBc/Hz, respectively. The phase noise of the 5 MHz signal corresponds to a frequency stability of approximately 7.6 × 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.
We designed ultra-low-noise regenerative divide-by- 2 circuits that operate at input frequencies of 10, 20, and 40 MHz. We achieved output-referred single-sideband residual phase noise equal to -164 dBc/Hz at 10 Hz offset and estimated residual Allan deviation, σ(y)(τ) less than 3 × 10(-15)τ(-1) for a single divider, which is, to our knowledge, the lowest noise of any divider ever reported at these frequencies. To measure such a low noise, we also built a cross-spectrum measurement system that has a noise floor of -175 dBc/Hz at 10 Hz offset from the carrier frequency. The low noise of the divider and the measurement system are achieved by using custom-built mixers/phase detectors that use 2N2222A bipolar junction transistors (BJTs) in a conventional double-balanced diode ring.
Abstract-We implement an ultra-low-noise frequency divider chain from 8 GHz to 5 MHz that utilizes custom-built regenerative frequency divide-by-2 circuits. The single-sideband (SSB) residual phase-noise of this regenerative divider at 5 MHz output is -163 dBc/Hz at 10 Hz offset frequency. This level is achieved with custom-built mixers that use 2N2222A bipolar junction transistors in a conventional double-balanced diode ring. We report absolute phase-noise of radio-frequency (RF) signals at 10 MHz and 5 MHz obtained by dividing an 8 GHz signal generated from ultra-stable optical comb-based frequency division. The absolute SSB phase-noise for a 10 MHz and 5 MHz signal at 1 Hz offset is -143 dBc/Hz and -150 dBc/Hz, and at 100 kHz offset is -174 dBc/Hz and -177 dBc/Hz, respectively.
The measurement of close-to-carrier phase modulation (PM) noise of state-of-the-art oscillators is always challenging. Quite often the residual noise of the phase detector used in these measurements is higher than the noise of the source at Fourier offset frequencies between 5 and 100 Hz. A conventional double balanced mixer using 2N2222A transistors as the nonlinear components of a diode ring was constructed for use as a phase detector. Residual single-sideband PM noise measurements at 5 MHz for this device have shown a low flicker noise floor of L(10 Hz) ¼ 2163 dBc/Hz. When this mixer design is implemented in a dual-channel measurement system, a cross-correlated PM noise floor of better than L(10 Hz) ¼ 2170 dBc/Hz is expected.Introduction: The double balanced mixer (DBM) is the most widely used phase detector for high-resolution phase modulation (PM) noise detection at most carrier frequencies. Often, the measurement of PM noise is difficult owing to the high dynamic range that exists between the carrier and the modulated sidebands. In typical measurement systems, a phase detector is used to remove the carrier and downconvert noise sidebands to baseband. For offset frequencies close to the carrier, the residual flicker noise of the DBM is often the limiting factor of a phase noise measurement system. The most difficult range of offset frequencies to measure is between 5 and 100 Hz, where the oscillator noise has a slope of f 23 , while the measurement system noise floor follows f 21 . The 2N2222A bipolar junction transistor (BJT) has been successfully used in low-flicker PM noise circuits [1,2] and is chosen as the low noise nonlinear element in a custom-built DBM design. A pair of mixers using this design can be used to construct a cross-correlation PM measurement system to reduce the PM residual noise floor further.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.