• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.121-126
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• 2019

The voltage-controlled oscillator is one of the fundamental building blocks that determine the signal quality and power consumption in RF transceivers for wireless sensor networks. Ring oscillators are attractive owing to their small form factor and multi-phase capability despite the relatively poor phase noise performance in comparison with LC oscillators. The phase noise of a ring oscillator can be improved by using a coupled structure that works at a lower frequency. This paper introduces a 2.4 GHz low-noise ring oscillator that consists of two 3-stage coupled ring oscillators. Each sub-oscillator operates at 800 MHz, and the multi-phase signals are combined to generate a 2.4 GHz quadrature output. The voltage-controlled ring oscillator designed in a 65-nm standard CMOS technology has a tuning range of 800 MHz and exhibits the phase noise of -104 dBc/Hz at 1 MHz offset. The power consumption is 13.3 mW from a 1.2 V supply voltage.

• Journal of electromagnetic engineering and science
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• v.5 no.4
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• pp.153-160
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• 2005

In this paper, the novel microwave oscillator incorporating a planar cavity resonator(PCR) is presented to reduce the phase noise of the oscillator in a planar environment. Compared to the conventional planar( $\lambda$/4 open stub resonator), the phase noise is improved about 16 dBc/Hz @100 kHz. The design of the oscillator is based on a reflection type configuration using the low 1/f SiGe HBT transistor(LPT16ED). The output power is measured 2.76 dBm at 12.5 GHz. In this paper, the oscillator used to the PCR can be expected to provide a solution for low phase noise oscillator in microwave circuits.

• Current Optics and Photonics
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• v.2 no.1
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• pp.96-100
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• 2018

A tunable low-phase-noise microwave generation structure that utilizes an optoelectronic oscillator (OEO) and a fiber Bragg grating (FBG) is proposed and experimentally demonstrated in this article. This structure has no particular requirement for the band width of the laser, and its tunability is realized through adjusting the central frequency of the tunable FBG. A detailed theoretical analysis is established and confirmed via an experiment. A high-purity microwave signal with a frequency tunable from 6 to 12 GHz is generated. The single-sideband phase noise of the generated signal at 10.2 GHz is -117.2 dBc/Hz, at a frequency offset of 10 kHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.180-185
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• 2000

In this paper, we designed 2303.15MHz Sequency synthesizer for the purpose of the phase noise prediction. For the modeling of phase noise Oersted in the designed system through inooducing the noise-modeling method suggested by Lascari we analyzied a variation of phase noise as according as that of offest frequency. Especially, for the third-order system of the PLL among some kinds of phase noise generated from VCO we analyzed the aspect of 1/f-noise appearing troubles in the low frequency band. Since it is difficult to analyze mathematically 1/f-noise in the third-order system of the PLL, introducing the concept of pseudo-damping factor has made an ease of the access of the 1/f-noise variance. we showed a numerical formula of 1/f-noise variance in the third-order system of the PLL which is compared with that of 1/f-noise variance in the second-order system of the PLL

• Journal of electromagnetic engineering and science
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• v.4 no.3
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• pp.137-142
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• 2004

In this paper, we present a new current-current negative feedback(CCNF) differential voltage-controlled oscillator (VCO) with 1/f induced low-frequency noise suppressed. By means of the CCNF, the 1/f induced low-frequency noise is removed from the proposed CCNF VCO. Also, high-frequency noise is stopped from being down-converted into phase noise by means of the increased output impedance through the CCNF and the feedback capacitor $C_f. The proposed CCNF VCO represents 11-dB reduction in phase noise at 10 kHz offset, compared with the conventional differential VCO. The phase noise of the proposed CCNF VCO is measured as - 87 dBc/Hz at 10 kHz offset frequency from 5.5-GHz carrier. The proposed CCNF VCO consumes 14.0 mA at 2.0 V supply voltage, and shows single-ended output power of - 12 dBm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1180-1186
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• 2008

The LNB phase noise of user terminal for high data rate satellite transmission was analyzed in this paper. The phase noise severely affects the service performance in low data rate transmission as well as multi-mode signal for high data rate. As the satellite link frequency is increased, the effects of phase noise for multi-mode signal is increased. The phase noise of LNB, which is operated in high frequency band, is about equal to the transmission system phase noise and have an major effects on service performance degradation. The available transmission mode was analyzed in presence of phase noise of LNB and analysis method for LNB phase noise spectrum distribution was proposed in multi-mode signal.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.166-171
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• 2013

In this study, low noise designs of a Savonius wind turbines are numerically investigated. From a previous study, it was found that the high harmonic components whose fundamental frequency is higher than the BPF were found to be dominant in noise spectrum of a Savonius wind turbine. On a basis of this observation, S-shaped blade tip is proposed as a low design factors that decrease wind turbine noise by inducing phase differences in vortex shedding. The conventional Savonius and S-shaped turbines are investigated using Hybrid CAA method where flow field around the turbine are computed using CFD techniques and the radiated noise are predicted by applying acoustic analogy to the computed flow data. Noise reductions by these design factors are confirmed by comparing the predicted noise levels from these turbines.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.2
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• pp.123-128
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• 2020

A low phase noise phase locked loop (PLL) with negative feedback loop including frequency variation sensing circuit (FVSC) has been proposed. The FVSC senses the frequency variation of voltage controlled oscillator output signal and controls the volume of electric charge in loop filter capacitance. As the output frequency of the phase locked loop increases, the FVSC reduces the loop filter capacitor charge. This causes the loop filter output voltage to decrease, resulting in a phase locked loop output frequency decrease. The added negative feedback loop improves the phase noise characteristics of the proposed phase locked loop. The size of capacitance used in FVSC is much smaller than that of loop filter capacitance resulting in no effect in the size of the proposed PLL. The proposed low phase noise PLL with FVSC is designed with a supply voltage of 1.8V in a 0.18㎛ CMOS process. Simulation results show the jitter of 273fs and the locking time of 1.5㎲.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1805-1810
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• 2014

The phase noise spectrum distribution for remote controller using the BPSK mode and low data rate of 50 kbps was designed and proposed in this paper. In case of applying the BPSK that transmission performance is superior to FSK method, the performance degradations due to phase noise are generated. To minimize the phase noise effect, it is important to dispatch the digital signal in channel environment with required phase noise characteristics. To provide the terminal design technique and the proper channel environment with required phase noise characteristics, the phase noise spectrum distribution was designed for required phase noise characteristics. By analyzing the phase noise effects for damping factor and noise bandwidth of the carrier recovery circuit, the phase noise spectrum design that consider the damping factor and noise bandwidth was performed. Based on the IESS-308 standards, also, the phase noise effects was analyzed. The phase noise spectrum design techniques and phase noise spectrum that is suitable to remote controller were proposed.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3184-3186
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• 1999

In this paper, a new structure of fully differential delay cell VCO using quadrature phase for low phase noise and high speed operation is suggested. It is realized by inserting voltage clamp circuit into input pairs of delay cells that include three-control current source having high output impedance. In this reason. this newly designed delay cell for VCO has the low power supply sensitivity so that the phase noise can be reduced. The whole characteristics of VCO were simulated by using HSPICE and SABER. Simulation results show that the phase noise of new VCO is quite small compared with conventional fully differential delay cell VCO and ring oscillator type VCO. It is also very beneficial to low power supply design because of wide tuning range.