scispace - formally typeset
Search or ask a question
Topic

Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.


Papers
More filters
Journal ArticleDOI
TL;DR: It is shown that despite its lack of stationarity it is possible to derive a closed form expression for its effect on an oscillator PSD and that the oscillator output can be considered to be wide-sense stationary.
Abstract: In this paper, we apply correlation theory methods to obtain a model for the near-carrier oscillator power-spectral density (PSD). Based on the measurement-driven representation of phase noise as a sum of power-law processes, we evaluate closed form expressions for the relevant oscillator autocorrelation functions. These expressions form the basis of an enhanced oscillator spectral model that has a Gaussian PSD at near-carrier frequencies followed by a sequence of power-law regions. New results for the effect of white phase noise, flicker phase noise and random walk frequency modulated phase noise on the near-carrier oscillator PSD are derived. In particular, in the case of 1/f phase noise, we show that despite its lack of stationarity it is possible to derive a closed form expression for its effect on an oscillator PSD and show that the oscillator output can be considered to be wide-sense stationary

117 citations

Patent
13 Jun 2008
TL;DR: In this paper, a switching voltage regulator is disclosed operable to regulate a voltage supplied to system circuitry, and a comparator compares an oscillator signal generated by a ring oscillator to a reference signal produced by a frequency generator, and control circuitry adjusts a number of delay elements in the ring oscillators and a divider value of the frequency generator to generate hysteresis in the comparison.
Abstract: A switching voltage regulator is disclosed operable to regulate a voltage supplied to system circuitry. A comparator compares an oscillator signal generated by a ring oscillator to a reference signal generated by a frequency generator. Switching circuitry charges a charging element in response to the comparison, and control circuitry adjusts a number of delay elements in the ring oscillator and a divider value of the frequency generator to generate hysteresis in the comparison. In one embodiment, the charging element is charged while a frequency of the reference signal is above a frequency of the oscillator signal.

117 citations

Patent
John E. Gersbach1, Masayuki Hayashi1
23 Dec 1993
TL;DR: In this paper, the center frequency is calibrated by imposing a selected center frequency at the output of the phase-locked loops and driving the control voltage V c across the PLL's filter to a predefined, steady state voltage indicative of PLL circuit calibration.
Abstract: Calibration systems and techniques for phase-locked loops (PLLs) provide precise setting of the center frequency and/or uniform voltage controlled oscillator (VCO) gain characteristics. Center frequency is calibrated by imposing a selected center frequency at the output of the PLL and driving the control voltage V c across the PLL's filter to a predefined, steady state voltage indicative of PLL circuit calibration. The approach can be employed to calibrate any imposed VCO frequency output. VCO gain calibration is accomplished by employing the center frequency calibration technique only with a low frequency point imposed on the VCO output. A high frequency point on the transfer function is calibrated by applying a known voltage across the filter and driving the VCO output to a corresponding calibration frequency. Once a low frequency point and a high frequency point are calibrated, the slope of the VCO transfer function is defined. Various integrated PLL/calibration system embodiments are presented.

117 citations

Journal ArticleDOI
29 May 2009
TL;DR: In this paper, a spin torque nano-oscillator (STNO) is proposed for RF transceivers based on two spintronic effects, the tunneling magnetoresistance (TMR) and the spin momentum transfer torque.
Abstract: A nano-sized oscillator for RF applications is presented which is based on two spintronic effects, the tunneling magnetoresistance (TMR) and the spin momentum transfer torque. The oscillation frequency is several GHz and can be tuned by both a DC bias current and an external DC magnetic field. High compactness, high tunability and full compatibility with standard CMOS process make this spin torque nano-oscillator (STNO) a promising candidate for future RF transceivers. The main issues to be addressed are spectral purity and output power. First measurements on a hybrid built connecting the STNO to a dedicated wideband amplifier show that today's performance in terms of power is close to but not yet compatible with telecommunication standard requirements. Using time domain analysis we show that frequency fluctuations are an issue for spectral purity. Frequency synthesis concepts based on STNOs are also discussed.

117 citations

Journal ArticleDOI
TL;DR: In this article, a novel circuit topology of voltage-controlled oscillators (VCOs) suitable for ultra-low-voltage operations is presented, which can operate at reduced supply voltage and power consumption while maintaining remarkable circuit performance in terms of phase noise, tuning range and output swing.
Abstract: In this paper, a novel circuit topology of voltage-controlled oscillators (VCOs) suitable for ultra-low-voltage operations is presented. By utilizing the capacitive feedback and the forward-body-bias (FBB) technique, the proposed VCO can operate at reduced supply voltage and power consumption while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output swing. Using a standard 0.18-mum CMOS process, a 5.6-GHz VCO is designed and fabricated for demonstration. Consuming a dc power of 3 mW from a 0.6-V supply voltage, the VCO exhibits a frequency tuning range of 8.1% and a phase noise of -118 dBc/Hz at 1-MHz offset frequency. With an FBB for the cross-coupled transistors, the fabricated circuit can operate at a supply voltage as low as 0.4 V. The measured tuning range and phase noise are 6.4% and -114 dBc/Hz, respectively

117 citations


Network Information
Related Topics (5)
CMOS
81.3K papers, 1.1M citations
91% related
Amplifier
163.9K papers, 1.3M citations
88% related
Integrated circuit
82.7K papers, 1M citations
86% related
Transistor
138K papers, 1.4M citations
85% related
Electronic circuit
114.2K papers, 971.5K citations
85% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023168
2022344
2021269
2020388
2019469
2018530