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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
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Patent
31 Aug 1989
TL;DR: In this article, the frequency of a VCO is switched by changing the division ratio of a variable ratio frequency divider in the feedback path of the loop, at the time of switching, a prepositioning voltage is applied to the VCO to realize fast frequency switching.
Abstract: In a phase locked loop frequency synthesizer, the frequency of a VCO is switched by changing the division ratio of a variable ratio frequency divider in the feedback path of the loop. At the time of switching, a prepositioning voltage is applied to the VCO to realize fast frequency switching. To correct for nonlinear response of the VCO, the prepositioning voltage is adjusted according to information received from a voltage measuring circuit connected to the VCO control circuit.

85 citations

Journal ArticleDOI
TL;DR: This paper describes the first 32 kHz low-power MEMS-based oscillator in production, designed to provide a small form-factor oscillator for use as a crystal replacement in space-constrained mobile devices.
Abstract: This paper describes the first 32 kHz low-power MEMS-based oscillator in production. The primary goal is to provide a small form-factor oscillator (1.5 × 0.8 mm 2 ) for use as a crystal replacement in space-constrained mobile devices. The oscillator generates an output frequency of 32.768 kHz and its binary divisors down to 1 Hz. The frequency stability over the industrial temperature range (–40 °C to 85 °C) is ±100 ppm as an oscillator (XO) or ±3 ppm with optional calibration as a temperature compensated oscillator (TCXO). Supply currents are 0.9 µA for the XO and 1.0 µA for the TCXO at supply voltages from 1.4 V to 4.5 V. The MEMS resonator is a capacitively-transduced tuning fork at 524 kHz. The circuitry is fabricated in 180 nm CMOS and includes low power sustaining circuit, fractional-N PLL, temperature sensor, digital control, and low swing driver.

85 citations

Journal ArticleDOI
TL;DR: In this paper, a 3D-deployed RF front-end system-on-package (SOP) in a standard multi-layer low temperature co-fired ceramic (LTCC) technology is presented.
Abstract: Presents design, implementation, and measurement of a three-dimensional (3-D)-deployed RF front-end system-on-package (SOP) in a standard multi-layer low temperature co-fired ceramic (LTCC) technology. A compact 14 GHz GaAs MESFET-based transmitter module integrated with an embedded bandpass filter was built on LTCC 951AT tapes. The up-converter MMIC integrated with a voltage controlled oscillator (VCO) exhibits a measured up-conversion gain of 15 dB and an IIP3 of 15 dBm, while the power amplifier (PA) MMIC shows a measured gain of 31 dB and a 1-dB compression output power of 26 dBm at 14 GHz. Both MMICs were integrated on a compact LTCC module where an embedded front-end band pass filter (BPF) with a measured insertion loss of 3 dB at 14.25 GHz was integrated. The transmitter module is compact in size (400 /spl times/ 310 /spl times/ 35.2 mil/sup 3/), however it demonstrated an overall up-conversion gain of 41 dB, and available data rate of 32 Mbps with adjacent channel power ratio (ACPR) of 42 dB. These results suggest the feasibility of building highly SOP integrated RF front ends for microwave and millimeter wave applications.

85 citations

Journal ArticleDOI
24 Oct 2012
TL;DR: This paper presents a low-power high-bit-rate phase modulator based on a digital PLL with single-bit TDC and two-point injection scheme, which becomes critically sensitive to the delay spread between the two injection paths, considerably degrading the achievable error-vector magnitude and causing significant spectral regrowth.
Abstract: Polar or outphasing radio transmitter architectures promise higher efficiency than their Cartesian counterparts [1], but require the adoption of phase modulators with bandwidth about one order of magnitude wider than the channel bandwidth. In contrast to phase-switching approaches [2], efficient implementations of wideband phase modulators are based on the direct frequency modulation (FM) of a PLL and on the two-point signal-injection scheme [3]. Unfortunately, meeting the noise/bandwidth requirements of 4G wireless standards (such as WiMAX) demands fine frequency resolution, tight VCO linearity and accurate synchronization between the two signals injected into the PLL. This paper introduces a digital-intensive phase modulator circuit, which is able to enforce an arbitrary carrier phase change (up to ±π radians) in one clock sample. For a clock frequency of 40MHz, the modulation error, expressed in terms of error vector magnitude (EVM), is below −36dB for a 20Mb/s QPSK-modulated or a 10Mb/s GMSK-modulated carrier at 3.6GHz.

85 citations

Journal ArticleDOI
27 Nov 2007
TL;DR: Continuous frequency tuning by control of the magnetic field of a transformer - capacitor tank, in a selective oscillator, is explored in this work, and oscillation amplitude, frequency tuning band, phase noise, and phase accuracy are analyzed.
Abstract: Continuous frequency tuning by control of the magnetic field of a transformer - capacitor tank, in a selective oscillator, is explored in this work. A quadrature generator is built connecting two identical transformer - capacitor oscillator cells in a feedback loop. The topology itself assures the currents in the transformer windings are aligned in phase, while their relative amplitude determines, via magnetic coupling, oscillators' tank reactance, i.e., oscillation frequency. This paper introduces the idea, analyzes oscillation amplitude, frequency tuning band, phase noise, and phase accuracy, and discusses design and experiments. Prototypes, realized in 65 nm CMOS, employing MOS varactors to further extend operation bandwidth, show the following performances: 3.2 GHz and 7.3 GHz minimum and maximum oscillation frequency, respectively. Phase noise figure of merit of 176.5 dB at 3.2 GHz and 170.5 dB at 6.4 GHz is observed, with 24 mW maximum power consumption and 1.5 maximum deviation from quadrature.

84 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023168
2022344
2021269
2020388
2019469
2018530