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This work presents a dual-band transformer-based voltage controlled oscillator (VCO) with phase noise optimization. Transformers consisting of four inductors are employed to reduce area. Four cross-coupled VCO cores are connected to the four wings of two pairs of transformers to allow individual control of the cores, whose mutual inductance is utilized to enhance the frequency tuning. Also, the capability...
This paper presents a wide-tuning frequency generation scheme based on bottom-series coupled quadrature VCO (QVCO). The low band and middle band frequency signal is generated from the QVCO while the high band signal is obtained from a gilbert mixer. The tuning-range enhancement technique allows a three band frequency generation in the range from 2.4GHz to 8.4GHz without penalizing its phase noise...
This paper presents a capacitive-coupling technique for multi-phase oscillators. The proposed capacitive coupling techniques can improve the phase noise performance while maintain good phase accuracy over wide frequency range for multi-phase oscillators. A prototype two-phase VCO is analyzed using injection-locking theory and implemented to demonstrate the effectiveness of the capacitive-coupling...
A 4.8–6.8GHz phase-locked loop (PLL) with a power optimized multi-modulus divider (MMD) for wireless and radar applications is presented in this paper. Based on the timing delay analysis and the self-oscillation frequency of the divider cells, the power consumption of the divide-by-two circuit (DTC) and divide-by-2/3 cells can be optimized, and thus minimum power consumption for divider chain can...
This paper presents a 0.6-V quadrature voltage-controlled oscillator (QVCO) with enhanced swing for low power supply applications. The QVCO comprises a novel capacitive coupling technique that is employed not only for quadrature signal coupling, but also for phase noise reduction. As a result, the proposed QVCO can even achieve 4.6 dB lower phase noise than its single-phase counterpart at 3-MHz offset...
This paper presents a 0.6V quadrature voltage-controlled oscillator (QVCO) with a novel capacitive coupling technique, which is employed not only for quadrature signal coupling, but also for noise reduction. As a result, the proposed QVCO can even achieve 3 to 5dB lower phase noise than a single-phase VCO of the same kind. Optimized capacitive coupling combined with inductive enhance-swing technique...
This paper presents a phase noise analysis for all-PMOS Voltage-Controlled Oscillators (VCOs) in 1/f2 region. A closed-form equation for VCO phase noise is derived as an auxiliary optimization tool for designers. The maximum operating frequency of divide-by-two circuit (DTC) is predicted to help reduce the phase noise introduced by the DTC. Based on the derived formulas, size optimization for noise...
A 434/868 MHz FSK/OOK transmitter with integrated PLL is reported. Direct digital modulation of a fully integrated Sigma-Delta fractional-N PLL frequency synthesizer is used to ensure fine frequency resolution and low phase noise. A wide-band VCO together with an Adaptive Frequency Calibration (AFC) is used to cover the desired bands. A differential-to-single output programmable power amplifier is...
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