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.

A 2GHz, 17% tuning range quadrature CMOS VCO with high figure–of–merit and 0.6° phase error

Abstract: This paper presents a quadrature VCO implemented in a standard 0.35µm CMOS process. The VCO draws 16mA from a 1.3V power supply, can be tuned between 1.91 GHz and 2.27GHz, and displays a phase noise of -140dBc/Hz or less at 3MHz offset frequency from the carrier, for a minimum phase-noise figure-of-merit of 184 dB. The maximum departure from quadrature between the VCO phases is 0.6°.

Double vernier time interval measurement using triggered phase-locked oscillators

Abstract: Measurement of a time interval between a start and a stop event is made by activating a start oscillator in response to the start event and activating a stop oscillator in response to the stop event. The number of cycles of each respective oscillator signal which occur between the activation of each oscillator and the coincidence of the respective oscillator signal with that of an independent time base is determined. The number of cycles of the time base signal between the coincident points of it and the start and stop oscillator signal is also determined. These numbers, which are always integers, are used along with the values for the time base period and the difference in frequency between the time base oscillator and the start and stop oscillators to calculate the time interval. Resolution of the measurement is dependent on the frequency difference between the time base signal and the start and stop oscillator signals. Two triggered-phase oscillators, which are phase-locked to the reference oscillator, are used to supply the start and stop frequencies. The start trigger and stop signals are used for phase shifting, i.e., restarting of the oscillators rather than starting the oscillators. This allows for pre-trigger frequency control, and essentially eliminates post trigger frequency drift which usually occurs when an oscillator is first started. The coincidence signals are provided by the phase cross-over between the phase locked oscillator and the reference by a digital mixer.

A Pulse Frequency Modulation Interpretation of VCOs Enabling VCO-ADC Architectures With Extended Noise Shaping

Abstract: In this paper, we propose to study voltage controlled oscillators (VCOs) based on the equivalence with pulse frequency modulators (PFMs). This approach is applied to the analysis of VCO-based analog-to-digital converters (VCO-ADCs) and deviates significantly from the conventional interpretation, where VCO-ADCs have been described as the first-order $\Delta \Sigma $ modulators. A first advantage of our approach is that it unveils systematic error components not described by the equivalence with a conventional $\Delta \Sigma $ modulator. A second advantage is that, by a proper selection of the pulses generated by the PFM, we can theoretically construct an open loop VCO-ADC with an arbitrary noise shaping order. Unfortunately, with the exception of the first-order noise shaping case, the required pulse waveforms cannot easily be implemented on the circuit level. However, we describe circuit techniques to achieve a good approximation of the required pulse waveforms, which can easily be implemented by practical circuits. Finally, our approach enables a straightforward description of multistage $\Delta \Sigma $ modulator architectures, which is an alternative and practically feasible way to realize a VCO-ADC with extended noise shaping.

Electronically tunable and modulatable quasi-optic grid oscillator

Abstract: The present invention discloses an electronically frequency tunable and phase modulatable quasi-optic grid oscillator. The oscillator includes a reference signal input port whereby a small external reference signal is introduced that entrains the frequency and phase of the oscillator signal to it. Amplitude modulation techniques are introduced to further enhance the utility of the oscillator as a modulator.

A coupled two-stage ring oscillator

Abstract: Modeling, analysis and test results of a fabricated coupled two-stage ring oscillator are presented in this paper. The oscillator consists of two two-stage ring oscillators which are coupled to each other and oscillate with the same frequency, but with 45 degrees phase difference resulting in two sets of quadrature outputs. It has been proven analytically that the coupled ring oscillator has an inherent capability of oscillating with frequencies as high as 1.96 times that of a single three-stage ring. A coupled two-stage ring oscillator, fabricated in CMOS 0.18 /spl mu/m technology, is described. This VCO has frequency tuning range of 2.5 - 9 GHz for a 1.8 V power supply voltage.