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.

LC resonance circuit and voltage-controlled oscillation circuit

Abstract: A control voltage Vin that has been input is sequentially reduced at NMOS's 11 1 ˜11 3 constituting means for voltage reduction The individual voltages resulting from the voltage reduction are applied to control electrodes of MOS varactors 21 1 ˜21 3 constituting voltage-controlled variable-capacitance elements which are connected in parallel and, thus, the capacitance values of the individual MOS varactors 21 1 ˜21 3 are determined An LC resonance circuit constituted of the MOS varactors 21 1 ˜21 3 and a coil 22 resonates at a specific frequency, NMOS's 23 and 24 constituting means for switching engage in on/off operation and oscillation occurs at an oscillation frequency corresponding to the voltage Vin resulting in an oscillation signal output through output terminals 3 and 4 Thus, an LC resonance circuit that allows the rate at which the capacitance values of the voltage-controlled variable-capacitance elements change to be set freely in correspondence to the particulars of design and a high-performance voltage-controlled oscillation circuit (VCO) that employs this LC resonance circuit and enables good control are provided

Inductive angle sensor that adapts an oscillator frequency and phase relationship to that of an interference frequency

Abstract: An inductive angle sensor for a motor vehicle has an oscillator circuit that generates a periodic AC oscillator-frequency signal in an exciting coil, at least one receiving coil, an evaluation circuit for detecting the signal induced in the at least one receiving coil, and a movable inductive coupling element that influences a strength of inductive coupling between the exciting coil and the at least one receiving coil. The oscillator circuit is a "soft" or "flexible" oscillator circuit such that when an interference frequency close to the oscillator frequency is coupled into the coil system, the oscillator circuit adapts the oscillator frequency and phase relationship to that of the interference frequency. Undesired overlapping effects are thus efficaciously prevented.

High speed, wide bandwidth phase locked loop

Abstract: A PLL may include a voltage regulator for providing a regulated voltage to one or more PLL components (e.g. a charge pump, a voltage controlled oscillator, etc.). The PLL components may be noise sensitive components, and the regulated voltage may reduce noise received from the power supply. Additionally, a level shifter may be coupled between the PLL components and a phase/frequency detector. The level shifter may be supplied by the regulated voltage from the voltage detector. In another implementation, a PLL may include a programmable charge pump and a programmable loop filter. For example, the reference current to the charge pump may be changed, thus changing the rate at which the charge pump can change an output voltage (the control voltage to a voltage controlled oscillator in the PLL). The loop filter components may be changed to change the frequency ranges filtered by the loop filter.

Fractional-N synthesizer having modulation spur compensation

Abstract: A synthesizer circuit (10) with spur compensation utilizes fractional division in the synthesizer loop. The fractional divider (12) includes means for compensating the spurs when the fractional numerator N ¸ 0. The synthesizer (10) includes means for selecting a reference divisor R such that a non zero value of fractional numerator is produced and such that the generated spurs fall below the side band noise limits of the synthesizer's voltage controlled oscillator (15).

Controllable multi-phase ring oscillators with variable current sources and capacitances

Abstract: An electrically controlled oscillator circuit having multi-phase outputs with programmable frequency. The circuit includes a ring oscillator having a plurality of inverting stages. Each stage has an output which is connected to a switch that can be programmed to select one of a plurality of capacitors with different values to change the frequency range of the oscillator. Controlled current is fed to the stages to vary the frequency of the oscillator within a selected frequency range. Using capacitors to change the frequency range of the oscillator reduces variations of the oscillator output frequency.