Abstract:
PROBLEM TO BE SOLVED: To provide a system for controlling the frequency of the output signal of a controllable oscillator (202) in a frequency synthesizer (200). SOLUTION: One such system comprises a controllable oscillator (202) and a frequency control circuit (208). The controllable oscillator (202) is configured to generate an output signal that has a predetermined frequency. The controllable oscillator (202) is also configured with a plurality of operational states that are controlled by the frequency control circuit (208). Each operational state of the controllable oscillator (202) defines a distinct frequency for the output signal of the controllable oscillator (202). The frequency control circuit (208) receives the output signal of the controllable oscillator (202) and determines the distinct frequency for the output signal that best approximates the predetermined frequency. The frequency control circuit (208) may also provide a control signal to the controllable oscillator (202) that is configured to change the controllable oscillator (202) to the operational state corresponding to the distinct frequency that best approximates the predetermined frequency. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide an oscillator suppressing variations in electric power and C/N ratio of output signals by oscillation frequencies. SOLUTION: The oscillator includes: oscillation units 11 to 1n outputting oscillation signals of different frequencies; a transmission line 15 to which outputs of the oscillation units 11 to 1n are connected, the transmission line having a characteristic impedance corresponding to an output impedance of an output terminal Tout; and a low-pass filter 18 connected between the transmission line 15 and the output terminal. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a high-frequency IC which is equipped with a built-in PLL circuit that contains an oscillator which generates local oscillation signals of prescribed frequency and is hardly unlocked even if VCO varies in oscillation frequency with a temperature change. SOLUTION: The built-in PLL circuit is equipped with the VCO 11 where an oscillation frequency band is changeable, a variable dividing circuit 12, a phase comparison circuit 15, and an loop filter 17. A switch which applies one of two or more prescribed stationary voltages to the VCO 11 in an open loop state where the loop filter 17 is isolated from the VCO 11, a judging circuit 22 which judges whether the output of the variable dividing circuit 12 is slower or faster in phase than the reference signals of the prescribed frequency, and an automatic band switching circuit 23 which generates signals of switching the frequency band of the VCO 11 resting on the output of the judging circuit 22 are provided. An optimal frequency band is found by switching the frequency band of the VCO 11 through a bisection inquiry method, and a stationary voltage applied to the VCO 11 is switched to an optimal voltage through the bisection inquiry method, and the optimal voltage is applied to the VCO 11 to lock the PLL loop. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator for widely securing an oscillated frequency band and decreasing a variance in a VCO gain at the entire oscillated frequency band. SOLUTION: A variable capacitor circuit group 3 is provided with a second variable capacitor circuit 32 and a third variable capacitor circuit 33 having fixed capacitive elements Cf0, Cf1, Cf2 in addition to a first variable capacitor circuit 31 having a first variable capacitor Cv1 whose capacitance is continuously varied with a frequency control signal CONT. The second variable capacitor circuit 32 includes: second variable capacitors Cv20, Cv21, Cv22 whose capacitance is continuously changed in response to the frequency control signal CONT; and switch circuits S20 to S22 for selecting the second variable capacitors in response to frequency band control signals BIT0, BIT1. The oscillated frequency is changed by using only the first variable capacitor Cv1 for a high oscillated frequency band, and the oscillated frequency band is changed by using also the second variable capacitors Cv20 to Cv22 as the oscillated frequency is lowered toward a low oscillated frequency band. COPYRIGHT: (C)2004,JPO
Abstract:
An integrated oscillator circuit comprises an oscillator configured to be switched between a first frequency and a second frequency. A switching circuit receives an input representing a target frequency and switches the oscillator between the first and second frequencies at intervals determined by the input, so as to cause the average output frequency of the oscillator to approximate the target frequency.
Abstract:
A digitally controlled oscillator comprising: an oscillator core configured to output an adjustable frequency output; and an oscillator tuner comprising at least one switchable impedance stage configured to control the oscillator core frequency output.
Abstract:
Embodiments feature techniques and systems for analog and digital tuning of crystal oscillators. In one aspect, some implementations feature a method for tuning a frequency of a crystal oscillator that can include adjusting the tuning frequency of the crystal oscillator from a nominal frequency via a switched-capacitor frequency tuning circuit, the switched-capacitor frequency tuning circuit can have switchable sections to adjust the tuning of the crystal oscillator. The method can include controlling an analog control input that is coupled to a varactor within each of the switchable sections, where each of the switchable sections can include a fixed capacitor in series with the varactor and a switch. The method can involve controlling a digital control input, where the digital control input can electrically connect or disconnect one or more of the switchable sections from the crystal. There can be independent control between the digital and analog tuning mechanisms.
Abstract:
A method of selecting fabrication parameters for an on-chip inductor of an integrated circuit. The integrated circuit includes a capacitor fabricated prior to the inductor. The capacitance of the capacitor is measured and, based on the measured capacitance and on a desired frequency range, a suitable inductor is fabricated. The integrated circuit may include a voltage controlled oscillator (VCO), and the selection of the fabrication parameters of the inductor includes the selection of a lithography mask for the fabrication of the inductor for maximizing yield across the wafer. Therefore, the integrated circuit can have exactly one VCO for covering the desired frequency range, as opposed to at least two VCO's with overlapping frequency ranges, thereby saving significant silicon area and increasing the yield per wafer.
Abstract:
A discrete clock generator (100, 200, 300) and/or a timing and frequency reference using an LC-oscillator topology, having a frequency controller (3015), a stable resonant frequency (fo), provided to other circuitry such as a processor or controller (1000, 1010, 1074, 1218, 1219, 1204, 3040). Frequency stability is provided over variations in a selected parameter such as temperatu and fabrication process variations. A sensor to provide a signal in response to at least one parameter.
Abstract:
A multi-band VCO employs a coupled-inductor based resonator having ports. Each port has an inductor and at least one capacitor. The N inductors for the N ports are magnetically coupled. The inductors/ports may be selectively enabled and disabled to allow the VCO to operate at different frequency bands. The capacitor(s) for each port may include one or more fixed capacitors, one or more variable capacitors (varactors), one or more switchable capacitors, or any combination of fixed, variable, and switchable capacitors. The switchable capacitors (if any) in the enabled ports may be selectively enabled and disabled to vary the VCO oscillation frequency. The varactors (if any) in the enabled ports can vary the oscillation frequency to lock the VCO to a desired frequency. The multi-band VCO may be implemented with various oscillator topologies and can replace multiple single-band VCOs.