Zero Phase Shift Patents (Class 331/136)
  • Patent number: 7414482
    Abstract: A resonator-synchronized oscillator for resonance mode selection is disclosed. In one embodiment, the resonator-synchronized oscillator comprises an oscillation loop, at least one capacitor switching circuit coupled to the oscillation loop, and a multi-mode resonator having an output coupled to the at least one capacitor switching circuit. The output signal of the resonator is used to synchronize the oscillator using switched capacitor structures to instantaneously reset the phase of the resonator-synchronized oscillator.
    Type: Grant
    Filed: February 10, 2006
    Date of Patent: August 19, 2008
    Assignee: Broadcom Corporation
    Inventor: Jan R. Westra
  • Patent number: 7391840
    Abstract: A phase locked loop (PLL) circuit (1) comprising a loop input (11); a phase detector section (2) for detecting a phase difference between an input signal and a reference signal. The phase detector section (2) has a detector input connected to the loop input, a reference input and a detector output for outputting a signal related to the phase difference. A controlled oscillator (4) is connected with an input to the detector output and an oscillator output is connected to a loop output (12). The PLL has a feedback circuit which connects the oscillator output to the reference input, wherein the feedback circuit includes a device (7;71-74) having a transfer function with at least one zero.
    Type: Grant
    Filed: July 3, 2002
    Date of Patent: June 24, 2008
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventor: Johannes Wilhelmus Theodorus Eikenbroek
  • Patent number: 7146140
    Abstract: Briefly, exemplary embodiments of the invention may provide devices and methods to provide precise and/or low phase-noise quadrature oscillation signals. A quadrature oscillator in accordance with an exemplary embodiment of the invention may include, for example, a phase-shift generator to provide a phase-shift of substantially ?/2 radians to an oscillation signal between a first oscillation tank, which provides substantially no phase-shift, and a second oscillation tank.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: December 5, 2006
    Assignee: Intel Corporation
    Inventors: Ashoke Ravi, Krishnamurthy Soumyanath
  • Patent number: 6504441
    Abstract: A frequency sweep voltage controlled oscillator (VCO), with a selectable range of output frequencies is provided. The VCO includes a frequency range circuit to accept an input signal, differentially delay the signal, and selectably sum the delayed signals to provide signals in discrete frequency ranges. A frequency sweep circuit accepts the signal output from the frequency range circuit, differentially delays the signal, and sums the delayed signal in such a way as to modify the previously selected frequency range. A method for generating a signal from a frequency sweep VCO is also provided.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: January 7, 2003
    Assignee: Applied Micro Circuits Corporation
    Inventor: Mehmet M. Eker
  • Patent number: 6396360
    Abstract: Method and circuitry for implementing an inductor-capacitor voltage-controlled oscillator with improved overall performance. In an exemplary embodiment, the present invention includes two phase shifters and an interpolator. The two phase shifters are coupled to the interpolator in a loop configuration. That is, output from the two phase shifters are fed into the interpolator. The output of the interpolator, in turn, is fed back to the two phase shifters. The two phase shifters and the interpolator respectively utilize LC tanks having different fixed resonant frequencies, with the first phase shifter resonant frequency being the lowest, the interpolator resonant frequency being in the middle and the second phase shifter resonant frequency being the highest. Signals from the first and second phase shifters are selectively combined by the interpolator according to a control signal. Thus, the VCO can be continuously tuned near the resonant frequency of the interpolator.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: May 28, 2002
    Assignee: Broadcom Corporation
    Inventor: Yijun Cai
  • Patent number: 5546056
    Abstract: An injection-locked oscillator having a non-reciprocal four-port network with a pair of input ports (1, 2) and a pair of output ports (3, 4) in which the signal transfer path from a first input port (1) to a first output port (3) is non-reciprocal, the signal transfer path from a second input port (2) to a second output port (4) is non-reciprocal, the signal transfer path from a second input port (2) to a first output port (3) is non-reciprocal, and an amplifier with the input port coupled with said first output port and the output port coupled with said second input port, is locked to an injection signal applied to said first input port and provides oscillation output to said second output port (4). The circuit between the first input port (1) and the second input port (2), and the circuit between the first output port (3) and the second output port (4) are isolated. The present oscillator is implemented in a small IC chip, and has feature to be injection-locked in wide frequency band.
    Type: Grant
    Filed: January 27, 1995
    Date of Patent: August 13, 1996
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventor: Tsuneo Tokumitsu
  • Patent number: 5148125
    Abstract: Monitoring of the average dielectric constant in an extended volume of a medium such as soil is achieved using an oscillator incorporating a transmission line to be embedded in the medium. The transmission line is connected as the feedback loop of an amplifier, for one-way propagation of an electrical signal with a delay determined largely by the dielectric properties of the medium, such as its moisture content. The oscillation frequency is indicative of the dielectric constant of the medium.
    Type: Grant
    Filed: June 21, 1991
    Date of Patent: September 15, 1992
    Assignee: Lincoln College
    Inventors: Ian M. Woodhead, Stephen J. J. Hirsch