With Parasitic Oscillation Control Or Prevention Means Patents (Class 331/105)
  • Patent number: 5677650
    Abstract: A ring oscillator comprising an odd number of inverters connected in a ring, and apparatus for driving the ring oscillator so that it oscillates at a frequency slightly less than its maximum oscillating frequency such that harmonics of the oscillating frequency are suppressed.
    Type: Grant
    Filed: December 19, 1995
    Date of Patent: October 14, 1997
    Assignee: PMC-Sierra, Inc.
    Inventors: Tadeus Kwasniewski, Maamoun Abou-Seido, Stephan Iliasevitch
  • Patent number: 5675295
    Abstract: A millimeter or microwave oscillator device for a receiver or a transmitter is described. The oscillator device including a high frequency oscillating circuit including an active device 41; said active device 41 having a first and a second contact 56, 52, a signal line 49 of said oscillator device 41 being connected to said first contact 56 for connection to a load circuit 43; a biasing circuit 47 for said active device; and a low frequency oscillation suppression circuit; wherein said low frequency oscillation suppression circuit includes a decoupling capacitor 45 and one electrode of said decoupling capacitor 45 is connected to said second contact 52. A manufacturing method for the oscillator device is also disclosed.
    Type: Grant
    Filed: May 8, 1996
    Date of Patent: October 7, 1997
    Assignee: IMEC vzw
    Inventors: Steven Brebels, Kristel Fobelets, Philip Pieters, Eric Beyne, Gustaaf Borghs
  • Patent number: 5568096
    Abstract: An apparatus and method are provided for increasing the effective Q-value of an oscillator so that the required Q-value can be reached with the use of a low Q-value oscillator. In this apparatus and method, the FM noise is measured at the output of the oscillator by an FM detector and the output of the FM detector is fed back to the control input of the oscillator. By using this negative FM feedback, frequency variations in the oscillator output are suppressed by applying a correction signal at the control input of the oscillator. The amount of suppression depends on the loop gain of the FM feedback loop and the amount of suppression is proportional to the loop gain so that the effective Q-value of the oscillator is proportional to the loop gain.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: October 22, 1996
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventor: Jacobus Haartsen
  • Patent number: 5302921
    Abstract: A piezoelectric oscillator in which radiation of higher harmonic components is reduced. A piezoelectric vibrator and a semiconductor device are provided in an oscillation circuit for making the piezoelectric vibrator oscillate, as is a filter for cutting components in a predetermined frequency band or higher harmonic components of an oscillation signal outputted from the semiconductor device. The piezoelectric vibrator, the semiconductor device and the filter are packed in one package. Radiation of the higher harmonic components is reduced by placing the filter close to the oscillator, by providing a shielding or by operating portions of the oscillator output circuit with a reduced supply voltage.
    Type: Grant
    Filed: April 16, 1992
    Date of Patent: April 12, 1994
    Assignee: Seiko Epson Corporation
    Inventors: Mikio Shigemori, Toru Oida, Shigeru Hirasawa, Katsumi Yamamura
  • Patent number: 5185585
    Abstract: Crystal oscillator and method which in one embodiment have a crystal element connected in a positive feedback loop with a charge amplifier and an integrator, with the gain of the loop being maintained at a level of unity. Compensation is provided to offset the effects of shunt capacitance in the crystal element, and precise phase control is maintained around the loop. In other embodiments, a crystal element is connected in a series feedback loop with a buffer amplifier, and operation is provided by maintaining the oscillation signal at level at which distortion, clipping, and saturation do not occur. Compensation for shunt capacitance across the crystal element is provided by applying a compensation signal which is equal in amplitude but opposite in phase to the signal passing through the shunt capacitance to the input terminal of the buffer amplifier to cancel the effect of the shunt capacitance.
    Type: Grant
    Filed: September 10, 1991
    Date of Patent: February 9, 1993
    Assignee: New SD, Inc.
    Inventors: Gerald R. Newell, Michael W. Nootbaar, Pradeep Bhardwaj, Robert C. Willson
  • Patent number: 5053726
    Abstract: An oscillator includes a mechanical resonator, such as a crystal, and having an amplifier arranged for oscillating at a first frequency. A resonant circuit is coupled in series with the crystal. The resonant circuit is antiresonant at an undesired harmonic frequency of the crystal thus prohibiting oscillation of the oscillator at said undesired harmonic frequency. The present oscillator is a portion of a phase locked loop used in a television receiver for demodulating a composite stereophonic audio signal.
    Type: Grant
    Filed: April 10, 1990
    Date of Patent: October 1, 1991
    Assignee: Thomson Consumer Electronics, Inc.
    Inventors: Todd J. Christopher, Robert E. Morris, Jr.
  • Patent number: 5047734
    Abstract: A series-feedback crystal oscillator has a crystal element in series with a buffer amplifier. The oscillator maintains a linear oscillation signal by using an amplitude control circuit to hold the oscillation signal to a certain level at which distortion, clipping, or saturation does not occur. A control signal indicative of the amplitude of the oscillation signal linearly multiplies the oscillation signal to control the amplitude of the oscillation signal. Shunt capacitance across the crystal is compensated for by connecting a compensating capacitor to the same input terminal of the buffer amplifier as is connected the crystal. A compensating signal, which is equal in amplitude but opposite in phase to the signal passing through the shunt capacitance of the crystal is fed to the input terminal of the buffer amplifier to cancel the effect of the shunt capacitance. A noninverted tracer signal is injected in the feedback loop and passes through the shunt capacitance.
    Type: Grant
    Filed: May 30, 1990
    Date of Patent: September 10, 1991
    Assignee: New SD, Inc.
    Inventors: Gerald R. Newell, Michael W. Nootbaar, Pradeep Bhardwaj
  • Patent number: 4864256
    Abstract: An oscillator for producing an oscillating signal with reduced harmonics includes an oscillator stage coupled to an output stage having a relatively fast switching speed yet producing an oscillating signal having relatively slow rise and fall times so that the harmonics output by the oscillator are reduced. In one embodiment, the oscillator includes an output stage having low power Schottky circuitry, and in a second embodiment, the output stage includes a capacitor connected across the output stage of the oscillator to increase the rise and fall times of the oscillator.
    Type: Grant
    Filed: September 9, 1988
    Date of Patent: September 5, 1989
    Assignee: Spectrum Control, Inc.
    Inventor: Armin Barnert
  • Patent number: 4616193
    Abstract: A solid state oscillator circuit for operation at very high frequencies includes a field effect transistor having an input network connected between its gate and source electrodes and an output network connected between its drain and source electrodes, the input and output networks each including three discrete capacitors connected in a "pi" configuration, the input and output networks being connected in series with one another, and an inductor being connected in parallel with the series connected networks, the equivalent circuit impedance of the networks in series and the inductance determining the operating frequency of the oscillator circuit, and the relative ratio of impedance of the networks determining the amount of oscillator feedback.
    Type: Grant
    Filed: January 22, 1985
    Date of Patent: October 7, 1986
    Assignee: Northern Illinois Gas Company
    Inventor: Walter Meyer
  • Patent number: 4571558
    Abstract: The invention relates to a crystal controllable oscillator circuit. The oscillator includes an amplifier and an oscillation sustaining feed-back loop coupled between an output and an input of the amplifier the loop including two integrators in series for inhibiting oscillation at crystal overtones. Each integrator provides 90.degree. phase shift independently of the oscillators defining RC product which determines only the gain thereby making the oscillator less sensitive to variations in circuit time constants due to temperature and manufacturing tolerance effects. The invention is particularly suitable for incorporating in integrated circuit form where only a single pin connection is required for the controlling crystal.
    Type: Grant
    Filed: October 29, 1984
    Date of Patent: February 18, 1986
    Assignee: Motorola, Inc.
    Inventors: Michael J. Gay, Johannes Gutmann
  • Patent number: 4542352
    Abstract: A modulated elongate cavity oscillator with minimized modulation nonlinearities includes a first cavity having dimensions which determine the fundamental resonant frequency of the oscillator, a gain element disposed in said first cavity that provides amplification to sustain oscillation, and a varactor diode disposed in said first cavity for modulating the fundamental frequency. A first waveguide is coupled to the first cavity for absorbing modes higher than the mode of the fundamental frequency which have an electric field maxima concurrent with the longitudinal center line of the first cavity. A second waveguide is coupled to the first cavity for absorbing modes higher than the mode of fundamental frequency which have an electric field minima concurrent with the longitudinal center line of the first cavity, whereby the first and second waveguides provide effective attenuation of higher order modes such that modulation nonlinearities due to the existence of higher order modes are substantially eliminated.
    Type: Grant
    Filed: June 17, 1983
    Date of Patent: September 17, 1985
    Assignee: Motorola, Inc.
    Inventors: Francis R. Yester, Jr., Paul H. Gailus, Edward V. Louis
  • Patent number: 4518931
    Abstract: A microwave transistor oscillator/doubler comprising a Field-Effect Transistor with Terminals G, D and S in combination with a coupling network connected to the terminals G, D and S and composed of microstrip lines with lengths equal to a quarter wavelength at the second harmonic of a fundamental frequency. The doubler further comprises a bias circuit for supplying appropriate voltages to the FET terminals, and an impedance coupler for coupling from the FET D-S terminals to a waveguide load. The coupling network optimizes feedback at the second harmonic between the D-S and G-S ports of the FET to prevent destructive harmonic feedback interaction with the desired signal while providing optimum conditions for feedback at the fundamental frequency. The bias circuit is connected to the coupling network and includes a second network of transmission line elements of lengths equal to a quarter wavelength at the fundamental in order to prevent dissipation of the fundamental frequency therein.
    Type: Grant
    Filed: May 5, 1983
    Date of Patent: May 21, 1985
    Inventor: Christen Rauscher
  • Patent number: 4482820
    Abstract: A circuit arrangement includes an integrated semiconductor circuit with a plurality of connection leads in which stray capacitances with equal temperature coefficients exist between one connection lead and the two adjacent, second and third, connection leads. A voltage is present between the first and second connection leads, and produces a current through the stray capacitance between these connection leads. In order to cancel the effect of this temperature-dependent current, a compensation voltage is applied between the first and second connection leads, which compensation voltage causes a current which is equal and opposite to the current through the stray capacitance between the first and second connection leads to flow through the stray capacitance between the first and third connection leads.
    Type: Grant
    Filed: May 17, 1982
    Date of Patent: November 13, 1984
    Assignee: U.S. Philips Corporation
    Inventor: Cord H. Kohsiek
  • Patent number: 4100510
    Abstract: A stabilization system for IMPATT diode microwave oscillators, comprising: means for electrical and mechanical support of said IMPATT diode, forming the return conductor of the feeding, the thermal dissipator and the terminal of a transmission line; a power supply feeding conductor for said diode comprising a substantially filamentary conducting element, inductively associated for a portion thereof to a ferrite, said ferrite being characterized in having high losses in the frequency spectrum where spurious oscillations might appear, and practically neglectable losses at the operating frequencies of said IMPATT diode.
    Type: Grant
    Filed: August 22, 1977
    Date of Patent: July 11, 1978
    Assignee: Selenia-Industrie Elettroniche Associate S.p.A.
    Inventors: Marcello Reggiani, Franco Marchetti