With Voltage Sensitive Capacitor Patents (Class 331/177V)
  • Patent number: 6154095
    Abstract: An oscillator circuit having a first programmable divider for obtaining a reference signal by dividing the frequency of an oscillation signal of a piezoelectric resonator by a frequency dividing number M. A PLL circuit using the reference signal as input thereto to obtain a multiplied signal, the multiplied signal being formed by multiplying the input signal by a second frequency dividing number N for a second programmable divider provided in a feedback circuit. A third programmable divider capable of dividing the frequency of the multiplied signal by a third frequency dividing number X and outputting the frequency-divided signal. The frequency dividing numbers M, N, and X can be set to values independent of each other. Therefore, innumerable combinations of the frequency dividing numbers M, N, and X can be used and the number of frequencies producible by one oscillator can be largely increased by enabling selection of any suitable one of such combinations.
    Type: Grant
    Filed: January 21, 1999
    Date of Patent: November 28, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Mikio Shigemori, Hideo Karasawa, Toshihiko Kano, Kazushige Ichinose
  • Patent number: 6147567
    Abstract: A method and apparatus for synthesizing high-frequency signals is disclosed that overcomes integration problem associated with prior implementations while meeting demanding phase noise and other impurity requirements. In one embodiment, a phase-locked loop (PLL) frequency synthesizer is disclosed having a voltage controlled oscillator (VCO) with a variable capacitance that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance, and the continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance. In a further detail, a digital control signal is disclosed to control the overall capacitance for the discretely variable capacitance circuit, and a variable control signal is disclosed to control an overall capacitance for the continuously variable capacitance circuit.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: November 14, 2000
    Assignee: Silicon Laboratories Inc.
    Inventors: David R. Welland, Jeffrey W. Scott
  • Patent number: 6137372
    Abstract: A method and apparatus for synthesizing high-frequency signals is disclosed that overcomes integration problem associated with prior implementations while meeting demanding phase noise and other impurity requirements. In one embodiment, a phase-locked loop (PLL) frequency synthesizer is disclosed having a voltage controlled oscillator (VCO) with a variable capacitance that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance, and the continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance. In a more general terms, a frequency synthesizer is disclosed having a first variable and a second capacitance circuits and frequency control circuitry to coarsely tune the output frequency by adjusting the first control signal and to finely tune the output frequency by adjusting the second control signal.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: October 24, 2000
    Assignee: Silicon Laboratories Inc.
    Inventor: David R. Welland
  • Patent number: 6133795
    Abstract: A stabilised voltage controlled oscillator circuit comprises a closed loop circuit containing a voltage controlled oscillator (34), a local oscillator (40) and a harmonic mixer (38) that mixes a stabilised local oscillator (LO) frequency signal and a radio frequency (RF) signal from the voltage controlled oscillator (34) to obtain an intermediate frequency (IF) signal. An IF amplifier (42) is connected to a linear frequency discriminator (44) that provides an output signal to a summing amplifier (46), which is connected to the voltage controlled oscillator (34). The closed loop circuit uses the linear frequency discriminator (44) to provide a feedback signal that stabilises the voltage controlled oscillator (34).
    Type: Grant
    Filed: July 10, 1998
    Date of Patent: October 17, 2000
    Inventor: Roscoe Charles Williams
  • Patent number: 6127900
    Abstract: The present invention includes a Voltage Controlled Oscillator (VCO) having a resonant circuit capable of being quickly switched between two resonant frequencies in order to generate two different LO frequencies. In a preferred embodiment, the present invention includes a VCO having a dual-frequency resonant circuit attached to the VCO's resonant circuit input leads. The dual-frequency resonant circuit is constructed in a differential architecture in order to create a number "virtual ground" points within the circuit that nearly eliminate any ground currents, and thus minimize the time required to switch the resonant circuit between the two LO frequencies. The switching between two resonant frequencies is achieved by creating a short circuit across certain components within the circuit to eliminate them from the resonant circuit.
    Type: Grant
    Filed: September 30, 1998
    Date of Patent: October 3, 2000
    Assignee: Conexant Systems, Inc.
    Inventors: Dana Vincent Laub, Julian L. Tham, Roy H. Fladager
  • Patent number: 6124767
    Abstract: An RF/Microwave oscillator is disclosed that has the high-Q, low-loss, and phase noise performance of a DRO, without the need of a dielectric resonator to achieve such performance. The RF/Microwave oscillator includes a field effect transistor having a drain coupled to an output circuit, a source coupled to a series feedback circuit, and a gate coupled to a resonator circuit. Each of these circuits are comprised of cascaded pairs of coupled transmission lines designed to resonate at the operating frequency of the oscillator. The RF/Microwave oscillator may also include a frequency-adjustable bias circuit, a frequency-adjustable FET gate return, and a frequency tuning circuit.
    Type: Grant
    Filed: July 14, 1999
    Date of Patent: September 26, 2000
    Assignee: Delphi Components, Inc.
    Inventor: Donnie W. Woods
  • Patent number: 6124766
    Abstract: A local oscillation circuit in a frequency converter circuit includes a resonant circuit, and a differential amplifier circuit connected to the resonant circuit. The differential amplifier circuit includes two transistors constituting a differential stage. One end of the resonant circuit is connected to the base of one transistor via a capacitive element, and to the collector of the other transistor via a capacitive element. The other end of the resonant circuit is connected to only the base of the other transistor via a capacitive element. Accordingly, an unbalanced oscillate operation is performed in the local oscillation circuit, leading to reduction of the phase noise caused by decrease in an oscillation output due to the trap phenomenon, and an improvement in reception quality.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: September 26, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Syuuji Matsuura
  • Patent number: 6121847
    Abstract: A method for centering the frequency of an injection locked oscillator or (ILO) includes producing measurements of the magnitude and sign of the phase difference between ILO output signals in response to alternate high level and low level RF drive signals, and tuning the center frequency of the ILO in accordance with the measurements to minimize the phase difference.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: September 19, 2000
    Assignee: Broadband Innovations, Inc.
    Inventors: Ron D. Katznelson, Branislav A. Petrovic
  • Patent number: 6107892
    Abstract: Phase noise in an RF oscillator is significantly reduced by loosely couping another quieter RF oscillator having noise patterns uncorrelated to the first RF oscillator so that it frequency locks with the first RF oscillator. The coupling is increased until a significant reduction in phase noise occurs at high coupling levels where the first RF oscillator displays phase noise similar to the the second RF oscillator.
    Type: Grant
    Filed: April 14, 1999
    Date of Patent: August 22, 2000
    Assignee: AT&T Corp.
    Inventor: Robert Raymond Miller, II
  • Patent number: 6100770
    Abstract: An electrical device having a voltage dependent capacitance is provided comprising a first region of a semiconductor material, and a second region and a third region of a semiconductor material formed in the first region, the second and third regions being separated by a separation region, and an electrically insulating layer formed on the first region at least at a region corresponding to the separation region, and a substantially conductive element formed on the insulating layer at least at a region corresponding to the separation region such that the insulating layer electrically insulates the substantially conductive element from the first, second and third regions, and a first electrode connected to the substantially conductive element, and a second electrode and third electrode are connected to the second and third regions. A method of manufacturing the device is also disclosed.
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: August 8, 2000
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Andrej Litwin, Sven Erik Mattisson
  • Patent number: 6097258
    Abstract: An oscillator is formed by a resonator (RES) coupled to an amplifier (AMP) via a coupling path (COP). In order to counter unwanted oscillations due to parasitic resonances in the coupling path (COP), the coupling path (COP) includes a series resistance (RS). This allows better performance in terms of noise for countering unwanted oscillations, despite the fact that the series resistance is in itself a source of noise. An even better noise-performance is obtained if the coupling path (COP) also includes a series capacitance. Such a series capacitance will also effectively widen a frequency range over which the oscillator can be tuned.
    Type: Grant
    Filed: September 24, 1998
    Date of Patent: August 1, 2000
    Assignee: U.S. Philips Corporation
    Inventor: Hendrik G. Van Veenendaal
  • Patent number: 6091304
    Abstract: A multi-band phase lock loop (PLL) device for use in a communication system. The PLL comprises a frequency reference oscillator, a reference frequency divider, a phase and frequency detector, a filter and compensation circuit, a microcontroller, a multi-band voltage controlled oscillator (VCO), and a feedback divider. A fast feedback signal is provided to the VCO for phase locking operation. A slow feedback signal is used by the microcontroller to generate a frequency adjust signal for frequency band centering for the VCO. The microcontroller also controls the VCO to change the frequency band of operation. The PLL device may be used in a communication system that operate in both the cellular frequency band and the PCS frequency band.
    Type: Grant
    Filed: September 22, 1998
    Date of Patent: July 18, 2000
    Assignee: LG Information & Communications, Ltd.
    Inventor: James Richard Harrer
  • Patent number: 6091309
    Abstract: An oscillator comprises an active device with a phase shift of less than 180 degrees. A first delay line has first and second ends. The first end of the first delay line is coupled to an active port of the active device. A ring mode trap filter is coupled to the second end of the first delay line. A second delay line has first and second ends. The first end of the second delay line is coupled to the ring mode trap filter. The second end of the second delay line is coupled to a resonance means. The total delay of the first and second delay lines allows the resonance means to oscillate at its natural frequency in spite of the less-than-180-degree phase shift of the active device.
    Type: Grant
    Filed: January 26, 1998
    Date of Patent: July 18, 2000
    Inventors: Joseph P. Burke, Peter D. Heidmann
  • Patent number: 6081167
    Abstract: A fully integratable voltage controlled oscillator (VCO) circuit includes a tuned circuit having a spiral inductance connected in parallel with a varactor controlled by a control voltage. Damping of the tuned circuit is counteracted by a cross-coupled NIC (Negative Impedance Converter). The cross-coupling of the NIC, which transforms a negative resistance into the tuned circuit, is provided by AC coupling of two outputs. Bipolar transistors are provided only for current source transistors, while in contrast CMOS transistors are provided in a current switch. The VCO can be used, for example, in DECT units.
    Type: Grant
    Filed: March 1, 1999
    Date of Patent: June 27, 2000
    Assignee: Siemens Aktiengesellschaft
    Inventor: Oliver Kromat
  • Patent number: 6075421
    Abstract: A voltage controlled oscillator (1) comprising a voltage controllable variable resonant circuit (2) having a control input (Vctrl), a positive feedback input (6) and a controllable variable frequency output (7). The voltage controlled oscillator (1) also has an amplifier (3) having an amplifier input coupled to the controllable variable frequency output (7) and an oscillator output (Out). A positive feedback path (4) couples the amplifier (3) to the a positive feedback input (6) and a frequency dependent negative feedback path (5) provides increased negative feedback to the amplifier (3) as the Radio Frequency increases.
    Type: Grant
    Filed: January 30, 1998
    Date of Patent: June 13, 2000
    Assignee: Motorola, Inc.
    Inventor: Chee Khon Chong
  • Patent number: 6072373
    Abstract: A voltage control oscillator capable of obtaining the desired output voltage by lowering the higher order harmonic level, is provided. Further, in the voltage control oscillator, a resonance circuit achieves the resonance by switching two different resonance frequencies. Moreover, inductors of a matching circuit are selectively used to change the inductance by turning on/turning off a diode of an impedance regulation circuit according to the respectively switched frequencies. Furthermore, the synthesized impedance with a matching capacitor is changed to achieve the matching with each of two frequencies.
    Type: Grant
    Filed: December 2, 1998
    Date of Patent: June 6, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Hisao Hayafuji, Hiroyuki Yamamoto
  • Patent number: 6057741
    Abstract: A radio frequency oscillator having: a resonant circuit; a gain element coupled in feedback relationship with the resonant circuit; and a variable reactance device, such as a varactor diode, adapted for coupling to a control signal for varying the reactance of the device. The variable reactance device is coupled to the resonant circuit with a coupling factor less than one. The resonant circuit comprises a planar microstrip transmission line structure. The varactor diode is coupled to the microstrip transmission line through a strip conductor disposed adjacent to, and dielectrically spaced from, a strip conductor of the resonant circuit. In one embodiment, the strip conductors are disposed in a side-by-side, dielectrically spaced relationship. In another embodiment, the strip conductors are disposed in a face-to-face, dielectrically spaced relationship.
    Type: Grant
    Filed: April 25, 1997
    Date of Patent: May 2, 2000
    Assignee: Raytheon Company
    Inventor: Roberto Alm
  • Patent number: 6052036
    Abstract: A highly stable single chip crystal controlled oscillator with automatic gain control. An amplitude detector monitors the output of a crystal controlled oscillator amplifier and produces a feedback signal proportional to the output signal of the amplifier to ensure oscillation is induced at startup and that the amplitude of oscillation is limited to a preselected value during operation to conserve power consumption by the amplifier. The capacitor tank circuit connected to the input of the amplifier includes a voltage variable capacitor the voltage across which is initially established at manufacture to tune the oscillation frequency to a preselected value. The voltage across the voltage variable capacitor is also adjusted to compensate for temperature variations in the circuit.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: April 18, 2000
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventors: H.ang.kan Enstrom, Erik Bengtsson, Torbjorn Gardenfors
  • Patent number: 6046647
    Abstract: A Voltage Controlled Oscillator (VCO) mitigates the effects of package parasitics by providing positive feedback connections, to sustain a desired oscillation, external to the IC package, thereby mitigating the effect of the bond wires and internal parasitics to allow the oscillation to be controlled by the desired external components. The VCO includes an electronic circuit with gain that is at least part of an integrated circuit (IC) and a package for the IC. A passive resonant circuit may be provided external to the IC package. The positive feedback of the electronic circuit is provided through at least one additional lead of the package, such that the connection is external to the package.
    Type: Grant
    Filed: December 8, 1998
    Date of Patent: April 4, 2000
    Assignee: Lucent Technologies Inc.
    Inventor: Dale Harvey Nelson
  • Patent number: 6046650
    Abstract: A voltage controlled oscillator circuit (58) having a modulation input port (60) for receiving a modulation input signal through modulation circuit (62, 64, 66, 68) and a frequency resonator circuit (28, 74, 76, 80, 82, 84) operable coupled to the modulation input port (60) for providing a modulation dependent impedance. A semiconductor element (90) has three ports, a gate port (98), a source port (96) and a drain port (92), and the modulation circuit is operably coupled to the gate port (98) of the field effect transistor (90) via a first capacitance (70) and the source port (96) of the field effect transistor (90) via a second capacitance (71). This enables the modulation sensitivity to be substantially independent of temperature variations of circuit elements.
    Type: Grant
    Filed: April 17, 1998
    Date of Patent: April 4, 2000
    Assignee: Motorola, Inc.
    Inventor: Stefan Lichterfield
  • Patent number: 6040744
    Abstract: In a temperature-compensated crystal oscillator, a series connection of an AT-cut crystal resonator, a MOS capacitor, and a first fixed capacitor is coupled in parallel with an amplifier and a second fixed capacitor, making up a crystal oscillation circuit. A first control signal generating circuit for temperature compensation is connected directly or via a first input resistor to one terminal of the MOS capacitor of the crystal oscillation circuit, and a second control signal generating circuit for temperature compensation is connected dirty or via a second input resistor to the other terminal of the MOS capacitor. The first control signal generating circuit serves as a rectilinear correction signal generating circuit on the lower temperature side while the second control signal generating circuit serves as a rectilinear correction signal generating circuit on the higher temperature side.
    Type: Grant
    Filed: July 8, 1998
    Date of Patent: March 21, 2000
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Yasuhiro Sakurai, Hiroyuki Fukayama
  • Patent number: 6037843
    Abstract: A controllable reactance implemented within an integrated circuit includes a first sub-circuit (20) comprising a reactive element, for example a capacitor 12, coupled in series with a transistor (14). A controllable current source (16) injects a controllable bias current through the transistor (14) to vary the effective resistance of the transistor (14) and hence the effective complex impedance of the capacitor combination. A second transistor (18) amplifies the current to increase the effective capacitance. Preferably, a second sub-circuit (24) includes corresponding components (26, 28, 30) to mirror the real component of the current flowing in the first sub-circuit (20), and transistors (32 and 34) to reflect an inverse current to the coupling node line (22) to cancel the real component of the current at the node, to thus simulate a purely capacitive circuit. An oscillator embodying this circuit is also disclosed.
    Type: Grant
    Filed: October 20, 1998
    Date of Patent: March 14, 2000
    Assignee: LSI Logic Corporation
    Inventor: Kenneth Stephen Hunt
  • Patent number: 6020791
    Abstract: The frequency of a quartz oscillator having a trimmer 2, a quartz oscillator 3 on which its temperature characteristic is printed in the form of a bar code 6, and a storage device 4 is adjusted to a predetermined frequency, and the temperature at that time is measured by a noncontact temperature sensor of a frequency adjusting device 10, and is written into the storage device 4. The temperature characteristic of the quartz oscillator is read by a bar code reader 21, and optimally suited temperature compensating data is selected from among a plurality of pieces of temperature compensating data stored in advance in a temperature-compensating-data writing device. Further, a frequency deviation between the temperature at the time of adjustment and a standard temperature is calculated, and the temperature compensating data including that frequency deviation is stored in the storage device 4.
    Type: Grant
    Filed: April 22, 1998
    Date of Patent: February 1, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasushi Watanabe, Takehiko Hayashi
  • Patent number: 6016081
    Abstract: A tunable oscillator includes an input for receiving an input signal from a source of precision frequency such as a CMOS quartz crystal oscillator. The tunable oscillator converts the frequency of the input signal to a first current using a frequency to current converter. The current produced is proportional to a first capacitor, C1. The first current is replicated to produce a subsequent current using a current mirror structure. The subsequent current is then used to generate a periodic signal using a current to frequency converter. The output frequency of the current to frequency converter is inversely proportional to a second capacitor, C2. As such the output frequency of the tunable oscillator is tunable by changing the value of the capacitance ratio C1/C2. The invention is suitable for applications that require a precision tunable source of frequency such as automated test equipment (ATE) and electrical instrumentation.
    Type: Grant
    Filed: July 17, 1998
    Date of Patent: January 18, 2000
    Inventor: Timothy G. O'Shaughnessy
  • Patent number: 6016082
    Abstract: A microprocessor includes an on-chip low phase noise CMOS LC capacitance oscillator. The LC oscillator is relatively insensitive to power supply fluctuations. In addition, the LC oscillator is operable over a range of frequencies sufficient to support both normal full power operation, and reduced power operation of the microprocessor. The LC oscillator minimizes clock jitter problems and so permits extension of the microprocessor operating frequency to even higher levels than heretofore were possible. An output signal from a phase-frequency detector is a frequency control signal on a frequency control input line of a level converter and filter circuit of the LC oscillator. The output signal from level converter and filter circuit is a filtered frequency control signal on a control voltage input line to a continuously modifiable gigahertz frequency voltage controlled oscillator (VCO) circuit.
    Type: Grant
    Filed: February 13, 1998
    Date of Patent: January 18, 2000
    Assignee: Sun Microsystems, Inc.
    Inventors: Jose M. Cruz, Robert J. Bosnyak, Robert J. Drost
  • Patent number: 6014064
    Abstract: A voltage controlled oscillator includes a varactor (201) and a transistor (202) and a ground via (203), of epitaxially grown silicon that is etched to provide respective pedestals embodying the varactor (201) and the transistor (202) and the ground via (203), an L-C resonator circuit, the varactor (201) and an inductor providing a tank circuit that changes the frequency of the L-C resonator circuit, and that shifts the average frequency of the oscillator to that of an input voltage to the collector of the transistor (202).
    Type: Grant
    Filed: July 9, 1997
    Date of Patent: January 11, 2000
    Assignee: The Whitaker Corporation
    Inventors: Timothy E. Boles, Joel L. Goodrich, Paulette R. Noonan, Brian Rizzi
  • Patent number: 6008702
    Abstract: A Colpitts-type voltage-controlled oscillator includes a transistor having a collector which is connected to a power terminal through a stripline. A capacitor is connected between the collector and the emitter thereof. A diode is connected to the capacitor and an inductor is connected to a point between the capacitor and diode. Another capacitor is connected between the base and the emitter of the transistor. An inductive reactance is formed by a stripline which is connected between the base of the transistor and the ground, two capacitors for DC blocking, and a variable-capacitance diode. Bypass capacitors are connected between the collector of the transistor and the ground. A resistor is connected between the emitter of the transistor and the ground. Two other resistors are provided for dividing a power voltage at the power terminal and for supplying a base voltage to the transistor. Turning the diode on and off allows the oscillating frequency of the voltage-controlled oscillator to vary by a large amount.
    Type: Grant
    Filed: March 23, 1998
    Date of Patent: December 28, 1999
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Hiroyuki Yamamoto
  • Patent number: 6002303
    Abstract: An oscillator circuit (100) provides improved noise immunity by utilizing a differential common base configuration. The oscillator includes a differential transistor pair (102, 104) having common bases (110) coupled through an AC ground (108) and emitters coupled through a differential common mode point (120). First and second resonant tank circuits are each referenced to the differential common mode point (120) for generating a differential output (OUT, OUTX).
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: December 14, 1999
    Assignee: Motorola, Inc.
    Inventors: Cesar Carralero, Raul Salvi, Branko Avanic
  • Patent number: 5999061
    Abstract: An oscillator having two oscillation circuits with widely different frequencies with a common passive switched output circuit. Each oscillator circuit includes a transmission line inductive impedance between the oscillator output and ground. The inductive impedances are selected to be open at the operating frequency of the associated oscillator circuit and a short or a low impedance at the frequency of the other oscillator circuit. Each inductive impedance forms a portion of an impedance matching pad for the other oscillator circuit.
    Type: Grant
    Filed: May 4, 1999
    Date of Patent: December 7, 1999
    Assignee: Vari-L Company, Inc.
    Inventors: Matthew D. Pope, Jeffrey T. Gudewicz
  • Patent number: 5994982
    Abstract: A switched resonator formed from a series capacitor and a single microstrip transmission line with a plurality of RF switches to connect it to ground along its length. The microstrip transmission line is grounded at one end and the RF switches are used to tune its length. The other end of the microstrip transmission line is connected to the capacitor to form a resonator. The resonant frequency of the resonator is varied by grounding the center conductor through RF switches connected to ground at different points along its length, which effectively varies the electrical length of the transmission line connected to the capacitor thereby forming a switched resonator. The switched resonator is suitable for use with a single VCO to provide relatively wideband tuning of the significantly reduced size due to the use of a single VCO.
    Type: Grant
    Filed: July 18, 1997
    Date of Patent: November 30, 1999
    Assignee: TRW Inc.
    Inventors: Mark Kintis, John J. Berenz
  • Patent number: 5986515
    Abstract: A temperature compensated crystal oscillator comprises a crystal oscillating circuit having an AT-cut crystal resonator; a linearizing correction circuit for transforming a temperature characteristic curve of an oscillating frequency of the crystal resonator into a straight line using a fixed coefficient common to all crystal resonators; a gradient correction circuit for eliminating the gradient of the linearized temperature characteristic of the oscillating frequency usmg a variable coefficient depending on the type of crystal resonator; and an f0 adjustment circuit for adjusting the gradient corrected temperature characteristic of the oscillating frequency so as to cause the oscillating frequency to lie within an allowable range. Thus, upon the temperature compensation of the oscillating frequency, there are separately performed the linearizing correction, the gradient correction and the f0 adjustment, to achieve a fast temperature compensation adjustment of the oscillating frequency.
    Type: Grant
    Filed: January 14, 1998
    Date of Patent: November 16, 1999
    Assignee: Citizen Watch Co., Ltd.
    Inventor: Yasuhiro Sakurai
  • Patent number: 5982243
    Abstract: An electronic oscillator of the Colpitts type with an amplifying element and a tank circuit. The tank circuit includes a parallel tuned resonant circuit, a series tuned resonant circuit and a switching circuit that selectively connects one of the resonant circuits to the tank circuit. The oscillator operates at a first frequency in the parallel tuned mode and a second frequency that is substantially twice the first frequency in the series tuned mode.
    Type: Grant
    Filed: May 4, 1999
    Date of Patent: November 9, 1999
    Assignee: Vari-L Company, Inc.
    Inventor: Matthew D. Pope
  • Patent number: 5982244
    Abstract: A voltage controlled oscillator provides a trimming stub (3) for adjusting a free-running frequency in parallel to a microstrip line resonator (4). This arrangement makes it possible to easily perform fine adjustment of a free-running frequency used in the voltage controlled oscillator capable of supplying 2 GHz or higher oscillating frequency.
    Type: Grant
    Filed: December 30, 1993
    Date of Patent: November 9, 1999
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Hirotaka Fujisaki
  • Patent number: 5977839
    Abstract: A digital temperature compensation oscillator by which its AFC operation to a receive signal cannot be disturbed by temperature compensation operation. A digital temperature compensation oscillator comprises a temperature sensor, an address creating section, a ROM, latching means, and a voltage-controlled crystal oscillator. The temperature sensor produces an output signal varied according to ambient temperatures. The address creating section converts an output from the temperature sensor into a signal and then creating it as a ROM (read-only memory) address. The ROM stores a control voltage to compensate a frequency variation due to ambient temperatures of a voltage-controlled crystal oscillator. The latching means holds or passes data output from the ROM according to an external control signal. The D/A converter produces a control voltage for the voltage-controlled crystal oscillator according to the latching means.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: November 2, 1999
    Assignee: NEC Corporation
    Inventor: Soichi Tsumura
  • Patent number: 5977840
    Abstract: A temperature compensated crystal oscillator with an improved phase noise characteristic and a fast start up time includes a large time constant low-pass filter coupled to a temperature compensation circuit. At start up the low pass filter is effectively bypassed to enable the temperature compensation voltage and oscillator output frequency to settle quickly. A capacitance in the low-pass filter is precharged by a precharge circuit to match the temperature compensation voltage without disturbing the temperature compensation circuit and the concurrent settling of the oscillator. When the capacitance is fully charged, the low-pass filter is enabled without unsettling the oscillator output frequency.
    Type: Grant
    Filed: April 29, 1998
    Date of Patent: November 2, 1999
    Assignee: CTS Corporation
    Inventors: Lawrence E. Connell, Alexander Dribinsky
  • Patent number: 5973519
    Abstract: A voltage controlled oscillator circuit having a negative resistance section for supplying electric power to the voltage controlled oscillator circuit and a parallel resonance circuit includes a first variable capacitance diode and a second variable capacitance diode which are connected in parallel. The first variable capacitance diode varies its capacitance according to a first control voltage and thereby varies oscillation frequency of the voltage controlled oscillator circuit. The second variable capacitance diode varies its capacitance according to a second control voltage which is independent of the first control voltage, and thereby varies the oscillation frequency of the voltage controlled oscillator circuit independently. Coupling condensers are provided between the negative resistance section and the first variable capacitance diode, and between the first variable capacitance diode and the second variable capacitance diode to cut off direct current.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: October 26, 1999
    Assignee: NEC Corporation
    Inventor: Osamu Yamashita
  • Patent number: 5973575
    Abstract: A voltage controlled oscillator for wide tuning range of frequency with less phase noise has a bipolar transistor provided with a positive feedback circuit between a base and an emitter of the transistor, an impedance matching circuit coupled with a collector of the transistor and an output terminal, a resistor coupled between the base of the transistor and a control source which provides control voltage for adjusting oscillation frequency of the oscillator. The base of the transistor shows capacitive negative impedance, and an inductive element is coupled with the base of the transistor for oscillation. The emitter of the transistor is grounded for D.C. voltage through an inductor or a transmission line, or coupled with a control voltage.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: October 26, 1999
    Assignee: Nippon Telegraph and Telephone Corp.
    Inventors: Kenji Kamogawa, Kenjiro Nishikawa, Ichihiko Toyoda, Tsuneo Tokumitsu
  • Patent number: 5966054
    Abstract: A method that includes the steps of producing a digital code (104) based at least in part on an integrated circuit capacitance and adjusting a frequency of the clocking signal in response to the digital code (106). A method that includes the steps of in a first mode of operation, producing a fixed frequency clocking signal, the fixed frequency clocking signal having a frequency tolerance less than 20 units per million and, in a second mode of operation, producing a variable frequency clocking signal, the variable frequency clocking signal having a frequency variability range greater than 200 units per million. An apparatus for providing a clocking signal includes a tuner circuit (12) and an oscillator circuit (16) responsive to the tuner circuit (12). The tuner circuit (12) is responsive to a clock signal source (38), an integrated circuit capacitance, and a reference resistor (18). The tuner circuit (12) produces a digital code signal.
    Type: Grant
    Filed: January 29, 1998
    Date of Patent: October 12, 1999
    Assignee: Motorola, Inc.
    Inventors: Michael R. May, Michael D. Cave, Joseph C. Fong
  • Patent number: 5963098
    Abstract: A canceler loop is used to provide negative feedback to a crystal oscillator to reduce the effects of shock and vibration on the spectral purity of the crystal oscillator. The canceler loop demodulates the output of the crystal oscillator and supplied a stabilizing voltage representative of the demodulated output to cancel frequency modulation induced by shock and vibration. The stabilizing voltage is used to cancel the noise sidebands of the frequency spectrum of the crystal oscillator output without tuning the center frequency.
    Type: Grant
    Filed: August 22, 1997
    Date of Patent: October 5, 1999
    Assignee: Technology Service Corporation
    Inventors: Alexander MacMullen, Vaughn L. Wright
  • Patent number: 5955929
    Abstract: A voltage-controlled oscillator (VCO) generates an oscillating signal that is substantially resistant to noise fluctuations in the supply voltage. The VCO is a delay-based VCO which preferably includes a compensation circuit for each delay cell and a noise-immune reference current generator for providing a noise-immune bias current to the conditioning circuit of the VCO. The compensation circuit preferably adjusts the capacitance of the delay cell to compensate for the variations in current caused by the supply noise. The noise-immune reference current generator preferably utilizes a configuration of transistors which maintains through at least one transistor a substantially constant current which is used to bias the conditioning circuit.
    Type: Grant
    Filed: August 27, 1997
    Date of Patent: September 21, 1999
    Assignee: Silicon Image, Inc.
    Inventors: Yongsam Moon, Deog-Kyoon Jeong
  • Patent number: 5945884
    Abstract: The object of this invention is an oscillation circuit that increases the Q of the parallel resonance circuit and increases the C/N (carrier-to-noise) ratio. The oscillation circuit contains two feedback capacitors connected between the base and emitter and between the emitter and collector of a transistor. Two inductors are also connected in series between the base and the collector of the transistor. One end of a resistor is connected to the emitter of the transistor and the other end is connected between the two inductors. The feedback capacitors and inductors constitute a parallel resonance circuit that may be tuned to create an equipotential across the ends of the resistor so that no current flows through it thus increasing both Q and the C/N ratio.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: August 31, 1999
    Assignee: Alps Electric Co., Ltd.
    Inventor: Kenji Nakatsuka
  • Patent number: 5942950
    Abstract: A low noise wide tuning bandwidth voltage controlled oscillator employs a resonator circuit formed from at least two microstrip lines which are electromagnetically coupled to one another. Each of the microstrip lines has one end electrically coupled to circuit ground to provide a substantially inductive resonator circuit which is substantially immune to parasitic end effects and radiation loses. The frequency of the voltage controlled oscillator circuit is controlled by a variable capacitance varactor circuit coupled to at least one of the microstrip transmission lines. The resonator circuit is well suited for use with a bipolar transistor configured as a negative resistance oscillator.
    Type: Grant
    Filed: May 11, 1998
    Date of Patent: August 24, 1999
    Assignee: AIL Systems, Inc.
    Inventor: Joseph Leonard Merenda
  • Patent number: 5936480
    Abstract: A voltage controlled oscillator (1) comprising a voltage controllable variable resonant circuit (2) having a control input (Vctrl), a positive feedback input (6) and a controllable variable frequency output (7). There is an amplifier (3) having an amplifier input coupled to the controllable variable frequency output (7). A positive feedback path (4) couples the amplifier (3) to the positive feedback input (6) and there is selectable load (5) in parallel with the positive feedback path (4) for selectively reducing the SideBand Noise Ratio.
    Type: Grant
    Filed: January 30, 1998
    Date of Patent: August 10, 1999
    Assignee: Motorola, Inc.
    Inventor: Chee Khon Chong
  • Patent number: 5936474
    Abstract: An electronic device is disclosed having an oscillation circuit included in a phase-locked loop. The phase-locked loop includes a phase detector and a variable divider having a selected dividing ratio. A control circuit is provided which melts a fuse as a function of the magnitude of the output of the phase detector for each dividing ratio of the divider, indicating a bad or good locking of the loop.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: August 10, 1999
    Assignee: U.S. Philips Corporation
    Inventor: Samuel Rousselin
  • Patent number: 5937340
    Abstract: The invention relates to an oscillator OSC intended to provide an output signal having a frequency which is variable as a function of a tuning voltage Vtun. The oscillator OSC includes a passive part having two series-arranged variable capacitances Cs, biased by the tuning voltage Vtun, and connected to a power supply VCC via two inductances Lext, and an active part having a first transistor T1 and a second transistor T2 whose collectors are connected to the output terminals C1 and C2 of the passive part, the base of one transistor being connected to the collector of the other transistor via a coupling capacitor Cfb. According to the invention, the passive part includes two high-pass filters, each being inserted between one of the output terminals S1 or S2 and one of the variable capacitances Cs, which allows a reduction of the active part's sensitivity to low-frequency noise.
    Type: Grant
    Filed: October 7, 1997
    Date of Patent: August 10, 1999
    Assignee: U.S. Philips Corporation
    Inventors: Pascal Philippe, Mihai Murgulescu, Fabrice Jovenin
  • Patent number: 5929712
    Abstract: A phase locked loop includes a voltage controlled oscillator, a frequency divider for frequency-dividing an output from the voltage controlled oscillator, a phase comparator for comparing an output from the frequency divider with a phase of a reference signal, and a control circuit for controlling the oscillator frequency of the voltage controlled oscillator on the basis of an output from the phase comparator. The voltage controlled oscillator and the frequency divider are formed within a single integrated circuit chip, and the input terminal of the frequency divider is connected to a short stub having an open end connected to the voltage controlled oscillator.
    Type: Grant
    Filed: March 9, 1998
    Date of Patent: July 27, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yasuhiko Kuriyama
  • Patent number: 5926071
    Abstract: A method is presented for minimizing the current consumption and the operating voltage of a voltage controlled oscillator. According to the invention the oscillator's (Q2) output signal (RFout) is detected as a DC voltage signal (Vgs) in a clamp/voltage multiplier circuit (U1, U2), preferably after a isolating amplifier (Q1). This detected signal is supplied in a feedback loop to a field effect transistor (FET1) controlling the oscillator's (Q2) current, whereby the field effect transistor controls the current (Ib) in the main current path to a predetermined minimum value. In this superimposed arrangement of the oscillator and the isolating amplifier the supply voltage (B) can be minimized by arranging, regarding the DC current, the isolating amplifier (Q1) in parallel with the field effect transistor (FET1) in the emitter branch of the oscillator (Q2).
    Type: Grant
    Filed: January 7, 1998
    Date of Patent: July 20, 1999
    Assignee: Nokia Mobile Phones
    Inventor: Osmo Kukkonen
  • Patent number: 5923221
    Abstract: An oscillator operable in the gigaHertz range includes a transistor having an emitter coupled to a tank circuit and an additional feedback path coupling the tank circuit back to the base of the transistor. The inductive elements of the tank circuit are in printed foil form as is a transmission line that provides the additional feedback path. This arrangement improves the phase noise characteristics of the oscillator while extending its operating frequency range.
    Type: Grant
    Filed: March 12, 1997
    Date of Patent: July 13, 1999
    Assignee: Zenith Electonics Corporation
    Inventor: Pierre Dobrovolny
  • Patent number: 5920235
    Abstract: A voltage controlled oscillator has a cross-coupled negative resistance cell formed as an integrated circuit connected to off-chip components of a high-Q resonant tank circuit. To counteract spurious oscillations brought about by package parasitics caused by the interconnection of the chip to the external components, the cell is provided with a degeneration impedance. Typically, a pure inductor is used if all the elements of the tank circuit are off-chip. In a case where the tank circuit includes an on-chip fixed capacitor, the degeneration impedance may take the form of a capacitor.
    Type: Grant
    Filed: June 25, 1997
    Date of Patent: July 6, 1999
    Assignee: Northern Telecom Limited
    Inventors: Ronald Douglas Beards, Samuel Alfred Tiller
  • Patent number: 5912594
    Abstract: A Pierce oscillator has been modified to replace the large capacitor with an amplifier element in order to make it more compact. A first amplifier element has a control terminal and a main current path extending between first and second output terminals. A network feeds back the signal at the first output terminal of the first amplifier to the control terminal of the first amplifier element and includes a series-arranged piezoelectric oscillation element. The oscillator also includes a reactive circuit element such as a resonant LC circuit or inductor (herein called an output dipole) coupled to the first output terminal of the first amplifier element and a DC current defining element coupled to the second output terminal of the first amplifier element.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: June 15, 1999
    Assignee: U.S. Philips Corporation
    Inventor: Dick Burkhard