With Varactor Patents (Class 332/136)
  • Patent number: 9077284
    Abstract: A radio frequency rectifier circuit may include a resistive termination to circuit ground, a plurality of inductors, and at least a first pair of rectifier components. The plurality of inductors may be connected electrically in series between an input node for receiving an input RF signal and the resistive termination. Each pair of electrically adjacent inductors of the plurality of inductors may be connected together at a respective in-line node. The first pair of rectifier components may electrically couple a first one of the in-line nodes to a respective direct current output node. Each rectifier component may have a cathode and an anode. A first rectifier component of the first pair of rectifier components may have the cathode electrically connected to the first in-line node and a second rectifier component of the first pair of rectifier components may have the anode electrically connected to the first in-line node.
    Type: Grant
    Filed: June 26, 2013
    Date of Patent: July 7, 2015
    Assignee: Werlatone, Inc.
    Inventors: Ky-Hien Do, Peter Kuring
  • Patent number: 8816785
    Abstract: An oscillator which oscillates electromagnetic waves includes a negative differential resistance element, a resonator configured to prescribe oscillation frequencies of the electromagnetic waves, a voltage modulation unit configured to modulate the negative differential resistance element, a stabilizing circuit configured to suppress parasitic oscillation, and a bias circuit, including a power supply and a line, used to control an operating point voltage of the negative differential resistance element. The voltage modulation unit is connected to the bias circuit through the stabilizing circuit.
    Type: Grant
    Filed: September 14, 2011
    Date of Patent: August 26, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventor: Ryota Sekiguchi
  • Patent number: 8395458
    Abstract: The present invention is a high power direct transmitter with frequency-shift keying (FSK) modulation. The transmitter implements a high power, high efficiency power voltage-controlled oscillator (VCO) which allows for production of a modulated RF signal at the final stage (ex.—right at the antenna), thereby eliminating all driving stage power amplification and frequency translation. The transmitter further provides a low SWAP-C alternative to currently available solutions.
    Type: Grant
    Filed: September 22, 2011
    Date of Patent: March 12, 2013
    Assignee: Rockwell Collins, Inc.
    Inventors: Chenggang Xie, Gamal M. Hegazi
  • Patent number: 8169271
    Abstract: With some embodiments, a VCO (voltage controlled oscillator) operates at an integer multiple (N) above a desired transmission frequency. In accordance with one embodiment, a chip is provided with a VCO to generate a signal and a frequency dividing circuit to provide a reduced frequency version of the signal to a transmit mixer. The transmit mixer is followed by a power amplifier that is on the same die as the VCO. The power amplifier is to generate an OFDM output transmission.
    Type: Grant
    Filed: March 6, 2009
    Date of Patent: May 1, 2012
    Assignee: Intel Corporation
    Inventors: Pankaj Goyal, Christopher Hull
  • Patent number: 7968973
    Abstract: A semiconductor element for macro and micro frequency tuning, and an antenna and a frequency tuning circuit having the semiconductor element, are provided. The semiconductor element includes first and second semiconductors which have a same polarity, a third semiconductor which has a polarity opposite to the polarity of the first and second semiconductors and is interposed between the first and the second semiconductors, a first intrinsic semiconductor which is interposed between the first and the third semiconductors, and a second intrinsic semiconductor which is interposed between the third and the second semiconductors.
    Type: Grant
    Filed: March 28, 2007
    Date of Patent: June 28, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chang-won Jung, Jung-han Choi, In-sang Song, Young-eil Kim
  • Patent number: 7893788
    Abstract: A charge pump-based frequency modulator is provided. The charge pump-based frequency modulator comprises an analog phase correction path comprising a varactor and a charge pump. The varactor is coupled to an output of the charge pump-based frequency modulator. The charge pump is coupled to a node between the varactor and the output and receives a signal containing the modulated data.
    Type: Grant
    Filed: February 12, 2009
    Date of Patent: February 22, 2011
    Assignee: Mediatek Inc.
    Inventors: Ping-Ying Wang, Hsiu-Ming Chang
  • Patent number: 7868712
    Abstract: A circuit arrangement for frequency modulation is provided, which includes a voltage-controlled oscillator having at least one varactor diode that is driven by a drive signal, wherein a capacitance of the varactor diode depends on the drive signal, includes a modulating unit that creates a modulation signal for frequency modulation of the voltage-controlled oscillator, and includes a drive unit that generates the drive signal for the at least one varactor diode from the modulation signal, wherein the drive unit generates the drive signal from the modulation signal in such a manner that a linear relationship results between the modulation signal and the capacitance of the varactor diode.
    Type: Grant
    Filed: December 14, 2007
    Date of Patent: January 11, 2011
    Assignee: Atmel Automotive GmbH
    Inventor: Andreas Hanselmann
  • Patent number: 7847644
    Abstract: A modulation-signal generating circuit includes a temperature monitoring unit that detects a casing temperature of the circuit, a voltage control oscillator including two variable impedance circuits that independently control oscillation frequency based on an input control voltage, a frequency-correction-voltage generating unit that outputs a voltage for compensating for a temperature drift of an oscillation frequency according to the casing temperature detected by the temperature monitoring unit, to one of the variable impedance circuits, and an FM-modulation-voltage generating unit that outputs a modulation voltage containing a constant DC component not depending on temperature and a predetermined AC component, to the other variable impedance circuit, under a temperature drift compensation condition of the frequency-correction-voltage generating unit.
    Type: Grant
    Filed: July 21, 2006
    Date of Patent: December 7, 2010
    Assignee: Mitsubishi Electric Corporation
    Inventor: Takuya Suzuki
  • Patent number: 7609123
    Abstract: Transistors M11 and M12 are cross-coupled to each other so as to form a negative resistance circuit. First and second variable capacitor sections 10 and 20 are connected in parallel with an inductor circuit so as to form a parallel resonant circuit. A first reference voltage Vref1 and a control voltage VT1 corresponding to a carrier wave component are fed to both terminals, respectively, of each of variable capacitors VC11 and VC12 included in the first variable capacitor section 10. A second reference voltage Vref2 and a control voltage VT2 corresponding to a modulated wave component are fed to both terminals, respectively, of each of variable capacitors VC21 and VC22 included in the second variable capacitor section 20.
    Type: Grant
    Filed: December 10, 2007
    Date of Patent: October 27, 2009
    Assignee: Panasonic Corporation
    Inventor: Masakatsu Maeda
  • Patent number: 7567120
    Abstract: To avoid intermodulation interferences, a varactor diode alternative circuit has at least three varactor diodes connected in series alternatingly opposite to one another and a resistor and/or inductor network. At each of the varactor diodes, a control voltage supplied to the circuit for adjusting capacitance is at least approximately at full extent. An alternating voltage applied at the series connection, which is at a higher frequency than the control voltage, is distributed at least approximately uniformly to the varacter diodes. Even for an at least not substantially larger tuning voltage than the amplitude of a signal voltage to be processed in the oscillator circuit that has the alternative circuit, reactions of the signal voltage on the set capacitance of the varactor diode alternative circuit remain negligible, or at least low. The circuit may be used in an electrical, e.g., battery-operated, unit in which only one small operating voltage is available.
    Type: Grant
    Filed: January 24, 2005
    Date of Patent: July 28, 2009
    Assignee: Robert Bosch GmbH
    Inventor: Gerhard Kottschlag
  • Patent number: 7388446
    Abstract: A variable capacitor modulator for use in a voltage controlled oscillator, includes a differential varactor block, coupling capacitors for connecting nodes of the varactor block to a tank circuit, and an element connected between the respective nodes and ground to trim the gain of the variable capacitor modulator.
    Type: Grant
    Filed: February 10, 2005
    Date of Patent: June 17, 2008
    Assignee: Zarlink Semiconductor Ab
    Inventors: Viatcheslav Igorevich Souetinov, Alexander Alekseevich Krasin, Alexander Victorovich Koulakov
  • Patent number: 7289004
    Abstract: The present invention relates generally to the field of frequency modulation, and in particular to dual port frequency modulators. The present invention provides a frequency modulator comprising a phase lock loop circuit (108) for receiving and modulating a carrier signal according to the low frequency component of a modulating signal, the phase lock loop circuit comprising a voltage controlled oscillator (118) for outputting a modulated carrier signal and a loop filter (116) for outputting a steering voltage to the VCO, the VCO having a tank circuit (120) comprising a voltage controlled capacitance (VAR1). The frequency modulator also comprises an external voltage controlled capacitance (122) which is arranged to modulate its capacitance according to a high frequency component of the modulating signal, the second voltage controlled capacitance being coupled to the tank circuit.
    Type: Grant
    Filed: August 15, 2005
    Date of Patent: October 30, 2007
    Assignee: Motorola, Inc.
    Inventors: Evelyn L Chan, Fuad Haji Mokhtar, Ann Yen Lim
  • Patent number: 7155176
    Abstract: A system for synchronizing a portable transceiver to a network is disclosed. Embodiments of the system for synchronizing a portable transceiver to a network include a crystal oscillator, a frequency synthesizer adapted to receive an output of the crystal oscillator, logic coupled to the crystal oscillator, the logic configured to estimate a frequency error of a received signal; and a first control signal supplied from the logic to the frequency synthesizer, the first control signal configured to adjust the frequency synthesizer to compensate for the error.
    Type: Grant
    Filed: April 8, 2004
    Date of Patent: December 26, 2006
    Assignee: Skyworks Solutions, Inc.
    Inventors: Jaleh Komaili, Darioush Agahi, Ricke W. Clark
  • Publication number: 20020027479
    Abstract: An FM signal oscillator circuit includes a resonator having a graded- or abrupt-junction variable capacitance diode that is producible through standard IC manufacturing processes but causes an inconstant modulation level. The FM signal oscillator circuit, therefore, is provided with a function of maintaining a constant modulation level irrespective of oscillation frequencies. Namely, to maintain a constant modulation level without regard to oscillation frequencies that change depending on a control voltage applied to the variable capacitance diode, the FM signal oscillator circuit employs a variable gain amplifier whose gain changes in response to the control voltage. The variable gain amplifier amplifies a modulating signal, and the amplified modulating signal is superimposed onto the control voltage.
    Type: Application
    Filed: June 15, 2001
    Publication date: March 7, 2002
    Inventor: Minoru Nagata
  • Patent number: 6353370
    Abstract: A method and apparatus for modulation of a voltage-controlled oscillator (VCO). The VCO receives a tuning control voltage for adjusting a center frequency of an output periodic signal formed by the VCO. In addition, the VCO receives a modulation control voltage for modulating the output periodic signal by a content-carrying signal according to frequency modulation techniques. A frequency deviation obtained in the output periodic signal in response to changes in the modulation control voltage is linearized by forming the modulation control voltage as the result of a linear correction polynomial. A linear correction circuit forms the modulation control voltage. More particularly, a first amplifier having a gain of K1 receives the tuning control voltage. A first summing block then receives the output of the first amplifier and adds the constant K0. A second amplifier having a gain of m receives the content-carrying signal.
    Type: Grant
    Filed: October 4, 2000
    Date of Patent: March 5, 2002
    Assignee: Micro Linear Corporation
    Inventors: Robert Cox, Gwilyn Luff
  • 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: 5905414
    Abstract: A voltage controlled oscillator having a reduced oscillation frequency-modulation sensitivity variation and having a positive modulation function is designed to: (a) reduce the modulation variation by making the rate of change in oscillation frequency with a certain change in a modulation signal generally constant with respect to a wide range of oscillation frequencies; (b) reduce the manufacturing cost by using only one varactor diode; and (c) reduce the cost of a system using the voltage controlled oscillator by eliminating the need for correction of the modulation variation on the side of a system using the oscillator. In a variable capacitance circuit of the voltage controlled oscillator, the cathode of a varactor diode is connected to a control voltage terminal and is also connected to a modulation signal input terminal by a coupling resistor and a voltage dividing resistor.
    Type: Grant
    Filed: November 17, 1997
    Date of Patent: May 18, 1999
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Yasuo Motoi
  • Patent number: 5900788
    Abstract: A low-noise oscillator circuit with an amplifier element for negative feedback, specifically a transistor. In addition to a positive feedback of the oscillator transistor, provision is made for a negative-feedback loop with a pass band of 0 (thus DC coupling) to 1/4 to 1/100 of the oscillation frequency of the oscillator, in order to regulate out fluctuations of the current of the amplifier element.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: May 4, 1999
    Assignee: Sennheiser Electronic GMBH & Co. KG
    Inventor: Frank Hagemeyer
  • Patent number: 5870005
    Abstract: A broadcast transmitter for generating low power modulated signals, especially for a wireless speaker system. A signal source such as a source of composite audio signals including left and right audio signals and a pilot signal are applied to a radio frequency signal oscillator. The radio frequency signal oscillator includes a bipolar transistor connected in a common base configuration, and having a stripline element as a frequency determinative component in the collector circuit of the bipolar transistor. The modulating signal is applied to the base of the bipolar transistor which modulates the collector junction capacitance of the transistor thereby frequency modulating the signal produced by the oscillator. Varactor tuning is provided for setting a nominal frequency of oscillation.
    Type: Grant
    Filed: July 3, 1997
    Date of Patent: February 9, 1999
    Inventor: Shiu Hung Cheung
  • Patent number: 5801592
    Abstract: An oscillator circuit is provided for stabilizing the amplitude of a HF oscillation of an audio signal. In such an oscillator circuit, an audio signal having a frequency in the range of 20 Hz . . . 20 kHz is coupled into the oscillator circuit, is modulated with a high frequency and is emitted in the form of an RF audio signal having a frequency of more than 2 MHz. Such an oscillator circuit is used for instance in an infrared transmitting unit, wherein a low frequency audio signal is transformed into a higher frequency infrared signal. The higher frequency audio signals are transmitted via infrared channel to an appropriate receiving unit--for instance to infrared head phones--which comprises a receiving unit having an appropriate demodulator and preferably also a stereo-decoder in order to reproduce the low frequency audio signals.
    Type: Grant
    Filed: May 21, 1997
    Date of Patent: September 1, 1998
    Assignee: Sennheiser electronic GmbH & Co. KG
    Inventors: Wolfgang Mann, Horst Schaefer
  • Patent number: 5731745
    Abstract: The high frequency circuit includes an oscillator connected in a Colpitts configuration. Negative feedback to the oscillator is applied through an amplifier, both to stabilize the circuit and to permit frequency modulation of the carrier signal generated by the circuit. This feedback incorporates a capacitance to neutralize the Miller effect, thereby enabling it to operate at exceedingly high carrier frequencies. A variation of the circuit permits it to be simultaneously controlled by both a voltage and a current control signal. Also, by applying a frequency modulated carrier signal at a particular node of the oscillator, a demodulated output signal may be obtained.
    Type: Grant
    Filed: February 15, 1997
    Date of Patent: March 24, 1998
    Assignee: PSI Electronics, LLC
    Inventor: O. D. Parham
  • Patent number: 5606737
    Abstract: In a structure adopted for an FM-CW radar, a corner waveguide for connecting each of transmission and reception antennas to a sensor unit is integrated with a sensor unit case. In a waveguide/strip line converter for converting the transmission mode between the waveguide and the strip lines in the circuits of the sensor unit, a ditch is dug in the inner wall of an opening of the waveguide in order to prevent oozing of conductive adhesive. The strip line board is abutted on the inner wall of the waveguide in order to restrict a length of a projecting portion of a line conductor on the strip line board. By employing an oscillator mixer or a multiplier mixer, the circuitry in the sensor unit can be simplified without using lots of expensive millimeter wave devices. Furthermore, power can be utilized effectively even when a switching radar is off, which enables measurement of an absolute speed. Moreover, cost reduction can be achieved.
    Type: Grant
    Filed: March 8, 1993
    Date of Patent: February 25, 1997
    Assignees: Fujitsu Limited, Fujitsu Ten Limited
    Inventors: Hiroshi Suzuki, Hiroyuki Sogou, Kenichi Kudo, Yoshihiro Miura, Kiyokazu Sugai, Masayoshi Shono, Hideki Shiratori
  • Patent number: 5600279
    Abstract: A VCO circuit has a voltage variable capacitance CVD2 connected in series with or in parallel to a condenser C3 connected in series with an inductance L1, which constitutes a resonator of the VCO circuit. An adjustment voltage VD2 is applied to a cathode of the voltage variable capacitance CVD2, such that the relation between a control voltage VD1 and an oscillation frequency f0 of the VCO circuit is electrically adjusted to improve the fabrication yield.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: February 4, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Kazuhiro Mori
  • Patent number: 5589804
    Abstract: A pullable overtone crystal oscillator (201) includes an impedance buffer (217) for buffering an input impedance (109) to an amplifier stage (203). This structure enables construction of an overtone oscillator with increased pullability because a drive level of a crystal (221) can be set independent of the input impedance (109) of the amplifier stage (203).
    Type: Grant
    Filed: July 17, 1995
    Date of Patent: December 31, 1996
    Assignee: Motorola Inc.
    Inventor: Stanley Wrzesinski
  • Patent number: 5502420
    Abstract: A voltage controlled oscillator apparatus for generating a desired frequency, set by a tuning voltage, toward modulating a transmission signal on the desired frequency. The voltage controlled oscillator apparatus includes an oscillator transistor the base of which is RF live so as to destabilize the transistor such that it oscillates. The oscillator transistor emitter is operably connected through a capacitor to a tank circuit, which stores RF energy at the desired frequency, based on the tuning voltage, to set the oscillator transistor frequency. The inherent collector-base junction capacitance serves to provide voltage variable capacitance resulting in the generation of a carrier signal. The oscillator transistor collector is electrically connected to an amplifier transistor's emitter, such that the amplified transistor and oscillator transistor are in cascode configuration. The amplifier transistor amplifies the transmission signal input at its base and presents a signal output on its collector.
    Type: Grant
    Filed: June 1, 1994
    Date of Patent: March 26, 1996
    Assignee: VTech Communications, Ltd.
    Inventor: Michael J. Barclay
  • Patent number: 5495208
    Abstract: A tuning circuit for a reference oscillator (200) including voltage variable capacitors (222, 224) in a back to back configuration and providing a control terminal for voltage controlled tuning of the reference oscillator (200). Also included in the tuning circuit is a modulation bias circuit for modulating the reference oscillator (200).
    Type: Grant
    Filed: April 4, 1994
    Date of Patent: February 27, 1996
    Assignee: Motorola, Inc.
    Inventors: Armando J. Gonzalez, Kenneth D. Cornett, Jaime A. Borras
  • Patent number: 5428404
    Abstract: An apparatus and method for demodulating and remodulating a transmitted signal prior to presentation to a television receiver, the transmitted signal comprising a video signal, a first channel signal, and a second channel signal, wherein one of the two channel signals is selected, demodulated and remodulated with the video signal prior to presentation to the television receiver. The apparatus allows the viewer of a television receiver which accepts a single channel signal to select between one of two alternate channel signals associated with a video broadcast without the need to modify the television receiver. The apparatus is particularly well suited for television broadcasts using a dual carrier transmission format. A novel varactor diode tuning means is used in one embodiment for changing the center frequency of a frequency modulation demodulator. The disclosed apparatus also transparently allows stereo demodulation for television receivers which are capable of such stereo demodulation.
    Type: Grant
    Filed: January 29, 1993
    Date of Patent: June 27, 1995
    Assignee: Scientific-Atlanta, Inc.
    Inventors: Eric J. Ingram, James O. Farmer
  • Patent number: 5357222
    Abstract: The invention relates to a biased electronic circuit in which a voltage-controlled component has a characteristic with a non-linear portion and a substantially linear portion. The circuit is biased by a voltage being applied to one terminal of the component thereby shifting the operation of the component to the linear portion.
    Type: Grant
    Filed: October 7, 1992
    Date of Patent: October 18, 1994
    Assignee: Nokia Mobile Phones Ltd.
    Inventor: Seppo Hietala
  • Patent number: 5302918
    Abstract: A fundamental or subharmonic optically injection locked oscillator is coupled to a phase locked loop circuit. The injection locked oscillator has two single stage HEMT amplifiers with parallel feedback from the drain of a second transistor to a gate of a first transistor. A feedback resonant network controls the oscillator frequency. A microwave/millimeter wave source modulates a laser diode and the signal from the laser diode is then transmitted via an optical fiber to a PIN photodetector diode. The signal from the photodetector diode is injected into the oscillator at an nth subharmonic of the oscillator frequency. The feedback network may consist of a microstrip gap resonator with two tuning varactors at the ends of the resonator. The phase locked loop includes a balanced mixer used as a phase detector to compare the nth harmonic of the signal from the photodetector diode to the sampled output of the oscillator.
    Type: Grant
    Filed: June 1, 1993
    Date of Patent: April 12, 1994
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Dana J. Sturzebecher, Thomas P. Higgins, Afshin S. Daryoush
  • Patent number: 5254958
    Abstract: Biomedical information is directly digitally telemetered from the patient through a frequency modulated transmitter to a remote receiver and computer station. A phase-lock-loop circuit in the digital transmitter compensates for DC data bias by averaging and generating a scaled measure of the DC content of the digital data fed into the phase-lock-loop circuit. The average signal is then provided as a control signal to a first voltage controlled crystal oscillator, the output of which is then used as a reference frequency for the phase-lock-loop circuit. Frequency modulation of the digital data is provided by coupling the digital data directly into the voltage control input of the voltage controlled oscillator which generates the output frequency. Further control of the phase-lock-loop circuit in the transmitter is achieved by prepositioning the operating frequency of the voltage controlled oscillator by means of a microcontroller.
    Type: Grant
    Filed: September 30, 1992
    Date of Patent: October 19, 1993
    Assignee: Pacific Communications, Inc.
    Inventors: Terry E. Flach, William C. McBride
  • Patent number: 5187451
    Abstract: For minimization of a microstrip line and improvement of a Q value, the line length and width of the microstrip line are minimized, and the high frequency trend of the resulting resonant frequency is lowered and corrected to the resonant frequency near the oscillation frequency of an oscillator by connecting an additional capacitance component to the microstrip line. Thereby, the minimization of the microstrip line or the minimization of an oscillation circuit and characteristics equivalent to a dielectric coaxial resonator may be readily obtained. The strip line and the additional capacitance component are made as one piece circuit elements. The microstrip line is connected with a stub such that the stub may be trimmed to adjust the oscillation frequency. A cascode connecting amplifier which lessens the oscillation frequency fluctuation due to load variations is used.
    Type: Grant
    Filed: January 28, 1991
    Date of Patent: February 16, 1993
    Assignee: Kyocera Corporation
    Inventors: Yasuhiro Nakamoto, Hiroki Uemura
  • Patent number: 5151668
    Abstract: A frequency-modulation modulator in a cellular wireless telephone for modulating frequency after uniformly and linearly compensating for frequency characteristics to be suitable for each engaged channel in a cellular wireless telephone. Since frequency modulation characteristics are compensated uniformly and linearly according to each one of a plurality of channels, an error due to the frequency distorted modulation can be prevented and the cellular wireless telephone becomes more reliable.
    Type: Grant
    Filed: November 5, 1991
    Date of Patent: September 29, 1992
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Jong-Hae Kim
  • Patent number: 5140287
    Abstract: A diode circuit in which the flicker noise generated by the diode is reduced comprises a diode (D1) connected in series with a resistor (R2) having a by-pass capacitor (C1) in parallel therewith. In one embodiment the side of the diode remote from this resistor (R2) is connected to one input of a DC differential inverting amplifier (A1) via a low pass filter (L1, C2). The amplifier's output is negatively fed back to the junction of the diode (D1) and the resistor (R2) so that the latter forms the amplifier load. A control voltage is applied to the other input of the amplifier of such value as to produce the required diode bias. The basic diode circuit can be extended to perform functions such as amplitude limiting, frequency control and modulation.
    Type: Grant
    Filed: April 30, 1991
    Date of Patent: August 18, 1992
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventor: Henry W. Hawkes
  • Patent number: 5126697
    Abstract: Voltage controlled oscillator provided with a resonant network, an amplifier and a reactive network, all incorporated in an oscillator loop, the reactive network having one or more reactive components whose values depend on a control signal fed to a control input, so that the oscillator frequency can be regulated with said control signal. A control loop is provided between the resonant network and the reactive network, with which control loop the difference is determined between a measure of the imaginary part of the impedance or admittance of the resonant network and the control signal acting as reference quantity. The imaginary part of the impedance or admittance of the reactive network is regulated with said difference. The control loop contains a derivation circuit for deriving said measure and a differential amplifier, to one input of which the output signal of the derivation circuit is fed and to the other input of which the control signal is fed.
    Type: Grant
    Filed: November 21, 1990
    Date of Patent: June 30, 1992
    Assignee: Catena Micro-Electronics B.V.
    Inventors: Hendrikus C. Nauta, Ernst H. Nordholt
  • Patent number: 5075643
    Abstract: An improved frequency modulation apparatus (100) is provided comprising a generator (102), a biasing voltage line (116), and an interface circuit (110). The generator (102) is utilized to generate a carrier signal. A control line input (104) on the generator (102) adjusts the frequency of the carrier signal. The biasing voltage line (116) provides DC power in order to DC bias the generator (102). The interface circuit (110) couples an information signal (114) to the biasing voltage line (116) for altering the biasing of the generator (102) in response to the information signal (114). The alteration of the biasing of the generator (102) results in the carrier signal being frequency modulated by the information signal (114).
    Type: Grant
    Filed: December 24, 1990
    Date of Patent: December 24, 1991
    Assignee: Motorola, Inc.
    Inventor: Stephen B. Einbinder
  • Patent number: 5075644
    Abstract: Briefly, according to the invention, a voltage controlled oscillator 200 having a control input, an information signal input, and an output is disclosed. The voltage controlled oscillator 200 comprises a tank circuit 202 for generating a carrier signal and a modulator 206 for modulating the carrier signal in response to the information signal 210 at the information signal input of the voltage controlled oscillator 200. The voltage controlled oscillator 200 includes a filter 208 coupling the modulator 206 to the tank circuit 202 for rejecting out of band signals from altering the bias point of the modulator 206.
    Type: Grant
    Filed: December 3, 1990
    Date of Patent: December 24, 1991
    Assignee: Motorola, Inc.
    Inventor: Clarke J. Calvin
  • Patent number: 5030928
    Abstract: A method and apparatus for modulating a radio frequency signal with digital data including: a variable oscillator, a modulator for varying the oscillator's output, a network for detecting when the oscillator's output crosses its zero axis, a storage device for storing an applied data bit, and wherein the storage device applies the data bit to the modulator when the oscillator's output is at its zero crossing point.
    Type: Grant
    Filed: October 1, 1990
    Date of Patent: July 9, 1991
    Inventor: Wilson H. K. Ho
  • Patent number: 4959625
    Abstract: A frequency modulator is provided, in which, for instance, a video signal is used as a modulation signal. A differential amplifier is formed by first and second transistors. First and second load resistors are connected between respective collectors of the first and second transistors and a power supply terminal (A). A series circuit of first and second feedback capacitors is inserted between the collector of the first transistor and a base of the second transistor. A series circuit of third and fourth feedback capacitors is inserted between the collector of the second transistor and a base of the first transistor. The respective same electrodes of first and second variable capacitance diodes are connected with each other and the other electrodes thereof are connected respectively to a junction point of the first and second feedback capacitors and to a junction point of the third and fourth feedback capacitors.
    Type: Grant
    Filed: July 5, 1989
    Date of Patent: September 25, 1990
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Fusahiro Kameoka, Noriaki Omoto, Toshihiro Shogaki
  • Patent number: 4926144
    Abstract: A circuit for use in conjunction with a voltage controlled oscillator (VCO). The circuit introduces modulation into a radio system (to create a substantially flat frequency response) at the same VCO port at which VCO frequency centering and negative bias control signals are introduced. A potentiometer is utilized both for providing an adjustable negative bias to the varactor in the VCO resonant circuit and for setting the VCO to the appropriate center frequency. Modulation compensation circuitry is coupled to the control arm of the potentiometer and to the anode of the varactor (via a choke 4). The modulation compensating circuitry is preferably designed to have a transfer function that is substantially the inverse of the closed loop transfer function of the phase locked loop system with respect to the frequency modulation of the VCO.
    Type: Grant
    Filed: September 29, 1988
    Date of Patent: May 15, 1990
    Assignee: General Electric Company
    Inventor: Robert K. Bell