L-c Type Patents (Class 331/117R)
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Patent number: 5834983Abstract: A bipolar negative resistance UHF oscillator having a voltage tunable resonator in its emitter circuit is operated at a fixed collector bias current and an RF detector is used as a convenient way to determine the RF current at which the oscillator is operating, by sensing the amplitude of the oscillator's output RF voltage across a constant load. An integrating error amplifier referenced to a desired detector output level responds to the actual detector output level to control the collector bias voltage for the oscillator and maintain the output of the oscillator at a fixed amplitude. Since the collector bias current is fixed, this keeps the operating point at fixed relation with respect to emitter cutoff. That relationship is chosen to be "just below" by initial selection of the constant collector bias current and the reference voltage used by the integrating error amplifier.Type: GrantFiled: September 30, 1997Date of Patent: November 10, 1998Assignee: Hewlett-Packard CompanyInventor: Thomas M. Higgins, Jr.
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Patent number: 5831487Abstract: An oscillator circuit includes a resonant circuit having a capacitor and an inductor. The inductor has two main terminals, a center tap and two further taps disposed symmetrically relative to the center tap. The inductor is constructed as a U-shaped stripline in which the center tap is disposed at a turning point of the U-shaped stripline, the main terminals are disposed at ends of legs of the U-shaped stripline and the further taps are each located at the same distance from an end of a respective leg.Type: GrantFiled: February 24, 1997Date of Patent: November 3, 1998Assignee: Siemens AktiengesellschaftInventors: Thomas Heilmann, Adam Bexley
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Patent number: 5821820Abstract: A voltage controlled oscillator operable on two widely separated frequency bands, such as 900 MHz and 1.8 GHz for example. The voltage controlled oscillator includes two negative resistance generators (32, 34) which share a common tunable tank circuit (26) and a common impedance matched combiner circuit (28) which provides the RF output (36). The VCO uses only one varactor (30) to tune both frequency bands. Separate negative resistance generators (32, 34) are used to provide optimum frequency selectivity within each frequency band.Type: GrantFiled: August 15, 1997Date of Patent: October 13, 1998Assignee: Motorola Inc.Inventors: James R. Snider, Glen O. Reeser
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Patent number: 5821825Abstract: An optically controlled oscillator utilizes a HEMT or a PIN diode as a photodetector and either a HEMT or HBT as an active inductor. The optically controlled HEMT active inductor provides a means for tuning the frequency of the oscillator. The optical receiver includes an optically tunable active inductor using a photodetector which includes a resonant tank circuit of an electronic oscillator to allow both optical/digital quench and unquench of an oscillator or digital AM detection with an improved signal to noise ratio, or optical FM modulation and analog AM detection by tuning/shifting the frequency of the oscillation through the detection of the optical light intensity.Type: GrantFiled: November 26, 1996Date of Patent: October 13, 1998Assignee: TRW Inc.Inventor: Kevin W. Kobayashi
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Patent number: 5815044Abstract: A variable-reactance circuit comprising an amplifying section, a first differential section and a second differential section. The amplifying section has first to third bipolar transistors. These transistors are driven by three constant-current sources, respectively. The first differential section receives an output signal of the amplifying section. The first differential section has fourth and fifth bipolar transistors, which are driven by a first variable-current source. The second differential section receives the output signal of the amplifying section. The second differential section has sixth and seventh bipolar transistors, which are driven by a second variable-current source. The output currents of the first and second variable-current sources are controlled by two control signals, respectively.Type: GrantFiled: August 14, 1996Date of Patent: September 29, 1998Assignee: Kabushiki Kaisha ToshibaInventors: Atsusi Ogawa, Tsuneyuki Murayama
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Patent number: 5801592Abstract: 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: GrantFiled: May 21, 1997Date of Patent: September 1, 1998Assignee: Sennheiser electronic GmbH & Co. KGInventors: Wolfgang Mann, Horst Schaefer
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Patent number: 5777522Abstract: A capacitor (200) having an actual physical capacitance value of Cact and is coupled to an oscillator (36). The oscillation frequency of the oscillator (36) can be changed by changing the effective capacitance of the capacitor (200). The actual capacitance (Cact) of capacitor (200) can be altered to appear to be any effective capacitance (Ceff) between zero and a value much greater than Cact by using a Miller effect. In order to alter the effective capacitance of the capacitor (200), a representation of the output osculation signal (16) is provided to a frequency adjust stage (22). The frequency adjust stage either passed the signal (16) with 0.degree. phase shift or with 180.degree. phase shift. In addition to shifting the phase, the stage (22) will amplify or attenuate the signal (16) to result in the phase shifted and amplified/attenuated frequency adjusting signal (24).Type: GrantFiled: January 3, 1997Date of Patent: July 7, 1998Assignee: Motorola, Inc.Inventors: Mathew A. Rybicki, Michael D. Cave
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Patent number: 5767745Abstract: An oscillator circuit having a phase control circuit performing phase control on the oscillation signal based on a signal representing a phase difference between a signal input from outside and the oscillation output so that the oscillation frequency follows the frequency variation of the signal input from outside. The phase control circuit includes a phase shifting circuit for forming the oscillation signal into first and second signals having a phase, difference of approximately 45.degree.. The phase control circuit subtracts the second signal from the first signal vectorially to form a third signal, and also inverts the second signal to form a fourth signal. Depending on the level of the phase difference signal, the phase control circuit outputs a composite signal of either the second and third or the third and fourth signals.Type: GrantFiled: July 25, 1996Date of Patent: June 16, 1998Assignee: Rohm Co., Ltd.Inventor: Sadakazu Murakami
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Patent number: 5748578Abstract: A Colpitts type oscillator circuit for mitigating the effects of undesired oscillator ringing when write pulses are supplied, such as those encountered in compact disc, laser disc, and magneto-optical players or recording devices. Circuit elements are provided for mitigating the effects of oscillator ringing including replacement of an inductor with a suitable resistive load and an oscillator supply voltage maintained above a predetermined minimum voltage which is a function of the specific values of the related circuit elements.Type: GrantFiled: April 11, 1995Date of Patent: May 5, 1998Assignee: Discovision AssociatesInventor: David L. Schell
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Patent number: 5748051Abstract: An oscillator circuit is described which exhibits low phase noise characteristics and has special application in UHF and microwave technologies. The oscillator circuit of the invention includes a band pass filter having specific capacitor and inductor values which can be optimized so that the circuit has a loaded Q very close to the resonator's unloaded Q.Type: GrantFiled: May 16, 1996Date of Patent: May 5, 1998Assignee: Z-Communications, Inc.Inventor: Charles Lewis
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Patent number: 5745013Abstract: A variable-frequency oscillator configuration, in particular for tuners, includes a feedback network for an oscillator amplifier. The feedback network contains a series circuit formed by two resonant circuit inductors and a resonant circuit capacitor, connected in parallel with a series circuit formed by a further resonant circuit capacitor and a variable capacitor. A switching device is connected to a coupling node between the two inductors, for short circuiting the first resonant circuit capacitor and the resonant circuit inductor connected thereto under the control of a switching signal. The feedback network can consequently be switched over between two frequency bands and is symmetrical with regard to the high-frequency effect.Type: GrantFiled: November 26, 1996Date of Patent: April 28, 1998Assignee: Siemens AktiengesellschaftInventor: Henning Hohmann
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Patent number: 5739729Abstract: In a voltage-controlled LC oscillator, a series LC resonance circuit is connected between two transistor amplifying stages which provide low impedance input and output circuits for the LC circuit. The collector of the first transistor stage is connected through a coil to the operating voltage. The emitter of the second transistor stage is connected to the reference voltage through a coil. This will result in narrowband transistor stages and significant advantages in the power consumption and other characteristics of the oscillator.Type: GrantFiled: November 22, 1996Date of Patent: April 14, 1998Inventors: Nikolay Tchamov, Petri Jarske
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Patent number: 5731745Abstract: 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: GrantFiled: February 15, 1997Date of Patent: March 24, 1998Assignee: PSI Electronics, LLCInventor: O. D. Parham
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Patent number: 5726608Abstract: The invention provides a trimmable multi-terminal capacitor. The multi-terminal capacitor comprises a plurality of capacitors with each of the capacitors having a common terminal. The capacitors are formed on a layer of dielectric material having a common plate of conductive material disposed on its top surface, and a plurality of separate plates of conductive material disposed on its lower surface. The capacitance value of each of the capacitors is separately tunable to tight tolerances. The capacitor is particularly suited to be used in a voltage controlled oscillator (VCO) to couple a plurality of devices to a resonator.Type: GrantFiled: October 17, 1995Date of Patent: March 10, 1998Assignee: Telefonaktiebolaget LM EricssonInventor: Michael .ANG.rlin
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Patent number: 5721517Abstract: A resonance inductor of a resonant circuit is formed of a chip inductor and an inductance fine adjustment pattern. A resonance capacitor is formed of a plurality of chip layered capacitors connected in parallel to each other via connection patterns formed on a substrate. The connection patterns are sequentially disconnected to adjust the capacitance of the resonance capacitor. Then, the inductance fine adjustment pattern is partially removed to adjust the inductance of the resonance inductor.Type: GrantFiled: March 28, 1995Date of Patent: February 24, 1998Assignee: Murata Manufacturing Co., Ltd.Inventors: Shinji Goma, Tatsuo Bizen
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Patent number: 5714914Abstract: A high power, low noise voltage-controlled oscillator (VCO) eliminates the drive-stage amplifier and costly surface-acoustic wave (SAW) inter-stage filter in a transmitter such as a cellular radiotelephone. The VCO includes a resonant circuit, an active part connected to the resonant circuit, and a buffer amplifier, connected to the active part, for isolating the VCO from a load connected to the buffer amplifier. The active part includes at least one transistor in a Colpitts configuration; capacitances connected in parallel with junction capacitances of the transistor, each capacitance having a value that is greater than a value of the respective junction capacitance with which it is connected in parallel; and a resistance for providing negative feedback at low frequencies. A second resistance may be provided for reducing the gain of the active part when oscillation starts.Type: GrantFiled: February 28, 1995Date of Patent: February 3, 1998Assignee: Ericsson Inc.Inventor: Xue-Song Zhou
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Patent number: 5712599Abstract: An oscillating signal generator for generating an oscillating signal having a variable oscillation frequency that can be near the unity gain frequency of the gain devices within the oscillating signal generator (Generation of High-Frequency Oscillating Signal Techniques, "GHOST"). Two gain stages, each with a respective effective resistance R.sub.eff, an emitter load capacitance C.sub.E, and a respective gain device having a unity gain frequency .omega..sub.T, are cascaded and configured to provide a respective gain with a phase at substantially 180.degree.. In that case, the oscillation frequency, of the oscillating signal generated by the oscillating signal generator of the present invention, .omega.=?.omega..sub.T /(R.sub.eff C.sub.E)!.sup.1/2. A feedback with a feedback gain is provided between the output to the input of the cascade of the two gain stages. The feedback gain is designed such that a product of the feedback gain and the gain through the cascade of the two gain stages is substantially one.Type: GrantFiled: June 19, 1996Date of Patent: January 27, 1998Inventor: Leonard L. Kleinberg
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Patent number: 5703543Abstract: A switching oscillator constituted by two inverters is provided with a system of current mirrors each arranged to provide a small proportion of load current from the load of one transistor to the load circuit of the other such as to drive the load currents into equilibrium.Type: GrantFiled: May 6, 1996Date of Patent: December 30, 1997Inventor: Clive Roland Taylor
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Patent number: 5694092Abstract: A Colpitts voltage-controlled oscillator is provided with a variable capacitance section 11 connected in parallel to a resonator 12, which is the inductance element of an inductance section 1. Variable capacitance section 11 is provided with varactors X1 and X2 having differing voltage/capacitance ratios. A fixed control voltage Vc is applied to the commonly connected cathodes of varactors X1 and X2. A control voltage Va which produces a reverse bias voltage (Vc-Va) is applied to the anode of varactor X1, and a control voltage Vb which produces a reverse bias voltage (Vc-Vb) independent of control voltage Va is applied to the anode of varactor X2. When control voltage Va is fixed, control voltage Vb is made the frequency control signal, and when control voltage Vb is fixed, control voltage Va is made the frequency control signal.Type: GrantFiled: June 28, 1996Date of Patent: December 2, 1997Assignee: NEC CorporationInventors: Hiroaki Oba, Shigeru Otsuka
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Patent number: 5675478Abstract: An oscillator voltage regulator includes a substantially constant voltage device in series with the bias network dividing resistors to reduce current flow and provide a substantially constant voltage drop, and an impedance connected between the first and second resistors of the dividing resistors and the tank circuit and the base of the amplifier transistor so as to reduce the loading on the tank circuit and so as to improve stability, reduce phase noise, and increase power output from the amplifier. The use of a silicon PN junction and a NPN transistor provides temperature compensation for hot and cold ambients to allow the oscillator to operate with substantially a constant supply current.Type: GrantFiled: July 15, 1996Date of Patent: October 7, 1997Assignee: Vari-L Company, Inc.Inventor: Joseph H. Kiser
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Patent number: 5650754Abstract: Voltage controlled oscillator (VCO) circuits include a VCO and voltage regulator provided on an integrated VCO module, balanced control input for the VCO, buffering of the VCO and frequency multiplication of the VCO output signal. Such improved VCO circuits are especially useful in phase-locked loop (PLL) circuits. Improved PLL circuits are also provided, including a PLL circuit with separate analog and digital grounds.Type: GrantFiled: February 15, 1995Date of Patent: July 22, 1997Assignee: Synergy Microwave CorporationInventors: Shankar R. Joshi, Ulrich L. Rohde, Klaus Eichel
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Patent number: 5635884Abstract: The grounded inductance circuit utilizing a gyrator circuit includes a first operational transconductance amplifier, a second operational transconductance amplifier and a first capacitor. A first output terminal of the first operational transconductance amplifier is connected to a first input terminal of the second operational transconductance amplifier, and a second output terminal of the first operational transconductance amplifier is connected to a second input terminal of the second operational transconductance amplifier. A first output terminal of the second operational transconductance amplifier is connected to a second input terminal of the first operational transconductance amplifier and a second output terminal of the second operational transconductance amplifier is connected to a first input terminal of the first operational transconductance amplifier.Type: GrantFiled: June 3, 1996Date of Patent: June 3, 1997Assignee: NEC CorporationInventor: Tomohiro Fujii
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Patent number: 5627498Abstract: An oscillator comprises a first inverter provided with a resonant feedback circuit, a second inverter having its signal input terminal at the same DC level as the signal input terminal of the first inverter, and a current source having a current supply terminal connected to the power supply terminals of the first and second inverters.Type: GrantFiled: February 9, 1996Date of Patent: May 6, 1997Assignee: Nvision, Inc.Inventor: Charles S. Meyer
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Patent number: 5625327Abstract: A Colpitts-type oscillator circuit suitable for use with electronic identification systems is disclosed. The oscillator circuit utilizes a pair of transistors coupled together with a feedback loop that includes a parallel LC circuit such that the output amplitude can be as high as a factor of 20 times the supply voltage or more while maintaining a high Q, low distortion output. The oscillator circuit is a modified Colpitts oscillator that includes a NPN transistor and a PNP transistor coupled together and a Colpitts type feedback loop containing a parallel LC circuit. The capacitance of the parallel LC circuit consists of at least two capacitors in series forming a capacitive divider which provides a low impedance feedback via the base of the NPN transistor into the emitter of the PNP transistor. The collector of the PNP transistor taps into the inductor of the parallel LC circuit such that the inductor is driven to resonance.Type: GrantFiled: July 13, 1995Date of Patent: April 29, 1997Assignee: GnuCo Technology CorporationInventors: Gary T. Carroll, J. Donald Pauley
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Patent number: 5621362Abstract: An oscillator (100) includes a tank circuit (102) coupled to a an active circuit (108). The feedback (104) provides the necessary feedback between the tank and the active circuit necessary for oscillation. The active circuit (108) is biased via a biasing circuit (106) and coupled out to a load via an external coupling (110). The active circuit (108) includes two transistors (124, 126) coupled to each other in a cascode configuration. Transistor (126) provides the collector current for transistor (124) while preventing it from entering saturation prematurely. The biasing circuit (106) provides sufficient current drain for the transistor (126) in order to provide for optimum phase noise and bandwidth performance of the oscillator 100.Type: GrantFiled: February 5, 1996Date of Patent: April 15, 1997Assignee: Motorola, Inc.Inventors: John K. McKinney, Peter J. Yeh, Branko Avanic
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Patent number: 5606294Abstract: An automatic gain control circuit and method ensure feedback for oscillator circuitry fabricated on a single semiconductor chip to adapt to the Q value established by a resonator circuit connected to the oscillator circuitry, and to ensure that gain is maximized and linearity of operation preserved within the voltage rails of the power supply.Type: GrantFiled: January 29, 1996Date of Patent: February 25, 1997Assignee: IC Works, Inc.Inventor: Roy Richards
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Patent number: 5602515Abstract: In order to improve the efficiency of a self-starting high-frequency generator, where for self-starting power is fed back from the anode circuit to the control grid of the grid-controlled electron tube used as amplifier element, the following measures are provided. An additional oscillating circuit (L.sub.A3, C.sub.A3) which is tuned to a multiple of the operating frequency (f.sub.1) is arranged in the anode circuit. An oscillating circuit (L.sub.G31, L.sub.G32, C.sub.G3) tuned to a multiple of the operating frequency (f.sub.1) is likewise arranged in the control-grid circuit. Components (L.sub.G31) belonging to the feedback circuit are at the same time components of the oscillating circuit arranged in the control-grid circuit.Type: GrantFiled: August 28, 1995Date of Patent: February 11, 1997Assignee: Siemens AktiengesellschaftInventors: Michael Held, Jochen Stahl
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Patent number: 5596302Abstract: A ring oscillator having an even number of differential amplifier stages is disclosed wherein each stage includes a differential amplifier using two N-channel MOSFETs whose gates serve as the inputs and whose drains serve as the outputs of the stage. The sources of the two MOSFETs are connected together and to a current sink consisting of a cascoded structure of N-channel MOSFETs. The drains of each of the two N-channel MOSFETs serving as the differential amplifier are each connected to a respective current source provided by a P-channel MOSFET. All of the current sinks in the stages are connected as secondary legs of a first current mirror which establishes a current of I in the sinks. All of the current sources are connected as secondary legs of a second current mirror which attempts to establish a current of (1+.varies.)I/2 in each of the sources, where .varies. is a number greater than zero.Type: GrantFiled: January 17, 1996Date of Patent: January 21, 1997Assignee: Lucent Technologies Inc.Inventors: Angelo R. Mastrocola, Jeffrey L. Sonntag
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Patent number: 5587629Abstract: A transformerless high-voltage generator circuit includes an amplifier and a feedback circuit connected together to form an oscillator. Due to the configuration of the feedback circuit, a high-voltage output is obtained at an intermediate point within the feedback circuit without the use of a transformer. The resulting circuit may be used in various applications, such as an electronic photoflash unit, in order to reduce the size, weight and cost of the finished product by eliminating the need for a transformer to obtain the desired high voltage.Type: GrantFiled: August 28, 1995Date of Patent: December 24, 1996Assignee: Philips Electronics North America CorporationInventor: Viktor L. Gornstein
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Patent number: 5576667Abstract: An inexpensive voltage control type oscillator suitable for use with a mobile radio communication system within a predetermined frequency band range. The oscillator includes a resonance circuit and an oscillation stage formed on a printed wiring board and operating such that the oscillation frequency of the oscillation stage is varied within a predetermined frequency band range by varying the resonance frequency of a parallel resonance circuit included in the oscillation stage on the basis of a control voltage. The parallel circuit comprises a strip line connected in series with a bias resistor and a chip capacitor connected parallel to the strip line. The strip line has an inductance sufficiently larger than that of the resistor and the chip capacitor has a capacitance value so determined that the capacitor resonates at a predetermined frequency in cooperation with the strip line.Type: GrantFiled: November 21, 1995Date of Patent: November 19, 1996Assignee: Murata Manufacturing Co., Ltd.Inventor: Shinji Goma
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Patent number: 5561399Abstract: An apparatus and method are provided for increasing the Q-value of an oscillator so that a net gain in the stability of the oscillators is obtained. In the apparatus and method, a plurality of units, which each include a passive frequency-selective circuit and an active amplifier, are cascaded and the required isolation between the passive frequency-selective circuits is maintained by the active amplifier acting as a buffer. As a result, interaction and loading is prevented between the passive frequency-selective circuits so that the net gain in the stability of the oscillator is achieved because the Q-value of the oscillator is increased.Type: GrantFiled: April 19, 1995Date of Patent: October 1, 1996Assignee: Telefonaktiebolaget LM EricssonInventor: Jacobus Haartsen
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Patent number: 5534825Abstract: In a voltage-controlled oscillation circuit, a parallel resonance circuit which is formed by connecting a coil (an inductive element) and a capacitor (a capacitive element) in parallel with each other is provided between a control terminal and a resonance circuit. A control voltage is inputted at the control terminal and is supplied to the resonance circuit through the parallel resonance circuit, so that the resonance frequency of the resonance circuit is responsive to the control voltage; an oscillation stage of the voltage-controlled oscillation circuit oscillates at that resonance frequency. The oscillation output of the oscillation stage is outputted at an output terminal from a buffer stage through an output matching stage.Type: GrantFiled: April 28, 1995Date of Patent: July 9, 1996Assignee: Murata Manufacturing Co., Ltd.Inventors: Shinji Goma, Tatsuo Bizen
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Patent number: 5525937Abstract: An integrated oscillation circuit used for frequency conversion circuit in which UHF frequency conversion and VHF frequency conversion are selectively energized to use a common IF amplifier. The integrated oscillation circuit is used for a local oscillation circuit. The integrated oscillation circuit including a connection terminal connected to an external resonance circuit and an input line of a mode switching signal which is set at a different level in response to an operation mode, an oscillation element, a bias terminal of which is connected to the connection terminal, a detection circuit detecting the level of the mode switching signal applied to the bias terminal of the oscillation element, and a switching circuit turning on and off a power source for driving the oscillation element in response to the level detected at the detection circuit.Type: GrantFiled: December 20, 1993Date of Patent: June 11, 1996Assignee: Sony CorporationInventors: Shinchi Kitazono, Fumio Ishikawa, Shinichi Tsutsumi, Naoyasu Gamou
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Patent number: 5506547Abstract: A frequency modulation circuit which varies the resonance frequency of an LC resonance circuit, and which corresponds to the frequency modulation conversions of all TV methods with a simple constitution. Each of a plurality of passive element series circuits for varying a time constant of the LC resonance circuit is composed of, for instance, a capacitor and a resistor, which is switched and controlled by connecting to or separating from the LC resonance circuit by a switching circuit such as a transistor. Thereby, the oscillation frequency of the LC resonance circuit can be easily converted to a predetermined frequency.Type: GrantFiled: April 4, 1995Date of Patent: April 9, 1996Assignee: Sony CorporationInventor: Nobuyuki Ishikawa
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Patent number: 5502420Abstract: 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: GrantFiled: June 1, 1994Date of Patent: March 26, 1996Assignee: VTech Communications, Ltd.Inventor: Michael J. Barclay
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Patent number: 5486794Abstract: A variable frequency oscillator which can be implemented entirely in a semiconductor chip, which is variable over a broad frequency range and which has relatively low phase noise, includes a variable impedance circuit, a reactive load connected to an output terminal pair of the variable impedance circuit, and a negative impedance circuit having an output terminal pair connected to the output terminal pair of the variable impedance circuit. In one embodiment, the negative impedance circuit has an input terminal pair connected to an input terminal pair of the variable impedance circuit to serve as a positive feedback path for the variable impedance circuit. In another embodiment, the negative impedance circuit includes a pair of level shifters which ensure that the variable impedance circuit is properly biased and works in a forward active region.Type: GrantFiled: December 15, 1994Date of Patent: January 23, 1996Assignee: National Science Council of R.O.C.Inventors: Jieh-Tsong Wu, Wei-Zen Shen
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Patent number: 5486796Abstract: An oscillator provided with an oscillation circuit provided with two oscillation transistors comprising a differential pair and a resonance circuit connected in common to the bases of the oscillation transistors. The bases of the oscillation transistors are short-circuited by a coil, a center tap coil is connected in parallel to the resonance circuit, and variable capacitive diodes in the resonance circuit are driven by a coil connected to a mixing circuit. Due to this, it is possible to prevent the occurrence of low frequency noise, possible to realize a completely balanced operation, possible to avoid the oscillation carrier flowing into the power source and ground, and possible to reduce the noise in a television picture.Type: GrantFiled: December 8, 1994Date of Patent: January 23, 1996Assignee: Sony CorporationInventors: Nobuyuki Ishikawa, Tadashi Imai
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Patent number: 5479137Abstract: An oscillator, constructed partially within the confines of a monolithic integrated circuit, includes a differential-input, differential-output, differential amplifier within the monolithic integrated circuit. First and second resistive potential dividers located within the monolithic integrated circuit respectively divide the potentials appearing at the first and second output terminals of the differential amplifier in a predetermined ratio for respective application to the first and second input terminals of the differential amplifier, thereby respectively completing first and second direct-coupled regenerative feedback connections. An inductor located outside the monolithic integrated circuit is connected between the first and second input terminals of the differential amplifier and is anti-resonated by one or more capacitors, which may be located inside or outside the monolithic integrated circuit.Type: GrantFiled: December 14, 1993Date of Patent: December 26, 1995Assignee: Samsung Electronics Co., Ltd.Inventor: Jack R. Harford
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Patent number: 5469119Abstract: The frequency of a resonant circuit in the emitter path of an output transistor is caused to vary linearly with control voltage. The control voltage is applied to a circuit that constrains the ac current through the resonant circuit to be supplied through the emitters of a two-transistor current steering circuit. The sum of the two transistor's dc emitter currents is constant while the dc current through one of the two transistors' emitters varies as the square root of the control voltage.Type: GrantFiled: July 14, 1993Date of Patent: November 21, 1995Assignee: AT&T Corp.Inventor: Irving G. Post
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Patent number: 5469117Abstract: An oscillator comprising an amplifier device, a capacitive divider bridge whose terminals are connected between a control electrode of the device and a reference voltage, the intermediate junction point of this bridge being connected to a principal electrode of the device, and also comprising, in parallel between the control electrode and the reference voltage, a tuning circuit having parallel branches: a first branch with an inductance in series with a variable capacitance, and, a second branch equivalent to a variable capacitance. The tuning circuit has a third branch constituted by a capacitance in parallel with the first branch, while a series inductance whose value is smaller than that of the tuning inductance is arranged between the junction point connecting the two latter branches and the junction point connecting the control electrode of the device to the second branch and to the divider bridge.Type: GrantFiled: April 5, 1994Date of Patent: November 21, 1995Assignee: U.S. Philips CorporationInventor: Pascal Philippe
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Patent number: 5463354Abstract: A proximity switch circuit including first and second transistors Q4, Q6 connected as a long tail pair with an inductive sensing circuit LC connected to one leg thereof and an emitter follower circuit Q7, Q8 connected between said one leg and the base of the transistor of the other leg, whereby an oscillator circuit can be provided which is non-critically damped to enable faster speed of operation of the proximity switch.Type: GrantFiled: June 15, 1994Date of Patent: October 31, 1995Assignee: Square D CompanyInventors: Douglas W. Calder, Arthur J. Bizley
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Patent number: 5444422Abstract: A low phase noise, high frequency low voltage integrated circuit oscillator has a minimum number of live pins. It includes a three transistor current mirror defining a voltage node and a current node with an emitter follower transistor coupled between the voltage node and the current node. An output is taken from the emitter follower transistor and a tuned circuit is coupled to the voltage node. A pair of power supply pins are provided for power application to the integrated circuit and one live pin is coupled to the voltage node. A tuning circuit for affecting capacitance changes for varying the frequency of the oscillator is connectable to the voltage node. In some versions of the oscillator that use a separate crystal, additional pins are needed.Type: GrantFiled: September 20, 1994Date of Patent: August 22, 1995Assignee: Zenith Electronics Corp.Inventor: Victor G. Mycynek
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Patent number: 5440276Abstract: A voltage controlled oscillating circuit is disclosed. The circuit includes: a .mu.-strip resonance circuit for deciding the resonance frequency in accordance with an external tuning voltage; an oscillation amplifying circuit for performing oscillations in accordance with the resonance frequency signals of the .mu.-strip resonance circuit; and a buffer amplifying circuit provided between the oscillating circuit and the load, and for preventing the load pulling phenomenon. The oscillation amplifying circuit forms a common collector oscillating circuit in with a single oscillation amplifying transistor, and the buffer amplifying circuit forms a single step amplifying circuit with a single buffer amplifying transistor. The oscillation amplifying transistor and the buffer amplifying transistor form a cascode amplifying transistor with a signal inducing coil and an RF choke coil for blocking the ac components and for forming a series of dc bias paths.Type: GrantFiled: November 24, 1993Date of Patent: August 8, 1995Assignee: Samsung Electro-Mechanics Co., Ltd.Inventor: Jung H. Kim
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Patent number: 5434544Abstract: An oscillator which inhibits unwanted oscillations and requires a comparatively small power supply voltage is described. The oscillator includes an amplifier transistor 110 (220), an output current of which flows into the emitter of a load transistor 120 (220) via a load signal path. The amplifier stage acquires a bandpass characteristic by a passive capacitive bootstrap signal transfer from this signal path to the base of the load transistor. The oscillator thus preferably oscillates within the passband of the amplifier stage. The amplifier stage has a comparatively large gain within the passband even without a load resistor in the load signal path. Such a load resistor would cause a voltage drop and, hence, increase the required power supply voltage.Type: GrantFiled: September 2, 1994Date of Patent: July 18, 1995Assignee: U.S. Philips CorporationInventor: Hendrik G. Van Veenendaal
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Patent number: 5434543Abstract: Oscillator having first frequency-determining elements provided for a first oscillation frequency. In order to provide an oscillator, particularly for use in video signal processing, which can be switched and tuned to at least two oscillation frequencies, at least a second frequency-determining element is provided which can be connected to the first frequency-determining element for adjusting the oscillator to a second oscillation frequency.Type: GrantFiled: May 2, 1994Date of Patent: July 18, 1995Assignee: U.S. Philips CorporationInventors: Joachim Brilka, Wolfgang Weltersbach
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Patent number: 5418500Abstract: A high-frequency oscillator circuit designed to efficiently output fundamental and second harmonic waves. A second harmonic resonance circuit is inserted between bases of a pair of transistors having collectors connected to each other. Each of a pair of capacitors is inserted between the base and an emitter of the corresponding one of the pair of transistors, and each of another pair of capacitors is inserted between the emitters of the transistors. Further, a pair of fundamental wave output terminals for outputting fundamental waves are respectively connected to the bases of the transistors, and a pair of second harmonic output terminals for outputting second harmonic waves are respectively connected to a connection between the second pair of capacitors and a connection point between the collectors of the pair of transistors.Type: GrantFiled: March 16, 1993Date of Patent: May 23, 1995Assignee: Alps Electric Co., Ltd.Inventor: Sadao Igarashi
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Patent number: 5418497Abstract: BiCMOS technology is used in the design of a VCO (200) to improve low DC operation. The VCO (200) includes two coupled oscillator circuits (201,219) tuned to different fixed frequencies such that the oscillator resonant frequencies define the tuning range of the VCO (200). The oscillator circuits (201, 219) are coupled such that the frequency of oscillation of the VCO (200) is adjustable via variable resistors (206, 214) by manipulating the bias currents to the two oscillator circuits (201,219). A biasing circuit (208) along with variable resistors (206 and 214) provide the DC bias to the oscillator circuits (201 and 219). The biasing circuit (208) maintains the sum of the biasing currents to the oscillator circuits constant. The oscillator circuits (201, and 219) are interconnected utilizing an RF coupling circuit (211). The VCO (200) is capable of operating at voltages as low as 1.8 volts DC.Type: GrantFiled: July 5, 1994Date of Patent: May 23, 1995Assignee: Motorola, Inc.Inventor: Frederick L. Martin
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Patent number: 5396527Abstract: A logic circuit is driven by a single alternating voltage power supply so that the energy stored in parasitic capacitances can be mostly recovered, rather than dissipated, as in conventional logic designs. Successive stages of the logic circuit are of opposite conductivity types such that the successive stages are activated in alternate half cycles of the power supply without separate clock signals. Each stage of the logic circuit is precharged during a respective first half cycle of the power supply and is active in logical processing during a second half cycle. The half cycles are defined by the rising and falling edges of the power supply. The logic circuit resonates with an inductor coupled across the power supply but closely coupled to the logic circuit. This inductor and the method of charging and discharging the capacitors in the logic circuit serve to minimize the power dissipated during logical processing.Type: GrantFiled: July 8, 1994Date of Patent: March 7, 1995Assignee: Massachusetts Institute of TechnologyInventors: Martin F. Schlecht, Roderick T. Hinman
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Patent number: 5379003Abstract: A voltage-controlled oscillation circuit includes a power supply terminal for supplying power to an oscillation stage, a buffer stage, and an output matching stage. Connected between the power supply terminal and ground is a high frequency bypass capacitor for bypassing electrical noise superimposed on the power supply to the side of ground, a voltage feedback resistor is connected in series in a power supply line connected to the power supply terminal, the high frequency bypass capacitor and the voltage feedback resistor constitute a low-pass filter, and the capacitance value of the high frequency bypass capacitor and the resistance value of the voltage feedback resistor are determined so that the cut off frequency of the low-pass filter is at most the frequency f0 of noise.Type: GrantFiled: December 9, 1993Date of Patent: January 3, 1995Assignee: Murata Manufacturing Co., Ltd.Inventor: Tatsuo Bizen
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Patent number: 5373264Abstract: Problems associated with compromise, fixed base inductances in negative resistance oscillators are overcome by use of an electronically tunable base network. Parameters such as phase noise and output power can thereby be optimized over a wide range of operating conditions. The disclosure is illustrated with reference to a 500-1000 Mhz voltage controlled oscillator employing base-tuning varactors that are slaved to the VCO's tuning signal.Type: GrantFiled: January 21, 1993Date of Patent: December 13, 1994Assignee: Hewlett-Packard CompanyInventor: Thomas M. Higgins, Jr.