Electromechanical Resonator Controlled Patents (Class 331/116R)
  • Patent number: 6150894
    Abstract: An oscillator circuit, whose output signal has minimum fluctuation with changes in temperature, has an amplifier. Within the amplifier, a compensation resistor is connected to compensate for changes in amplitude and frequency of the output signal with temperature. A first impedance is connected between an output and a first input of the amplifier, a second impedance is connected between the first input and a second input, and a third impedance is connected between the output and the second input. A method for designing the oscillator begins by choosing an inductor with a high quality factor and a low temperature coefficient. The interconnections are designed to minimize temperature effects of parasitic impedances. A degenerative resistor is connected between the emitter of the bipolar transistor and the emitter resistor. The degenerative resistor varies in resistance with a change in temperature opposite that of an input resistance of the bipolar junction transistor.
    Type: Grant
    Filed: March 18, 1999
    Date of Patent: November 21, 2000
    Assignee: Tritech Microelectronics Ltd.
    Inventors: Yap Hwa Seng, Aruna Bopaiah Ajjikuttira
  • Patent number: 6133801
    Abstract: A crystal oscillation circuit includes a main oscillation circuit, an auxiliary oscillation circuit, and a control circuit. The main oscillation circuit has a crystal resonator. The auxiliary oscillation circuit increases an exciting current of the crystal resonator to assist the start of oscillation of the main oscillation circuit. The control circuit connects the auxiliary oscillation circuit parallel to the main oscillation circuit at the start of oscillation to increase an exciting current of the crystal resonator.
    Type: Grant
    Filed: April 23, 1997
    Date of Patent: October 17, 2000
    Assignee: NEC Corporation
    Inventor: Shoichi Tanaka
  • Patent number: 6111473
    Abstract: An integrated circuit (IC) comprising an oscillator (OSC) has a first amplifier (AMP.sub.1) and a second amplifier (AMP.sub.2). The first and the second amplifier (AMP.sub.1, AMP.sub.2) each have a non-inverting input, an inverting input, and an output. The output of the first amplifier (AMP.sub.1) is connected to the non-inverting input of the first amplifier (AMP.sub.1) and also to the non-inverting input of the second amplifier (AMP.sub.2). The output of the second amplifier (AMP.sub.2) is connected to the inverting input of the first amplifier (AMP.sub.1) and also to the inverting input of the second amplifier (AMP.sub.2). The first amplifier (AMP.sub.1) is loaded with a capacitor (C) connected between the output of the first amplifier (AMP.sub.1) and an external power supply terminal (1). The second amplifier (AMP.sub.2) is loaded with a further capacitor (C.sub.F) connected between the output of the second amplifier (AMP.sub.2) and the external power supply terminal (1).
    Type: Grant
    Filed: May 11, 1999
    Date of Patent: August 29, 2000
    Assignee: U.S. Philips Corporation
    Inventor: Johannes A. T. M. Van Den Homberg
  • Patent number: 6091307
    Abstract: A crystal tank circuit is connected between the ac cross-coupled outputs of two transistors that are selectively biased to an appropriate common mode voltage to cause rapid build-up of oscillation when the circuit is turned on and in which oscillation is sustained in the desired mode regardless of battery voltage fluctuation without wasting power. The differentially driven frequency-controlling crystal tank circuit receives balanced driving voltage excursions from the circuit.
    Type: Grant
    Filed: July 29, 1998
    Date of Patent: July 18, 2000
    Assignee: Lucent Techmologies Inc.
    Inventor: Dale Harvey Nelson
  • 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: 6018274
    Abstract: The present invention relates to a radio receiver, particularly to a receiver for use in single-frequency applications, such as GPS, and to a frequency generator, which may be used in such a radio receiver, or elsewhere. The frequency generator comprises a tuned circuit connected between the emitter of the transistor and ground, such that a voltage signal at the basic frequency appears on the emitter terminal of the transistor. This arrangement has the advantage that the two frequencies appear on separate ports, and provides a radio receiver including radio receiver circuitry for connection to digital signal processing circuitry, reducing the complexity of the overall circuit. Additionally, there is a radio receiver wherein separate first and second local oscillator signals are generated from the terminal of s single transistor, avoiding the need for cascade multiplication stages, again reducing the size and complexity of the overall circuit.
    Type: Grant
    Filed: June 21, 1996
    Date of Patent: January 25, 2000
    Assignees: STMicroelectronics Limited, University of Bristol
    Inventors: Philip G. Mattos, Mark A. Beach
  • Patent number: 5999062
    Abstract: A crystal oscillator drive circuit controls the maximum amplitude of the drive signal to a crystal by limiting the bias current of a gm cell which senses the oscillation amplitude of the crystal. The bias current is commutated by the gm cell responsive to the crystal oscillation. The commuted current is converted to a single-ended current by a current mirror. An output stage converts the current to an output voltage having a voltage swing that is determined by the resistance of a load resistor. The output voltage is then fed back to drive the crystal through a positive feedback path. The output voltage swing and the drive signal to the crystal are limited by the bias current of the gm cell. A fully complementary implementation of the drive circuit includes two complementary gm cells, two current mirrors, and an output stage having two load resistors.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: December 7, 1999
    Assignee: Analog Devices, Inc.
    Inventor: Barrie Gilbert
  • Patent number: 5962986
    Abstract: A transformerless power oscillator for driving a high intensity electrodeless light bulb. The driver uses a silicon carbide static induction transistor (SIT) operating as a power oscillator powered by an unregulated power supply potential generated by a full wave rectifier bridge connected to an AC power line. A CW output signal is generated at S-band and is coupled to the excitation coil of an electrodeless lamp by means of a matching network.
    Type: Grant
    Filed: May 19, 1997
    Date of Patent: October 5, 1999
    Assignee: Northrop Grumman Corporation
    Inventor: Alfred W. Morse
  • 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: 5952894
    Abstract: A resonant circuit of the present invention has a ceramic substrate, a quartz element provided on said substrate, and a capacitor for temperature compensation. Connection terminals are formed on the rear of the substrate in order to mount the resonant circuit to another substrate. A seam ring for air-tight sealing is positioned at the edges of the substrate. The quartz oscillator with this configuration can be mounted without resorting to leads.
    Type: Grant
    Filed: November 5, 1996
    Date of Patent: September 14, 1999
    Assignee: NEC Corporation
    Inventor: Eiichi Fukiharu
  • Patent number: 5923222
    Abstract: An oscillating circuit includes a low power inverting amplifier (10) having an input (208) and an output (209) and having a relatively high resistance d.c. biasing path (2) associated therewith. A relatively low resistance path (3) can be switched so as to couple the amplifier input (208) and output (209) together during a bias settling phase of the circuit. A detector (50) detects the voltage at either the amplifier input (208) or the output (209) and switches the relatively low resistance path (3) so that it does not couple the input (208) and output (209) together when the detected voltage reaches a level just before a required operating voltage level.
    Type: Grant
    Filed: April 2, 1997
    Date of Patent: July 13, 1999
    Assignee: Motorola, Inc.
    Inventors: Ian Lawson Russell, Andreas Rusznyak
  • 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
  • Patent number: 5883550
    Abstract: A temperature-compensated quartz oscillator comprises a stabilized power supply circuit (1) for supplying a constant voltage, an oscillation circuit (2) comprising a quartz resonator (21) and a varicap (22), a temperature detecting circuit (3) for producing a detected voltage signal (V.sub.Temp) corresponding to an oscillator part temperature by the use of the temperature-voltage characteristic of a temperature detecting element located in the vicinity of the oscillation circuit (2), and a temperature characteristic compensating portion (4) for producing through analog processing of the detected voltage signal (V.sub.Temp) a varicap control voltage signal (V.sub.VR) to be supplied to the varicap (22).
    Type: Grant
    Filed: April 15, 1997
    Date of Patent: March 16, 1999
    Assignee: Mitsumi Electric Co., Ltd.
    Inventors: Shigemitsu Watanabe, Hiromi Katoh
  • Patent number: 5834982
    Abstract: Supplied with a power source, an output level of an oscillating circuit gradually increases until the oscillator circuit reaches its steady oscillation. A level monitor monitors the output level, and produces a control signal if the output level is less than a predetermined level. A current producing circuit receives the control signal and produces a boost current to increase a collector current at an oscillating transistor. The output level of the oscillating circuit suddenly increases as the collector current increases. After the output level of the oscillator reaches the predetermined level, the level monitor stops production of the control signal. Therefore, the boost current stops. As a result, the collector current of the oscillating transistor has a predetermined value dependent on the circuit structure of the oscillating circuit.
    Type: Grant
    Filed: August 29, 1997
    Date of Patent: November 10, 1998
    Assignee: Mitsumi Electric Co., Ltd.
    Inventors: Shigemitsu Watanabe, Hiromi Katoh
  • Patent number: 5805028
    Abstract: A temperature-compensating piezo-oscillator uses a piezo-oscillator with temperature coefficient of frequency changing approximately linearly and includes a stabilized source circuit, a temperature-compensating circuit, a voltage control oscillator circuit and a buffer-amplifier circuit. The stabilized source circuit is for stabilizing an inputted voltage and outputs a stabilized voltage. The temperature-compensating circuit is for receiving this stabilized voltage and outputs a temperature-compensated voltage corresponding to the ambient temperature. The voltage control oscillator circuit is for receiving this temperature-compensated voltage and causes the resonance frequency of the piezo-oscillator to change according to this received temperature-compensated voltage, outputting a high-frequency signal. The buffer-amplifier circuit receives and amplifies this high-frequency signal and outputs a high-frequency output voltage.
    Type: Grant
    Filed: January 29, 1997
    Date of Patent: September 8, 1998
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Akira Kato
  • Patent number: 5789990
    Abstract: A crystal-controlled oscillator circuit is modified by the present invention by replacing the crystal with the first signal port of a two-port SAW resonator filter that has a low-loss primarily inductive characteristic and taking the oscillation output from the other port of the filter to provide an oscillator frequency with harmonics that are reduced significantly when compared to the output of a crystal-controlled oscillator.
    Type: Grant
    Filed: February 14, 1996
    Date of Patent: August 4, 1998
    Assignee: RF Monolithics, Inc.
    Inventors: Darrell L. Ash, Benjamin P. Abbott
  • Patent number: 5777524
    Abstract: A temperature compensation circuit (10) for a crystal oscillator module (12) used in a communication device (200). An existing microcontroller (210) of the communication device (200) is used to provide temperature compensating digital data (30) for a crystal oscillator (18). The temperature compensating digital data (30) is converted to a temperature compensation signal (22) in a digital-to-analog converter (32) which controls the crystal oscillator frequency. The crystal oscillator module (12) includes an onboard voltage regulator (34) which supplies a characterized regulated voltage (36) to the digital-to-analog converter (32) such that the temperature compensation signal (22) from the digital-to-analog converter (32) is inherently corrected for voltage variations in the voltage regulator (34). Changes in the temperature compensation of the crystal oscillator (18) are allowed only when the communication device (200) is not transmitting or receiving.
    Type: Grant
    Filed: July 29, 1997
    Date of Patent: July 7, 1998
    Assignee: Motorola, Inc.
    Inventors: Carl E. Wojewoda, James F. Caruba, Richard N. Sutliff
  • Patent number: 5767745
    Abstract: 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: Grant
    Filed: July 25, 1996
    Date of Patent: June 16, 1998
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Patent number: 5760656
    Abstract: A temperature compensation circuit (10) for a crystal oscillator module (12) used in a communication device (200). An existing microcontroller (210) of the communication device (200) is used to provide temperature compensating digital data (30) for a crystal oscillator (18). In this way, the crystal oscillator module (12) does not require an on-board memory which substantially cuts costs. The temperature compensation digital data (30) is converted to a temperature compensation signal (22) in a digital-to-analog converter which controls the crystal oscillator frequency. However, typical digital-to-analog converters are driven by voltage regulators which vary over temperature.
    Type: Grant
    Filed: December 17, 1996
    Date of Patent: June 2, 1998
    Assignee: Motorola Inc.
    Inventors: Richard N. Sutliff, Syed S. Raza, Matthias F. Laurich, Vladimir Telemaque
  • Patent number: 5731744
    Abstract: An apparatus and a method are provided to obtain oscillations from a crystal at a particular frequency by introducing real and imaginary components of voltage to the crystal. The imaginary component of voltage is different from the real component of voltage by a particular phase angle such as 90.degree.. The voltage introduced to the crystal is processed to produce a first current having characteristics corresponding to such voltage and to produce a second current having characteristics related to the imaginary component of such voltage. The first and second currents are combined to produce a first current corresponding to the real component of the voltage introduced to the crystal. This current is shifted through a phase angle of 90.degree. to produce a second current corresponding to the imaginary component of the voltage introduced to the crystal. The first current is converted to a first voltage which is regulated to provide a particular gain.
    Type: Grant
    Filed: May 28, 1996
    Date of Patent: March 24, 1998
    Assignee: Brooktree Corporation
    Inventor: Jan C. Diffenderfer
  • Patent number: 5726536
    Abstract: A cold cathode tube is used for a back light illuminating a liquid crystal with a light from the back. A ceramic transformer is used instead of a conventional wound transformer for a power source to light this cold cathode tube to eliminate various problems caused by transformers. The output voltage and current of this ceramic transformer are coordinated with the cold cathode tube by utilizing the frequency characteristic of the boosting ratio of the ceramic transformer to light the cold cathode tube and adjust the light. The output from an oscillator is amplified and is applied to a ceramic transformer. The output frequency from the oscillator is swept from the higher side to the lower side. When the output frequency decreases from fa.fwdarw.fb, the output voltage of the ceramic transformer in the case that the load resistance indicated by the solid line is large will be Vb and the cold cathode tube will be lighted.
    Type: Grant
    Filed: December 21, 1995
    Date of Patent: March 10, 1998
    Assignee: Tamura Corporation
    Inventor: Nobumi Hagiwara
  • Patent number: 5712599
    Abstract: 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: Grant
    Filed: June 19, 1996
    Date of Patent: January 27, 1998
    Inventor: Leonard L. Kleinberg
  • Patent number: 5712596
    Abstract: In an oscillator arrangement (VCXO), an oscillation loop (OSL) oscillates at, approximately, the fundamental frequency of a crystal (XTL) included therein. The output signal (Sosc) of the oscillator arrangement (VCXO) is a harmonic extracted from the oscillation loop (OSL). To vary the frequency of the output signal (Sosc), a tuning circuit (VAR) is included in the oscillation loop (OSL). A stage (FIL) in the oscillator arrangement (VCXO) prevents harmonic feedback into the oscillation loop (OSL). Such an oscillator arrangement (VCXO) can be tuned over a relatively large frequency range and has a monotonous tuning characteristic.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: January 27, 1998
    Assignee: U.S. Philips Corporation
    Inventor: Alfonsus M. Van Amesfoort
  • Patent number: 5708394
    Abstract: An apparatus and method are disclosed for improving the stability of the frequency of vibration of an oscillator signal produced by an oscillator circuit. In a preferred embodiment of the present invention, a quartz crystal resonator is one arm of a bridge which generates a bridge signal which varies in accordance with the vibrating frequency of the resonator. A synchronous demodulator responds to the bridge signal for producing an error signal which is converted into a control signal. A control circuit receives the control signal and changes its reactance when the resonator is no longer vibrating at its unperturbed resonance frequency so that the vibration frequency of the resonator connected to the control circuit is returned to its resonant frequency. An automatic level control circuit is also included for controlling the drive level of the signal exciting the resonator.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: January 13, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Richard K. Karlquist
  • Patent number: 5703543
    Abstract: 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: Grant
    Filed: May 6, 1996
    Date of Patent: December 30, 1997
    Inventor: Clive Roland Taylor
  • Patent number: 5696469
    Abstract: A clock oscillator having a pair of pins adapted for coupling to an external crystal, a first one of such pair of pins being adapted for coupling to an external clock. A switch, formed on the chip, is provided for electrically decoupling the crystal excitation circuit from one of the pair of pins in response to a control signal. In accordance with one embodiment of the invention, the switch is disposed between the output of a crystal excitation circuit and the second one of the pair of output pins and, in another embodiment, the switch is placed in circuit between the input to the crystal excitation circuit and the first one of the pair of pins. In each of these embodiments, when the switch is in a first condition, clock pulses are prevented from being coupled to the second one of the output pins, either: by preventing the external clock from feeding the input to the crystal excitation circuit; or, by preventing the output of the crystal excitation circuit from feeding the second one of the pair of pins.
    Type: Grant
    Filed: February 12, 1996
    Date of Patent: December 9, 1997
    Assignee: Analog Devices, Inc.
    Inventors: Thomas J. Meany, Patrick R. Hickey
  • Patent number: 5675296
    Abstract: A drive voltage is supplied to a piezoelectric oscillator from an A.C. drive power source. Attached to an electrode of the piezoelectric oscillator is a loop circuit in which an amplifier having a (N+1) voltage amplification factor and an electrostatic capacitor are connected in series. When the electrostatic capacity is set to 1/N of a damping capacity of the piezoelectric oscillator, the current flowing through the damping capacity is replaced and shared by current from the electrostatic capacity, thus the drive current will not be consumed by the damping capacity. Therefore, a condition where the damping capacity is minimized depends on a capacity value of the electrostatic capacity and amplification factor of the amplifier only and does not depend on the frequency.
    Type: Grant
    Filed: January 11, 1996
    Date of Patent: October 7, 1997
    Inventor: Yoshiro Tomikawa
  • Patent number: 5654678
    Abstract: An oscillation circuit using a quartz oscillator. When the output level of the oscillation circuit falls, this output level change is detected and the reactance of the quartz oscillator is changed such that the circuit oscillates at a frequency which reduces the resistance of the oscillator. Hence, the oscillation of the circuit does not fall in level or stop regardless of temperature and other ambient conditions.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: August 5, 1997
    Assignee: NEC Corporation
    Inventor: Shinichi Miyazaki
  • Patent number: 5646580
    Abstract: A multi-crystal controlled oscillator (10) and method includes a first crystal resonator (11), second crystal resonator (14), oscillator circuit (23), and a switch (29). The switch (29) is coupled between the first crystal resonator (11) and the oscillator circuit (23) and between the second crystal resonator (14) and the oscillator circuit (23), and electrically couples either the first (11) or the second crystal resonator (14) to the oscillator circuit (23) in response to a crystal select input (XTAL SELECT).
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: July 8, 1997
    Assignee: Motorola, Inc.
    Inventor: Geoffrey W. Perkins
  • Patent number: 5627498
    Abstract: 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: Grant
    Filed: February 9, 1996
    Date of Patent: May 6, 1997
    Assignee: Nvision, Inc.
    Inventor: Charles S. Meyer
  • Patent number: 5596311
    Abstract: A method and system employing a feedback signal indicative of monitored motion of an electro-mechanical acoustic transducer to generate one or both of a control signal for driving the transducer at its natural resonance frequency, and a warning signal indicating that the transducer is not vibrating at a frequency within a selected frequency range. In preferred embodiments, the transducer is a voice coil loudspeaker mounted in or on a vehicle. In other preferred embodiments, the electro-mechanical transducer is driven by an initial electrical pulse followed by a sequence of electrical pulses. A feedback signal indicative of monitored motion of a moving portion of the transducer is generated. Each pulse (following the initial pulse) is applied at a time (determined by the feedback signal) so as to drive the transducer at its actual natural resonance frequency.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: January 21, 1997
    Assignee: Preco, Inc.
    Inventors: Emery L. Bess, Harry S. Erskine
  • 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: 5528201
    Abstract: A Pierce crystal oscillator circuit for a digital integrated circuit has a capacitance element (such as a field effect capacitor) of an appropriate capacitance value disposed on-board the integrated circuit. One lead of the capacitance element is coupled to the input lead of the gain stage of the Pierce oscillator circuit whereas a second lead of the capacitance element is coupled to the output lead of the gain stage. Providing the capacitance element facilitates oscillator startup and reliability by effectively eliminating the upper gain limit for oscillation. Specific circuit embodiments are also disclosed.
    Type: Grant
    Filed: March 31, 1995
    Date of Patent: June 18, 1996
    Assignee: National Semiconductor Corporation
    Inventor: Timothy D. Davis
  • Patent number: 5481228
    Abstract: A controller circuit adjusts the output signal duty cycle of an oscillator circuit. The controller circuit changes the effective bias voltage of an amplifier in a Pierce oscillator by enabling a sequence of transistor stages. Changes to the amplifier bias voltage proportionally alter the duty cycle of the oscillator output signal. Each transistor stage includes a first and second transistor selectively coupled in parallel with the amplifier. Each transistor in the circuit has smaller process parameters than the amplifier transistors so that the amplifier bias voltage can be incrementally increased or decreased to produce an output signal with a high precision duty cycle.
    Type: Grant
    Filed: October 15, 1993
    Date of Patent: January 2, 1996
    Assignee: Hewlett-Packard Corporation
    Inventor: Rajeev Badyal
  • Patent number: 5473288
    Abstract: The oscillation circuit 30 has the two input terminals 32a and 32b connected to the piezoelectric elements 3a and 3b of vibrator 1. These input terminals 32a and 32b are connected to the two input terminals of the adder 36 via the buffers 34a and 34b. The output terminal of the adder 36 is connected to the inversion input terminal of the operational amplifier 44 used as a comparator and the input terminal of the control signal generator 46. The output terminal of the operational amplifier 44 is connected to the collector of the transistor 62 and the output terminal of the control signal generator 46 is connected to the base of the transistor 62. The emitter of the transistor 62 is connected to the output terminal 80 via the phase-shifting circuit 70. The output terminal 80 of the oscillation circuit 30 is connected to the piezoelectric element 3c of the vibrator 1.
    Type: Grant
    Filed: December 28, 1994
    Date of Patent: December 5, 1995
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Akira Kumada
  • Patent number: 5473287
    Abstract: An improved electronic oscillator of limited bandwidth for better phase noise and linearity characteristics, and method for production, where a transmission line of specific characteristics is introduced between major components of the frequency source to significantly improve phase noise and linearity, and minor adjustments to the L/C ratio of the transmission line during production testing further optimize phase noise and linearity without adverse effects on other circuit parameters. The improvement chiefly relates to the length, configuration and accessibility of a transmission line connecting a resonator and main tuning capacitor in a series resonant tank circuit of an oscillator.
    Type: Grant
    Filed: November 14, 1994
    Date of Patent: December 5, 1995
    Assignee: Micronetics, Inc.
    Inventors: David F. Robbins, Richard J. Landry
  • Patent number: 5473289
    Abstract: A temperature compensated crystal oscillator including: an oscillation circuit having a quartz crystal resonator and a control terminal, for providing an oscillating signal determined by the quartz crystal resonator and a control signal, the control signal being applied to the control terminal; a temperature detecting circuit for detecting an operation temperature and outputting a temperature signal based on the operation temperature; and a control signal generating circuit for receiving the temperature signal from the temperature detecting circuit, generating the control signal based on a characteristic curve, and outputting the control signal to the control terminal; the characteristic curve essentially consisting of a plurality of straight lines and being an approximation of an ideal control curve in a predetermined operation temperature range including the operation temperature, the ideal control curve having a relationship between the control signal and the temperature signal for ideally compensating a f
    Type: Grant
    Filed: January 25, 1994
    Date of Patent: December 5, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toshio Ishizaki, Yuki Satoh, Koji Hashimoto
  • Patent number: 5457433
    Abstract: A low-power inverter (53) reduces power consumption over known inverter designs and is especially well-adapted for serving as a buffer in a Pierce crystal oscillator with a large load capacitance. The inverter (53) includes P- and N-side source-follower stages (310, 320) driving CMOS output transistor pairs (350, 360). The source followers are current-limited through current sources (311, 313, 321, 323) which are biased by a stable reference voltage such as a bandgap reference voltage. Clamping devices (331, 332) are provided to limit the voltages on the gates of the output transistors (350, 360), thereby limiting maximum currents thereof. In addition, a helper device (332) is connected to the gate of a P-channel output transistor (350). The P-channel output transistor (350) typically has a large gate area and thus a large capacitance, and the helper device (332) quickly increases the voltage at the gate when an input signal changes to a high voltage.
    Type: Grant
    Filed: August 25, 1993
    Date of Patent: October 10, 1995
    Assignee: Motorola, Inc.
    Inventor: Alan L. Westwick
  • Patent number: 5455542
    Abstract: An oscillator circuit provides a symmetrical signal without halving the frequency of a crystal oscillator 12. The input 14 of the crystal oscillator 12 is low pass filtered, and the output 18 of the filter 16 is differential voltage compared with the input 14 of the crystal oscillator 12. The output 22 of the differential voltage comparator 20 is symmetrical and of the same frequency as the crystal oscillator 12. The crystal oscillator 12 is preferably a Pierce oscillator.
    Type: Grant
    Filed: November 22, 1993
    Date of Patent: October 3, 1995
    Assignee: Rockwell International Corporation
    Inventors: John R. Spence, Rajiv Gupta, Ming M. Zhang
  • Patent number: 5444422
    Abstract: 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: Grant
    Filed: September 20, 1994
    Date of Patent: August 22, 1995
    Assignee: Zenith Electronics Corp.
    Inventor: Victor G. Mycynek
  • Patent number: 5428319
    Abstract: A modified temperature compensation signal (110) is provided in a temperature compensated crystal oscillator (TCXO) circuit (100) in the following manner. A temperature dependent current generator (104) produces a temperature compensation signal (108) whose amplitude changes responsive to changes in ambient temperature. The temperature compensation signal (108) is scaled, based on a plurality of discrete frequency adjust values (212), to produce the modified temperature compensation signal (110).
    Type: Grant
    Filed: November 29, 1993
    Date of Patent: June 27, 1995
    Assignee: Motorola, Inc.
    Inventors: Dennis F. Marvin, Daniel J. Russell
  • Patent number: 5422605
    Abstract: A low phase noise oscillator 10 having a balanced feedback transformer 24 and a push-pull resonant circuit 12 for generating an oscillation excitation signal. The resonant circuit 12 is loaded by an output buffer 20 connected between first and second feedback terminals 16 and 18. The feedback transformer 24 provides first and second feedback paths of opposite phase polarity which link the resonant circuit 12 with the first and second feedback terminals 16 and 18.
    Type: Grant
    Filed: March 21, 1994
    Date of Patent: June 6, 1995
    Assignee: Hughes Missile Systems Company
    Inventors: Steve S. Yang, Yiu-Man So
  • Patent number: 5416448
    Abstract: The disclosure is directed to a Lever oscillator for use in high resistance resonator applications, especially for use with quartz resonator sensors. The oscillator is designed to operate over a wide dynamic range of resonator resistance due to damping of the resonator in mediums such as liquids. An oscillator design is presented that allows both frequency and loss (R.sub.m) of the resonator to be determined over a wide dynamic range of resonator loss. The Lever oscillator uses negative feedback in a differential amplifier configuration to actively and variably divide (or leverage) the resonator impedance such that the oscillator can maintain the phase and gain of the loop over a wide range of resonator resistance.
    Type: Grant
    Filed: August 18, 1993
    Date of Patent: May 16, 1995
    Assignee: Sandia Corporation
    Inventor: Otto Wessendorf
  • Patent number: 5341112
    Abstract: A stabilized oscillation circuit includes a bias circuit which controllably biases a bipolar-transistor-driven crystal oscillator circuit. The bipolar-transistor-driven crystal oscillator circuit is a modified version of a conventional transistor-driven oscillator, such as a Hartley, Pierce or Colpitts-type circuit. The bias circuit includes a first current providing a reference current through a Schottky diode and a pair of bipolar transistors. The bipolar-transistor-driven crystal oscillator circuit includes an input and an output, where the input of the bipolar-transistor-driven crystal oscillator circuit is coupled to the bias circuit. The bipolar-transistor-driven crystal oscillator circuit includes a second current through a second bipolar transistor. The second current tracks the reference current so that the output of the bipolar-transistor-driven oscillator circuit is substantially constant over variations in ambient temperature.
    Type: Grant
    Filed: June 9, 1993
    Date of Patent: August 23, 1994
    Assignee: Rockwell International Corporation
    Inventor: Leo J. Haman
  • Patent number: 5339051
    Abstract: A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning.
    Type: Grant
    Filed: March 30, 1993
    Date of Patent: August 16, 1994
    Assignee: Sandia Corporation
    Inventors: Dale R. Koehler, Jeffry J. Sniegowski, Hugh M. Bivens, Kurt O. Wessendorf
  • Patent number: 5332979
    Abstract: An RF power-generator system for the frequency range of 2 to 30 MHz and a programmable sinusoidal power output of 0 to 1000 W. The system is constructed of modules (10, 30, 50, 70 and 90) accommodated in a shallow parallelepipedal housing (1) with a capacity of 4.6 l. The housing essentially comprises two lateral lengths (4) of structural section, a sheet-metal front (6), a sheet-metal bottom (5), and a lid. A crystal-controlled power-oscillator module (10) communicates by way of an RF line (121) with an intermediate module (30). The intermediate-amplifier module communicates by way of still another RF line (122) with a terminal power-amplifier module (50). The terminal power-amplifier module communicates by way of still another RF line (123) with a high-power filter (70). The filter communicates by way of still another RF line (124) with a high-power directional coupler (90). The RF power output can be intercepted at an RF plug (2).
    Type: Grant
    Filed: September 13, 1991
    Date of Patent: July 26, 1994
    Inventors: Janusz Roskewitsch, Matthias Huttl
  • Patent number: 5309116
    Abstract: A multimode oscillator is disclosed which employs a single gain loop for exciting at least two modes of a resonator to cause the oscillator to oscillate simultaneously at at least two frequencies. The multimode oscillator comprises the resonator, an amplifier to provide gain at the appropriate operating frequencies to support simultaneous oscillation at such frequencies and an equalizing network with amplitude and phase characteristics versus frequency to support the simultaneous modes of oscillation. The single loop oscillator permits separate control of the two simultaneous different frequencies of oscillation. In order to minimize thermal hysteresis, at least the active portion of the feedback loop does not include inductors. In some applications, the multimode oscillator may include one or more rejection networks to suppress unwanted oscillations. The useful outputs of the multimode oscillator are one or more of the operating frequencies, harmonics and intermodulation products.
    Type: Grant
    Filed: November 2, 1992
    Date of Patent: May 3, 1994
    Assignee: Frequency Electronics, Inc.
    Inventor: Charles S. Stone
  • Patent number: 5302921
    Abstract: A piezoelectric oscillator in which radiation of higher harmonic components is reduced. A piezoelectric vibrator and a semiconductor device are provided in an oscillation circuit for making the piezoelectric vibrator oscillate, as is a filter for cutting components in a predetermined frequency band or higher harmonic components of an oscillation signal outputted from the semiconductor device. The piezoelectric vibrator, the semiconductor device and the filter are packed in one package. Radiation of the higher harmonic components is reduced by placing the filter close to the oscillator, by providing a shielding or by operating portions of the oscillator output circuit with a reduced supply voltage.
    Type: Grant
    Filed: April 16, 1992
    Date of Patent: April 12, 1994
    Assignee: Seiko Epson Corporation
    Inventors: Mikio Shigemori, Toru Oida, Shigeru Hirasawa, Katsumi Yamamura
  • Patent number: 5268657
    Abstract: A high performance oscillator with low frequency pulling at turn on includes an oscillator transistor, a resonating element and a common base buffer transistor. The resonating element of the oscillator is a circuit having a crystal resonator that is connected in parallel with a transformer winding. This resonating element is connected between the emitter of the oscillator transistor and the emitter of the buffer transistor. More specifically, a tap connects the emitter of the buffer transistor to the transformer winding of the resonating element. With this connection, a low transformed power oscillating output is taken from the collector of the buffer transistor with minimized degradation in the symbol of merit for the crystal oscillator.
    Type: Grant
    Filed: July 10, 1992
    Date of Patent: December 7, 1993
    Assignee: Hughes Aircraft Company
    Inventors: Vaughn H. Estrick, John P. Safford