Abstract: An oscillation circuit according to the present invention includes a first oscillation circuit including a first diode having a first negative differential resistance and first composite inductor having a first inductor and a second inductor connected in series to the first diode in series. The oscillation circuit also includes a second diode that has a second negative differential resistance that is connected to the first inductor in parallel, and a third diode having a third negative differential resistance is connected to the first diode in series and is also connected to the first composite inductor in parallel. A burst pulse is output from a common connection point of the first inductor, the second inductor, and the second diode.

Abstract: A non-Boolean analog system includes a first Mott memristor having a first value of a characteristic, and a second Mott memristor having a second value of the characteristic different than the first value. The system includes a resistance in series with the first and second Mott memristors to form a network having a capacitance and that is operable as a relaxation oscillator. Responsive to electrical excitation, a temperature of the network operating an environment including ambient thermal noise settles at an equilibrium corresponding to a global minimum that is a maximally optimal global solution to a global optimization problem to which the network corresponds.

Abstract: An inductor simulation method and nonlinear equivalent circuit model enabling dynamic simulation of nonlinear characteristics when a direct current is superimposed with high precision. An equivalent circuit of an inductor is represented using a series circuit of passive circuit elements. Characteristic change ratios of the passive circuit elements when a direct current is superimposed are expressed as an approximate function on the basis of actually measured values. A reference current measured by each of voltage source models is referred to by a control voltage source connected in series to the passive circuit elements. The characteristic change ratios are calculated in accordance with the reference current Iref. Difference voltages are generated on the basis of the characteristic change ratios and voltages occurring when no direct current is superimposed, they are superimposed on the voltages VL1 and VR1 occurring when no direct current is superimposed, thereby simulating the nonlinear characteristics.

Abstract: A terahertz wave oscillator that oscillates includes a negative resistance element, a resonator including a first conductor, a second conductor, and a dielectric, and a transmission line configured to supply a bias voltage to the negative resistance element. In this case, the negative resistance element and the dielectric are disposed between the first conductor and the second conductor, and the first conductor and the transmission line are connected at a node of an electric field of terahertz waves having oscillation frequency fOSC and standing in the resonator.

Abstract: An oscillator and a method of fabricating the oscillator are described. The oscillator includes a resonator with a plurality of transmission lines. An oscillation frequency of the oscillator is independent of at least one dimension of the plurality of transmission lines. The oscillator also includes a negative resistance circuit coupled to the resonator that cancels internal loss resistance of the resonator.

Abstract: An oscillator and a method of fabricating the oscillator are described. The oscillator includes a resonator with a plurality of transmission lines. An oscillation frequency of the oscillator is independent of at least one dimension of the plurality of transmission lines. The oscillator also includes a negative resistance circuit coupled to the resonator that cancels internal loss resistance of the resonator.

Abstract: A method includes providing an oscillator having a field effect transistor connected with a resonant circuit. The field effect transistor has a gate electrode coupled to a source of gate voltage, a source electrode, a drain electrode and a graphene channel disposed between the source electrode and the drain electrode and electrically connected thereto. The method further includes biasing the graphene channel via the gate electrode into a negative differential resistance region of operation to cause the oscillator to generate a frequency signal having a resonant frequency f0. There can be an additional step of varying the gate voltage so as to bias the graphene channel into the negative differential resistance region of operation and out of the negative differential resistance region of operation so as to turn on the frequency signal and to turn off the frequency signal, respectively.

Abstract: An oscillator has a negative resistance element and a resonator along with a capacitor electrically connected in parallel with the negative resistance element relative to a power bias circuit, a capacitance of the capacitor being so selected as to suppress any parasitic oscillation due to the power bias circuit and allow oscillation at a resonance frequency due to the negative resistance element and the resonator.

Abstract: An oscillator having a negative resistance device and a resonator includes: a transmission line connected to the negative resistance device, a three-terminal device including a first terminal connected to the signal line side of the transmission line at a terminal part, a second terminal connected to the grounding line side of the transmission line and a third terminal receiving a control signal applied thereto; a first regulation unit for regulating the control signal to be applied to the third terminal; and a second regulation unit for regulating the voltage to be applied to the second terminal, the first and the second regulation unit being adapted to regulate respectively the control signal and the voltage so as to make the characteristic impedance of the transmission line and the impedance between the first and the second terminal show an impedance matching. The power consumption rate of the stabilizing circuit can be reduced.

Abstract: A stabilization network and a semiconductor device having the stabilization network wherein the stabilization network includes an active element having a negative resistance accompanying a high frequency negative resistance oscillation; and a tank circuit composed of a resistance connected to a main electrode of the active element, an inductance and capacitance which are connected in parallel with the resistance and synchronize with an oscillating frequency of the high frequency negative resistance oscillation, wherein the stabilization network is performed for suppressing a negative resistance accompanying a Gunn oscillation and obtaining stable and highly efficient power amplification.

Abstract: A baseband signal processing unit changes the collector current of a transistor (20) formed by a bias control circuit (7) in accordance with a baseband transmission signal input from a baseband signal input terminal (18), changing the drain bias of a high-frequency transistor (1) to realize frequency modulation by changing the oscillation frequency, and the radiation wave thereof forms a transmit RF signal, whereby the transmission operation is performed. On the other hand, the oscillation signal is synchronized with a frequency modulated RF signal that arrives from outside, the change in frequency caused by the frequency modulation is generated as a change in the drain bias of the high-frequency transistor (1), and reception operation is performed by taking out that change as a voltage amplitude change from the baseband signal output terminal (14). As a result, it is possible to provide a microwave/millimeter wave communication apparatus that is simple in structure, low cost, and low power consumption.

Abstract: The present invention provides an oscillator and a communication system using the oscillator, in particular, an LC oscillator adapted to lessen phase noise deterioration due to harmonic distortions and increase the amplitude of oscillation, thereby having a favorable low phase noise characteristic. The oscillator comprises at least one voltage to current converter consisting of a transistor and a resonator comprising two LC tanks consisting of a pair of conductive elements and inductive elements. A feedback loop is formed such that an output terminal of the voltage to current converter is connected to the resonator and a current input to the resonator is converted to a voltage which is in turn fed back to an input terminal of the voltage to current converter. Inductive elements constituting the two LC tanks constituting the resonator are mutually inductively couple and a coefficient of the mutual induction is about ?0.6.

Abstract: Circuitry is provided that closely emulates biological neural responses. Two astable multivibrator circuits (AMCs), each including a negative differential resistance device, are coupled in series-circuit relationship. Each AMC is characterized by a distinct voltage-dependant time constant. The circuitry exhibits oscillations in electrical current when subjected to a voltage equal to or greater than a threshold value. Various oscillating waveforms can be produced in accordance with voltages applied to the circuitry.

Abstract: Circuitry is provided that closely emulates biological neural responses. Two astable multivibrator circuits (AMCs), each including a negative differential resistance device, are coupled in series-circuit relationship. Each AMC is characterized by a distinct voltage-dependant time constant. The circuitry exhibits oscillations in electrical current when subjected to a voltage equal to or greater than a threshold value. Various oscillating waveforms can be produced in accordance with voltages applied to the circuitry.

Abstract: A microwave/millimeter wave sensor apparatus including a planar radiation type oscillator substrate having an inner-layer GND interposed between a front surface side dielectric substrate and a rear surface side dielectric substrate and a pair of conductor patches in an axis-symmetric manner on the side of the front surface layer. A gate and drain of a microwave transistor are respectively connected to the conductor patches to supply power to the gate and the drain of the microwave transistor through a gate-side RF choke circuit and a drain-side RF choke circuit. An impedance line satisfying an oscillation condition is connected to a source and a transmit RF signal in an RF zone as a planar radiation type oscillator is transmitted and a receive RF signal as reflected waves is received from a measured object, thus obtaining an IF signal as the sensing information through homodyne mixing.

Abstract: An oscillation circuit including: a negative resistance element; a resonance circuit connected to the negative resistance element; and a stabilization circuit connected in parallel with the negative resistance element to suppress parasitic oscillation, wherein the stabilization circuit includes a variable shunt resistor and a adjusting device for adjusting the shunt resistor.

Abstract: An oscillator which oscillates electromagnetic waves includes a negative differential resistance element, a resonator configured to prescribe oscillation frequencies of the electromagnetic waves, a voltage modulation unit configured to modulate the negative differential resistance element, a stabilizing circuit configured to suppress parasitic oscillation, and a bias circuit, including a power supply and a line, used to control an operating point voltage of the negative differential resistance element. The voltage modulation unit is connected to the bias circuit through the stabilizing circuit.

Abstract: A high performance radio frequency receiver includes an isolated transconductance amplifier with large binary and stepped gain control range, controlled impedance, and enhanced blocker immunity, for amplifying and converting a radio frequency signal to multiple electrically isolated currents; a pulse generator for generating in-phase and quadrature pulses; a crossover correction circuit and pulse shaper for controlling a crossover threshold of the pulses and interaction between in-phase and quadrature mixers; and a double balanced mixer for combining the RF signal with the pulses to generate an intermediate frequency or baseband zero intermediate frequency current-mode signal. The intermediate frequency signal and second order harmonics may be filtered with a high frequency low pass filter and a current injected complex direct-coupled filter. IIP2 calibration of the in-phase and quadrature channels may be optimized using the isolated transconductance amplifier.

Abstract: An injection-locked frequency divider is provided. The injection-locked frequency divider includes a voltage control oscillator (VCO) and a mixer. The VCO includes a LC resonance tank and a negative-resistance generator for generating a differential oscillation signal including a first and a second oscillation signals. The LC resonance tank adjusts a VCO reactance and resonates for generating the differential oscillation signal. The negative-resistance generator coupled to the LC resonance tank eliminates an equivalent resistance generated by the LC resonance tank and maintains the VCO to continuously oscillate.

Abstract: A resonant tunneling diode or diode array oscillator (10) including a resonant diode (11) is coupled to a millimeter-wave source (14) and a quench generator (16) for periodically quenching the oscillations so that the average oscillation time of the oscillator is proportional to signal strength of the source (14). The signal source can be from an antenna such as a dipole or tapered slot line antenna.

Abstract: The present invention relates to an oscillator circuit. In the oscillator circuit, the level of the output signal is monitored and compared to a desired reference level. An error signal is then generated and used to modify the feedback so that the negative resistance of the active device presented to the resonator exactly equals the magnitude of the positive resistance of the resonator without having to rely upon saturation in the active device and for very linear operation of the device such that over the full swing of the output, the negative impedance presented to the resonator remain extremely constant—thus reducing the sensitivity of the oscillator to any noise present.

Abstract: An apparatus for generating an oscillating signal that includes a circuit to accelerate the time in which an oscillating signal reaches a defined steady-state condition from a cold start. The apparatus includes an oscillating circuit to generate an oscillating signal; a first circuit to supply a first current to the oscillating circuit; and a second circuit to supply a second current to the oscillating circuit, wherein the first and second currents are adapted to reduce the time duration for the oscillating signal to reach a defined steady-state condition. The apparatus may be useful in communication systems that use low duty cycle pulse modulation to establish one or more communications channels, whereby the apparatus begins generating an oscillating signal at approximately the beginning of the pulse and terminates the oscillating signal at approximately the end of the pulse.

Abstract: A voltage-controlled oscillator has: an LC resonant circuit including an inductor and a variable capacitor that are connected in parallel between a pair of output terminals; a plurality of negative resistance circuits provided between a power source and the LC resonant circuit; a plurality of capacitor groups; a first switch circuit selecting an arbitrary number of negative resistance circuit from the plurality of negative resistance circuits; and a second switch circuit selecting an arbitrary number of capacitor group from the plurality of capacitor groups. The LC resonant circuit and the selected capacitor group constitute a resonant circuit. The resonant circuit is electrically connected to the power source through the selected negative resistance circuit, oscillates at an oscillation frequency depending on total capacitance of the resonant circuit, and outputs a differential signal of the oscillation frequency from the pair of output terminals.

Abstract: An oscillator circuit comprising a resonant circuit which includes a negative resistor, an inductor and an oscillation frequency setting capacitor whose capacitance is varied according to a control voltage based on oscillation frequency data and which outputs a signal having an oscillation frequency based on the oscillation frequency data, a temperature detector which outputs temperature compensation data, based on the temperature, and temperature compensating capacitors which are electrically connected to the resonant circuit and which are supplied with the temperature compensation data to change capacitance values thereof based on the temperature compensation data, thereby adjusting the oscillation frequency.

Abstract: A system on chip such as a radio receiver has reduced suceptibility to voltages in the bulk silicon by using gyrator elements in the receiver with each gyrator element including a plurality of current sources interconnected to provide output transconductance voltages, and a variable load for the current sources including first and second load resistors each serially connected with one other plurality of current sources. A variable resistance interconnects nodes of the load resistors with the variable resistance comprising a pair of native MOS transistors having low threshold voltages. In a preferred embodiment the first and second load resistors comprise first and second MOS transistors with the pair of native transistors serially connected between source elements of the first and second MOS transistors.

Abstract: An oscillator circuit comprising a resonant circuit which includes a negative resistor, an inductor and an oscillation frequency setting capacitor whose capacitance is varied according to a control voltage based on oscillation frequency data and which outputs a signal having an oscillation frequency based on the oscillation frequency data, a temperature detector which outputs temperature compensation data, based on the temperature, and temperature compensating capacitors which are electrically connected to the resonant circuit and which are supplied with the temperature compensation data to change capacitance values thereof based on the temperature compensation data, thereby adjusting the oscillation frequency.

Abstract: In the high-frequency piezoelectric oscillator, capacitors C1, C2 as a part of a load capacitor are connected between a base of a transistor TR1 and the ground. The connection point of the capacitors C1, C2 is connected to an emitter of the transistor TR1, and is grounded via an emitter resistor R1. A base bias circuit consisting of resistors RB1 and RB2 is connected to the base of the transistor TR1. A piezoelectric vibrator, an inductor, and a resistor are connected in parallel, and connected between the base of the transistor TR1. A capacitor is connected to the parallel circuit and grounded. A collector of the transistor and a power supply line are connected together.

Abstract: A stable high-frequency clock pulse apparatus and method including frequency source, overtone crystal unit coupled with a negative resistance oscillator, a bandpass overtone filter and a drive level control is provided. The apparatus can include a frequency multiplier. The frequency source can be a micromechanical resonator.

Abstract: A circuit and method are disclosed herein for a crystal oscillator, wherein the Q of the resonant network is not reduced through the loading effects of the oscillator's resistive bias network. The oscillator is configured as an operational transconductance amplifier (OTA) coupled to the resonant network. The OTA creates a negative resistance, which compensates for energy lost to resistance within the resonant network, thereby sustaining oscillation at the resonant frequency. Instead of using bias resistors to set and maintain the operating point of the oscillator, another OTA (with a high output impedance) injects a current into the resonant network to bias the oscillator. Advantageously, this technique avoids the reduction in Q that occurs when bias resistors are connected across the high effective parallel resistance of the resonant crystal. The higher Q benefits frequency stability and phase jitter characteristics of the oscillator.

Abstract: There is disclosed a SAW resonator-based oscillator circuit having low phase noise that is tunable across a comparatively wide frequency range. The oscillator circuit comprises: 1) a tuning element coupled to the input port and having a variable capacitance responsive to the frequency tuning signal; 2) a first inductor coupled in series with the tuning element; 3) a SAW resonator coupled in series with first inductor; 4) a second inductor coupled in parallel with the SAW resonator; 5) a negative resistance generating circuit coupled to the SAW resonator. Across the tunable operating frequency range of the oscillator circuit, the reactance looking into the input port is maintained at approximately zero and the resistance looking into the input port remains negative.

Abstract: In order to provide an oscillation circuit that is capable of achieving stable oscillation over a large frequency range, oscillating operation is carried out by connecting an LC resonance circuit, of which resonance frequency is adjustable, to the collector of a pair of transistors that function as 3-terminal active element, and feeding back the resonance signal of the LC resonance circuit to the base of the pair of transistors. At this time, a voltage appearing across both terminals of the LC resonance circuit is converted into a current by a Q-factor tuning voltage-current converter circuit, and the current is fedback to the LC resonance circuit thereby changing the Q factor of the LC resonance circuit.

Abstract: A tuning signal is injected into an LC tank circuit oscillator, e.g., through an impedance (either reactive, inductive, capacitive and/or resistive) to tune the phase and/or frequency of the LC tank circuit oscillator. A negative resistance is included in parallel with the LC tank circuit oscillator to compensate for losses in the LC tank circuit, and a bias signal is provided to power the operation of the LC tank circuit. Multiple LC tank circuit oscillators may be used to provide stable multiplied or divided frequencies. In another embodiment, the nominal frequency of the LC tank circuit oscillator may be adjusted using a varactor or other voltage-controlled element in the LC tank circuit oscillator under the control of, e.g., the output of a separate PLL loop including another LC tank circuit oscillator. In one application, the injection tuned LC tank circuit forms a clock recovery cell using a clock signal embedded in a NRZ (Non Return to Zero) pseudo-random data stream.

Abstract: There is disclosed a SAW resonator-based oscillator circuit having low phase noise that is tunable across a comparatively wide frequency range. The oscillator circuit comprises: 1) a tuning element coupled to the input port and having a variable capacitance responsive to the frequency tuning signal; 2) a first inductor coupled in series with the tuning element; 3) a SAW resonator coupled in series with first inductor; 4) a second inductor coupled in parallel with the SAW resonator; 5) a negative resistance generating circuit coupled to the SAW resonator. Across the tunable operating frequency range of the oscillator circuit, the reactance looking into the input port is maintained at approximately zero and the resistance looking into the input port remains negative.

Abstract: An AC tuning signal is injected into an LC tank circuit oscillator through an impedance (either reactive, inductive, capacitive and/or resistive) to tune the phase and/or frequency of the LC tank circuit oscillator. A negative resistance is included in parallel with the LC tank circuit oscillator to compensate for losses in the LC tank circuit, and a bias signal is provided to power the operation of the LC tank circuit. The AC tuning signal may be injected into the LC tank circuit using capacitors, resistors, FET or bipolar transistors, and/or inductors. Multiple LC tank circuit oscillators may be used to provide stable multiplied or divided frequencies. In this case, the output of one LC tank circuit oscillator may be used to tune another LC tank circuit oscillator. In another embodiment, the nominal frequency of the LC tank circuit oscillator may be adjusted using a varactor or other voltage-controlled element in the LC tank circuit oscillator under the control of, e.g.

Abstract: A high-frequency oscillating circuit that is not degraded by external electromagnetic interference. The high-frequency oscillating circuit includes first and second oscillating transistors wherein the bases are connected together directly or via a capacitor having a sufficiently low impedance at an oscillating frequency, and wherein a differential signal output is obtained between the emitters of the first and second oscillating transistors. Also provided is a resonating circuit formed in a module and a separate negative-resistance-generating circuit formed on an integrated circuit for achieving an oscillator that has a high Q factor and a high C/N ratio.

Abstract: An inductorless voltage controlled oscillator that may be fabricated using CMOS circuit elements. In one aspect, the present invention includes a synthetic inductance formed on a substrate and having first and second power supply terminals and a signal port. Additionally, an active admittance transformation network is formed on the substrate and coupled to the synthetic inductance and to the port. The synthetic inductance manifests an admittance at the port which has an inductive component and a positive real component. The active admittance transformation network transforms the positive real component of the synthetic inductance admittance to a negative real component and preserves the inductive character of the synthetic inductance admittance. The synthetic inductance can provide an effective Q of greater than twenty. The active admittance transformation network and the synthetic inductance cooperate to produce a voltage-variable oscillation frequency in excess of fifty megahertz.

Abstract: A voltage controlled oscillator (VCO) CMOS circuit wherein back gate terminals of CMOS transistors are used to vary the parasitic capacitances of the transistors. The back gate terminals receive a signal from a variable voltage source so that oscillation can be controlled by adjusting the variable voltage. The CMOS transistors are connected across an inductor and the transconductance characteristics of the transistors reduce the resistance of the inductor, thereby improving circuit oscillation and providing enhanced stability and capabilities at high operating frequencies.

Abstract: A voltage controlled oscillator has a cross-coupled negative resistance cell formed as an integrated circuit connected to off-chip components of a high-Q resonant tank circuit. To counteract spurious oscillations brought about by package parasitics caused by the interconnection of the chip to the external components, the cell is provided with a degeneration impedance. Typically, a pure inductor is used if all the elements of the tank circuit are off-chip. In a case where the tank circuit includes an on-chip fixed capacitor, the degeneration impedance may take the form of a capacitor.

Abstract: A BJT, an inductor, and an RTD are configured to define a negative resistance oscillator circuit that is suitable for monolithic integration. The BJT is forward biased so that the RTD operates at a DC operating point (I.sub.Q,V.sub.Q) on its characteristic I-V curve in its negative differential resistance region. The thermal noise inherent in the circuit causes it to start oscillating about the DC operating point (I.sub.Q,V.sub.Q) where the RTD's negative resistance R.sub.n provides positive feedback that amplifies the oscillations until equilibrium is established thereby producing a sinusoidal waveform. The low power BJT/RTD oscillator operates at power levels approximately one-tenth those of known integrated feedback oscillators and oscillates at frequencies in the hundreds of Ghz range that are currently only achievable using waveguide oscillators.

Abstract: A monolithic CMOS phase-lock loop (PLL) circuit provides a high frequency of operation suitable for RF applications. The PLL produces an output clock with high spectral purity and very low jitter. The output clock has a low static phase error relative to a reference input, making the PLL also useful for clock synchronizing applications, such as clock recovery elements in transmission/recycling channels. The PLL provides in-phase and quadrature signals from a VCO which has two differential transconductor stages having negative output conductance.

Abstract: An electronically-controlled variable propagation delay digital signal inverter comprises a digital signal inverter having an input signal port and an output signal port, and an electronically-controlled negative resistance (ECNR). The ECNR is coupled to the output port of the inverter in a configuration so as to render the propagation delay of the digital signal inverter capable of being varied by varying the resistance of the ECNR. The electronically-controlled variable propagation delay digital signal inverter may be included in a ring oscillator configuration.

Abstract: An electrical circuit comprising means for receiving an input signal for encoding or modulating and amplification. Multiple amplification stages including at least one transconductance amplifier are provided. There are means for having the input signal modulate the oscillator constituted by the multiple amplification stages to provide a 360.degree. phase-shifted signal at a predetermined frequency. Gain control means are also provided for developing level for permitting oscillation under conditions including at least the conditions of turn on of the circuit and other operating conditions. The gain control means includes a transistor and resistor network for adjusting the gain to sustain the oscillation. The transistor and resistor also regulate amplification of an intermediate stage of the amplifier. The preamplifier directly converts an EKG and/or other signals to linearized control currents which modulate the oscillator.

Abstract: A voltage controlled oscillator (VCO) including a negative feedback circuit operates in response to a negative feedback signal generated during active transistor region operation of transistors in transconductance amplifying stages coupled thereto. As a result, harmonic distortion and problems of noise and unstable frequency oscillation are obviated or significantly reduced. The VCO includes first and second variable transconductance (gm) amplifying stages whose non-inverting (+) and inverting (-) terminals are respectively grounded and a first condenser connected between an output terminal of the first transconductance (gm) amplifying stage and a non-inverting (+) terminal of the second transconductance (gm) amplifying stage. A negative-resistive circuit is used to provide a negative feedback.

Abstract: An electrically controllable oscillator circuit (30) comprises two balanced transconductance circuits (G1, G2), each including transistor pairs arranged as inverters (Inv14) and as resistors (Inv5-6). The oscillation frequency (f) and the quality factor (Q) of the oscillator circuit (30) are controlled by means of a single control signal provided by a combined control circuit (Inv7, Dif, IM1, IM2). The current mirror circuit (IM1, IM2) and a differential pair (Dif) derived the control signal for adjusting the quality factor (Q) from a resistor-connected further transistor pair (Inv7) connected to the control signal for adjusting the frequency (f). The quality factor of an electrically controllable filter arangement including similar transconductance circuits (G-3-9) is adjusted by means of the control signal generated by the control circuit via a buffer circuit (B) and a low-pass circuit (C3).

Abstract: A voltage-controlled oscillator includes a negative resistance generator, a resonant circuit, a first series circuit, a second series circuit, and a third series circuit. The first series circuit controls an oscillation frequency for changing a resonant frequency of the resonant circuit, and the second series circuit modulates this frequency. The third series circuit consists of a capacitor and a variable capacitance diode to which the modulation signal is supplied. The third series circuit changes the resonant frequency of the resonant circuit in a direction for cancelling a change in modulation sensitivity caused by the second series circuit.

Abstract: An oscillator is disclosed comprising a pair of gm stages wherein the output of the second gm stage is coupled to the inverting input of the first stage and the output of the latter is coupled to the non-inverting input of the former; first and second capacitors coupled respectively between the outputs of the two gm stages and ground and feedback circuitry coupled between the output of the first gm stage and the non-inverting input of thereof while the inverting input of the second gm stage being coupled to ground. Because the first gm stage is operated as a negative gm, this stage simulates an inductor using the first capacitor that is coupled to the output of the stage.

Abstract: An overcoupled resonator having a resonant cavity defined by a thin film of magnetic material with a pair of end walls parallel to a transducer. Because this resonator is overcoupled, it is suitable for use in a broadband oscillator.

Abstract: Disclosed is a circuit providing a controllable effective resistance which comprises of transistor means that provides current at an input node responsive to an input voltage at the input node. The transistor means is coupled to a settable current source which operates to control the effective value of the controllable effective resistance. The invention also includes a filter which employs the controllable effective resistance to vary the breakpoint frequency of the filter. Also, a phase-locked loop apparatus employing the filter is disclosed.

Abstract: A high-frequency negative resistance circuit for use in a voltage controlled crystal oscillator has a pair of input terminals thereby defining an input current and input voltage. The high-frequency negative resistance circuit includes a sensing circuit for sensing the input current, a biasing voltage source and a load impedance connected to the voltage source. The high-frequency negative resistance circuit further comprises a current mirror circuit connected to the sensing circuit and to the load impedance for producing a current in the load impedance. The current in the load impedance is approximately equal to the input current. The current mirror circuit also controls the sensing circuit to cause the input voltage to decrease as the input current increases. Decreasing input voltage with increasing input current defines the negative resistance. When this negative resistance circuit is configured with a crystal and a voltage controlled capacitance, an oscillator capable of high-frequency operation results.

Abstract: A low frequency sinusoidal oscillator, comprises a circuit which contains operational amplifiers, resistors and capacitors and has no inductor. The circuit, however, operates as an inductor. The circuit is arranged to resonate at a frequency which may be chosen by acting on only one component which preferably is a resistive component.