Abstract: An apparatus (200) and method for adjusting the bias current of the oscillating device (320) in a VCO (202) in response to changes in the tuning voltage of the VCO to achieve reduced sideband noise.

Abstract: A voltage controlled oscillator comprises a resonant circuit having at least a coil and a first variable capacitance diode, and resonating within predetermined variable frequency ranges; and an active circuit having an input, an output, and an active element connected between the input and the output, the input being connected to the resonant circuit in order to receive a resonant output therefrom. A variable capacitance ratio circuit, having a second variable capacitance diode and at least one capacitor, is connected in a positive feedback manner, between the input and the output of said active circuit means in order to oscillate the active element of the active circuit at a resonant frequency of the resonant circuit, between the input and the output of the active circuit.

Abstract: A voltage-controlled oscillator capable of very high ratios of modulation to oscillation frequency is disclosed embodying a resonant circuit with an inductance and two tuning diodes connected with opposite polarity in series across the inductance, a cross-coupled feedback amplifier circuit with two matched MMIC inverting amplifiers capacitively cross-coupled to the resonant circuit for driving the resonant circuit into oscillation at its resonant frequency to produce an output carrier wave, and a transmission line resonator connected to the resonant circuit between the tuning diodes to couple a wide band frequency modulating voltage thereto for modulating the output carrier wave.

Abstract: A modulation circuit that is particularly suited for a communication modem and provides for each of the channels precise carrier mark and space frequencies generated in response to external signals from an FSK communication station. The modulation circuit includes first and second frequency controlling circuits arranged with an inductor to form a resonant circuit of a voltage variable oscillator. The modulation circuit further includes a feedback control network and a voltage-frequency control adjustment circuit. The feedback control network generates a loop error signal applied to both frequency controlling circuits. The voltage-frequency control adjustment circuit generates a voltage-frequency adjustment control signal and has a switching circuit responsive to the external signals. The voltage-frequency control adjustment circuit includes an inverting network and a bias network.

Abstract: A monolithic microwave IC oscillator includes a feedback amplifier having a field effect transistor and a varactor diode. The varactor diode has a junction capacitance that varies according to the bias voltage applied to said diode and capacitively couples the amplifier to an external load. Any variation of the capacitance of the load-coupling capacitor caused by design errors or by variations in the manufacturing process can be easily corrected when the device is used. As a consequence, the oscillator can always be operated with good oscillaitng characteristics without hindering integration of individual components and without increasing costs.

Abstract: A voltage-controlled oscillator using planar microstrip technology and primarily for the 37 to 39.5 GHz frequency band comprises a strip-line resonator, a negative resistance device mounted adjacent the center of the resonator, respective variable capacitance devices mounted adjacent the ends of the resonator, a high impedance coupling the resonator to an output path, and bias signals are applied to the negative resistance device and said variable capacitance devices.

Abstract: An oscillator circuit with a voltage controlled oscillator (VCO) comprises a range changing circuit that adapts the d.c. control voltage of the circuit to a control signal suitable for adjusting the VCO to the full frequency range. The voltage level for the control signal can be outside the voltage range delimited by the supply voltages for the circuit. In order to obtain a voltage supply of a sufficient voltage level the output signal of the VCO is used as the input of an a.c. to d.c. converter that provides the necessary higher supply voltage for the range changing circuit.

Abstract: A diode circuit in which the flicker noise generated by the diode is reduced comprises a diode (D1) connected in series with a resistor (R2) having a by-pass capacitor (C1) in parallel therewith. In one embodiment the side of the diode remote from this resistor (R2) is connected to one input of a DC differential inverting amplifier (A1) via a low pass filter (L1, C2). The amplifier's output is negatively fed back to the junction of the diode (D1) and the resistor (R2) so that the latter forms the amplifier load. A control voltage is applied to the other input of the amplifier of such value as to produce the required diode bias. The basic diode circuit can be extended to perform functions such as amplitude limiting, frequency control and modulation.

Abstract: A voltage controlled oscillator and buffer amplifier circuit (211) is disclosed. The circuit is in a stacked configuration, whereby, the current from the power supply (361) is used by the buffer amplifier circuit and reused by the VCO circuit. The VCO circuit includes two transistors (333, 325). The transistors are set-up in a mirrored configuration, so that one of the transistors (325) controls the bias current in the other transistor (333). Both of the transistors are integrated into a semiconductor circuit die (365), thus, matching the thermal characteristics of the transistors (333, 325) and improving control of the bias current. The die (365) is bonded to a ceramic substrate (601). The substrate (601) has connectivity paths for connecting components in the circuit die to components external to the circuit die. Some of the connectivity paths are made of a material and length to form passive circuit elements.

Abstract: A broadband, varactor-tuned shorted coax resonator is provided with a single point coupling port that facilitates coupling of discrete circuitry to the distributed resonator to form an oscillator. The coupling port is defined by adding a second shorted coax line across the end of the first. The outer conductors of the two lines are interconnected. The inner conductors of the two lines are serially coupled and define a coupling gap, either along their length or at their ends, across which discrete circuitry can be connected. In a preferred form of the invention, the discrete circuitry is positioned in a region within the periphery of one of the inner conductors in order to provide an electromagnetic shield for the circuitry.

Abstract: A voltage-controlled oscillator according to the present invention comprises: a transistor, where the drain electrode is grounded, the gate electrode is connected to a resonator whose resonant frequency is adjustable according to a voltage applied to a voltage-dependent capacitance diode electromagnetically coupled with the resonator, an output signal is output from the source electrode; a resistor connected in gate bias circuit or source voltage supply circuit for detecting a low-frequency noise component generated in the transistor, where the detected low-frequency noise component is amplified and fed back to the voltage-dependent capacitance diode so as to cancel a phase-noise component generated in the voltage-controlled oscillator. The above-described voltage-controlled oscillator may be further provided with a reference crystal oscillator to which the voltage-controlled oscillator is phase-locked.

Abstract: Voltage controlled oscillator provided with a resonant network, an amplifier and a reactive network, all incorporated in an oscillator loop, the reactive network having one or more reactive components whose values depend on a control signal fed to a control input, so that the oscillator frequency can be regulated with said control signal. A control loop is provided between the resonant network and the reactive network, with which control loop the difference is determined between a measure of the imaginary part of the impedance or admittance of the resonant network and the control signal acting as reference quantity. The imaginary part of the impedance or admittance of the reactive network is regulated with said difference. The control loop contains a derivation circuit for deriving said measure and a differential amplifier, to one input of which the output signal of the derivation circuit is fed and to the other input of which the control signal is fed.

Abstract: A W-band waveguide variable controlled oscillator incorporating a capacitively coupled Gunn diode and varactor diode arranged in such a manner that adverse environmental conditions do not deleteriously effect the stability of the output of the oscillator. The Gunn diode is electrically connected to a waveguide chamber within the oscillator and includes a resonator electrically connected to its end cap. The resonator is electrically connected to a DC bias source by means of a DC bias filter and a wire inductor. Opposite and above the Gunn diode is a varactor assembly including a varactor diode, which is also electrically connected to a DC bias source through a DC bias filter. A variable coupling spacer within the varactor assembly adjusts the distance between the varactor diode and the Gunn diode such that the capacitive coupling between the two can be adjusted. In addition, an adjustable back-short is incorporated within the waveguide channel to adjust the power output of the oscillator.

Abstract: A microwave circuit intended for either direct modulation or direct demodulation of a microwave link communications signal is characterized in that a local oscillator (8) is incorporated in the circuit. The local oscillator supplies two signals that are in phase opposition at 180 degrees. Each signal is sent to a phase shifter. The first phase shifter (9) supplies two signals that are in quadrature, at 0 and 90 degrees. The second phase shifter supplies two signals in quadrature at 180 and 270 degrees. The 0 and 180 degree signals are sent to a first mixer (2), while the 90 and 270 degree signals are sent to a second mixer (3). In the case of a modulator, the first and second mixers receive, respectively, in-phase and quadrature signals, and the outputs of the mixers are combined to form a modulated signal. In the case of a demodulator, a modulated signal is applied through a .div.2 divider to inputs of the two mixers, and in-phase and quadrature signals are obtained at respective mixer outputs.

Abstract: An electrically tuned super-regenerative receiver (10) comprises a feedback type oscillator having a signal output and a signal input, phase shift components (30) connected in a feedback loop for coupling the signal output to the signal input to cause oscillations, and a quench oscillator (35) coupled to the signal input for switching the oscillator between an oscillating and a non-oscillating condition. A variable capacitance device (40), such as a varactor diode, is connected between the signal output and a reference potential (21), and a microprocessor (105) provides a tuning voltage (42) which is applied at the signal output for varying the current in the varactor diode, thereby varying the oscillator center operating frequency. The oscillator center operating frequency is detected by a spectrum analyzer (112) and compared to a desired center operating frequency by a controller (118).

Abstract: An RF oscillator is disclosed that can be tuned to operate over a wide range of frequencies while maintaining advantageous bias conditions. The oscillator includes circuitry that adjusts an oscillator bias signal in response to changes in oscillator frequency and/or ambient temperature, and does so without resort to using the same signal for both bias and frequency control. By so doing to control parameters such as phase noise, output power and compression angle, both the frequency range and temperature range of an oscillator can be extended, while simultaneously improving the oscillator's performance.

Abstract: A voltage controlled oscillator having an active network and a tuning network that includes a transmission line impedance transformer having a first end coupled to an output circuit of the VCO, and having a selectable effective width that determines the tuning bandwidth of the oscillator. A varactor diode is coupled to the second end of the transformer line, and a bias line is coupled between a tuning port and the varactor diode. The transmission line impedance transformer more particularly includes a main transformer line, a plurality of transmission lines adjacent the main transformer line, and wire bonds for electrically connecting selected ones of the plurality of lines to the main transformer line, whereby connection of selected ones of the transmission lines to the main transformer line increases the effective width of the impedance transformer.

Abstract: An improved frequency modulation apparatus (100) is provided comprising a generator (102), a biasing voltage line (116), and an interface circuit (110). The generator (102) is utilized to generate a carrier signal. A control line input (104) on the generator (102) adjusts the frequency of the carrier signal. The biasing voltage line (116) provides DC power in order to DC bias the generator (102). The interface circuit (110) couples an information signal (114) to the biasing voltage line (116) for altering the biasing of the generator (102) in response to the information signal (114). The alteration of the biasing of the generator (102) results in the carrier signal being frequency modulated by the information signal (114).

Abstract: A pulse repetition frequency (PRF) pushing compensation circuit to negate PRF-induced frequency shifts and ambient temperature change-induced frequency shifts in pulsed RF sources. The PRF pushing compensation circuit samples PRF voltage and feeds it into a resistor-capacitor (RC) network so that the DC voltage component across the capacitor is directly proportional to the PRF. The DC voltage is then amplified, via a transistor, and fed to a varactor diode circuit coupled to the source's frequency determining element (e.g., dielectric resonator, microwave cavity, or other element). With a varactor diode tuning the source, the capacitor voltage derived from the PRF voltage is applied to the varactor diode to effect a frequency shift in the pulsed RF source which is equal and off-setting to the PRF-induced frequency shift. Temperature sensitive resistors can be used in the DC offset voltage of the varactor diode circuit to compensate for frequency changes due to ambient temperature variances.

Abstract: An oscillator operational in the millimeter wave and microwave range, including frequencies greater than 60 GHz, is provided with reduced phase noise by enhancing Q of the resonant circuitry by reactively terminating fundamental frequency oscillation and increasing stored fundamental frequency energy in the resonant circuitry. A two frequency system is provided with constructive reflection of energy at fundamental frequency back to the resonant circuitry, and with isolation of fundamental frequency energy from the output load. Energy to the output load is obtained from the in-situ generated second harmonic of the active element. Phase noise is reduced by enhancing Q by more than an order of magnitude.

Abstract: A PLL synthesizer includes a voltage-controlled oscillator generating an output signal having a frequency based on a first signal supplied thereto, a PLL control circuit which generates a second signal based on the output signal and a set frequency, a lowpass filter having an input terminal and an output terminal, for filtering the second signal supplied through the input terminal to thereby generate the first signal supplied to the voltage-controlled oscillator through the output terminal, and a switch circuit which is coupled between the input and output terminals of the lowpass filter and which supplies the second signal directly to the voltage-controlled oscillator during a predetermined time when the set frequency is changed.

Abstract: A voltage controlled oscillator includes a resonant circuit formed of an impedance in series with a voltage variable capacitance. The impedance consists of a surface acoustic wave resonator in parallel with either an inductance coil or another acoustic wave resonator.

Abstract: A diode tuned resonant circuit (42) with an inductor (L1) a first variable reactance diode (VAR1) connected in parallel with the inductor (L1), and a second variable reactance diode (VAR2) connected in series with the parallel combination of the inductor (L1) and first diode (VAR1) is used in an oscillator circuit. The resonant frequency of the circuit may be adjusted over a relatively broad frequency range while maintaining a relatively constant Q-factor by applying a biasing voltage to the first and second diodes (VAR1, VAR2).

Abstract: A voltage controlled crystal oscillator circuit, such as a Pierce oscillator circuit, includes an amplifier and is balanced by the addition of another varactor connected directly to the amplifier, whereby the frequency pull range is increased. Further, greater linearity can be achieved by adding another pair of varactors to the circuit.

Abstract: A Colpitts oscillator has an integrated circuit. The integrated circuit includes a transistor having an equivalent large size, a bypass capacitor connected between a collector of the transistor and a ground, a first feedback capacitor connected between a base and an emitter of the transistor, a second feedback capacitor connected between the emitter of the transistor and the ground, and an emitter follower connected to the emitter of the transistor. In a package, a stray reactance and a bonding wire are designed so as to agree with an element value and a Q value which can be used as parts of a resonator. A surface elastic wave resonator disposed outside the integrated circuit is connected between the base of the transistor and the ground. The oscillator is voltage controlled by a variable capacitance diode connected in series with the resonator.

Abstract: A stable sampling clock signal is supplied from a VCO circuit which is able to operate in a synchronous manner with an external sync signal that does not posses good phase stability while also providing an enlarged range of variable frequency output. The VCO circuit of this invention comprises an oscillation output circuit, such as NAND or NOR circuit, having one input connected to receive an external sync signal and having its output for providing the desired oscillation or sampling clock frequency. A control voltage circuit is connected to the other input of the oscillation output circuit and to the output of the oscillation output circuit.

Abstract: Flicker (1/f) noise is suppressed in an oscillator by reducing oscillator voltage-frequency pushing to zero. A varactor (56) is incorporated in the resonator circuit and is biased with a tuning voltage setting the varactor to a capacitance value providing the zero oscillator pushing at a given frequency. A common bias connection (62) is provided between the varactor and the active element (64) such that a random perturbation voltage change across the active element also causes a change in voltage across the varactor, to compensate a change in oscillator frequency otherwise caused thereby. The varactor capacitance versus voltage characteristic is shaped such that a change in active element voltage provides a change in varactor voltage, and the combination of these voltage changes results in a zero change in oscillator frequency. The tuning slope of the oscillator provided by the varactor is opposite the tuning slope of the oscillator resulting from a change in active element voltage.

Abstract: A voltage controlled oscillator having improved frequency linearization characteristics. A radial line, (top-hat) disc geometry in conjunction with a varactor diode are disposed in a broadband, ridged waveguide oscillator circuit to produce a frequency linearized voltage controlled oscillator. A negative resistance device is recessed into the ridged waveguide and coaxially coupled via an impedance transformer to the ridged waveguide cavity. The present invention uses a disc resonator in a ridged waveguide to transform the microwave impedance of a non-RF generating element, a varactor diode, to values which provide improved voltage controlled oscillator tuning linearity. The disc resonator or radial line is located above the varactor diode. The radial line transforms the microave impedance of the varactor diode to a new value which is then coupled into the ridged waveguide circuit and subsequently to the RF generating diode.

Abstract: A varactor diode tuned voltage controlled oscillator which simultaneously optimizes several techniques to minimize AM to FM conversion in the LC resonant circuit to provide an RF signal having minimum phase noise is described. A high gain current limiting RF amplifier is coupled to a high Q, high capacitance, low impedance LC resonant circuit by an impedance transformation network to provide a high tank circulating power having minimum RF voltage fluctuations. The RF voltage across the varactor tuning diodes is further reduced by connecting two varactor diodes in series, back-to-back, or by connecting a fixed capacitance in series with the parallel connected varactor diodes.

Abstract: In a waveguide oscillator, a Gunn diode or other negative-resistance oscillator device (2) has a resonant cap (3) for coupling to the waveguide (1), and a tuning varactor diode (11) is coupled by a probe (13) to the electromagnetic filed in the vicinity of the cap (3). In accordance with the invention, a mechanically simple, compact and cheap oscillator arrangement is obtained by integrating both the varactor diode (11) and the probe (13) in a circuit body (10) mounted in the waveguide (1), preferably in an area below the plane of the cap (3) so as to reduce perturbation of the filed. The probe is formed as a conductive track (13) on the circuit body (10), for example as a transmission line coupling to the electric field and preferably located at the front surface (18) of the body (10) or as a current loop extending on a side wall of the body (10) and coupling to the magnetic field.

Abstract: A tuning circuit (4) for a VCO includes a coarse tuning section (6) and a fine tuning section (7). The coarse tuning section includes three varactors (13, 14, 15) connected in series. These varactors together with their housings are designed to operate at considerably lower frequencies than the VCO, so that they behave as inductances at the VCO frequency. A capacitance (16) connected in parallel with the varactor inductances forms a resonant circuit therewith and serves to widen the tuning band of the VCO in adjustable manner. A capacitance (17) connected between the coarse and fine tuning sections adjusts the central oscillation frequency. An adjustable transmission line (12) in the fine tuning section adjusts fine tuning sensitivity.

Abstract: An electronically controlled oscillator capable of operating in the rf/microwave frequency range, and using a stacked crystal filter as the frequency determining element in the oscillator. A non-linear element including an appropriately biased high frequency amplifier has the stacked crystal filter connected in its feedback path and provides a loop gain of greater than 1 to meet one aspect of the Barkhausen criteria. An electronically variable impedance, such as a hyperabrupt junction varactor, is connected in the feedback loop along with the stacked crystal filter to controllably insert a phase adjustment into the feedback path, to be compensated by a phase adjustment by the stacked crystal filter, thereby to controllably maintain a loop phase shift which is an integral number of 2.pi. radians at the oscillator frequency, and to vary the oscillator output frequency about the frequency of the stacked crystal filter in a controllable fashion.

Abstract: A circuit for temperature compensation of a varactor voltage controlled oscillator control signal includes a proportional to absolute temperature (PTAT) current source and an adjustable, temperature stable current source. The difference between these two current sources defines an offset current. The varactor control signal voltage is shifted by a predetermined reference voltage and offset by an offset voltage proportional to the offset current, in a differential amplifier portion of the circuit, to provide a tuning signal for controlling the varactor so as to compensate for the varactor capacitance temperature drift. The adjustable, temperature stable current source allows tuning the circuit in order to precisely tune the VCO to a desired frequency under a predetermined set of operating conditions in order to correct component and process variations.

Abstract: A voltage variable capacitor (VVC) having two terminals in a variable frequency crystal oscillator integrated into a common substrate with the oscillator circuitry and isolated therefrom. The VVC is constructed using the same processing steps as the oscillator circuitry and achieves low series resistance and wide capacitance variation by utilizing a substrate or epitaxial layer (body) having a well with a diffused region therein. The region, of the same conductivity type as the well and a first one of the two terminals, forms a rectangular ring in the well. Over the region and insulated therefrom, a conductive layer is deposited to provide a second one of the two terminals. Both terminals are electrically isolated from the body.

Abstract: A varactor tuned oscillator (10), VCO, operational in the millimeter wave range including frequencies greater than 30 GHz, includes a lumped element active circuit (12) with a negative resistance, a lumped element tuning circuit (16) coupled to the active circuit and providing resonant circuitry in combination therewith, and a VCO output (26) reactively terminated at the fundamental frequency of oscillation and generating a higher order output harmonic at least as high as the second order. The reactive termination at fundamental frequency eliminates the intrinsic diminishing effect on tuning range of resistive loading, to extend tuning range and provide an ultrabroadband VCO. The VCO output (26) is resistively loaded at the higher order harmonic. The output is obtained from the higher order harmonic generated in-situ in the active element (14). Measured performance included continuous tuning from 46 to 66 GHz, a 20 GHz tuning range, with a maximum power output of +6 dBm.

Abstract: A frequency modulator is provided, in which, for instance, a video signal is used as a modulation signal. A differential amplifier is formed by first and second transistors. First and second load resistors are connected between respective collectors of the first and second transistors and a power supply terminal (A). A series circuit of first and second feedback capacitors is inserted between the collector of the first transistor and a base of the second transistor. A series circuit of third and fourth feedback capacitors is inserted between the collector of the second transistor and a base of the first transistor. The respective same electrodes of first and second variable capacitance diodes are connected with each other and the other electrodes thereof are connected respectively to a junction point of the first and second feedback capacitors and to a junction point of the third and fourth feedback capacitors.

Abstract: An oscillator (10) operational in the millimeter wave range including frequencies greater than 30 GHz includes a lumped element active circuit (12) including an active element (14) with a negative resistance, a lumped element resonator circuit (16) in parallel therewith, and an antenna (18) extending directly from the oscillator without an intermediate impedance matching section therebetween and without an isolation element therebetween. The antenna has a length of nominally a quarter wavelength at the desired fundamental frequency, and has zero connection length from the oscillator. The antenna serves a dual function of radiating the energy generated by the oscillator and also transforming the output impedance of the oscillator to the impedance of transmission media providing a load, such as free space or a wave guide.

Abstract: An oscillator having a dielectric resonator and being electronically tuned in frequency by a varactor, in particular in the 22 GHz range, the oscillator comprising an active electronic component having negative resistance (17), at least two dielectric resonators (40, 41), and a substrate (13) on the surface of which there are three striplines (10, 11, 12), with the first and second striplines (10 and 11) being in line and having their adjacent ends connected to two respective electrodes of the active component (17). The third stripline (12) which runs parallel to the first two striplines (10, 11) is connected to the varactor (26), with all of the dielectric resonators (40, 41) being coupled to the first stripline (10).

Abstract: A circuit for use in conjunction with a voltage controlled oscillator (VCO). The circuit introduces modulation into a radio system (to create a substantially flat frequency response) at the same VCO port at which VCO frequency centering and negative bias control signals are introduced. A potentiometer is utilized both for providing an adjustable negative bias to the varactor in the VCO resonant circuit and for setting the VCO to the appropriate center frequency. Modulation compensation circuitry is coupled to the control arm of the potentiometer and to the anode of the varactor (via a choke 4). The modulation compensating circuitry is preferably designed to have a transfer function that is substantially the inverse of the closed loop transfer function of the phase locked loop system with respect to the frequency modulation of the VCO.

Abstract: A first transistor is connected in grounded-collector-emitter-follower configuration to generate a high enough negative resistance to overcome the oscillating resistance of the crystal resonator connected to the base electrode. A second transistor connected in grounded-base configuration serves as a buffer and impedance transformer between the low impedance output of the first transistor and the high impedance of a load. An inductor connected between the resonator and the first transistor input and a variable capacitance approximating the shunt capacitance of the resonator connected across the first transitor input form an impedance inverter which absorbs the resonator shunt capacitance and converts the effect of the resonator to a parallel tuned circuit that can be broadly tuned.

Abstract: A timing recovery apparatus for a burst mode communication receiver. The apparatus provides for optimum sampling and digitizing of received data at a plurality of data rates. In particular, a VCO is phase-locked to a local frequency reference prior to data being received. A reference timing preamble transmitted prior to the data is filtered and fed to the VCO causing it to injection lock such that the VCO becomes phase aligned with the preamble. The VCO is then permitted to "free run" during data transmission and continues to operate at substantially the same frequency. A synchronous divider and multiplexer, responsive to the VCO, allows selection of sampling clocks for the plurality of data rates. The divider is forced to a known state during VCO injection locking, to assure that the sampling clocks have maintained the proper phase for optimal sampling at the corresponding data rate. Further, means is provided to monitor the frequency of the VCO.

Abstract: A voltage-controlled oscillator (VCO) especially designed for use in the millimeter wave frequency band (Ka-band) and which exhibits an adjustable tuning sensitivity. A low tuning sensitivity is easily obtained, making it suitable for narrow-band FMCW applications. It comprises a Gunn diode as a negative resistance device and a voltage variable capacitance diode (varactor) as a tuning element. A fixed capacitance element is coupled in RF series with the varactor and microstrip transmission lines are configured to function as impedance matching, resonating and filtering elements. By incorporating the fixed capacitance in RF series with the varactor, the tuning sensitivity, measured in volts/Hz is markedly reduced. The VCO uses a novel RF structure which puts the fixed capacitance in RF series with the varactor, without introducing the fixed capacitance element in the varactor bias circuitry.

Abstract: An improved voltage controlled oscillator (VCO) is provided whereby the control voltage is utilized for modulation compensation by a modulation compensation network (90). The modulating signal is variably coupled into the voltage controlled oscillator (70) to compensate for the variation in the VCO's gain factor to yield a constant modulation level over a frequency band.

Abstract: A UHF-feedback oscillator for a frequency range of at least 300 MHz to 1000 MHz includes an amplifier stage, a voltage controlled tuning filter and a feedback quadripole. The feedback quadripole comprises a two- or three- loop helical waveguide resonator. Thus, the oscillator is easily adjustable to its oscillating condition within the very wideband frequency range of between 300 MHz and 1000 MHz and can be miniaturized in the simplest manner.

Abstract: A microwave microstrip oscillator includes a thin dielectric substrate, a Gunn diode mounted within the thickness of the substrate, an annular conductive resonator lying on the surface of the substrate and at least partially surrounding the Gunn diode, and a varactor diode associated with the Gunn diode for controlling the frequency of oscillation of the Gunn diode. A microstrip circuit coupled to the Gunn diode extracts an output power signal at a desired microwave frequency.

Abstract: An electronically tuned dielectric resonator stabilized oscillator has a dielectric resonator that is fine tuned by an electronic method of tuning which includes a varactor coupled to a microstrip. This varactor microstrip transmission line is positioned below the dielectric resonator but above the plane in which a transmission line for the carrier frequency resides. By not placing the fine tuning microstrip line on the same plane as the main oscillator line, spurious oscillation between the fine tuning transmission line and the primary carrier wave resonator frequency line are minimized. Additionally, the fine tuning microstrip line is positioned orthogonal to the pathways along which the main signal transmission lines are coupled.

Abstract: An ultrahigh-frequency oscillator. To double the frequency of an oscillator having a single field-effect transistor (10), whose fundamental frequency is adjusted by an impedance of gate (13) and an impedance of source (15), a filter (16+17) is mounted between the drain of transistor (10) and the ground. This filter, formed by a self-induction coil (16) in series with a varactor (17) is adjusted to the fundamental frequency: it assures the rejection, and favors the generation of the second harmonic, at double frequency. Application to ultrahigh-frequency sources.

Abstract: A temperature-compensated piezoelectric oscillator is disclosed. This oscillator comprises an oscillating circuit consisting of an amplifier, the output of which is looped back to the input through a piezoelectric resonator which is series mounted with a variable capacitance element, a circuit for the regulation of frequency according to temperature giving a compensation voltage and a circuit for frequency adjustment giving a variable in time resetting voltage, wherein the circuit for regulating the frequency according to temperature is connected to one of the terminals of the variable capacitance element through a means, the gain of which varies according to the resetting voltage delivered by the frequency adjusting circuit.

Abstract: A temperature-compensated oscillator circuit utilizes a quartz oscillator for producing an oscillating signal having a variable oscillator frequency which fluctuates in response to ambient temperature change. A variable semiconductor capacitor having a variable capacitance is connected to the quartz oscillator for regulating the oscillating frequency thereof according to the variable capacitance. The variable semiconductor capacitor comprises a semiconductor substrate, a floating electrode disposed on and electrically insulated from the semiconductor substrate, an injection electrode formed in the semiconductor substrate for injecting a given amount of electric charge into the floating electrode to set the value of the variable capacitance, and a capacitance electrode formed in the semiconductor substrate and receptive of a bias voltage effective to adjust the set value of the variable capacitance.

Abstract: A monolithic microwave voltage-controlled oscillator including one or more FETS integrated with a wide-ratio varactor. The varactor includes interdigitated anode and cathode patterns laid out on a single thin epitaxial layer. The punch through voltage of the epitaxial layer, and hence the resistivity-thickness product of the epitaxial layer, must be low. Since the substrate is semi-insulating, punch through to the substrate does not become uncontrollable, but simply permits modulation of the capacitance over a very wide range. The FETS are formed in the same epitaxial layer with the varactor, and complicated doping profiles are not required.