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.

Abstract: A high-frequency circuit device includes a varactor diode having a first terminal and a second terminal, a first strip line connected to the first terminal of the varactor diode, a voltage being applied to the varactor diode via the first terminal, a second strip line having a first end connected to the second terminal of the varactor diode, and a second open end. The second strip line has a length so as to obtain an equivalent strip line length taking into capacitances of the varactor diode and the second strip line. The equivalent strip line length determines a characteristic of the high-frequency circuit device.

Abstract: A dual voltage controlled oscillator including a transistor with a negative differential resistance diode coupled to a first terminal and an inductance coupled to a second terminal. Operating voltages are applied to the gate and drain of the transistor to set the oscillator to operating in a negative differential resistance region of the diode. The diode, the inductance and the operating voltages are connected so that varying either of the operating voltages varies the frequency of the oscillations at the output.

Abstract: In order to improve the phase noise and the temperature stability of a dielectric resonator oscillator, the cylindrical dielectric resonator which is important for the oscillation frequency is mounted on the substrate standing on its curved surface rather than lying on its end face, as conventionally customary. It is coupled to the RF lines in a higher mode (TM.sub.xxx mode) rather than in the fundamental mode (TE.sub.01.delta. mode).

Abstract: The circuit employs two bipolar transistors, five resistors and a capacitor and can be primarily utilized as a broadband pre-amplifier and also as an oscillator or a mixer. A first transistor is connected to the circuit input and ground. A second transistor is connected to the collector of the first transistor and the supply voltage. One circuit output is connected to the second transistor. Another circuit output is connected to the first transistor via a resistor. The emitter of the first transistor is connected to the second transistor via a second resistor. A third resistor is connected between the base and collector of the first transistor. A fourth resistor is connected between the base and collector of the second transistor.

Abstract: A microwave oscillator includes a substrate having a circuit pattern on the top surface, a thin copper foil covering the bottom surface, and a hole. An electronic component is mounted to the top surface of the substrate. A metal plate is attached to the bottom surface of the substrate thereby closing the bottom of the hole. A dielectric resonator is attached to the metal plate through the hole. Since the dielectric resonator is attached to the metal plate by soldering, the bond between the dielectric resonator and the metal plate is stronger and more stable than that achieved by using a conventional adhesive. This enhances the reliability against temperature changes; mechanical impact or humidity.

Abstract: A monolithically integrated oscillator is implemented as ring oscillator with a line driver and a double line formed on one and the same chip. A running time of the double line is selected optimally long and a delay time of the line driver is selected optimally short. The double line can be loaded with controllable capacitors.

Abstract: An oscillator (100) includes a tank circuit (102) coupled to a an active circuit (108). The feedback (104) provides the necessary feedback between the tank and the active circuit necessary for oscillation. The active circuit (108) is biased via a biasing circuit (106) and coupled out to a load via an external coupling (110). The active circuit (108) includes two transistors (124, 126) coupled to each other in a cascode configuration. Transistor (126) provides the collector current for transistor (124) while preventing it from entering saturation prematurely. The biasing circuit (106) provides sufficient current drain for the transistor (126) in order to provide for optimum phase noise and bandwidth performance of the oscillator 100.

Abstract: A split dielectric resonator having two preferably half cylindrical dielectric elements is used to stabilize an oscillator operating at microwave frequencies. Fine tuning may be achieved by means of a tuning screw which has a thermal expansion coefficient between those of the dielectric elements and electrically conductive supporting walls. Additionally, fine tuning may be achieved by offsetting the two elements from each other within a horizontal or vertical plane. This oscillator can also be configured as an accelerometer or pressure or displacement sensor by substituting a movable deflecting member for the supporting wall.

Abstract: A monolithic microwave oscillator using a negative resistance cell includes a resonator, a negative resistance cell that employs an active device, an output buffer for voltage and current amplification, and a field effect transistor. The negative resistance cell includes a bipolar junction transistor as its active device, with the output buffer circuit coupled to a base of the BJT through the field effect transistor. The combination of the resonator and the negative resistance cell produce a periodic RF microwave signal that is sampled, amplified and buffered by the buffer circuit without degradation.

Abstract: An inexpensive voltage control type oscillator suitable for use with a mobile radio communication system within a predetermined frequency band range. The oscillator includes a resonance circuit and an oscillation stage formed on a printed wiring board and operating such that the oscillation frequency of the oscillation stage is varied within a predetermined frequency band range by varying the resonance frequency of a parallel resonance circuit included in the oscillation stage on the basis of a control voltage. The parallel circuit comprises a strip line connected in series with a bias resistor and a chip capacitor connected parallel to the strip line. The strip line has an inductance sufficiently larger than that of the resistor and the chip capacitor has a capacitance value so determined that the capacitor resonates at a predetermined frequency in cooperation with the strip line.

Abstract: The object of the invention is a voltage controlled oscillator with improved tuning linearity, which comprises an oscillating transistor (T, 1), a resonator circuit (C11, C12, 11, 12, 19, 20) formed by a capacitance diode (D, 20) and an inductance (L1, 19), whereby the resonator circuit is connected to one of the transistor's (T, 1) electrodes and defines together with the transistor's internal capacitance and external capacitances the oscillator output frequency provided by the transistor. The output frequency can be changed with an external control voltage (V.sub.cntrl) supplied to the cathode of the capacitance diode (D, 20), the control voltage having minimum and maximum values, whereby the oscillator output frequency (f.sub.vco) is arranged to change within a certain frequency band in accordance with the control voltage (V.sub.cntrl). The resonance circuit (RES) is arranged at the current draining electrode (collector) of the transistor to have an effect on the linearity between the control voltage (V.

Abstract: A printed circuit board includes an oscillator and a modulator. The oscillator includes a first printed inductor and a capacitive diode which are printed on one side of the printed circuit board. The modulator includes a second printed inductor coupled to the first printed inductor and printed on the same side of the printed circuit board as the oscillator. A conductive surface at a reference potential is arranged the other side of the printed circuit board and in the vicinity of the oscillator and the modulator and electrically coupled to the oscillator and the modulator using conductive through holes.

Abstract: An impedance adjustment capacitor connected in parallel to a choke coil formed by a conductive pattern formed on a substrate adjusts the impedance of a control voltage applying circuit. A control voltage is applied via the choke coil to a variable capacitance diode included in a resonance circuit. This control voltage determines a resonance frequency.

Abstract: An oscillator (100) includes a resonator (218) having a mirco-strip (217). The micro-strip (217) couples an inductive component (221) to a capacitive portion (219). To tune the oscillator (100), a number of cuts are made on the pad (221) in order to restrict the signal flow. The width of these cuts determine the degree of restriction posed on the signal flow. This controllable restriction of the signal flow provides the circuit (100) with enhanced tunability.

Abstract: An oscillator (200) with improved sideband noise is disclosed. This improvement is accomplished without affecting the Q or the output power of the oscillator (200). The improvement is realized by increasing the rate of change of reactance over frequency. The increase in the rate of change is realized by placing two transmission lines (208, 210) in close proximity of each other. This increase assures oscillation while minimizing the sideband noise, and providing maximum bandwidth.

Abstract: An oscillator arranged to operate at an oscillation frequency includes a resonant structure 137, preferably a coaxial resonator, selected to resonate at a frequency, and an impedance 210, preferably a transistor 101 based common collector circuit, parallel coupled to said resonant structure 137, having a negative real part with a real magnitude and an imaginary part with an imaginary magnitude, said real magnitude being a function of said imaginary magnitude, said imaginary magnitude selected such that said real magnitude falls within 50% of a maximum at the oscillation frequency.

Abstract: A voltage-controlled microwave oscillator having a field effect transistor (1) as an amplifier and having a varactor diode (2) as a frequency-determining element has high output power and a large enough frequency sweep in the microwave frequency range that S-parameter scatters of the active components have optimally little influence on the characteristic data of the oscillator. The varactor diode (2) is preceded by a tunable micro stripline filter (3) and the source electrode of the field effect transistor (1) is directly connected to ground in order to form a parallel feedback with the micro stripline filter (3).

Abstract: A CMOS coupled-tank oscillator for VLSI circuit applications is disclosed. The coupled-tank oscillator has two inverters coupled, input-to-output, by inductances that may be simply wires, and a capacitance acting in parallel with each inverter that may be, simply, the invert's gate capacitance. The invention permits 0.9-micron CMOS oscillators to produce high-frequency signals.

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.

Abstract: A microwave oscillator has a cavity which is excited with an active element. The phase noise characteristic of the oscillator is improved in that a frequency discriminator utilizes the same oscillator cavity. The waves transmitted and reflected by the cavity are measured, combined and detected by a pair of low noise diodes. The signals obtained are compared to produce a control signal for a phase shifter which is connected between the active element and the cavity. The cavity is preferably a dielectric resonator.

Abstract: A method of manufacturing a varactor circuit and a varactor circuit for tuning a dielectric resonator oscillator (DRO). The circuit pattern for the varactor circuit includes a minimum circuit pattern that is common to several circuit patterns for the varactor circuit that compensate for non-linearities in a connected non-linear varactor and provide the desired characteristics for the DRO. Other portions of the several circuit patterns are provided in isolated elements, each of which has a size and shape so that it does not resonate within the DRO's operating frequencies. The isolated elements are selectively connected to the minimum circuit pattern to form a suitable circuit pattern.

Abstract: In a microwave oscillation apparatus including a negative resistance element, a microstrip line having a first end connected to the negative resistance element and a second end connected to a terminating resistor, and a dielectric resonator magnetically coupled to the microstrip line, a capacitive stub is provided on the microstrip line at a distance (1/4) .lambda..sub.s (2N-1) from the first end thereof, where .lambda..sub.s is a wavelength of a spurious oscillation frequency component and N is a positive integer.

Abstract: A voltage controlled oscillating circuit is disclosed. The circuit includes: a .mu.-strip resonance circuit for deciding the resonance frequency in accordance with an external tuning voltage; an oscillation amplifying circuit for performing oscillations in accordance with the resonance frequency signals of the .mu.-strip resonance circuit; and a buffer amplifying circuit provided between the oscillating circuit and the load, and for preventing the load pulling phenomenon. The oscillation amplifying circuit forms a common collector oscillating circuit in with a single oscillation amplifying transistor, and the buffer amplifying circuit forms a single step amplifying circuit with a single buffer amplifying transistor. The oscillation amplifying transistor and the buffer amplifying transistor form a cascode amplifying transistor with a signal inducing coil and an RF choke coil for blocking the ac components and for forming a series of dc bias paths.

Abstract: A high-frequency oscillator is provided for a frequency range of 1.6 to 3 GHz. An oscillator stage includes an oscillator transistor and a voltage-controlled resonator unit. A buffer stage is connected at an output of the oscillator stage. The resonator unit includes an open resonator in the form of an etched structure with a wavelength which is shorter than lambda/4 (where lambda is an oscillator length). The resonator unit includes a voltage-controlled variable-capacitance diode, and a resonator terminal is connected between the voltage-controlled variable-capacitance diode of the resonator unit and the oscillator transistor of the oscillator stage. The resonator is preferably an open microstrip resonator, and the stages are disposed in a standardized housing in SMD (surface mounted device) technology.

Abstract: A voltage controlled push-push oscillator is provided having a variable frequency output over a range of frequencies. Usually, the range of frequencies is in the microwave range. The configuration is such that the collectors of a pair of transistors are tied together, and an inductive reactance is provided across the base and collector of each of the transistors, with the emitters of the pair of transistors being each connected to opposite phases (at the fundamental frequency) of a resonator which may comprise of one or more elements, bisected to provide an output tap at which an RF null at the fundamental frequency and an anti-null at the second harmonic exists, whereby the second harmonic output frequency of the push-push oscillator is derived. Particularly when the push-push oscillator operates at microwave frequencies, the resonator element is a microstrip line, having the output tap at the centre thereof.

Abstract: Low-power-dissipation CMOS oscillator circuits include inductors and capacitors forming tank circuitry. Cross-connected MOS devices provide positive feedback to replenish losses in the tank circuitry and thereby sustain oscillations. Each such oscillator circuit simultaneously generates complementary output sine-wave signals.

Abstract: A voltage controlled oscillator comprises more than one dissimilar diode. The dissimilar diodes have different capacitance versus voltage characteristic shapes. The dissimilarity causes the tuning gain factor of the resulting oscillator to be an increasing function of increasing frequency. Such an oscillator when properly incorporated into a phase lock loop can yield loop parameters which are a constant function of increasing frequency.

Abstract: The invention relates to a biased electronic circuit in which a voltage-controlled component has a characteristic with a non-linear portion and a substantially linear portion. The circuit is biased by a voltage being applied to one terminal of the component thereby shifting the operation of the component to the linear portion.

Abstract: A FET comprising two or more gate pads or terminals, and a reflection type oscillator including the above-mentioned FET. In this oscillator, a dielectric resonator is connected through a coupling line to the first gate pad of the FET and an output terminal is connected to the second pad. When the drain pad of the FET is connected to ground, and a suitable value of capacitive reactance is added to the source pad, then a negative resistance -R appears on the first gate pad, and thus oscillation occurs at a resonance frequency fo of the dielectric resonator. If the load resistance value viewed from the second gate pad is set to R, the maximum oscillation output occurs.

Abstract: A microwave oscillator circuit is provided for decreasing the number of passive elements such as inductance, etc. in microwave oscillators and frequency doublers. A microwave oscillator circuit is connected to a resonator circuit generating a signal at a frequency f, and produces at its output a signal of frequency nf, and comprises a first field effect transistor having a gate connected to the resonator circuit, a second field effect transistor whose source/drain path is connected in series with the source/drain path of the first field effect transistor and a connecting circuit for coupling either the gate or source of the first field effect transistor to the gate of the second field effect transistor. A signal of frequency nf is output at a node corresponding to a connection point between the source of the first field effect transistor and the drain of the second field effect transistor.

Abstract: An array of unit oscillators interconnected with one another in that the transistors of the oscillators are connected to common lines. Separate lines in proximity provide coupling capacitance for feedback to sustain the oscillation of the unit oscillators. The separate lines also form a grid which results in an antenna for emanation of the oscillators, radiation The array can effectively function at extremely high frequencies (i.e., greater than 30 GHz). The array is specially designed to accommodate monolithic implementation.

Abstract: A remote temperature sensor includes a microwave oscillator which generates n output signal having a frequency which is proportional to the temperature of the environment in which it is located. The oscillator includes a relatively high transition temperature superconducting (HTSC) ring coupled to a transistor in a plurality of microstrip line oscillator configurations including those of a reaction oscillator, a transmission oscillator, a reflection oscillator and a parallel feedback oscillator. The superconducting ring operates below its transition temperature and in so doing, acts as a high Q resonator whose resonant frequency is proportional to temperature.

Abstract: An improved oscillating circuit for use in microwave frequency bands has reduced power loss and is made smaller in vertical size. The local oscillating circuit includes an MMIC oscillator which comprises a FET, and a resonator connected thereto so as to stabilize the oscillating frequency of the oscillator. The resonator is ring-shaped and arranged as close as several .mu.m to several tens of .mu.m to a predetermined position of a micro strip line forming a feedback loop connected to the FET forming the oscillator. Moreover, the resonator is a thin film formed by depositing a high-temperature superconducting material. As exemplary embodiments, YBCO, niobium and the like, can be used as high-temperature superconducting materials. Furthermore, a portion of the micro strip line, closest to the resonator, is concentrically disposed therewith to form a circular arc portion whose central angle is set at 90 degrees.

Abstract: A fundamental or subharmonic optically injection locked oscillator is coupled to a phase locked loop circuit. The injection locked oscillator has two single stage HEMT amplifiers with parallel feedback from the drain of a second transistor to a gate of a first transistor. A feedback resonant network controls the oscillator frequency. A microwave/millimeter wave source modulates a laser diode and the signal from the laser diode is then transmitted via an optical fiber to a PIN photodetector diode. The signal from the photodetector diode is injected into the oscillator at an nth subharmonic of the oscillator frequency. The feedback network may consist of a microstrip gap resonator with two tuning varactors at the ends of the resonator. The phase locked loop includes a balanced mixer used as a phase detector to compare the nth harmonic of the signal from the photodetector diode to the sampled output of the oscillator.

Abstract: An oscillating circuit includes a substrate, a FET formed on the substrate, a series feedback capacitor connected to the source of the FET, a microstrip line formed on the substrate and connected to the gate of the FET, and a dielectric resonator which is electromagnetically coupled to the microstrip line. The dielectric resonator is located near the microstrip line.

Abstract: A push-push microwave oscillator has two branch oscillators fabricated of a transistor and transmission line elements extending from terminals of the transistor, and a resonator which is fabricated of an annulus of superconductor material and serves to phase lock oscillations of the two branch oscillators. The superconductor material is a composite of a rare earth element and copper oxide such as yttrium-barium-copper oxide. A first transmission line in each of the branch oscillators extends past the resonator with a spacing to provide for electromagnetic coupling between the branch oscillator and the resonator. A second transmission line in each of the branch oscillators has a length equal to approximately one-quarter wavelength of the oscillation frequency to tune the branch oscillator to a common oscillation frequency.

Abstract: In a voltage controlled oscillator, a dielectric resonator is mounted on a base of a conductive housing, and a dielectric substrate is secured to sidewalls of the housing in a position spaced from the dielectric resonator. A first stripline is secured to one surface of the substrate and electromagnetically coupled to the dielectric resonator, and an oscillating element is electrically connected to the first stripline. A second stripline is secured to the opposite surface of the substrate and capacitively coupled to the first stripline through the substrate. The second stripline is adapted to receive a frequency control voltage from an external circuit. A voltage-controlled variable capacitance element is secured to the substrate and electrically connected to the second stripline.

Abstract: A push-push oscillator including a resonator having a transmission line and a capacitance connected to the transmission line in parallel; an oscillating circuit responsive to the resonator for oscillating and for producing first and second outputs having an antiphase relation therebetween; an in-phase combining circuit for summing the first and second outputs of said oscillating circuit to produce a summed signal; and an antiphase combining circuit responsive to two components from the resonator having an antiphase relation for producing a differential signal in accordance with a difference between the two components. Alternatively, the in-phase combining circuit is connected to the resonator and the antiphase combining circuit is connected to the oscillating circuit. The antiphase combining circuit outputs a fundamental wave component of the resonator. The in-phase combining circuit outputs a second harmonic wave component.

Abstract: An oscillating apparatus comprising: an oscillator unit for oscillating in the microwave band; an output unit electromagnetically coupled to the outputting unit of the oscillator unit for taking an oscillation output outside; and an antenna element electromagnetically coupled to a part of the outputting unit, or a part of the output unit for radiating part of the oscillation output in an electromagnetic wave.

Abstract: The oscillating apparatus according to this invention includes a pulse doped FET 1, and a series feedback capacitor 2 connected to the source of the pulse doped FET 1. The pulse doped FET is a FET formed on a pulse doped epitaxial layer including a channel layer 23 with a high carrier density, and a cap layer 24 with a low carrier density formed on the channel layer 23. The series feedback capacitor 2 is a variable capacitor whose capacitance value increases when a gate bias voltage of the pulse doped FET 1 is changed to increase a drain current of the pulse doped FET 1. Consequently it is possible to reduce phase noises by controlling only the gate bias with an oscillation frequency set at a required value. As a result, the merits of the MMIC can be sufficiently utilized without the necessity of externally adding a dielectric resonator.

Abstract: A resonator (50) is connected in circuit with a negative resistance element (Q3,Q4) for producing oscillation at a resonant frequency of the resonator (50). A digital phase shifter (58) is incorporated into the resonant frequency in accordance with an applied digital signal. The resonator (50) can be connected in series with the negative resistance element (Q3), in which case the phase shifter (58) is connected as either a short-circuit or an open-circuit transmission line. Alternatively, the resonator (50) can be connected in parallel with the negative resistance element (Q4) in a feedback loop. An analog phase shifter (84) can also be provided in the resonator (50') for continuously variably setting the resonant frequency over the tuning increments of the digital phase shifter (58).

Abstract: A dielectric resonator oscillator having a resonant structure connected to an amplifier the output of which is fed back to the input of the resonant structure. The resonant structure includes a metal cavity in which a dielectric disk is centrally mounted by a low-loss dielectric post. A pair of microstrip transmission lines extend into the cavity to provide energy outputs and inputs. Dielectric and conductive tuning screws are mounted on the cavity walls. Electrical tuning is provided via a varactor diode whose bias is adjustable. The diode may be connected in series or parallel with the microstrip transmission line.

Abstract: The present invention resides in a push-push voltage controlled oscillator (VCO) utilizing parallel LC resonant tank circuits for improved phase noise characteristics. The push-push VCO of the present invention includes two voltage controlled oscillators connected in parallel and in phase opposition, with each oscillator including a transistor connected in series with the parallel LC resonant tank circuit. The oscillators operate at the same resonant frequency f.sub.0, but are 180 degrees out of phase. Therefore, the fundamental and odd harmonics of the resonant frequency f.sub.0 cancel each other out and the even harmonics add together to produce an output signal at twice the resonant frequency f.sub.0.

Abstract: A voltage controlled oscillator having a resonator wherein a substrate is made up of a plurality of dielectric layers; an inductor functioning conductive film and grounding electrode films are each formed at a boundary surface of one of the dielectric layers; the earth electrode films are arranged, in the direction in which the dielectric layers are laminated, at both sides of the conductor functioning conductive film; the inductor functioning conductive film and the grounding electrode films constitute the resonator; and electric lands are formed on the surface of the substrate so that other components of the oscillator are mounted on the surface of the substrate.

Abstract: A conducting plane resonator (10) is used to stabilize an oscillating means (12) typically operating at microwave frequencies. The conducting plane resonator (10) is in proximity to the oscillating means (12) and is magnetically coupled thereto. In a first implementation, the conducting plane resonator (10) is magnetically coupled to an input conductor (16) of the oscillating means (12). In a second implementation, the conducting plane resonator (10) is magnetically coupled to an output conductor (18), which is coupled to the oscillating means (12). In a third implementation, the conducting plane resonator (10) is magnetically coupled to both the input conductor (16) and the output conductor (18). The conducting plane resonator (10) preferably comprises a thin, substantially planar conducting plane and is dimensioned such that it is resonant at the desired operating frequency. The conducting plane resonator (10) is preferably fabricated of a superconductor material to achieve high-Q performance.

Abstract: YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres. A band reject filter is included inside the housing for rejecting second harmonics of desired oscillation frequencies only.

Abstract: For minimization of a microstrip line and improvement of a Q value, the line length and width of the microstrip line are minimized, and the high frequency trend of the resulting resonant frequency is lowered and corrected to the resonant frequency near the oscillation frequency of an oscillator by connecting an additional capacitance component to the microstrip line. Thereby, the minimization of the microstrip line or the minimization of an oscillation circuit and characteristics equivalent to a dielectric coaxial resonator may be readily obtained. The strip line and the additional capacitance component are made as one piece circuit elements. The microstrip line is connected with a stub such that the stub may be trimmed to adjust the oscillation frequency. A cascode connecting amplifier which lessens the oscillation frequency fluctuation due to load variations is used.

Abstract: An embodiment of the present invention is a voltage controlled oscillator (VCO) comprised of a differential pair of transistors that have respective positive feedback paths with phase-lead networks cross-coupled. Each positive feedback path on each side has two different phase-lead branches. The two phase-lead branches have the same phase differences on each side of the differential pair, in order to maintain a symmetry that improves common-mode noise rejection on a voltage control differential input. Current-steering is used to control the mixture of currents that arrive at the bases of the differential transistor pair from the respective two different phase-lead branches, and thereby changing the frequency of the VCO.

Abstract: An actively biased oscillator (200) includes a set of current sensing components (214,216) for sensing the amount of current flowing into the first terminal of the amplifier; and a differential amplifier (212) responsive to the current sensing components for automatically adjusting the amount of current flowing into the second terminal of the amplifier.