A one-coil multi-core inductor-capacitor (LC) oscillator is provided. The one-coil multi-core LC oscillator includes a main coil and at least one mode suppression device. The main coil includes an outer wire and a central wire, wherein the outer wire is coupled to a first core circuit and a second core circuit, and the central wire is coupled between a first node and a second node of the outer wire. More particularly, an outer loop formed by the outer wire corresponds to a first mode of the one-coil multi-core LC oscillator, and inner loops formed by the outer wire and the central wire correspond to a second mode of the one-coil multi-core LC oscillator, where the at least one mode suppression device is configured to suppress one of the first mode and the second mode.

An oscillator is provided. The oscillator includes two reverse amplification elements, and each of the reverse amplification elements forms a self-feedback structure by using an inductor. Output ends of the two reverse amplification elements are coupled to each other by using one or more inductors, and input ends of the two reverse amplification elements are coupled to each other by using a capacitor. A capacitance value of the capacitor may be adjusted, to change an oscillation frequency of a differential output oscillation signal output by the oscillator.

An oscillator configured to generate an oscillation signal is provided. The oscillator includes a transistor pair and a cross-coupled transistor pair. The transistor pair is coupled to a first current source and has a first transconductance. The first transconductance is changed in response to a current value of the first current source. The cross-coupled transistor pair is coupled to a second current source and has a second transconductance. The second transconductance is changed in response to a current value of second current source. The transistor pair and the cross-coupled transistor pair are mutually coupled by a plurality of inductors. A frequency of the oscillation signal is determined according to the first transconductance and the second transconductance. Furthermore, a clock generator and a method for generating a clock signal thereof are also provided.

An oscillator is provided. The oscillator includes two reverse amplification elements, and each of the reverse amplification elements forms a self-feedback structure by using an inductor. Output ends of the two reverse amplification elements are coupled to each other by using one or more inductors, and input ends of the two reverse amplification elements are coupled to each other by using a capacitor. A capacitance value of the capacitor may be adjusted, to change an oscillation frequency of a differential output oscillation signal output by the oscillator.

A synthetic crystal oscillator enables a conventional crystal to be replaced with purely active electronic elements. Stability and performance characteristics are shown to be comparable-to-superior to a conventional crystal oscillator with side-by-side simulations. The synthetic crystal oscillator with purely active electronic elements offers cost, miniaturization and performance benefits. In some examples, the purely active electronic elements include an RLC circuit generate multiple stable concentric oscillations associated with nonlinear resonance used as an oscillator without a conventional crystalline structure coupled to the electrical circuit.

A voltage controlled oscillator includes a variable capacitance circuit having a plurality of variable capacitance elements, each having a capacitance that is a function of a tuning voltage, two or more oscillator core circuits, each operable over a specified frequency band, and inductive elements connected between the variable capacitance circuit and the oscillator core circuits.

A voltage-controlled oscillator (VCO) having an operating frequency dependent on a total capacitance of selectable tuning capacitors can be fabricated within an integrated circuit (IC). The VCO can include active electronic devices fabricated within a set of lower layers of the IC and selectable tuning capacitors having electrically conductive structures separated by dielectric material fabricated within a set of upper layers of the IC. The upper layers of the IC are located above the set of lower layers of the IC. The VCO can also include a set of interconnect structures configurable to select a total capacitance of the selectable tuning capacitors by electrically interconnecting the first portion of the VCO to capacitors of the at least one selectable tuning capacitor.

A four-phase oscillator includes, a first oscillator configured to output a first differential signal, a second oscillator configured to output a second differential signal shifted in phase with respect to the first differential signal by 90 or 90 degrees, and a control circuit. The first oscillator includes a first tail current source and a second tail current source. The second oscillator includes a third tail current source and a fourth tail current source. The control circuit changes the frequency of the first and second differential signals by controlling at least one of a difference between a first current value supplied from the first tail current source and a third current value supplied from the third tail current source and a difference between a second current value supplied from the second tail current source and a fourth current value supplied from the fourth tail current source.

A voltage-controlled oscillator (VCO) having an operating frequency dependent on a total capacitance of selectable tuning capacitors can be fabricated within an integrated circuit (IC). The VCO can include active electronic devices fabricated within a set of lower layers of the IC and selectable tuning capacitors having electrically conductive structures separated by dielectric material fabricated within a set of upper layers of the IC. The upper layers of the IC are located above the set of lower layers of the IC. The VCO can also include a set of interconnect structures configurable to select a total capacitance of the selectable tuning capacitors by electrically interconnecting the first portion of the VCO to capacitors of the at least one selectable tuning capacitor.

A power oscillator using a GaN power amplifier, includes: the GaN power amplifier configured of a gallium nitride (GaN) element to amplify and output power of an input signal; a directional coupler for providing part of an output signal of the GaN power amplifier as a feedback signal; a phase shifter for changing a phase of the feedback signal provided by the directional coupler; and a first isolator for adjusting impedance mismatching generated by the phase shifter and transferring the feedback signal to the GaN power amplifier.