Abstract:
Certain aspects of the present disclosure provide a variable capacitor. The variable capacitor generally includes a semiconductor region, a dielectric layer disposed adjacent to the semiconductor region, and a first non-insulative region disposed above the dielectric layer, and a second non-insulative region disposed adjacent to the semiconductor region. In certain aspects, a doping concentration of the semiconductor region changes as a function of a distance across the semiconductor region from the dielectric layer or the second non-insulative region.
Abstract:
A voltage controlled oscillator (VCO) is disclosed. The VCO includes an active device. The VCO comprises an active device, wherein the active device further includes an n-type transistor having a drain, gate and bulk; a p-type transistor having a drain, gate and bulk. The n-type transistor and the p-type transistor share a common source. The active device further includes a first capacitor coupled between the gate of n-type transistor and the gate of p-type transistor; a second capacitor coupled between the drain of the n-type transistor and the drain of p-type transistor; and a third capacitor coupled between the bulk of n-type transistor and the bulk of p-type transistor. The VCO includes a tuning block coupled to the common source to form a common gate amplifier and at least one tuning element coupled to the active device for changing the overall capacitance of the VCO.
Abstract:
A plurality of varactors are coupled (102) via a first electrode to a shared terminal that in turn can operably couple (103) to a source of control voltage. A second electrode for each varactor couples (107) to a corresponding switch, where each switch couples to at least two different voltage levels. So configured, the second electrode of each varactor can be individually connected to either of two voltage levels. This can be leveraged to control, in coarse steps, the overall aggregate effective capacitance presented by these components. At least some of these varactors can have differing corresponding capacitances, the specific values of which can be selected in order to facilitate relatively equal spacing and substantially equal rates of reactance change versus the control voltage value between aggregate-capacitive reactance ranges as correspond to differing settings for the switches at various levels for the control voltage source.
Abstract:
Present invention relates to an oscillator circuit comprising: resonator means (102) and, first and second emitter followers (116, 118) being symmetrically coupled to the resonator means and been connected to further emitter followers (120, 122) for providing capacitive loading.
Abstract:
A frequency-adjustable oscillator (10) suitable for digital signal clock synchronization comprises a SAW oscillator circuit (12) for generating an analog controlled-frequency signal and a sinewave-to-logic level translator circuit (14, 114) in a double-sided package. (110) The SAW oscillator circuit (10) includes a tunable SAW resonator (16; 116), a gain stage (18) for energizing the SAW resonator (16; 116), a voltage-variable control input (122) for adjusting a frequency of the controlled-frequency signal, and a voltage-variable capacitive element (120) operably linked to the SAW resonator (16; 316) and responsive to the control input. The sinewave-to-logic level translator circuit (14; 114) is operably linked to the SAW oscillator circuit (10) and configured to generate a digital logic output signal (26) having substantially the same frequency as the controlled-frequency output signal. The double-sided package (110) includes a platform (211) with sidewalls extending substantially upwardly (235) to form a first cavity (215) adapted to receive and electrically connect the SAW resonator (16; 116) and sidewalls extending substantially downwardly (237) to form a second cavity (217) adapted to receive and electrically connect at least one electronic component. A cover (219) is coupled with the first cavity (215) to create an isolated environment for containing the SAW resonator (16; 116).
Abstract:
A feedback oscillator device formed with an integrated circuit having a semiconductor material substrate on a ground plane. The circuit has an amplifier having an input and an output is provided at least in part on said semiconductor material substrate. A directional coupler is used to couple the amplifier output signal to the amplifier input through a parallel separated transmission lines transfer system and a capacitor such as a varactor. The substrate can be of gallium arsenide.
Abstract:
A programmable capacitor array is used to trim the frequency of a crystal oscillator for initial offset. An apparatus includes the crystal oscillator and an integrated circuit (36) is coupled to the crystal (30) of the oscillator. The programmable capacitor array (32) is formed on the integrated circuit and is coupled to the crystal (30) and is responsive to a signal for setting the capacitance of the capacitor array to one of a number of capacitance values. A discrete controllable capacitance device (V03) not one the integrated circuit is coupled to the crystal (30) and is responsive to a control signal (AFC) to change its capacitance. The crystal oscillator frequency is dependent on the capacitances of both the programmable capacitor array (32) and the discrete capacitor (V03).
Abstract:
There is a manufacturing limit on how small ceramic coaxial resonators can be produced, which leads to a limit on the frequency of resonance for these resonators. One technique to double the effective frequency of a ceramic coaxial resonator is to couple each end of a resonator to a Colpitts oscillator, the oscillators being balanced and out-of-phase by 180 DEG . During operation, the resonator is effectively divided in half with a virtual ground forming in the center. This allows a single resonator to operate as two resonators of half the original size. Hence, the oscillation frequency for each of these balanced oscillators is doubled when compared to the frequency of similar oscillators that have separate ceramic coaxial resonators of similar size. If this technique is further implemented within a push-pull design tuned to the third harmonic, the output oscillation frequency becomes six times that of an oscillator using a separate ceramic coaxial resonator of similar size. This technique expands the range of use for a ceramic coaxial resonator so that, if used along side a subharmonically pumped mixer that allows for doubling of the local oscillator frequency, the maximum oscillation frequency is increased ideally to 60 GHz. This frequency range allows ceramic coaxial resonators to be used for high frequency applications such as LMDS.