摘要:
An antenna for receiving and/or transmitting circularly and linearly polarized RF signals includes a circularly polarized radiation element and a linearly polarized radiation element. The radiation elements are disposed co-planar and spaced apart from each other on a pane of glass. The linearly polarized radiation element is fed with a phase-shifted signal line. A ground plane is disposed parallel to the radiation elements to sandwich a dielectric of air. The antenna produces the effect of tilting a radiation beam from a higher to a lower elevation angle to achieve a higher gain at lower elevation angles.
摘要:
An apparatus, system and method are provided for low-latency start-up of a free-running harmonic oscillator. The exemplary apparatus embodiment comprises a first and second current sources to generate first and second currents; a bias current monitor adapted to detect a magnitude of the second current and to provide a control signal when the magnitude of the second current is equal to or greater than a predetermined magnitude; and a bias controller adapted to switch the first current from the oscillator and to switch the second current to the oscillator in response to the control signal. a reference voltage generator, a comparator, and a bias controller. Exemplary embodiments include reference voltage generator, a comparator, and a bias controller.
摘要:
Exemplary embodiments of the invention provide a system, method and apparatus for frequency calibration of a free-running, reference harmonic oscillator. An exemplary system comprises the harmonic oscillator, a frequency divider, a comparator, and a reactance modulator. The reference harmonic oscillator includes a plurality of switchable reactance modules controlled by corresponding coefficients, and provides an oscillation signal having an oscillation frequency, which is divided or multiplied by the frequency divider to provide an output signal having an output frequency. The comparator compares the output frequency to an externally supplied reference frequency using first and second predetermined levels of discrimination, and provides first or second comparison signals when the output frequency is higher or lower than the reference frequency. The reactance modulator determines a plurality of coefficients to control switching of the plurality of switchable reactance modules to increase or decrease a reactance of the oscillator in response to the first and second comparison signals.
摘要:
An antenna for receiving and/or transmitting circularly and linearly polarized RF signals includes a circularly polarized radiation element and a linearly polarized radiation element. The radiation elements are disposed co-planar and spaced apart from each other on a pane of glass. The linearly polarized radiation element is fed with a phase-shifted signal line. A ground plane is disposed parallel to the radiation elements to sandwich a dielectric of air. The antenna produces the effect of tilting a radiation beam from a higher to a lower elevation angle to achieve a higher gain at lower elevation angles.
摘要:
In various embodiments, the invention provides a frequency controller to control and provide a stable resonant frequency of a clock generator and/or a timing and frequency reference. Such stability is provided over variations in a selected parameter such as temperature and fabrication process variations. The various apparatus embodiments include a sensor adapted to provide a signal in response to at least one parameter of a plurality of parameters; and a frequency controller adapted to modify the resonant frequency in response to the second signal. In exemplary embodiments, the sensor is implemented as a current source responsive to temperature fluctuations, and the frequency controller is implemented as a plurality of controlled reactance modules which are selectively couplable to the resonator or to one or more control voltages. The controlled reactance modules may include fixed or variable capacitances or inductances, and may be binary weighted. Arrays of resistive modules are also provided, to generate one or more control voltages.