Abstract:
The present invention relates to a two-frequency switchover type crystal oscillator in which first and second IC chips and first and second crystal resonators are connected to wiring patterns of a circuit substrate to form first and second oscillation circuits, and the first and second oscillation circuits are selectively operated in accordance with a selection mechanism; a two-frequency switchover type crystal oscillator in which surfaces opposite to circuit function surfaces of the first and second IC chips are connected to form a two-stage structure; IC terminals of the circuit function surface of the first IC chip are directly connected both electrically and mechanically to the wiring patterns; and IC terminals of the circuit function surface of the second IC chip are connected electrically by wire bonding to the wiring patterns; wherein those wiring patterns of the wiring patterns that are connected to power source, output, and ground terminals of the first and second IC chips are connected in common with respect to the first and second oscillation circuits. This configuration reduces the mounting surface area of the first and second IC chips, facilitating the wiring patterns thereof, thus making it possible to provide a two-frequency switchover oscillator in which the surface area of the external plan view is reduced.
Abstract:
In various embodiments, the invention provides a clock generator and/or a timing and frequency reference using an LC-oscillator topology, having a frequency controller to control and provide a stable resonant frequency, which is integrated with other, second circuitry such as a processor or controller. Frequency 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.
Abstract:
A voltage controlled oscillator of the present invention includes power supply terminal (101), control terminal (2) for controlling an output frequency, output terminals (3a, 3b), cross-coupled transistors (5a, 5b), capacitances (6a, 6b, 7a, 7b), LC tanks (10a, 10b), resistor (117), grounding capacitance (18) and center frequency control circuit (16). Center frequency control circuit (16) includes resistors (11a, 11b), grounding capacitance (12), center frequency control terminal (4) for controlling a center frequency of the output frequency, and voltage-divider circuit (15). Resistors (11a, 11b) are connected to the base terminals of cross-coupled transistors (5a, 5b), the other ends of resistors (11a, 11b) are connected to each other, and, to this connecting point, one end of grounding capacitance (12) and one end of voltage-divider circuit (15) are connected. The other end of voltage-divider circuit (15) is connected to center frequency control terminal (4).
Abstract:
A frequency adjustable surface acoustic wave oscillator uses circuitry in which the phase relationship between the corresponding input and output signals and the voltage applied to or received by transducer fingers is controlled in such a manner that the frequency of the surface acoustic wave oscillator is arbitrarily controlled over a wide range by digital means. This provides an oscillator that exhibits a wide tunable frequency range while providing low phase noise.
Abstract:
A system and apparatus for varactor bank switching for a voltage controlled oscillator, is disclosed. Varactor bank switching involves partitioning a varactor bank switch into two anti-parallel branches, wherein each branch comprises a pass-gate circuit that is series-connected to a fixed varactor or capacitor; and maintaining an output common mode voltage of an actual oscillator signal at the varactor-side terminal of each pass-gate circuit, such that a threshold voltage of the switch transistor in the pass-gate circuit is not exceeded and the switch remains in an off-state.
Abstract:
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.
Abstract:
An oscillator, a PLL circuit, a receiver and a transmitter that allow the circuit scale to be reduced and that are suitable for integration. The electrostatic capacities of variable capacitance circuits 230, 230A are made variable, thereby varying the oscillation frequency of a voltage controlled oscillator 21. The variable capacitance circuit 230 comprises a plurality of variable capacitance elements 60-64 the electrostatic capacities of which can be continuously varied by use of a control signal; a plurality of capacitors 50-54 which are associated with the respective variable capacitance elements and the electrostatic capacities of which are fixed; and a plurality of switches 71-74, 81-84 that individually switch combinational circuits, each of which comprises one of the plurality of variable capacitance elements 60-64 and a respective associated one of the plurality of capacitors 50-54, for selective connections.
Abstract:
A circuit for providing an A.C. signal including a number N of nanomagnetic oscillators, N being an integer greater than or equal to 2, each nanomagnetic oscillator providing a periodic signal; a unit for providing a control signal that can take N values, each periodic signal being associated with one of the values of the control signal; and a multiplexer receiving the N periodic signals and the control signal and providing the A.C. signal equal to one of the periodic signals according to the value of the control signal.
Abstract:
The voltage controlled oscillator (VCO) circuit comprises a tank circuit, a first tuning section comprising first capacitor elements wherein each one of the first capacitor elements is individually utilizable for the tank circuit, and a second tuning section comprising second capacitor elements wherein each one of the second capacitor elements is individually utilizable for the tank circuit and the capacitance of each one of the second capacitor elements is continuously adjustable in a predetermined capacitance range in dependence on a tuning voltage.
Abstract:
A gain compensator compensates for the gain variation of a varactor-tuned voltage tuned oscillator (VCO) in a phase lock loop (PLL). The VCO includes a parallel LC circuit having multiple fixed capacitors that can be switched-in or switched-out of the LC circuit according to a capacitor control signal to perform band-select tuning of the VCO. The gain compensator compensates for the variable VCO gain by generating a charge pump reference current that is based on the same capacitor control signal that controls the fixed capacitors in the LC circuit. The gain compensator generates the charge pump reference current by replicating a reference scale current using unit current sources. The number of times the reference scale current is replicated is based on the fixed capacitance that is switched-in to the LC circuit and therefore the frequency band of the PLL. The reference scale current is generated based on a PLL control that specifics certain PLL characteristics such as reference frequency, loop bandwidth, and loop damping. Therefore, the reference pump current can be efficiently optimized for-changing PLL operating conditions, in addition to compensating for variable VCO gain.