摘要:
An oscillator circuit (100) comprises a first, high-Q crystal oscillator (10) and a second, low-Q oscillator (20) arranged for kick-starting the crystal oscillator (10) at switch-on by coupling the second oscillator (20) to the first oscillator (10) for a time period. The oscillator circuit (100) is arranged to select the frequency of the second oscillator (20) by placing the second oscillator in a phase locked loop with the first oscillator (10) providing a reference frequency, and adjusting the frequency of the second oscillator (20) towards the frequency of the first oscillator (10).
摘要:
Doubly-clamped nanowire electromechanical resonators that can be used to generate parametric oscillations and feedback self-sustained oscillations. The nanowire electromechanical resonators can be made using conventional NEMS and CMOS fabrication methods. In very thin nanowire structures (sub-micron-meter in width), additive piezoresistance patterning and fabrication can be highly difficult and thus need to be avoided. This invention shows that, in piezoresistive nanowires with homogeneous material composition and symmetric structures, no conventional and additive piezoresistance loops are needed. Using AC and DC drive signals, and bias signals of controlled frequency and amplitude, output signals having a variety of frequencies can be obtained. Various examples of such resonators and their theory of operation are described.
摘要:
An integrated oscillator circuit comprises an oscillator configured to be switched between a first frequency and a second frequency. A switching circuit receives an input representing a target frequency and switches the oscillator between the first and second frequencies at intervals determined by the input, so as to cause the average output frequency of the oscillator to approximate the target frequency.
摘要:
A clock generator includes, in part, a buffer, a peak detector and a control logic. The buffer generates a clock output signal in response to receiving a clock signal and a feedback signal that controls the gain of the buffer. If the peak detector detects that the amplitude of the output signal is higher than the upper bound of the predefined range, the gain value applied to the variable buffer is decreased. If the peak detector detects that the amplitude of the output signal is lower than the lower bound of the predefined range, the gain value applied to the variable buffer to increased. If the peak detector detects that the amplitude of the output signal is within the predefined range, no change is made to the gain value applied to the variable buffer. The control logic generates the feedback signal in response to the peak detector's output signal.
摘要:
An oscillator circuit is described comprising a piezoresistive resonator and a phase changing devices. Oscillator circuits with piezoresistive resonators do have the advantage that they can perform self-sustaining oscillation without additional active devices as e.g. transistors since they can be used as amplifiers. Phase changing devices as capacitors, coils and further piezoresistive resonator are used in order to compensate the π/2 phase shift of the piezoresistive resonator.
摘要:
A module for a surface acoustic wave oscillator includes a substrate having a top surface, a bottom surface and peripheral side faces. Several castellations are located about the outer peripheral side faces thereof. The castellations form an electrical connection between the top and bottom surfaces of the substrate. Connection pads are mounted on the top surface and are adapted for connection to the castellations. An oscillator circuit and a surface acoustic wave device are mounted on the top surface and connected to the connection pads. A cover is mounted over the substrate and has at least one tab adapted to be fitted within a respective one of the castellations. The overall module with the cover has a dimension of approximately 5mm in width, 7mm in length, and 2.7mm in height.