Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.

Compact, low-power chip-scale atomic clock

Abstract: We have successfully demonstrated a compact atomic frequency standard, the Chip-Scale Atomic Clock (CSAC), which achieves aggressive reductions in size and power while preserving good short-term stability. The device, based on Coherent Population Trapping (CPT), achieved volume less than 1 cm3, power consumption below 30 mW, and an Allan Deviation less than 1 times 10-11 (1 hour). This device incorporated a novel dual-pass reflective optical configuration based on a microstructured dual focus optic. Compact, low-power control electronics were developed based on an injection-locked voltage controlled oscillator (VCO) circuit. This approach enabled the combined power consumption of the VCO and microcontroller-based control electronics to be kept below 15 mW.

Microwave oscillator with noise degeneration feedback circuit

Abstract: A microwave oscillator is shown to include an oscillator having an output and a control port and a feedback circuit disposed between the output and the control port of the oscillator. The feedback circuit includes a modulated laser, having an input and an output, the input responsive to a portion of a signal from the output of the oscillator and a photo detector having an input and an output, the input of the photo detector responsive to a signal from the output of the modulated laser delayed by a predetermined amount of time. The feedback circuit further includes a detector having a first and a second input and an output, the first input of the detector responsive to a signal from the output of the photo detector, the second input responsive to a portion of the signal from the output of the oscillator shifted in phase to be in phase quadrature with the signal at the first input of the detector and the output of the detector coupled to the control port of the oscillator. With such an arrangement, a microwave oscillator having improved FM noise performance than known microwave oscillators is provided.

Phase locked loop lock detector including loss of lock and gain of lock detectors

Abstract: A phase lock detector circuit for detecting the lock state of a phase locked loop (PLL) such that it is known when a synthesized clock has achieved a stable phase relationship with its reference clock signal. The PLL includes an input for receiving the reference signal, a digital phase detector, a voltage controlled oscillator, and a frequency divider. The phase lock detector of the present invention includes a loss of lock detector (LOLD) connected to the frequency divider, the phase detector and the input. The LOLD detects the occurrence of a selected phase difference between the reference signal and an output of the frequency divider for a selected number of cycles. Also included is a gain of lock detector (GOLD) connected to the frequency divider and the input. The GOLD detects the occurrence of the reference signal within a selected phase difference of an output of the frequency divider for a second selected number of cycles. The outputs of the LOLD and the GOLD are connected to a latch for generating a composite signal responsive to signals generated by the LOLD and the GOLD such that the composite signal has a first state indicating when the PLL is in a locked condition and a second state indicating when the PLL is in an unlocked condition. The phase differences and the selected number of cycles of the LOLD and GOLD may be programmed, as desired.

Voltage detecting apparatus with voltage controlled oscillator and battery state control system

Abstract: In a voltage detecting apparatus, a voltage controlled oscillator, when an input voltage is applied thereto, outputs a signal with a logical value that is periodically inverted. A detector counts a number of logical inversion of the output signal from the voltage controlled oscillator over an interval between edges of pulses of a pulse signal to thereby generate, based on the counted number of logical inversion, digital data as a detected result of the input voltage. A determiner determines whether a reduction of a time required to detect the input voltage is higher in priority than an increase of a resolution of detection of the input voltage. A variably setting unit variably sets a frequency of the pulse signal based on a result of the determination of whether the reduction of the time required to detect the input voltage is higher in priority than the increase of the resolution of detection of the input voltage.

Electro-acoustic hybrid integrated circuit and manufacturing method thereof

Abstract: An electro-acoustic hybrid integrated circuit such as a voltage controlled oscillator wherein a semiconductor substrate (1) having an active element is bonded directly to a surface acoustic wave resonator or a quartz oscillator as an electro-acoustic element by using silicon or silicon compound films formed on the semiconductor substrate and on the electro-acoustic element. This structure can be used for a high frequency circuit to be used for movable body communication or the like. The hybrid integrated circuit is small, light and has good productivity.