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Frequency drift

About: Frequency drift is a research topic. Over the lifetime, 5054 publications have been published within this topic receiving 56191 citations. The topic is also known as: chirp rate.


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Patent
14 Jul 2006
TL;DR: In this article, an adaptive frequency calibration unit employing an N-target algorithm for a high speed automatic frequency calibration for CDMA application is provided, which includes a reference frequency divider dividing an output frequency of a temperature compensated crystal oscillator (TCXO), a feedback frequency dividers dividing output frequencies of a prescaler, and a frequency comparator comparing a frequency with the reference function divider output and the feedback function dividers output.
Abstract: An adaptive frequency calibration unit employing an N-target algorithm for a high speed automatic frequency calibration for CDMA application is provided. The adaptive frequency calibration device calibrating a frequency of a voltage controlled oscillator (VCO) bank of a phase-locked loop (PLL), the adaptive frequency calibration device includes: a reference frequency divider dividing an output frequency of a temperature compensated crystal oscillator (TCXO); a feedback frequency divider dividing an output frequency of a prescaler; a frequency comparator comparing a frequency with the reference frequency divider output and the feedback frequency divider output; and a state machine providing a predetermined bit with a predetermined frequency resolution for the VCO to calibrate the frequency of the VCO bank using the frequency comparison result. Accordingly, it is possible to reduce power consumption and have a small silicon region by designing the adaptive frequency calibration device using the TCXO input and the prescaler output. In addition, a short switching time, phase noise reduction, and low power consumption can be achieved.

19 citations

Journal ArticleDOI
TL;DR: In this article, a temperature-controlling AFC system was developed to realize high-frequency stability with semiconductor lasers, and the frequency drift in DC operation can be reduced to below 1 MHz peak-to-peak.
Abstract: A temperature-controlling AFC system has been developed to realise high-frequency stability with semiconductor lasers. The frequency drift in DC operation can be reduced to below 1 MHz peak-to-peak. When necessary, the laser frequency can be modulated directly in the AFC state while the centre frequency is kept stabilised within 3 MHz. A heterodyne experiment was also performed using two frequency stabilised lasers; a stable IF output could be obtained for 10 min.

19 citations

Proceedings ArticleDOI
22 May 2016
TL;DR: This paper presents a 13.5-MHz low-power, RC on-chip relaxation oscillator with split-capacitor technique for RFID application that implements only one comparator and one reference voltage to minimize power consumption and silicon area.
Abstract: This paper presents a 13.5-MHz low-power, RC on-chip relaxation oscillator with split-capacitor technique for RFID application. This oscillator implements only one comparator and one reference voltage to minimize power consumption and silicon area. A loop delay variation cancellation technique that employs an integrator loop and a split-capacitor architecture helps attained the temperature stability in the proposed oscillator. The proposed design is fabricated in 0.18-μm CMOS process. The relaxation oscillator consumes 48.8 μW at 1.8-V power supply. The measurement results show that the circuit can generate a stable frequency of 13.5 MHz. The output frequency variation is less than ±0.5% of temperature range from −30° C to 120° C, and the supply voltage variation coefficient is 0.5%/V across 1.5 V to 2.1V supply voltage.

19 citations

Journal ArticleDOI
TL;DR: The VCO topology exhibits a very wide tuning range from few Hz to 368.9 MHz and features the rapid voltage swing and the 48% duty cycle with good transient characteristics which is difficult to get from the conventional oscillator.
Abstract: design for a voltage-controlled ring oscillator (VCO) is presented. The design allows an implementation of low frequency ring oscillator using relatively small devices and less stage. It is implemented using .18um technology provided by TSMC technology using 3.3V power supply. The VCO topology exhibits a very wide tuning range from few Hz to 368.9 MHz. It also features the rapid voltage swing and the 48% duty cycle with good transient characteristics which is difficult to get from the conventional oscillator. Its power dissipation at the maximum oscillation frequency is 35.05 mW. A frame work for modeling the phase noise in complementary metal-oxide-semiconductor (CMOS) ring oscillators. Phase noise for simulated circuit is -88dbc when offset frequency is 10 5 HZ.

19 citations

Patent
10 Aug 2007
TL;DR: In this paper, the authors present a method for tuning a frequency of a crystal oscillator from a nominal frequency via a switched-capacitor frequency tuning circuit, which can have switchable sections to adjust the tuning of the crystal oscillators.
Abstract: Embodiments feature techniques and systems for analog and digital tuning of crystal oscillators. In one aspect, some implementations feature a method for tuning a frequency of a crystal oscillator that can include adjusting the tuning frequency of the crystal oscillator from a nominal frequency via a switched-capacitor frequency tuning circuit, the switched-capacitor frequency tuning circuit can have switchable sections to adjust the tuning of the crystal oscillator. The method can include controlling an analog control input that is coupled to a varactor within each of the switchable sections, where each of the switchable sections can include a fixed capacitor in series with the varactor and a switch. The method can involve controlling a digital control input, where the digital control input can electrically connect or disconnect one or more of the switchable sections from the crystal. There can be independent control between the digital and analog tuning mechanisms.

19 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202217
202150
202059
201963
201887