Topic
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.
Papers published on a yearly basis
Papers
More filters
Patent•
17 Jan 1983
TL;DR: In this paper, a high frequency electronic ballast which comprises a variable frequency oscillator having its frequency controlled by inputs (10 to 15) is presented. But the oscillator output is a source for a transformer or choke which directly drives a gas discharge lamp.
Abstract: A high frequency electronic ballast which comprises a variable frequency oscillator (1) having its frequency controlled by inputs (10 to 15). The oscillator (1) providing complementary outputs (16, 17) which controls an inverter (4) via a driver circuit (3). The inverter output is a source for a transformer or choke (5) which directly drives a gas discharge lamp (6). In this way the frequency of operation and hence the illumination of the lamp (6) can be changed by changing the driver (3) frequency by direct control (10 to 15) of the oscillator (1) and the lamp voltage is maintained substantially constant while reducing its current flow.
36 citations
Patent•
19 Oct 2006TL;DR: In this article, a variable frequency multi-phase oscillator for providing multiphase signals is described. But the frequency and duty cycles of the multiphased signals are adjustable.
Abstract: A variable frequency multi-phase oscillator for providing multi-phase signals is disclosed. The variable frequency multi-phase oscillator includes a correlator, a plurality of delay cells, and a NOR circuit. Each delay cell includes a current supply, a capacitor, a comparator, a switch, and a logic unit. The plurality of delay cells generate the multi-phase signals that are phase correlated within a large frequency range. The frequency and duty cycles of the multi-phase signals are adjustable.
36 citations
TL;DR: In this article, a peculiar microwave quasi-periodic pulsation (QPP) accompanying a hard X-ray (HXR) QPP of about 20 s duration occurred just before the maximum of an X6.9 solar flare on 2011 August 9.
Abstract: A peculiar microwave quasi-periodic pulsation (QPP) accompanying a hard X-ray (HXR) QPP of about 20 s duration occurred just before the maximum of an X6.9 solar flare on 2011 August 9. The most interesting aspect is that the microwave QPP consists of millisecond timescale superfine structures. Each microwave QPP pulse is made up of clusters of millisecond spike bursts or narrowband type III bursts. There are three different frequency drift rates: the global frequency drift rate of the microwave QPP pulse group, the frequency drift rate of the microwave QPP pulse, and the frequency drift rate of individual millisecond spikes or type III bursts. The physical analysis indicates that the energetic electrons accelerating from a large-scale highly dynamic magnetic reconnecting current sheet above the flaring loop propagate downward, impact the flaring plasma loop, and produce HXR bursts. The tearing-mode (TM) oscillations in the current sheet modulate HXR emission and generate HXR QPP; the energetic electrons propagating downward produce Langmuir turbulence and plasma waves, resulting in plasma emission. The modulation of TM oscillation on the plasma emission in the current-carrying plasma loop may generate microwave QPP. The TM instability produces magnetic islands in the loop. Each X-point will be a small reconnection site and will accelerate the ambient electrons. These accelerated electrons impact the ambient plasma and trigger the millisecond spike clusters or the group of type III bursts. Possibly, each millisecond spike burst or type III burst is one of the elementary bursts (EBs). A large number of such EB clusters form an intense flaring microwave burst.
36 citations
Patent•
20 Oct 2003
TL;DR: In this paper, a torsion oscillator is stabilized in operation by determining the current resonant frequency, observing the oscillator for change in resonant frequencies, and restoring the amplitude and median offset without changing the drive frequency.
Abstract: A torsion oscillator (FIG. 1 ) is stabilized in operation by determining the current resonant frequency ( 62 ); in a first procedure, observing the oscillator for change in resonant frequency ( 64 ), and then restoring the amplitude and median offset ( 66 ) without changing the drive frequency. In an alternative procedure, after determining the resonant frequency ( 62 ); setting the drive frequency close to but offset from the current resonant frequency ( 74 ), observing the oscillator for change in resonant frequency ( 76 ), and the restoring the close offset to the changed resonant frequency ( 78 ). By operating slightly off peak, the direction of resonant change is immediately known. The first procedure has less difficulties in implementation, but requires more power.
36 citations
12 Jun 1973
TL;DR: In this article, a very high stability microwave oscillator system was developed which has a high Q superconducting cavity as its frequency determining element and an intermediate frequency discriminator is used to produce a feedback voltage which maintains the oscillator at the center of the cavity resonance.
Abstract: : A very high stability microwave oscillator system was developed which has a high Q superconducting cavity as its frequency determining element. In stabilized oscillator (SCSO), the rf power is generated by a Gunn-Effect oscillator whose frequency is electronically tuned by a varactor diode. An intermediate frequency discriminator is used to produce a feedback voltage which maintains the oscillator at the center of the cavity resonance. An improved stabilization system is now reported which has higher short term stability.
36 citations