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Topic: Low frequency oscillation


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  techn120203t
In the case of the low frequency oscillation appearance at the oil fuel combustion can be drawn into evidence uncontrollable variations of pressure in the fuel-supply system and in the combustion chamber, variations of the temperature in the combustion chamber or at the discharge nozzle, as well as variation of the fuel discharge oscillation.
High frequency oscillation can be noticed in the case of using some medium pressures at a high rate in the chamber and of some risen flow pressures, characterized by lower amplitudes, but of a risen frequency, of the pressure in the chamber of the rocket engine.
The registration of the instantaneous discharge in the low frequency band, in relation with the pressure variation in the chamber, illustrates the fact that for the low pressures there is a variation in phase of the discharge pressure.
www.bjkmf.hu /bszemle2003/techn120203t.html   (1216 words)

  
 Very low frequency   (Site not responding. Last check: 2007-10-01)
Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz.
Because VLF waves can penetrate water only to a depth of roughly 10 to 40 metres (30 to 130 feet), depending on the frequency and the salinity of the water, they are used to communicate with submarines near the surface.
This frequency range is subject to no control on the part of the international communications organization (International Telecommunication Union) and may be used in some states by license-free.
www.hallencyclopedia.com /Very_low_frequency   (803 words)

  
 Stabilization and Low-Frequency Oscillation of Capillary Bridges with Modulated Acoustic Radiation Pressure   (Site not responding. Last check: 2007-10-01)
In the presence of gravity (which causes a static distortion of a bridge from a cylindrical shape) the critical length is known to be even shorter.
In the work reported here it is demonstrated that acoustic radiation pressure may be used in simulated low gravity to produce stable bridges significantly beyond the Rayleigh limit with S as large as 3.6.
Feedback increases the mode frequency in the naturally stable region since the effective stiffness of the mode is increased.
microgravity.grc.nasa.gov /fcarchive/fluids/papers/Marston/Stab_and_Low_Freq.htm   (444 words)

  
 Monsoon low-frequency intraseasonal oscillation and ocean-atmosphere coupling over the Indian Ocean
The impact of coupled interaction over Indian Ocean on the monsoon low-frequency intraseasonal oscillation is investigated by analysing the simulations of MRI coupled general circulation model (CGCM) and its stand alone atmospheric version (AGCM).
Composites of northward propagations constructed based on objective criteria show that the characteristics of CGCM simulated low-frequency intraseasonal oscillation are close to observation.
As a result, the simulated low frequency oscillation lacks many of the important features associated with its amplitude, phase and life-cycle.
www.agu.org /pubs/crossref/2004.../2003GL019031.shtml   (231 words)

  
 [No title]
The circuit gain is critical for low distortion and you may need to adjust the 500 ohm resistor to achieve a stable waveform with minimum distortion.
The op-amp based phase shift oscillator is much more stable than the single transistor version since the gain can be set higher than needed to sustain oscillation and the output is taken from the RC network which filters out most of the harmonic distortion.
As each correct key is pressed, a low level appears at the output of the dual NAND gate producing a high level at the output of the 8 input NAND at pin 13.
ourworld.compuserve.com /homepages/Bill_Bowden/page8.htm   (2630 words)

  
 Freeman: SPECTRAL ANALYSIS OF PREPYRIFORM AVERAGED EVOKED POTENTIALS IN CATS
The existence of multiple frequencies of oscillation is demonstrated by the nonlinear changes in both wave forms and spectra of AEP at four stages of stimulus intensity (Figures 7 and 8).
Both the peaks are found to be continuously displaced toward zero frequency with increasing stimulus current, and the height of the low-frequency peak increases relative to that of the high-frequency peak.
Superimposed on this the second upward peak at low frequency in the center appears to initiate ringing at the dominant frequency, provided the intensity is not so high as to "block" the focus.
sulcus.berkeley.edu /FreemanWWW/2/BioMedSys69.html   (3845 words)

  
 Low Power Negative Supply For Cars   (Site not responding. Last check: 2007-10-01)
All currents are low (no load current is only 10mA, rising to 30mA with a 20mA output current), so special techniques are not needed.
The switching frequency is high enough to be inaudible (unless your hearing is very good), but could damage tweeters if it were to be amplified.
If you wanted to do so, low power 9V regulators may be used on the +ve and -ve supplies, but this will not provide any real advantages to most opamp circuits.
sound.westhost.com /project95.htm   (897 words)

  
 Passive and active vibration isolation systems - Theory   (Site not responding. Last check: 2007-10-01)
Motions of a suspension bracket caused by roughnesses of the road are of various character, from individual pushes to periodic oscillation.
Vibrations with frequencies higher than resonant frequency of the system are exposed to significant damping, while the low-frequency oscillation of the stabilized table is about the same as the amplitude of platform oscillation.
We can conclude that the resonant frequency of the system has to be as low as possible and the damping should be big enough to avoid a substantial growth of amplitude of resonance oscillation.
physics-animations.com /Physics/English/spri_txt.htm   (1245 words)

  
 An Intrinsic Oscillation in Interneurons of the Rat Lateral Geniculate Nucleus -- Zhu et al. 81 (2): 702 -- Journal of ...
The frequency increased with the intensity of the current pulse in a fashion similar to that described previously for interneurons in the rat LGN (Williams et al.
that the bursting oscillation in thalamic interneurons was intrinsic
Note that the initial intraburst frequency was related to the depth of the preceding hyperpolarization, but the sustained portion of the oscillation was little affected by prior membrane potential.
jn.physiology.org /cgi/content/full/81/2/702   (4529 words)

  
 Analog Audio Amplifier Design
Low frequency gain and phase shift is controlled by the size of the screen bypass capacitor.
The low level stages and the driver circuit are isolated via L-C filtering from the output tube plate circuit.
These tests must be done at a low signal level into an 8 ohm load to avoid saturation of the core of the output transformer.
www.depalma.pair.com /Analog/analog.html   (5194 words)

  
 WIDEBAND & LOW-NOISE MICROWAVE VCO
The Q of varactor diodes is rather low and is inversely proportional to the operating frequency.
Therefore, the exact frequency, the stability of the oscillator and the phase noise are all determined by the phase response.
In the case of a variable-frequency oscillator, the frequency coverage is rather restricted since the influence of the feedback network is small compared to the active device itself.
www.clearlight.com /~vhfcomm/s53mvvco.htm   (3293 words)

  
 Polar amplification of global warming
The LFO dominates SAT fluctuations, with two distinct warming periods (in the 1920-50s and from the mid-1970s to the present) and two cooling periods (prior to the 1920s and in the 1960-70s).
The multidecadal LFO is stronger in the Arctic than in the Northern Hemisphere which may be attributed to the proximity of the Arctic to the North Atlantic, believed to be the origin of the LFO [e.g.
Because the LFO is stronger in the Arctic, it is reasonable to expect a stronger LFO-driven modulation of trends in higher latitudes.
www.frontier.iarc.uaf.edu /~igor/research/amplif/index.php   (1163 words)

  
 Audio DesignLine | DSP drives Velodyne subwoofers
This is accomplished with an on-screen graph of the system’s actual frequency response and feedback displayed on the TV screen as the user makes digital adjustments to subwoofer equalization, phase, and crossovers.
Low Pass Crossover - Low pass crossover passes only the low frequencies of the incoming signal to subwoofer.
By pressing NEXT on the frequency response graph screen, a settings screen is displayed that allows for adjustment of crossovers, subsonic filter, phase, polarity, volume, theater/music, auto-on options and night mode maximum volume.
www.audiodesignline.com /howto/homeentertainment/172301393   (2641 words)

  
 Publication Abstracts- Aerospace Medical Association
Background: Low frequency horizontal oscillation can cause motion sickness in some transportation systems, but the influence of the frequency, magnitude, direction, and duration of oscillation are poorly understood.
Hypothesis: It was hypothesized that motion sickness was independent of the direction of horizontal oscillation (fore-and-aft or lateral) and that there was no difference in the motion sickness produced by different frequencies of horizontal oscillation (between 0.2 and 0.8 Hz) when subjects were exposed to the same peak velocity of motion at each frequency.
An acceleration frequency weighting having a gain inversely proportional to frequency would provide a convenient simple method of evaluating this type of motion in transport.
www.asma.org /journal/abstracts/v73n6/v73n6p537.html   (379 words)

  
 IngentaConnect Motion Sickness: Effect of the Frequency of Lateral Oscillation
However, the relationship between occurrence of sickness and the frequency of lateral oscillation is not known.
Conclusions: Mild nausea caused by lateral oscillation may be predicted by an acceleration frequency weighting that is independent of frequency from 0.0315 to 0.25 Hz and reduces at 12 dB per octave (i.e., proportional to displacement) from 0.25 to 0.8 Hz.
The frequency weighting for lateral oscillation may not be applicable in those environments in which there is roll motion during lateral oscillation.
www.ingentaconnect.com /content/asma/asem/2004/00000075/00000008/art00001   (287 words)

  
 Design a Low-Jitter Clock for High-Speed Data Converters - Maxim/Dallas   (Site not responding. Last check: 2007-10-01)
Because of the inherent frequency drift, a phase-locked loop (PLL) is often required to lock the VCO output to the desired frequency by comparing the VCO output to a crystal oscillator frequency.
In this case, the comparison frequency is 1MHz; therefore, the two spurs next to the carrier are exactly 1MHz away from the carrier and the subsequent pair.
This frequency is first divided by the integer N, and then compared to the reference crystal oscillator frequency, whose frequency has also been divided by an integer R. If there is a phase difference between the two frequencies, the voltage at the PLL output changes accordingly.
www.maxim-ic.com /tarticle/view_article.cfm/article_id/800   (2427 words)

  
 HW4 - KDC
The working principle of this calibration method is that the encoder-based speed is bad at low speeds, but improves at higher speeds.
Therefore by fitting a curve the low speed behavior can be estimated from what happens at high speeds assuming it is linear.
The result of the fitting is of the form: y=Ax+b, were the A term is the calibration term and b is the offset which was neglected (was very small).
www.frc.ri.cmu.edu /~fcalder/HW4   (1991 words)

  
 Extremely low frequency (ELF) fields (EHC 35, 1984)
To characterize ELF fields, the strength, frequency, and orientation of the electric and magnetic fields have to be determined.
The preliminary nature of the epidemiological findings, the low levels of exposure, and the relatively small increment in the reported incidence of any effects, suggest that, though the epidemiological data cannot be dismissed, there must be considerable study before they can serve as useful inputs for risk assessment.
The alternating fields at low frequency are related to thunderstorm activity and magnetic pulsations that produce currents within the Earth (telluric currents).
www.inchem.org /documents/ehc/ehc/ehc35.htm   (16444 words)

  
 Evidence for a Central Origin of the Low-Frequency Oscillation in RR-Interval Variability -- Cooley et al. 98 (6): 556 ...   (Site not responding. Last check: 2007-10-01)
After LVAD placement, the LF oscillation of RR-interval variability is restored and is present even in the absence of LF oscillation in the SAP variability spectrum.
After LVAD placement, the LF oscillation of RR-interval variability is restored and is present even in the absence of LF and HF oscillations in the SAP variability spectrum.
Absence of low frequency variability of sympathetic nerve activity in severe heart failure.
circ.ahajournals.org /cgi/content/full/98/6/556   (3868 words)

  
 Learn how to build synth patches with the Arturia ARP2600 V— Read the Remix tech feature about synth patch building.
The sound from each oscillator is identical, as long as the range, Init(ial) Osc(illator) Frequency, Fine Tune and Pulse Width controls are set to the same relative positions.
Frequency should be set to max (30.0 Hz); and the Pulse Width should be set to 50 percent.
LFOs are typically used as a source of modulation, due to their extremely low frequency output.
remixmag.com /mag/remix_construction_kit   (1738 words)

  
 Sound Devices: Oscillation with Transformer-Balanced Inputs
This oscillation is often described as a "motorboating" condition since this low frequency oscillation sounds like a motor boat.
Microphones with low rejection to common-mode phantom voltages fluctuate their output level based on the phantom voltage supplied.
The power supply is suitable for most microphones, but is susceptible to oscillation with microphones prone to drawing current based on output level.
www.sounddevices.com /tech/oscillation.htm   (312 words)

  
 McLean Hospital | Research : Clinical Unit Based Research
Scientists at Kodak made a serendipitous observation that a few individuals staring at a blank screen did not have a normal low frequency oscillation in their peripheral temperature.
Children with ADHD had a reduced pattern of low frequency (0.01 to 0.04 Hz) oscillations in skin temperature at rest under low stimulus conditions.
Pharmacotherapy enhanced the low frequency oscillation of ADHD children to control levels.
www.mclean.harvard.edu /research/clinicalunit/dbrp/adddx.php   (191 words)

  
 WHO | Electromagnetic fields and public health: extremely low frequency (ELF)
Exposures to many EMF frequencies are increasing significantly as technology advances unabated and new applications are found.
The frequency is simply the number of oscillations in the wave per unit time, measured in units of hertz (1 Hz = 1 cycle per second), and the wavelength is the distance travelled by the wave in one oscillation (or cycle).
At frequencies this low, the wavelengths in air are very long (6000 km at 50 Hz and 5000 km at 60 Hz), and, in practical situations, the electric and magnetic fields act independently of one another and are measured separately.
www.who.int /mediacentre/factsheets/fs205/en/index.html   (2758 words)

  
 diyAudio Forums Archive - Supply depended oscillation
Removed the Zobel-network and that increased both the voltage and frequency of the oscillation.
The oscillation now was lower in amplitude, what I expected, but it was only slightly de-tuned to 4.1MHz.
If it would be the amp being unstabel, I would expect a bigger frequency shift, so it seems that the capacitance of the feedback network only slightly influences the oscillation, while the divider operation of the feedback resistors can kill the oscillation.
www.diyaudio.com /forums/showthread/t-96201.html   (1408 words)

  
 Curriculum Vita
A.A. Tsonis, 2002: Investigating the statistical significance of climate oscillations.
A.A. Tsonis, and J.B. Elsner, 1991: The spatial- temporal scaling properties of rain and the validity of Taylor's hypothesis in the atmosphere.
A.G. Hunt and A.A. Tsonis, 2000: The Pacific Decadal Oscillation and long-term climate prediction.
www.uwm.edu /~aatsonis/vita.html   (3451 words)

  
 Loudspeaker with low-frequency oscillation patent invention
[0008] A primary object of the invention to provide a loudspeaker with low-frequency oscillation that has a longer oscillation element under the condition of the same area of the housing for producing a low-frequency resonance effect, creating a low-frequency sound, and therefore enhancing the response effect.
[0009] Another object of the invention to provide a loudspeaker that produces low-frequency oscillation and exerts a massaging effect on the human ear of the user in addition to generating low-frequency sound.
whereby, when the coil is fed with electric current, a magnetic force is created to impart an up and down vibration to the oscillatable sound assembly, thereby enhancing the effect of the low-frequency sound field as well as the resonance effect.
www.freshpatents.com /Loudspeaker-with-low-frequency-oscillation-dt20061019ptan20060233418.php   (789 words)

  
 Dr. Michael E. Schlesinger   (Site not responding. Last check: 2007-10-01)
Temperature Oscillations in the North Atlantic, Science, 289, 547 (M. Schlesinger, N. Ramankutty and N. Andronova).
The Dependence on Convection Parameterization of the Tropical Intraseasonal Oscillation Simulated by the UIUC 11-Layer Atmospheric GCM, J.
The Dependence on Convective Parameterization of Tropical Intraseasonal Oscillations - An Assessment Using the UIUC GCM.
crga.atmos.uiuc.edu /people/mes.html   (5138 words)

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