scholarly journals Spectrum of frequency modulation of serpentine emission as a reflection of the solar fluctuation spectrum

2017 ◽  
Vol 3 (1) ◽  
pp. 59-62
Author(s):  
Борис Довбня ◽  
Boris Dovbnya ◽  
Борис Клайн ◽  
Boris Klain ◽  
Анатолий Гульельми ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Frequency Modulation ◽  
Carrier Frequency ◽  
Observation Time ◽  
Signal Frequency ◽  
Frequency Range ◽  
Fluctuation Spectrum ◽  
Using Data ◽  
Spectrum Matching ◽  
Serpentine Emission

We study frequency modulation of serpentine emission (SE), using data from the Vostok Antarctic station. It is shown that the previously observed 5-minute modulation of the SE carrier frequency is the most prominent and stable in the emission spectrum. Frequency fluctuations of this period are present in about 70 % of the total SE observation time under moderately quiet geomagnetic conditions (Kp=0–2). We performed a per-pixel processing of SE dynamic spectra and found that the power spectrum of the signal frequency modulation contains a clearly visi-ble peak at periods close to 5 minutes. A detailed study shows the emission spectrum matching the frequency range of the solar photospheric oscillations. The results of the analysis allow us to conclude that the 5-minute modulation of the SE carrier frequency can be viewed as a reflection of photospheric fluctuations with the same period that is typical for the solar eigenoscillations.

scholarly journals Spectrum of frequency modulation of serpentine emission as a reflection of the solar fluctuation spectrum

2017 ◽  
Vol 3 (1) ◽  
pp. 73-77
Author(s):  
Борис Довбня ◽  
Boris Dovbnya ◽  
Борис Клайн ◽  
Boris Klain ◽  
Анатолий Гульельми ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Frequency Modulation ◽  
Observation Time ◽  
Signal Frequency ◽  
Frequency Range ◽  
Fluctuation Spectrum ◽  
Dynamic Spectra ◽  
Using Data ◽  
Spectrum Matching ◽  
Serpentine Emission

We study frequency modulation of serpentine emission (SE), using data from the Vostok Antarctic station. It is shown that the previously observed 5-minute modulation of the SE carrier frequency is the most prominent and stable in the emission spectrum. Frequency fluctuations of this period are present in about 70 % of the total SE observation time under moderately quiet geomagnetic conditions (Kp=0–2). We performed a per-pixel processing of SE dynamic spectra and found that the power spectrum of the signal frequency modulation contains a clearly visi-ble peak at periods close to 5 minutes. A detailed study shows the emission spectrum matching the frequency range of the solar photospheric oscilla-tions. The results of the analysis allow us to conclude that the 5-minute modulation of the SE carrier fre-quency can be viewed as a reflection of photospheric fluctuations with the same period that is typical for the solar eigenoscillations.

A study of distress calls of song, swamp, and white-throated sparrows (Aves: Fringillidae). II. Interspecific responses and properties used in recognition

1972 ◽  
Vol 50 (12) ◽  
pp. 1513-1525 ◽  
Author(s):  
Raymond A. Stefanski ◽  
J. Bruce Falls
Keyword(s):  
Frequency Modulation ◽  
Carrier Frequency ◽  
Sympatric Species ◽  
The Other ◽  
Breeding Cycle ◽  
Frequency Range ◽  
Distress Calls ◽  
Modulation Rate ◽  
Similar Peak

Recorded distress calls of each species were played to territorial males of the other two, in successive stages of the breeding cycle. Responses were like those given to intraspecific calls and showed a similar peak of intensity in the late nestling and fledgling stage.Song and swamp sparrows (Melospiza spp.) responded strongly to each other's calls, which are alike in length, carrier frequency, and frequency range and overlap broadly in rate of frequency modulation. However, responses were generally weak between Melospiza spp. and the white-throated sparrow (Zonotrichia), whose calls differ in these properties.Song and swamp sparrows responded strongly to artificial sounds that simulated their natural distress calls, but white-throated sparrows responded weakly to sounds that resembled their natural calls in some but not all properties.Song sparrows were exposed to artificial sounds that were varied in length, carrier frequency, and frequency modulation rate. With respect to each property, they responded strongly if the value fell within the range found in natural calls, but weakly if it fell outside this range. Evidently, all three properties are used in call recognition.We conclude that interspecific responses among these sympatric species resulted from similarities in their distress calls. Possible advantages of this behavior are discussed.

scholarly journals On the origin of frequency modulation of serpentine emission

10.12737/9617 ◽  
2015 ◽  
Vol 1 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Анатолий Гульельми ◽  
Anatol Guglielmi ◽  
Александр Потапов ◽  
Alexander Potapov ◽  
Борис Довбня ◽  
...  
Keyword(s):  
Frequency Modulation ◽  
Carrier Frequency ◽  
Electromagnetic Emission ◽  
Standard Theory ◽  
Solar Photosphere ◽  
Polar Caps ◽  
Ion Cyclotron Waves ◽  
Unknown Property ◽  
Deep Modulation ◽  
Serpentine Emission

We consider a problem of the interpretation of the so-called "serpentine emission" (SE), which is ULF electromagnetic emission in the range of Pc1–2 (0.1–5 Hz) found in Antarctica. A distinctive feature of SE complicating its understanding within the standard theory of the magnetospheric oscillations is a deep modulation of the SE carrier-frequency. The characteristic time of the frequency modulation varies from case to case from 1 minute to 1 hour. It is assumed that the frequency-modulated oscillations penetrate into the polar caps from the interplanetary medium, where they are excited in the form of ion-cyclotron waves as a result of the instability of plasma with anisotropic ion velocity distribution. To verify the hypothesis of the SE extra-magnetospheric origin a test is proposed. A previously unknown property of SE is discovered, which supports the hypothesis. The property is that at times the emission carrier frequency undergoes a pronounced 5-minute modulation. Apparently, a 5-minute modulation SE is genetically related to the 5-minute oscillations of the solar photosphere.

Design of Control System for Hydraulically Vibrated Processing Tomato Fruit Seedling Separation Device

2014 ◽  
Vol 651-653 ◽  
pp. 693-696
Author(s):  
Li Hong Wang ◽  
Rong Qing Liang ◽  
Cheng Song Li ◽  
Za Kan ◽  
Jin Wei Qin
Keyword(s):  
Tomato Fruit ◽  
Simulation Software ◽  
Signal Frequency ◽  
System Control ◽  
Frequency Range ◽  
Hydraulic Simulation ◽  
Separation Device ◽  
Processing Tomato ◽  
Input Signal Frequency ◽  
Set Up

Eccentric style processing tomato fruit seeding separation device exist high machining and assembly precision or other issues. In order to solve this problem, the mode of vibration of hydraulic replaced the eccentric style to drive the fruit seedling separation roller to separate processing tomato effectively. To facilitate adjustment of the hydraulic system, a kind of control circuit PLC as the core was designed according to the actual production requirements. PLC and other elements were selected. The system control signal frequency was initially set up as 1~5 HZ, within the frequency range hydraulic simulation software was used to simulate and analyze the hydraulic vibration system. The result shows that the system rams steady when the input signal frequency range was 1~5HZ.

scholarly journals Parallel PWMs Based Fully Digital Transmitter with Wide Carrier Frequency Range

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Bo Zhou ◽  
Kun Zhang ◽  
Wenbiao Zhou ◽  
Yanjun Zhang ◽  
Dake Liu
Keyword(s):  
Carrier Frequency ◽  
Pulse Width ◽  
Power Efficiency ◽  
Intermediate Frequency ◽  
Delay Lines ◽  
Error Vector Magnitude ◽  
Frequency Range ◽  
Digital Transmitter ◽  
High Power Efficiency ◽  
Vector Magnitude

The carrier-frequency (CF) and intermediate-frequency (IF) pulse-width modulators (PWMs) based on delay lines are proposed, where baseband signals are conveyed by both positions and pulse widths or densities of the carrier clock. By combining IF-PWM and precorrected CF-PWM, a fully digital transmitter with unit-delay autocalibration is implemented in 180 nm CMOS for high reconfiguration. The proposed architecture achieves wide CF range of 2 M–1 GHz, high power efficiency of 70%, and low error vector magnitude (EVM) of 3%, with spectrum purity of 20 dB optimized in comparison to the existing designs.

The variability of naturally occurring magnetic field levels: 10 Hz to 8 kHz

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. F187-F197 ◽  
Author(s):  
Ben K. Sternberg
Keyword(s):  
Magnetic Field ◽  
Noise Level ◽  
Monsoon Season ◽  
Signal Frequency ◽  
Time Interval ◽  
Frequency Range ◽  
Noise Levels ◽  
Controlled Source ◽  
Naturally Occurring ◽  
Minimum Noise

The variability of naturally occurring magnetic fields in the frequency range from [Formula: see text] over a period of one year was studied. Contour plots for the [Formula: see text], [Formula: see text], and [Formula: see text] components and for frequencies of 10, 100, 1000, 2000, and 8000 Hz were produced. Average, minimum, maximum, and the standard deviations of these fields were also calculated for 12 distinctive time intervals. In the 1– to 8–kHz frequency range, the noise levels are typically higher at night. In the 10- to 100-Hz frequency range, the noise levels are typically higher during the day. During mid- to late-summer, there is frequent thunderstorm activity, known in the southwest United States as the monsoon season. The magnetic field levels are often very high during this time period. These variability ranges can be used to estimate the lowest levels of noise that may be encountered during field surveys, which iswhat the authors are looking for when running controlled-source electrical method surveys. These variability ranges can also be used to estimate the highest levels that may be encountered, which is what the authors are looking for when running natural-source electrical methods surveys, such as audio frequency magnetotelluric (AMT) surveys. These measurements of magnetic field strength variability show that better data for controlled-source electrical measurements can be obtained using the minimum noise level measurements, as opposed to using signal integration or signal averaging with all of the data. The minimum noise level is found by using frequency bins adjacent to the signal-frequency bin. Likewise, if one is interested in measuring the naturally occurring magnetic field data, using the maximum values during each time interval makes AMT measurements possible when the natural signal level is very low, particularly in the AMT dead zone around [Formula: see text].

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