ALGORITHMS FOR THE SPECTRAL ANALYSIS OF RADIO SIGNALS ON THE BACKGROUND OF PIECEWISE-STATIONARY NOISE

The analysis of pulsars is a complicated procedure due to the influence of background radio waves. Special radio telescopes designed to detect pulsar signals have to employ many techniques to reconstruct interstellar signals and determine if they originated from a pulsating radio source. The Discrete Fourier Transform on its own has allowed astronomers to perform basic spectral analysis of potential pulsar signals. However, Radio Frequency Interference (RFI) makes the process of detecting and analyzing pulsars extremely difficult. This has forced astronomers to be creative in identifying and determining the specific characteristics of these unique rotating neutron stars. Astrophysicists have utilized algorithms such as the Fast Fourier Transform (FFT) to predict the spin period and harmonic frequencies of pulsars. However, FFT-based searches cannot be utilized alone because low-frequency pulsar signals go undetected in the presence of background radio noise. Astrophysicists must stack up pulses using the Fast Folding Algorithm (FFA) and utilize the coherent dedispersion technique to improve FFT sensitivity. The following research paper will discuss how the Discrete Fourier Transform is a useful technique for detecting radio signals and determining the pulsar frequency. It will also discuss how dedispersion and the pulsar frequency are critical for predicting multiple characteristics of pulsars and correcting the influence of the Interstellar Medium (ISM).

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Cyclic spectral analysis of TH-PPM UWB impulse radio signals

2009 9th International Conference on Telecommunication in Modern Satellite, Cable, and Broadcasting Services ◽

10.1109/telsks.2009.5339424 ◽

2009 ◽

Author(s):

Desimir Z. Vucic ◽

Miljko Eric ◽

Ivan Pokrajac

Keyword(s):

Spectral Analysis ◽

Impulse Radio ◽

Radio Signals

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Investigation Of Pre-Earthquake Ionospheric Anomalies Before Albania 2019 Earthquake Using The Romanian Receivers Of The Vlf/Lf Infrep And Gnss Global European Networks

10.5194/egusphere-egu2020-13952 ◽

2020 ◽

Author(s):

Iren Adelina Moldovan ◽

Victorin Emilian Toader ◽

Christina Oikonomou ◽

Haris Haralambous ◽

Pier Francesco Biagi ◽

...

Keyword(s):

Spectral Analysis ◽

Seismic Event ◽

Global Network ◽

Electron Content ◽

European Network ◽

Total Electron ◽

Ionospheric Perturbations ◽

Analysis Techniques ◽

Radio Signals ◽

Significant Effort

The last two decades a significant effort has been invested in order to understand and interpret the link between seismic activity and ionospheric perturbations. Since not any individual seismo-ionospheric precursor can be used as an accurate stand alone for earthquake prediction it is required to integrate different kinds of precursors and analysis techniques.To this context, the aim of this study is to investigate pre-earthquake ionospheric anomalies that occurred prior to large 6.4 Mw earthquake in Albania (26th November 2019), following a multi-instrument and multi-technique approach, using subionospheric radio VLF/LF signals obtained from the Romanian receivers of the INFREP European network and Total Electron Content (TEC) observations from GNSS global network.To identify possible ionospheric anomalies before the earthquakes we applied the terminator time and nighttime fluctuation methods on the amplitude of subionospheric LF radio signals and spectral analysis on diurnal TEC variations several days prior the seismic event. It was found that sunrise terminator times are delayed approximately 20-40 min few days before and during the earthquake day. Intensified wave-like TEC oscillations with periods around 20 min were also revealed up to 5 days prior to the earthquake shocks in all cases that could be interpreted as possible ionospheric precursors of the impending earthquakes.&#160;&#160;&#160;&#160; &#160;

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Eavesdropping Detection of Radio Signals from Other Planets, with One Bit-Implementation Techniques Using Existing Computers

Symposium - International Astronomical Union ◽

10.1017/s0074180900146674 ◽

1985 ◽

Vol 112 ◽

pp. 335-339

Author(s):

Stephen H. Knowles

Keyword(s):

Spectral Analysis ◽

Doppler Shift ◽

General Purpose ◽

Analysis Techniques ◽

First Derivative ◽

Implementation Techniques ◽

Radio Signals ◽

Eavesdropping Detection

Detection of other civilizations by “eavesdropping” on accidental radiation from television and other self-oriented signals is proposed. One-bit spectral analysis techniques to implement this are discussed. These can utilize existing general-purpose computers, and provide flexibility of strategy in the analysis. The first derivative of doppler shift from an unknown planet can be compensated for with increased integration times possible.

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