1 
Universal approach for estimating unknown frequencies for unknown number of sinusoids in a signalAhmed, A., Hu, Yim Fun, Pillai, Prashant January 2013 (has links)
No / This paper presents a new approach to estimate the unknown frequencies of the constituent sinusoids in a noiseless signal. The signal comprising of unknown number of sinusoids of unknown amplitudes and unknown phases is measured in the time domain. The Hankel matrix of measured samples is used as a basis for further analysis in the Pisarenko harmonic decomposition. A new constraint, the Existence Factor (EF), has been introduced in the methodology based on the relationship between the frequencies of the unknown sinusoids and the eigenspace of Hankel matrix of signal's samples. The accuracy of the method has been tested through multiple simulations on different signals with an unknown number of sinusoidal components. Results showed that the proposed method has efficiently estimated all the unknown frequencies.

2 
A universal twoway approach for estimating unknown frequencies for unknown number of sinusoids in a signal based on eigenspace analysis of Hankel matrixAhmed, Adeel, Hu, Yim Fun, Noras, James M., Pillai, Prashant 25 April 2015 (has links)
Yes / We develop a novel approach to estimate the n unknown constituent frequencies of a noiseless signal that comprises of unknown number, n, of sinusoids of unknown phases and unknown amplitudes. The new two way approach uses two constraints to accurately estimate the unknown frequencies of the sinusoidal components in a signal. The new approach serves as a verification test for the estimated unknown frequencies through the estimated count of the unknown number of frequencies. The Hankel matrix, of the time domain samples of the signal, is used as a basis for further analysis in the Pisarenko harmonic decomposition. The new constraints, the Existence Factor (EF) and the Component Factor (CF), have been introduced in the methodology based on the relationships between the components of the sinusoidal signal and the eigenspace of the Hankel matrix. The performance of the developed approach has been tested to correctly estimate any number of frequencies within a signal with or without a fixed unknown bias. The method has also been tested to accurately estimate the very closely spaced low frequencies. / Innovate UK

3 
A ModelBased Receiver for CPM Signals in a Cochannel Interference Limited EnvironmentBarthelemy, Pierre 06 June 2002 (has links)
Cochannel interference (CCI) is a major impairment in narrowband cellular systems. To increase the spectral efficiency of the narrowband systems, identical carrier frequencies are reused in distant cells. The interference rejection capability of the receiver determines this frequency reuse and is therefore critical. In this thesis, we propose an improved demodulation scheme, employing highresolution frequency estimation techniques, for continuous phase modulated (CPM) signals in presence of CCI. Minimum shift keying (MSK), which is a special case of CPM, is a very popular modulation format around the world. Frequency detectors, such as the limiterdiscriminator permit the noncoherent demodulation of MSK signals. Highresolution frequency estimation appears as a very attractive alternative to the conventional noncoherent frequency detectors. The frequency estimation methods that we have studied are based on autoregressive modeling.
The contributions of this thesis include the implementation of various demodulation schemes employing parametric frequency estimation. The use of the Viterbi algorithm as a nonlinear equalization technique to mitigate intersymbol interference is considered. We verified that the modelbased sequence estimation schemes outperform the conventional noncoherent receivers for MSK with AWGN, flat fading, and CCI. Demodulator diversity is also investigated as a way to combat interference. An improved technique combining the proposed modelbased receiver and the conventional coherent receiver is implemented and simulated in presence of CCI. / Master of Science

4 
A HIGHACCURACY AND LOWCOMPLEXITY CARRIEROFFSETFREQUENCY ESTIMATORPalmer, Joseph 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The FortyThird Annual International Telemetering Conference and Technical Exhibition / October 2225, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / A singletone frequency estimator for a nonuniformly sampled sinusoid is proposed. A nonuniformly sampled sinusoid may be generated from the received training sequences of a telemetry link. The frequency of the sinusoid matches the carrierfrequencyoffset (CFO) of the received signal, and estimation of this quantity allows a receiver to compensate for the CFO. The performance bounds of this type of estimator have been investigated in the literature, though little work has been published on practical algorithms. The estimator proposed in this paper is a generalization of phaseincrement estimators previously described in the literature. It exhibits a low computational complexity yet converges to theoretical bounds at high SNR. The paper argues that a periodic training sequence structure, combined with the new estimator, allows for a highaccuracy and lowcomplexity CFO compensator.

5 
Rapid Frequency EstimationKoski, Antti E. 28 March 2006 (has links)
Frequency estimation plays an important role in many digital signal processing applications. Many areas have benefited from the discovery of the Fast Fourier Transform (FFT) decades ago and from the relatively recent advances in modern spectral estimation techniques within the last few decades. As processor and programmable logic technologies advance, unconventional methods for rapid frequency estimation in white Gaussian noise should be considered for real time applications. In this thesis, a practical hardware implementation that combines two known frequency estimation techniques is presented, implemented, and characterized. The combined implementation, using the well known FFT and a less well known modern spectral analysis method known as the Direct State Space (DSS) algorithm, is used to demonstrate and promote application of modern spectral methods in various real time applications, including Electronic Counter Measure (ECM) techniques.

6 
Synchronization for BurstMode APSKShaw, Christopher 10 1900 (has links)
ITC/USA 2009 Conference Proceedings / The FortyFifth Annual International Telemetering Conference and Technical Exhibition / October 2629, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / We derive bounds on the performance of dataaided joint estimators for timing offset, carrier phase offset, and carrier frequency offset for use in an APSK packetbased communication link. It is shown that the CramérRao Bound (CRB) is a function of the training sequence, the signaltonoise ratio (SNR), and the pulse shape. We also compute APSK training sequences of different lengths that minimize the CRB for each of the parameters.

7 
DOPPLER SHIFTED SPREAD SPECTRUM CARRIER RECOVERY USING REALTIME DSP TECHNIQUESScaife, Bradley J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 2629, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / In any satellite communication, the Doppler shift associated with the satellite’s position
and velocity must be calculated in order to determine the carrier frequency. If the satellite
state vector is unknown then some estimate must be formed of the Dopplershifted carrier
frequency. One elementary technique is to examine the signal spectrum and base the
estimate on the dominant spectral component. If, however, the carrier is spread (as in
most satellite communications) this technique may fail unless the chip ratetodata rate
ratio (processing gain) associated with the carrier is small. In this case, there may be
enough spectral energy to allow peak detection against a noise background.
In this paper, we present a method to estimate the frequency (without knowledge of the
Doppler shift) of a spreadspectrum carrier assuming a small processing gain and binaryphase
shift keying (BPSK) modulation. Our method relies on a simple, averaged discrete
Fourier transform along with peak detection. We provide simulation results indicating the
accuracy of this method. In addition, we will describe an alldigital hardware design
based around a Motorola DSP56303 and highspeed A/D which implements this
technique in realtime. The hardware design is to be used in NMSU’s implementation of
NASA’s demand assignment, multiple access (DAMA) service.

8 
Frequency Estimation Using TimeFrequency Based MethodsMai, Cuong 08 August 2007 (has links)
Any periodic signal can be decomposed into a sum of oscillating functions. Traditionally, cosine and sine segments have been used to represent a single period of the periodic signal (Fourier Series). In more general cases, each of these functions can be represented by a set of spectral parameters such as its amplitude, frequency, phase, and the variability of its instantaneous spectral components. The accuracy of these parameters depends on several processing variables such as resolution, noise level, and bias of the algorithm used. This thesis presents some background of existing frequency estimation techniques and proposes a new technique for estimating the instantaneous frequency of signals using short sinusoidlike basis functions. Furthermore, it also shows that the proposed algorithm can be implemented in a popular embedded DSPmicroprocessor for practical use. This algorithm can also be implemented using more complex features on more resourceful processing processors in order to improve estimation accuracy

9 
Statistical Spectral Parameter Estimation of Acoustic Signals with Applications to Byzantine MusicTsiappoutas, Kyriakos Michael 17 December 2011 (has links)
Digitized acoustical signals of Byzantine music performed by Iakovos Nafpliotis are used to extract the fundamental frequency of each note of the diatonic scale. These empirical results are then contrasted to the theoretical suggestions and previous empirical findings. Several parametric and nonparametric spectral parameter estimation methods are implemented. These include: (1) Phase vocoder method, (2) McAulayQuatieri method, (3) LevinsonDurbin algorithm,(4) YIN, (5) Quinn & Fernandes Estimator, (6) Pisarenko Frequency Estimator, (7) MUltiple SIgnal Characterization (MUSIC) algorithm, (8) Periodogram method, (9) Quinn & Fernandes Filtered Periodogram, (10) Rife & Vincent Estimator, and (11) the Fourier transform. Algorithm performance was very precise. The psychophysical aspect of human pitch discrimination is explored. The results of eight (8) psychoacoustical experiments were used to determine the aural just noticeable difference (jnd) in pitch and deduce patterns utilized to customize acceptable performable pitch deviation to the application at hand. These customizations [Acceptable Performance Difference (a new measure of frequency differential acceptability), Perceptual Confidence Intervals (a new concept of confidence intervals based on psychophysical experiment rather than statistics of performance data), and one based purely on musictheoretical asymphony] are proposed, discussed, and used in interpretation of results. The results suggest that Nafpliotis' intervals are closer to just intonation than Byzantine theory (with minor exceptions), something not generally found in Thrasivoulos Stanitsas' data. Nafpliotis' perfect fifth is identical to the just intonation, even though he overstretches his octaveby fifteen (15)cents. His perfect fourth is also more just, as opposed to Stanitsas' fourth which is directionally opposite. Stanitsas' tendency to exaggerate the major third interval A4F4 is still seen in Nafpliotis, but curbed. This is the only noteworthy departure from just intonation, with Nafpliotis being exactly Chrysanthian (the most exaggerated theoretical suggestion of all) and Stanitsas overstretching it even more than Nafpliotis and Chrysanth. Nafpliotis ascends in the second tetrachord more robustly diatonically than Stanitsas. The results are reported and interpreted within the framework of Acceptable Performance Differences.

10 
Online Market MonitoringWalchhofer, Norbert 22 February 2017 (has links) (PDF)
This thesis conceptualizes a generic monitoring framework for online markets, which has also been implemented in a prototypic fashion. Thereby identifying a set of arising challenges for which solutions have been developed.
An introductory section gives a short overview of the field of research, states identified scientfic challenges and derives research questions thereof. The following articles describe (i) the general approach of an online market monitor, (ii) how to encapsulate domaindependent configurations & functionalities from monitoring core modules to facilitate a generic approach, (iii) change frequency estimation for observational units in a dynamic and fuzzy population setting, (iv) the development of an adaptive harvest heuristic scheduling new observations by utilizing the change frequency estimator, (v) how to make use of collected market information in form of business intelligence reports and finally (vi) an exemplary metaanalysis showing how to draw further conclusions about market mechanisms.

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