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Weak narrow-band signal detection in multivariate non-gaussian clutterSistanizadeh, Mohammad K. January 1986 (has links)
This dissertation is concerned with the development and performance analysis of non-linear receivers for detection of weak narrow-band signals in multivariate non-Gaussian clutter. The novelty of the detection scheme lies in the utilization of both the complex measurement and the multivariate non-Gaussian character of the clutter. Two clutter models are developed based on the available partial information. Model (I) is based on the a priori knowledge of the first-order density, correlation structure of the amplitude, and the circular symmetric assumption of the in-phase and quadrature phase components. Model (II) is based on the first-order in-phase and quadrature phase densities and the complex correlation structure. These models completely specify a multivariate complex nonGaussian density and can be used for clutter generation.
A class of optimum non-linear receiver structures based on weak signal level, canonically known as Locally Optimum Detectors (LOD) are derived under clutter Model (I). This can be considered to be a generalization of the LOD for the independent and identically distributed (i.i.d) clutter. The detectors utilize complex measurements and their structures depend on whether the underlying hypothesis testing model is real or complex.
The performance of each of the proposed detector structures, based on the concept of Efficacy, is formulated. Then, the performance of the detectors are evaluated with respect to a reference detector using Asymptotic Relative Efficiency (ARE) criterion. Numerical evaluation of the performance expression is carried out for constant signal in Weibull distribution for various density parameters. Simulation results indicate that the performance of the developed detectors, based on ARE, is superior to (i.i.d) LOD detector and matched filter.
Finally, the sensitivity of the detector performance to parameter variation of the structural non-linearities is investigated. / Ph. D.
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A comparison of digital beacon receiver frequency estimatorsGendron, Paul John 29 September 2009 (has links)
Two algorithms for estimating the frequency and power of the carriers of 20 GHz and 30 GHz satellite signals are compared. Both algorithms operate on a prefiltered sequence generated by lowpass filtering followed by signal decimation for the purpose of sampling rate reduction. The lowpass filtering is accomplished via the overlap-add method of FIR filtering using the FFT. Carrier frequency prediction and tracking is accomplished with a Kalman predictor, for which the frequency drift process is modeled via polynomial extrapolation. The Kalman predictor operates on frequency measurements provided by one of two frequency estimators.
One of the frequency estimation algorithms, a refinement of the DFT-automatic frequency control technique, uses the Chirp-Transform algorithm in its aim for the maximum likelihood estimate of frequency and power. The averaged periodogram is computed from the prefiltered sequence and is used to measure the frequency of the drifting frequency signal as well as its power. One of the disadvantages of this algorithm is the bias present in the estimation of power. The bias can be removed only with knowledge of the noise power. The algorithm has the advantage of being almost exclusively a convolution and therefore is accomplished with minimal computation via the FFT.
An alternative parametric approach to frequency estimation is also investigated. In this approach the weighted least-squares modified Yule-Walker method of autoregressive model estimation is used on the prefiltered sequence to yield frequency estimates. Power estimation is accomplished next via modal decomposition of the estimated correlation sequence. The advantage of this approach is that for slowly varying frequency drift paths (24 hour cycle) the frequency estimates exhibit MSE approximately 3 dB less than the Chirp-Transform algorithm over a wide range of SNR. There are two disadvantages to the parametric algorithm. First the parametric algorithm estimates power with MSE approximately 2 dB greater than the nonparametric algorithm. Secondly the algorithm is more complicated than the nonparametric Chirp-Transform algorithm because it requires matrix inversions and the determination of the roots of a polynomial.
For the digital beacon receiver problem investigated here both algorithms perform similarly in two important respects. First both algorithms can lock onto a carrier signal whose frequency is drifting at the rate of 5 Hertz per second in a noise environment corresponding to a 15 dB/Hz SNR. Secondly both algorithms can make unbiased frequency estimates of the carrier signal allowing the receiver to track the carrier at 7 dB/Hz SNR. Both algorithms attain the Cramer-Rao bound for estimation of constant frequency sinusoids. For a simulated satellite signal with maximum frequency drift of 5 Hertz per second the Kalman frequency predictor is able to reduce the problem to nearly that of the constant frequency case so that the resulting performance corresponds to the Cramer-Rao bound for estimation of constant frequency sinusoids.
Where computational considerations are critical the nonparametric algorithm is preferred. In fact, unless the superior accuracy of the frequency prediction afforded by the parametric algorithm is paramount, the nonparametric algorithm is to be chosen. / Master of Science
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FM, PM and NPR CalculationsGallupe, Gary 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / System performance can be ascertained via a number of parameters; one of which is
Signal-to-Noise ratio (SNR). SNR is the ratio of the value of the signal to the value of
the noise. It is generally expressed in decibels and usually a function of the system
bandwidth. Another measure of performance is the Noise-Power ratio (NPR). NPR is
the ratio of the noise level within a specific measurement channel when noise is
applied to all channels, to the level that is measured within the specific channel with
noise applied to all of the channels but not the specific channel.
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THE GREAT FREQUENCY DEVIATION AUTOMATIC MEASURING OF TELEMETRY TRANSMITTERBixian, Luo, Jian, Luo, Wei, Zeng 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / At present, there is no means of instrument direct measurement to frequency deviation
when it is up 500kHz. But the frequency deviation of high bit rate telemetry transmitter is
700kHz or more. In this paper, an indirect measurement method using spectrum analyzer
and counter is put forward. It effectively solves the measurement problem of frequency
deviation and frequency response of high bit rate telemetry transmitters. Measuring theory,
summary of experiences and difficulties in measuring work, have been deeply studied with
the viewpoint of how to avoid the limitation of different methods of measurement. Focused
on the establishment of an automatic measuring system, expert system, skilled data and
software of the system are studied in detail. The data for comparison is also supplied.
Finally, the analysis to the measuring error and general uncertainty is given.
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THE USE OF TELEMETRY IN AN ELECTROMAGNETIC TEST ENVIRONMENTPapich, William J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The U.S. Army Redstone Technical Test Center (RTTC) uses telemetry as a vital part of
its data acquisition and analysis for electromagnetic environmental effects developmental
testing of U.S. Army weapon systems. Testing in an electromagnetic environment poses
several unique challenges. These challenges have resulted in the development of highly
customized telemetry and data acquisition systems. This paper discusses the design and
integration of past and current telemetry needs to incorporate real-time or near real-time
simulations or scene generations into the testing process.
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IFM EFFECTS ON PCM/FM TELEMETRY SYSTEMSLaw, Gene, Whiteman, Don 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Incidental Frequency Modulation (IFM) products in telemetry transmitters can be a
significant cause of bit errors in received Pulse Code Modulation/Frequency Modulation
(PCM/FM) telemetry data. Range Commanders Council (RCC) and other documents give
little or no guidance as to acceptable levels of IFM for telemetry applications. The
expected higher vibration levels of future high velocity missile systems means that IFM
levels are likely to be higher than previously encountered.
This paper presents measured data on Bit Error Rate (BER) versus IFM levels at given
Signal to Noise Ratios (SNR’s) for PCM/FM telemetry systems. The information
presented can be utilized with BER versus SNR plots in the Telemetry Applications
Handbook, RCC Document 119, to determine the additional link margin required to
minimize IFM effects on telemetry data quality.
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Modular approach to the development of a two-way radio receiver systemKellerman, Valpre Cecilia 12 1900 (has links)
Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The preliminary development of a FM radio receiver module is discussed. An existing narrowband
system operating between 48MHz and 50MHz will be replaced. Digital components were
investigated, compared and used with analogue techniques to build a more flexible two-way radio
receiver system. A direct digital synthesizer was considered as a replacement for the current
synthesized phased lock loop local oscillator and much attention was given to the local oscillator
and mixer design, characteristics and measurement procedures.
A detailed study of receiver systems was undertaken to determine the specifications needed for
every receiver component to achieve satisfactory receiver performance in the end. Receiver
characteristics as well as receiver measurement procedures are defined. A software tool was
developed to aid the design process, establishing computationally whether the receiver
specifications are met prior to the final design.
The complete design process, from fundamental specifications through to the developed final
receiver module is discussed. A modular design approach was used to guarantee easy
manufacturing, substitution and testing. This approach comprises the break-down of the receiver
into well defined components that are each matched to 50O. The separate components of the
system were designed, measured and characterized to make it possible to replace only a single
component instead of the entire system when a part becomes redundant. / AFRIKAANSE OPSOMMING: Die grondslag vir die ontwikkeling van ‘n FM radio ontvanger module word in hierdie dokument
gelê. ‘n Bestaande noubandstelsel wat tussen 48MHz and 50MHz ontvang word vervang deur
hierdie nuwe stelsel wat aangewend sal kan word in die bestaande tweerigtingradio se omhulsel.
Digitale komponente is ondersoek, vergelyk en gebruik saam met analoogtegnieke om ‘n meer
buigsame radiostelsel te bewerkstellig. ‘n Direkte digitale sintitiseerder is oorweeg as ‘n
vervanging vir die huidige fasesluitlus ossillator met heelwat klem op die oscillator-en
mengerontwerp, komponent spesifikasies en metingsprosedures.
‘n Diepgaande studie van ontvangerstelsels is gedoen om te bepaal wat die tipiese spesifikasies
vir elke ontvangerstadium is, sodat die finale ontvanger se spesifikasies behaal kan word.
Ontvanger eienskappe en meetprosedures word volledig gedefinieer. ‘n Sagtewareprogram is
ontwikkel om die ontvanger-ontwerpsproses te vergemaklik deur vooraf te kan vasstel watter
ontvangerspesifikasies bereik sal kan word al dan nie.
Die volledige ontwerpsproses, vanaf fundamentele spesifikasies tot by die finale ontvanger word
omskryf. ‘n Modulere-ontwerp prosedure is gebruik ter versekering van die maklike vervaardiging,
vervanging en toetsing van elke komponent. Die radio is tydens ontwerp opgebreek in
boublokkies wat elkeen aangepas word na 50O. Elke aparte boublokkie van die ontvangerstelsel
is afsonderlik ontwerp, gemeet en volledig gespesifiseer om dit moontlik te maak om slegs een
komponent te vervang in plaas van die hele stelsel wanneer ‘n enkele komponent nie meer
beskikbaar is nie.
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Benefits to processor load for quadrature baseband versus radio frequency demodulation algorithmsNdovi, Lusungu 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. / The continued advancement and improvement of software-defined radio technology has
been a key factor in furthering research into the implementation of most signal
processing algorithms at baseband. Traditionally, these algorithms have been carried
out at RF, but with the coming of SDR, there has been a need to shift the processing
down to baseband frequencies which are more compatible with the fast developing
software radio technology.
The study looks at selected demodulation algorithms and investigates the
possibility and benefits of carrying them out at QBB. The study ventures into the area
of beamforming, multipath compensation, Doppler shift compensation and matched
filter detection. The analysis is carried out using Matlab simulations at RF and QBB.
The results obtained are compared, not only to evaluate the possibility but also the
benefits in terms of the processing load. The results of the study showed that indeed,
carrying out the selected demodulation algorithms at QBB was not only possible, but
also resulted in an improvement in the processing speed brought about by the reduction
in the processing load.
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A numerical procedure for computing errors in the measurement of pulse time-of-arrival and pulse-widthHaden, Lonnie A. January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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The RMS phase error of a phase-locked loop FM demodulator for standard NTSC videoDubbert, Dale F January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Electrical and Computer Engineering.
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