Modified fast frequency acquisition via adaptive least squares algorithm

A method and the associated apparatus for estimating the amplitude, frequency, and phase of a signal of interest are presented. The method comprises the following steps: (1) inputting the signal of interest; (2) generating a reference signal with adjustable amplitude, frequency and phase at an output thereof; (3) mixing the signal of interest with the reference signal and a signal 90 deg out of phase with the reference signal to provide a pair of quadrature sample signals comprising respectively a difference between the signal of interest and the reference signal and a difference between the signal of interest and the signal 90 deg out of phase with the reference signal; (4) using the pair of quadrature sample signals to compute estimates of the amplitude, frequency, and phase of an error signal comprising the difference between the signal of interest and the reference signal employing a least squares estimation; (5) adjusting the amplitude, frequency, and phase of the reference signal from the numerically controlled oscillator in a manner which drives the error signal towards zero; and (6) outputting the estimates of the amplitude, frequency, and phase of the error signal in combination with the reference signal to produce a best estimate of the amplitude, frequency, and phase of the signal of interest. The preferred method includes the step of providing the error signal as a real time confidence measure as to the accuracy of the estimates wherein the closer the error signal is to zero, the higher the probability that the estimates are accurate. A matrix in the estimation algorithm provides an estimate of the variance of the estimation error

Efficient detection and signal parameter estimation with application to high dynamic GPS receiver

In a system for deriving position, velocity, and acceleration information from a received signal emitted from an object to be tracked wherein the signal comprises a carrier signal phase modulated by unknown binary data and experiencing very high Doppler and Doppler rate, this invention provides combined estimation/detection apparatus for simultaneously detecting data bits and obtaining estimates of signal parameters such as carrier phase and frequency related to receiver dynamics in a sequential manner. There is a first stage for obtaining estimates of the signal parameters related to phase and frequency in the vicinity of possible data transitions on the basis of measurements obtained within a current data bit. A second stage uses the estimates from the first stage to decide whether or not a data transition has actually occurred. There is a third stage for removing data modulation from the received signal when a data transition has occurred and a fourth stage for using the received signal with data modulation removed therefrom to update global parameters which are dependent only upon receiver dynamics and independent of data modulation. Finally, there is a fifth stage for using the global parameters to determine the position, velocity, and acceleration of the object

Optimum filters and smoothers design for carrier phase and frequency tracking

The report presents the application of fixed lag smoothing algorithms to the problem of estimation of the phase and frequency of a sinusoidal carrier received in the presence of process noise and additive observation noise. A suboptimal structure consists of a phase-locked loop (PLL) followed by post-loop correction to the phase and frequency estimates. When the PLL is operating under high signal-to-noise ratio, the phase detector is approximately linear, and the smoother equations then correspond to the optimal linear equations for an equivalent linear signal model. The performance of such a smoother can be predicted by linear filtering theory. However, if the PLL is operating near the threshold region of the signal-to-noise ratio, the phase detector cannot be assumed to be linear. Then the actual performance of the smoother can significantly differ from that predicted by linear theory. In this report we present both the theoretical and simulated performance of such smoothers derived on the basis of various models for the phase and frequency processes

NEW GENERATION CO-OPERATIVES (NGC) AS A MODEL FOR VALUE-ADDED AGRICULTURAL PROCESSING IN ALBERTA: APPLICATIONS TO FACTORS AFFECTING CHOICE OF PRICING AND PAYMENT PRACTICES BY TRADITIONAL MARKETING AND NEW GENERATION CO-OPERATIVES

This study examines the factors affecting choice of pricing and payment practices by traditional marketing and new generation co-operatives for commodities delivered by their members. These factors include the demographic variables related to type of co-operative organization, level of competition in commodity market, and risk-return perceptions of members and co-operatives. Data for the analysis were obtained through a mail survey. Questionnaires were send to one hundred and ninety five (195) co-operatives in mid-west states of the U.S.A. and Canada. Altogether 93 co-operatives responded to the survey. Mean score analysis, factor analysis and multinomial logit analysis were done. The results indicate that traditional marketing co-operatives are more likely to choose spot market cash price, while new generation co-operatives are more likely to choose pooling practices. Traditional marketing co-operatives appear to be concerned about the members' cash flow needs and members' uncertainty of return; they are also more responsive to increased competitive level in commodity market. New generation co-operatives are more concerned with avoiding the risk of co-operatives' operating deficits and survival of co-operatives. This has implications for new co-operatives just beginning in business.Agribusiness,

Design and Analysis of Absorption Refrigeration System Using H2o + [EMIM] [TFA]

With rapid industrialization and constantly increasing energy consumption, human kind is going to face a growing degradation of environment, if the activities continues as usual. This work is focused to design an absorption refrigeration cycle which gives solution to present cooling problems using low grade heat coming out from the industries. More importance has been given to the ionic liquid based working pairs which are eco-friendly in nature. Ionic Liquids (ILs) are polar compounds which are considered as a combination of organic cations and inorganic anions, and are liquid below 100ºC and have potential to replace common VOCs as solvents in chemical processes. ILs have many favorable attributes such as a low vapor pressure, stability over a large liquid working temperature range, and the ability to be designed to dissolve compounds of interest. This research redresses innovative solutions using ILs for absorption refrigeration cycle. Ionic liquids (ILs) are used as absorbents in absorption refrigeration systems, which present the possibility of overcoming some of the safety and environmental concerns of current systems. In general, absorption refrigeration is attractive since electrical energy is replaced with low grade heat energy. Many ILs are completely miscible with water, which leads the focus to investigate ILs and water for this application. Moreover, this research work aims at finding out the value of COP for H2O + [EMIM] [TFA], to design an optimal absorption refrigerator and to study the dependence of COP on various parameters. It also carries out study on the economic feasibility of the absorption refrigeration cycle using H2O + [EMIM] [TFA] working pair to compare with the conventional working pairs and compression refrigeration system. It further addresses the roadblocks in the simulation of the absorption refrigeration cycle using water and [EMIM] [TFA]

Stem Cell Antigen CD34 In Native And Engineered Form Alter Its Binding Ability To Stromal Cells And Ligands: A Classical Example Of Clinical Benefits Of Therapeutic Genetic Engineering Of Stem Cells In Transplantation

CD34 is a highly glycosylated surface-expressed sialomucin and, because it is present on hematopoietic stem cells (HSCs), has demonstrated immense clinical utility in their enumeration in aphaeresis products, immunoaffinity purification for transplantation, and disease monitoring. The success of CD34 based reagents in identifying hematopoietic progenitors led to the assumption that CD34 is expressed on cells with regenerative potential and is sufficient for hematopoietic reconstitution in marrow-ablated recipients. However, its role has not been identified in substantial detail. 

With the advent of the fact that CD34 binds adapter protein like CRK-L in cytosol and CD34 knock out studies identified a a signaling role, CD34 antigen has been proposed to play a signaling function. Since it is a sialomucin, a member of the group adhesion molecules, we attempted to identify a role by over-expreesing its gene in cell lines. We report here that CD34 and engineered forms (Ser306 & Tyr318) significantly regulates adhesion to stromal cells, like mesenchymal stem cells and bone marrow ligands. These enhance binding of cells overexpressing CD34 by upregulating integrins and we therefore propose that such cells may effectively potentiate the success of transplantation through greater homing if they are used for transfusion