New differentially coherent detectors for acquisition of direct sequence spread-spectrum signals are introduced. These detectors are alternatives to the noncoherent detectors that have been considered almost exclusively in the past. The proposed detectors are suitable for commercial code-division multiple-access (CDMA) systems which operate with a relatively large noise floor and provide a surp...

This paper considers the use of differentially coherent (DC) matched filter (MF) code acquisition in a direct-sequence (DS) spread-spectrum system. Simulation results in tone jamming and with data modulation are presented. The performance of structure is compared to conventional noncoherent (NC) MF acquisition. The performance measure is the mean acquisition time, TMA. The results indicate that...

This article presents a practical implementation of an ECG compression algorithm using a Max-Lloyd quantizer, to optimize the low resources of an ECG acquisition and transmission system (telemetry system) for dolphins and human divers. The algorithm scheme is based on a first-order differential pulse code modulation (DPCM) and uses a Max-Lloyd quantizer to code the difference between the curren...

The acquisition stage in GNSS receivers determines Doppler shifts and code phases of visible satellites. Acquisition is thus a search in two continuous dimensions, where the digital algorithms require a partitioning of the search space into cells. We present analytic expressions for the acquisition performance depending on the partitioning of the Doppler frequency domain. In particular, the imp...

This work was supported by the Brain Korea 21 Project. Abstract~A generalized code acquisition scheme for DS/CDMA systems with multiple antennas is proposed over frequency-selective fading channels. The proposed scheme is developed on the framework of a generalized configuration of multiple antennas and correlators. The nonconsecutive search method is generalized and extended to multiple antenn...

This work presents a useful frequency based acquisition method, built in a CypressTM MicroSystems Programmable System on Chip. The acquisition method implemented in the PSoC is a voltage to frequency-code converter based on the classical Indirect Couningt method. The topology of the PSoC performs as a versatile, precise and scalable platform for data acquisition, making the whole system a perfe...

Word Sense Disambiguation (WSD) is one of the fundamental natural language processing tasks. However, lack of training corpora is a bottleneck to construct a high accurate all-words WSD system. Annotating a large-scale corpus by experts costs enormous time and financial resources. Human Computation is a novel idea for integrating human resources behind the Web, which has been wasted, to solve p...

A generalized acquisition scheme is proposed for direct sequence code-division multiple-access systems with multiple antennas. The proposed scheme employs grouping of multiple antennas as a means of a tradeoff between two important factors determining the mean acquisition time, combining gain and search time. The performance of the proposed acquisition scheme is analyzed in frequency-selective ...

In this paper, we propose a side-peak cancellation scheme for code acquisition of composite binary offset carrier (CBOC) signals. We first model the family of CBOC signals in a generic form, and then, propose a side-peak cancellation scheme by combining correlation functions between the divided sub-carrier and received signals. From numerical results, it is shown that the proposed scheme remove...

A double-dwell acquisition system that can simultaneously operate search and verification processes, by employing two correlation blocks, is proposed. The search block continuously looks for threshold-crossing instants, and at those instants, the verification block is reset and reinitiated. The threshold is time varying and updated depending on the partial correlation. Computer simulation resul...