PN code tracking is one of the most important factors that affect the performance of spread spectrum receivers. It is desirable to maintain PN code tracking for a long period of time and with high accuracy. This paper presents a non-coherent digital delay-locked loop (DLL) for code tracking in direct-sequence spread spectrum (DS-SS) systems. The proposed technique utilizes three non-coherent co...

The impact of Doppler frequency hopping on code tracking performance is simulated. A design on pseudonoise (PN) Code Tracking Loop aided by the carrier tracking loop according to the carrier frequency hoping pattern is proposed in this paper. This scheme can be applied in the Telemetry, Tracking, and Commanding system which uses Direct Sequence/Frequency Hopping Spread Spectrum (DS/FH) hybrid s...

This paper presents the root-mean-squared tracking error performance analysis of a class of coherent digital delay-locked loops for multicode direct sequence spread spectrum signals in bandlimited correlated Rayleigh fading channels. In the transmit side, multiple independent PSK-modulated data streams in the in-phase and qudrature phase branches are spread by short mutually orthogonal codes be...

In this letter the antenna array based GNSS signal acquisition is proposed by firstly projecting the input signal vector onto the noise subspace which is orthogonal to interference subspace for strong interferences suppression. Then, considering that the projection matrix is rank-deficient, we propose to apply forward spatial smoothing to decorrelation of the coherent interference-free signal v...

The new GPS/Galileo/Compass signals use much longer code lengths and higher code frequencies than the GPS L1 C/A signal. As a result, they can provide improved ranging and anti-jamming performances. Unfortunately, their acquisition complexity is significantly higher, especially in the high sensitivity or weak signal acquisition context. Acquisition of very weak signals requires long integration...

BACKGROUND Bloodstream infections (BSI) occur in up to 350 000 inpatient admissions each year in the US, with BSI rates among patients receiving parenteral nutrition (PN) varying from 1.3% to 39%. BSI-attributable costs were estimated to approximate $US12 000 per episode in 2000. While previous studies have compared the cost of different PN preparation methods, this analysis evaluates both the ...

In this paper, for an odd prime p such that p ≡ 3 mod 4, odd n, and d = (pn +1)/(pk +1)+ (pn −1)/2 with k|n, the value distribution of the exponential sum S (a, b) is calculated as a and b run through Fpn . The sequence family G in which each sequence has the period of N = pn − 1 is also constructed. The family size of G is pn and the correlation magnitude is roughly upper bounded by (pk + 1) √...

Spread spectrum communication is a new theory and modulation technique, and different from the conventional communication system. A good correlation property and large linear period of Pseudo-random sequence is the basis of spread spectrum communication systems intern CDMA (code division multiple access communication systems). Out of several techniques to implement direct sequence spread Spectr...

CONTEXT Partial nephrectomy (PN) is the current gold standard treatment for small localized renal tumors.; however, the impact of duration and type of intraoperative ischemia on renal function (RF) after PN is a subject of significant debate. OBJECTIVE To review the current evidence on the relationship of intraoperative ischemia and RF after PN. EVIDENCE ACQUISITION A review of English-lang...