The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Based on information-theoretic security, physical-layer security in an optical code division multiple access (OCDMA) system is analyzed. For the first time, the security leakage factor is employed to evaluate the physicallayer security level, and the safe receiving distance is used to measure the security transmission range. By establishing the wiretap channel model of a coherent OCDMA system, the...
In this paper, we introduce an optical network with cross-layer security, which can enhance security performance. In the transmitter, the user's data is encrypted at first. After that, based on optical encoding, physical layer encryption is implemented. In the receiver, after the corresponding optical decoding process, decryption algorithm is used to restore user's data. In this paper, the security...
A novel type of all-optical D, S-R, J-K and T flip-flop based on polarization Sagnac loop is investigated in this paper, which adopts highly nonlinear of hollow-core photonic crystal fiber (HC-PCF). The novel all-optical flip-flops (AOFFs) can decrease the length of circuit, the input power, and the transmission loss. The principles and characteristics of Sagnac loop are analyzed and the design of...
The background noise and room reverberation severely degrade the performance of the speech enhancement system based on microphone array. Traditional transfer function generalized sidelobe canceller algorithm (TF-GSC) is good for coherent noise, but bad for reverberant speech with noncoherent noise. In this paper, we combine the TF-GSC with Wiener filter to achieve a good speech dereverberation performance...
We put forward the first all-optical optical code-division multiple-access(OCDMA) system with 2 users based on variable code shift keying(CSK). The all-optical exclusive OR logical gate in the system employs the ultrafast performance of optical fiber nonlinear effect and operates without wavelength transforming. In our system, the data rate is 10Gb/s and the transmission distance in optical fiber...
A new family of two-dimensional optical orthogonal code with zero cross-correlation zone (2-D ZCZ) is constructed, using primary LA sequence for time spreading and OCS (one-coincidence sequence) for wavelength hopping. Performances of autocorrelation and cross-correlation of 2-D ZCZ are analyzed. BER performance of two-dimensional OCDMA system is also analyzed.
An improved speech enhancement scheme is proposed based on log-spectral amplitude minimum mean-square error (LSA-MMSE) method in this paper. Burg spectrum and speech absent probability (SAP) are used to improve estimation of priori signal-to-noise ratios (SNR). The estimation of priori SNR is based on "decision-directed" criterion. Burg spectrum is introduced for noisy speech power spectrum...
Two kinds of BMA (Blind Mate A) connector for RFID (Radio Frequency Identification) system, which works at 5.8GHz, is investigated in this paper. The BMA connectors are modeled and simulated in HFSS (High Frequency Structure Simulator). By analyzing the simulation results, three specific steps are adopted to optimize and improve the performance of the RF (Radio Frequency) circuit which is used in...
Interleave Division Multiple Access (IDMA) is a novel approach for multiple access communications. In the IDMA systems, interleavers are the only means of user separation. Thus, the interleavers must be carefully designed. Good interleavers should meet three criteria including low memory requirement, easy generation and low correlation among interleavers. Although there are several existing interleavers...
From the perspective of government regulation behaviors, this paper addresses the effects of information goods market structure on the cooperative R&D innovation incentive and the coordinated effectiveness of supply chain contract.
The impacts of the home-appliance replacement with and without subsidy on the new product demand will affect the price decisions for new product. In this paper, considering two cases with subsidy and without subsidy, we studied the price decisions for the manufacturer and the retailer in three periods: in the first period, there is no home-appliance replacement and without the financial subsidy; in...
This paper presents design and realization of a Ka-band stripline bandpass filter. A single pair of transmission zeros at lower and upper stopbands are achieved by introducing cross coupling. The whole filter is designed as a three-dimension structure in LTCC multi-layers. EM simulation is employed to estimate the performance of the filter and do optimization. The dimension of the fabricated LTCC...
A 15-17GHz Transmit Receive module is developed using Ferro A6M LTCC multilayer substrate. The T/R module consists of a core RF T/R module and a down converter. Three types of T/R architecture are discussed and a T/R architecture based on system requirement is proposed. For the feasibility of the T/R module, each component is designed individually. Three key components, which are low noise amplifier,...
A very compact low-loss stripline diplexer for millimeter-wave applications is presented. For the most compact configuration, a parallel-coupled half-wavelength resonator filter, a folded staggered resonant array filter and a hairpin filter are compared to determine which filter is proper for the diplexer. Two configurations of T junctions are analyzed. A diplexer of 2.73 mm by 3.06 mm and consisting...
We propose a novel scheme of multi-rate quasi-synchronous coherent time-spreading OCDMA system, employing orthogonal variable spreading factor (OVSF) codes with a zero-correlation zone. Within permissible time delay, multiple-access interference and beat noise can be removed in multi-rate quasi-synchronous coherent time-spreading OCDMA system, and the near-far problem can also be eliminated. Simulation...
A power amplifier utilizing multilayer Low temperature co-fired ceramic (LTCC) substrates for a Ku-band transmitter module is presented. The disposition of the thru-plane thermal vias for heat dissipation is analyzed and the heat spreading capability of the entire substrate is calculated. A full passive model of the power amplifier is proposed and simulation in a full-wave EM solver is performed....
A Ku-band transmitter module which is fully integrated in Low temperature co-fired ceramic (LTCC) environment is presented in the paper. The module consists of two T/R switches, one phase shifter, one attenuator, one power amplifier and a circulator. Each of them is designed and assembled individually using Ferro's A6M tapes for the feasibility of the transmitter module. The switch shows a maximum...
This paper presents a low temperature co-fired ceramic (LTCC) bandpass filter, which is embedded into an eleven-layer substrate. A quasi-coaxial structure is employed to reduce the impedance discontinuity caused by GCPW to stripline transition. Vertical metal vias are utilized to realize grounding and shielding for the stripline filter. The measurements of the fabricated filter show an insertion loss...
Based on the analysis of the characteristic of ultrashort optical soliton, third-order dispersion (TOD ) and Raman scattering influences were taken into account. The quantitative relationship between the self-frequency shifting with distance, pulse width and TOD are found out using the Numerical simulation and fitting method. The size of the pulse time delay is also studied caused by the self-frequency...
Bipolar one-coincidence sequence (BOCS) is constructed for coherent 2-D optical code-division multiple access system. Compared with OCS, BOCS has much larger code cardinality under the same code length and the same wavelengths. Furthermore, BOCS has the same cross-correlation and auto-correlation performance, but has lower crosstalk value.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.