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In this paper, we study on the automatic gain control (AGC) scheme for pulse amplitude modulation (PAM) with low-precision analog-to-digital converters (ADCs). For M-PAM communication systems, we investigate the problem of AGC schemes under the assumption that low precision ADCs (e.g., 1–4 bits) are used at the receiver end. We adopt blind approach to estimate the amplitude of an unknown sequence...
In ultra-wideband (UWB) communications for power electronic systems, large power consumption and logic resource are occupied by multi-parallel sliding-block Viterbi decoders. A novel add-select-delay-compare architecture for Viterbi decoder is proposed to minimize these consumptions. In this architecture, a nested iteration of add-select and compare-select with balanced settling path is utilized to...
The nonlinear distortion from power amplifier (PA) distorts the signal and causes significant impact on the symbol-error-rate (SER) performance for the electric-power-systems (EPS) communications. This paper proposes a calculation of the optimal input power back-off (IBO) to resist PA nonlinearity, as well as guarantee an appropriate signal-to-noise ratio (SNR), by minimizing the mean square error...
A 300 GHz quadrupler has been developed use AS1 Schottky diode. The quadrupler use the balanced planar diode configuration. The diode n-layer and n+-layer conductivity are given by GaAs semiconductor doping theory. Rs is given combined low-frequency simulation with empirical formula. The linear region is simulated in the HFSS, the S-parameter is imported into in the ADS. The quadrupler exhibits that...
This paper presents a microwave stripline-to-stripline vertical interconnect in Low Temperature Co-fired Ceramic (LTCC) Technology. Two circular grooves are separately designed in the stripline lower ground plane and the stripline upper ground plane to reduce the insertion loss and improve the return loss. The mentioned structure has been simulated by HFSS. According to the simulation comparison results,...
In this paper, we propose a robust timing and frequency synchronization algorithm for the orthogonal frequency division multiplexing (OFDM) systems. The algorithm we proposed can achieve accurate timing and frequency synchronization in time-domain by using the preamble consisting of only one training symbol based on constant amplitude zero autocorrelation (CAZAC) sequence and a new weighting factor...
A novel mode converter is introduced in this paper, transferring the TE10 mode, which is the dominant mode in rectangular waveguide into TM01 mode in coaxial waveguide. The simulation and optimization is based on CST and good results have been achieved with the VSWR 1.2 at 34.5GHz center frequency and the efficiency is greater than 86%. The test results agree well with the simulation, certifying the...
OFDM-CPM is now a recognized alternative to conventional OFDM for the transmission of signals over Non-Continuous Wideband channel. This paper presents a characterization of nonlinear distortion effects in orthogonal frequency-division multiplexing/continuous phase modulation (OFDM-CPM) transmission systems on Non-Continuous Wideband. In a second step, a comparison with simulation results is carried...
A compact ultra-wideband (UWB) bandpass filter (BPF) with two notched bands based on ridged waveguide is presented. Capacitive loading short stub structures are introduced to reject the undesired wireless local-area network (WLAN) radio signals (i.e., 5.2-and-5.8-GHz bands). By independently adjusting the heights of the capacitive loading posts in the short stubs, the centre frequencies of two notched...
In this paper, a microstrip bandpass filter based on cross-coupled is designed. Ceramic substrate with high dielectric constant and SIR structure are adopted. Because of Quarter-Wave and ceramic substrate, the whole size of the filter can be fabricated very small. Specifically, when the center frequency is 3.5GHz, its volume is 7mm*6.2mm*0.127mm. Besides the compact size, wide stopband and narrow...
A modified application of luneburg lens has been demonstrated which is used in ns-pulse radiation. Such a situation has been simulated to have a remarkable enhancement in time-domain gain, radiation pattern and received signal peak-to-peak value. Despite of diffraction of electromagnetic wave, both TEM horn antenna and vivaldi antenna have been worked well focused by the lens. Besides, an modified...
In multicast communication based on LKH, when a group member is added or evicted from the communication group, the system needs to update the group key to ensure the security of communication. In order to further reduce the rekey overhead, LKH is modified into a new key tree structure, which is constructed by heuristic search algorithm based on the number of group members. Compared to the LKH key...
A practical method for extracting the coupling matrix from measured or electromagnetic simulated S-parameters of narrow band cross-coupled filters with large losses is presented in this paper. The method can be applied to computer-aided tuning or computer-aided design of microwave filters to accelerate the filter design and physical implementation. The modified band-pass to low-pass transformation...
A lossy filter rational model extraction technique based on modified Cauchy method is presented in this paper. The conventional Cauchy method is only for lossless case, not suitable for lossy filter. The rational polynomials model is the prerequisite to synthesize the low-pass prototype (the evaluation of the coupling matrix) for computer-aided tuning. To this purpose, we modify the conventional Cauchy...
Both the back and forward transient scattering mechanisms of dipole array with different loading forms have been investigated from time-domain and frequency-domain. Using 4×8 dipole array as an example, the data of scattering from the array under the incidence of Gaussian pulses are obtained by finite differential time-domain method. The influences of the incident angle on the waveforms and loading...
A pulse-radiating bow-tie antenna with enhanced electric-field focusing property in the near field is studied. The focusing property is achieved by placing an ellipsoid reflector around the bow-tie antenna. A section of microstrip reflection line combined with a photoconductive semiconductor switches is designed as a source to generate a short pulse for antenna excitation. In simulations, the surrounding...
WR-1.0 rectangular waveguide cavity band-pass filter based on micromaching technique is designed in this letter. The filter consists of two resonant cavities. A transmission zero is implemented by means of broaden stubs. The stub is broaden to the width of the resonant cavity, which simplify the fabrication. The proposed filter is fabricated using the deep reactive ion etching (DRIE) micromachining...
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