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In this paper, a control strategy of a modular serial parallel resonant converter (SPRC) modulator system is presented and verified by simulations. The system is based on two SPRC modules forming an input series output parallel (ISOP) stack. To obtain the given output voltage of 115kV, 8 of these ISOP stacks are connected in parallel at the input and in series at the output, forming an input parallel...
This paper presents transistor-level design of a 150 MHz bandwidth continuous-time (CT) ΔΣ modulator in a 0.85 V 28 nm CMOS process. Architectural-level design tradeoff for the high bandwidth requirement is discussed. A stand-alone DAC calibration scheme that suits the high-speed modulator is proposed for linearization. Simulation results show that the modulator achieves signal-to-noise-and-distortion...
In this paper Minimum Mean Square Error (MMSE) precoding for the Preprocessing aided Spatial Modulation (PSM) transmission scheme is investigated. PSM is capable to transmit data both in the spatial domain and in the modulation domain. We derive the upper bound for the Average Bit Error Probability (ABEP) for MMSE precoded PSM data transmission and we show by means of simulations that the bound is...
Using a multi-stage perturbation technique to compensate intra-channel nonlinearities, the computational complexity is reduced by a factor up to 9.3 and the Q-factor improvement over linear compensation is increased from 1.7 dBQ to 2.7 dBQ.
This paper describes a novel family of modified quasi-Z-source buck-boost multilevel inverters with reduced switch count. The inverters are derived by means of the modified inverter configuration with quasi-Z-source networks. The main benefits of the proposed solutions lie in the increased amount of levels with all possible sequences: reduced THD, reduced voltage stress on the transistors and size...
OFDMA and SC-FDMA were chosen as strong candidates for uplink transmission in 3GPP-LTE. OFDMA is a full-fledged multicarrier modulation scheme but has the disadvantage of high PAPR. SC-FDMA achieves low PAPR by spreading the constellation points over entire bandwidth but lacks efficient spectral utilization and prone to Inter Carrier Interference (ICI) at cell edge. Grouped Frequency Division Multiple...
A novel combined approach of SLM (Selective Mapping), PTS (Partial Transmit Sequence) and DSI (Dummy Signal Insertion) is proposed to diminish PAPR (Peak to Average Power Ratio) and OBI (Out of Band Interference) in OFDM (Orthogonal Frequency Division Modulation) systems. The efficiency of OFDM decreases while the cost of installing HPA (High Power Amplifier) increases when the PAPR factor is high...
This paper proposes a new compensation technique to reduce the clock jitter effects for the continuous-time sigma-delta (CT-ΣΔ) modulator by using divided-by-n (D-N) feedback DAC waveform. There are two types of clock jitter: independent clock jitter (random jitter) and accumulated clock jitter (deterministic jitter). This technique provides a useful approach to solve one of the critical non-idealities,...
Underwater acoustic (UWA) communication attracts lots of attention due to its rapid development in maritime applications. In order to meet the increasing service requirements, multicarrier modulation techniques are desired for underwater communication implementations. In this paper, we study three types of multicarrier modulation schemes, e.g., the orthogonal frequency division multiplexing (OFDM),...
Aiming at the large instantaneous common-mode voltage in traditional space vector modulation strategy for two-stage matrix converter (TSMC), on the basis of analyzing the laws of common-mode voltage, an improved modulation strategy to reduce common-mode voltage was proposed. To suppress common-mode voltage effectively, the sector of rectifier stage was doubled into twelve sectors from six sectors,...
In this paper a Nearest Level Control with open loop approach for modular multilevel converter (MMC) is proposed. By using open loop approach it is possible to suppress circulating currents without using feedback controllers. Moreover, with this method, both N+1 and 2N+1 levels (N=number of sub-modules) can be obtained at the output voltage. In addition, the voltage quality is improved and the total...
A low-power high-resolution Delta-Sigma modulator for audio codec, designed in Global-Foundries BCD 0.18µm 1P4M CMOS process, is presented. The modulator employs a fourth-order single-loop feedforward topology with a 3bit-quantizer. A novel structure of Switched-Opamp (SO) utilizing current-starvation and Slew-Rate (SR) boosting is adopted to meet the requirements of high performance and fast settling...
Numerical simulation can quantitatively depict the effect of jamming on the performance of TDLCS (tactical data link communication system). In this paper, main configuration and working principle of TDLCS are presented. Thus anti-jamming techniques such as MSK modulation/ demodulation and DSSS are introduced. Then the three typical modes of jamming and their characteristics are dwelt on. The anti-jamming...
Quadrature Amplitude Modulation (M-QAM) was developed to rapidly and automatically identify the modulation levels of digitally modulated signals at low signal-to-noise ratios (SNR). The method uses wavelet transforms with the optimal scale combining with manifold learning method to identify the modulation levels of the M-QAM signals. Simulation results show that when the SNR is not lower than − 22...
Silicon photonic components are key enablers for low-cost, compact, and reduced power-consumption coherent transceivers. This paper discusses models used to analyze the performance of silicon photonic ring modulators in coherent links, and presents simulation results for 32- and 16-Gbaud PM-QPSK back-to-back transceivers incorporating these modulators in comparison with designs using LiNbO3 MZMs....
We present a fully-digital digital-to-analog converter (FD DAC) architecture design for high-speed communication systems. The FD DAC design is based on the ΔΣ modulation. The specifications for the DAC includes a low 1.2 V supply voltage, a high 5 GS/s input sampling rate, and a wide 2.5 GHz bandwidth. We employ a combination of the time-interleaving, parallel, and pipelining techniques to reduce...
In this paper, we propose differential space-time modulation (DSTM) schemes for multiple input multiple output (MIMO) systems with 2, 4 and 8 transmit antennas, which can be applied where the channel coefficients are not available at both the transmitter and the receiver. For 2 transmit antennas, the transmission matrices are selected from the Weyl group. We use the Kronecker product of matrices of...
In this paper, we propose a latency reduction scheme for an Orthogonal Frequency Division Multiplexing (OFDM) modulator and apply it to a 3GPP LTE transmitter. In the OFDM modulator, latency is composed of the latencies of inverse fast Fourier transform (IFFT), re-ordering and cyclic prefix (CP) addition. The proposed scheme reduces this latency by adding a phase pre-rotator to the IFFT input part...
Presently, multi-string topology is considered the state of the art for grid integration of high power photovoltaic (PV) systems. In this paper, an improvement of the basic multi-string topology is presented which uses a three-level neutral point clamped (3L-NPC) converter as central grid tied inverter. Each of the two capacitors of the split dc link in 3L-NPC converter is fed from a separate multi-string...
In this paper we investigate a comprehensive analysis of Long Term Evolution Advanced (LTE) downlink (DL) physical layer performance using Multi Input Multi Output channel (MIMO) based on standard parameters. The work consists firstly in modeling LTE physical downlink shared channel (PDSCH). The developed model is based on an independent functional blocks in order to facilitate reproduction of signal...
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