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Analysis of synthetic aperture microwave radiometer errors in channel such as mutual-coupling, channel imbalance, system noise based on two-dimensional 16 cells array arrangement is given, and the simulation models are established. Then the error compensation method, noise elimination and Image reconstruction based on BG Algorithm is given. Simulations show compensation method of channel error is...
We propose a new algorithm inspired by the properties of diffusion processes for image filtering. We show that purely nonlinear diffusion process ruled by Fisher equation allows contrast enhancement and noise filtering, but involves a blurry image. By contrast, anisotropic diffusion, described by Perona and Malik algorithm, allows noise filtering and preserves the edges. We show that combining the...
This paper focuses on a pitch estimation method of noisy speech signal using the combination of empirical mode decomposition (EMD) and discrete Fourier transform (DFT). The noisy speech signal is filtered within the range of fundamental frequency. Normalized autocorrelation function (NACF) is computed from the pre-filtered noisy speech signal. The NACF is decomposed by EMD to generate a finite number...
This paper first addresses critical design issues and identifies key design specifications for emerging high-definition (HD) radio technology. A dual-path dual-IF receiver architecture is then proposed for potential low-power low-cost monolithic implementations. Two front-ends are tailored for AM and FM band operations, respectively, using IBM 0.18-μm CMOS process. Circuit techniques such as noise/distortion...
Since the coherent receivers are not feasible to implement low-cost ultra-wideband (UWB) impulse radio (IR) devices featuring extremely low power consumption, energy detector-based (ED-based) noncoherent receivers are more and more frequently chosen. The Pulse Polarity Modulation (PPM) scheme with a threshold compensated receiver is a promising candidate for the implementation of cheap and robust...
This paper presents a way to reduce the effect of narrowband interference (due to either an intentional jamming or the effect of traditional non-spread-spectrum transmission) in ultra-wideband (UWB) communication systems based on asynchronous direct-sequence code-division multiple access (DS-CDMA). To reach this goal, we derive a closed-form expression for the bit error probability in additive white...
The Army Research Laboratory (ARL) has recently developed the Recursive Side-lobe Minimization (RSM) technique (patent pending). The technique is integrated with a standard back-projection algorithm to form synthetic aperture radar (SAR) images with significant reduction in side-lobes and noise. We have achieved significant improvements in noise reduction by applying the RSM technique to our Ultrawideband...
The steady state response of a system to a periodic input is still corrupted by noise transients. For lightly damped systems these noise transients increase considerably the variance of the measured frequency response function (FRF). This paper presents a method that suppresses the influence of the noise transients (leakage errors) in FRF measurements. The method is based on a local polynomial approximation...
A fast-locked all-digital phase-locked loop (PLL) with supply noise suppression is presented. The analysis and design of this all-digital PLL is presented. While the supply noise exits, the loop bandwidth of this all-digital PLL is dynamically adjusted to suppress the jitter. This all-digital PLL is fabricated in a 0.18 um CMOS process. It achieves the locked time of 22.5 us and 78 us with and without...
In this paper, the one-dimensional grey polynomial interpolation (GPI) presented in is applied to impulse noise removal. The proposed approach is motivated by the following observations. First, a median based noise removal approach can be considered as a variation of neighborhood interpolation which is based on the zero-order polynomial. Second, it is well known that the performance of first-order...
This paper derives the utility of recursion based adaptive algorithm for the cancellation of interference in open space in a noisy environment. Several parameters of interest like polarization, transmitter power, noise profile, filter characteristics and sampling rate are contemplated. We test the proficiency and ability of recursive least square (RLS) adaptive algorithm for frequency, temporal and...
External interference is the major performance limiting factors of High frequency surface wave radar (HFSWR) for array signal processing. Especially when the interference falls into the main lobe, the beam pattern is distorted with conventional adaptive digital beam former for the sake of suppressing the main lobe interference. In this paper, a system for suppressing external interference is proposed...
In determining the dynamic range of analogue systems, the lower limit is defined by the rms output noise level Vno. A 50 MHz active bandpass filter (BPF) is designed and simulated using current feedback amplifiers (CFA). The designed circuit produced much lower noise level as well as better output signal level compared to traditional active BPF topologies. This is verified by signal and noise spectral-analysis...
Cyclic MUSIC is a high-resolution direction finding method that utilizes the cyclostationarity property of man-made signals to suppress noises and interferences with undesired cyclic frequency. However, its performance of direction finding can be severely degraded by sensor position errors of the sensor array. In this paper, a PSO based array shape calibration algorithm is proposed to alleviate this...
A salt & pepper noise fast filtering algorithm for grayscale images based on neighborhood correlation detection is presented. By utilizing a 4×4 pixel template, the algorithm can discriminate and filter various patterns of salt & pepper noise spots or blocks within 2×2 pixel size range. In contrast with many kinds of median filtering algorithm, which may cause image blurring, it has much higher...
This paper presents a combined denoising method based on an adaptive Wiener filtering in the wavelet domain and an adaptive Wiener filter in the spatial domain. First a pre-denoised image is obtained with the thresholding denoising in the wavelet domain and the residual noise variance of that is re-estimated. Then an adaptive Wiener filtering in spatial domain is applied to the reconstructed image...
A novel method for the canceling of directional interferences was presented. Tow ship noise is a typical directional interference when towed sonar works, which has bothered sonar researchers for years. Inverse beamforming is a novel method for the canceling of directional interference, but it has its limitation to cancel tow ship noise just because of its multi-path propagation characteristic. Based...
Crosstalk is the major source of performance degradation in DSL systems. In this paper, we propose an adaptive method from time domain for canceling both self and alien crosstalk in a mixed DSL environment. In this method, the current user first listens to the background interference information coming from self-crosstalk, alien crosstalk and noise before data transmission, the adaptive cancellation...
The main source of Electromagnetic Interference (EMI) emissions in power converters used for Telecom application comes from the high switching frequency of DC voltages. Power converters are generally operating in a periodic steady state, interested converter waveforms are typically periodic functions of time. Indeed the EMI emissions are a critical factor, which, can harm the system and degrade the...
Based on an in-circuit measurement approach, a systematic EMI filter design procedure is developed to suppress the noise from a digital board to the power supply. The two-probe technique adopted for the in-circuit measurement allows the impedances of the power supply and the PCB to be determined under its actual operating condition. With the measured impedance information, a suitable filter topology...
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