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.
This article investigates the interaction of white noise and the systematic noise of a time quantization that occurs in a time-interval counter (TIC). By buildiing a theoretical model, do analysis and simulatiion, understanding of quantization effect and noise interaction is achieved.
This paper presents an analytical comparison of two commonly used read-out structures for pulse oximeters, in a wearable application context. The objective is to analyze and highlight the trade-off between the SNR and the power consumption. The proposed analysis clarifies, by the means of analytical equations, the impact of the input photocurrent, the photodiode parasitic capacitance, the feedback...
This work describes a way to optimize the controller fixed-point representation in programmable logic devices (eg. FPGA) with genetic algorithms. The optimization uses the error between floating-point and fixed-point representation as well as a quantization noise error model. Thus, both terms allow weighting between the to be expected theoretical and actually occurred simulation error. This task could...
Compressed sensing allows for stable reconstruction of sparse source vectors from noisy, linear measurement vectors of much lower dimension than the source vectors. In many applications, low-bit rate quantization is unavoidable or even desired in further processing of the signal, and suitable algorithms need to be developed for minimizing negative effects on the recovered source signal due to the...
A single-input multiple-output (SIMO) multiple access channel with a large number of uncoded non-cooperating single antenna transmitters and joint processing at a finite precision multi-antenna receiver is considered. We fix the number of receiver antennas per transmitter and investigate the effects of receiver quantization on the recovery of the transmitted signals in the asymptotic limit of a large...
A key practical constraint on the design of Hybrid automatic repeat request (HARQ) schemes is the modem chip area that needs to be allocated to store previously received packets. The fact that, in modern wireless standards, this area can amount to a large fraction of the overall chip has recently highlighted the importance of HARQ buffer management, that is, of the use of advanced compression policies...
Fully-digital single-bit-output (DAC-less) frequency synthesizers with imbedded modulation capability are considered as the foundation for building fully-digital RF transmitters. The paper presents an overview of recent results and introduces a new architecture based on sigma-delta like feedback noise shaping.
In this paper, we analyse the effect of the quantization of signals used for system identification and show an optimal quantization scheme for minimizing estimation errors under a constraint on the number of subsections of the quantized signals. The optimal quantization scheme has the property that it is coarse near the origin and dense at a distance from it in the definition area of the signals....
This paper studies a Quantized Gossip-based Interactive Kalman Filtering (QGIKF) algorithm implemented in a wireless sensor network, where the sensors exchange their quantized states with neighbors via inter-sensor communications. We show that with the information loss due to quantization, the network can still achieve weak consensus, i.e., the estimation error variance sequence at a randomly selected...
Since 2010 we have been developing a quantum-voltage-calibrated Johnson noise thermometer at NIM to measure the Boltzmann constant k. With recent improvements in grounding and shielding of the electronics, and matching of the noise sources and transmission lines, the effects of electromagnetic interference and variations of fitting parameters with different bandwidths were greatly reduced. By combining...
This paper presents a novel adaptive safe-band for quantization based audio watermarking methods, aiming to improve robustness. Considerable number of audio watermarking methods have been developed using quantization based techniques. These techniques are generally vulnerable to signal processing attacks. For these conventional quantization based techniques, robustness can be marginally improved by...
This work presents Direct-Digital Frequency Synthesis architectures based on the classical Pulse-Direct Digital Synthesizer and using two quantization paths with opposite dithers or multi-path quantization with independent dithers to achieve spurs-free output with improved dynamic range. The proposed architectures are studied mathematically and the theory is supported by MATLAB simulation results.
The spectrum of Nyquist-rate, single-bit quantized, randomly-dithered, amplitude-modulated, sinewave is studied analytically. It is shown that by choosing the dithering sequence appropriately and imposing certain constraints on the modulating sequence, the output is spurs-free and the quantization noise is white. MATLAB simulation confirms the theoretical results.
It is of great value to study control systems employing sensors and actuators which are geographically separated. In this paper, we study a system with bounded noise and stabilize it under output quantized feedback. Some people have done research on full-state observable linear systems. Here we consider the general(not necessarily full-state observable) output feedback situation with system noise...
In this paper, the tracking of a slowly varying scalar Wiener process based on quantized noisy measurements is studied. An adaptive algorithm using a quantizer with adjustable input gain and bias is presented as a low complexity solution. The mean and asymptotic mean squared error of the algorithm are derived. Simulations under Cauchy and Gaussian noise are presented to validate the results and a...
The increasing attractiveness and trust on digital photography has given rise to new acceptability issues in the field of image forensics. There are many advantages to using digital images. Digital cameras produce immediate images, allowing the photographer to outlook the images and immediately decide whether the photographs are sufficient without the postponement of waiting for the film and prints...
This paper presents a two-path design of quadrature band-pass modulators and discusses the architectural level implementation issues for power reduction. The methodology uses an architecture which locks IF frequencies to the sampling frequency. The basic delay based solution is converted into integrator based solution for the implementation. Robustness of the structure against the mismatch...
The availability and position estimation performance of global navigation satellite systems (GNSS) can be enhanced with ground-based ranging sources, called pseudolites. Because of the high relative power of their signals, they usually transmit pulsed signals. In this way their interference on the satellite signals is restricted to only a fraction of time (duty cycle). To avoid mutual interference...
A delta-sigma modulator with digital signal feed-forward architecture is presented. Digital domain summation which is favorable in high speed operation is adopted in the proposed modulator by employing extra quantizers in each signal path. Additional quantization noise from the extra quantizers is effectively eliminated by digital cancellation logic. The prototype chip, fabricated in a 0.13µm CMOS...
A theoretical analysis on interframe predictive coding is presented in which special attention is paid on two issues that are practically important. First, the displacements between the target and reference images are usually given with limited accuracy due to quantization. Second, when the displacements are provided in subpixel accuracies, interpolation between the pixels is necessary to produce...
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.