A DSP-Based Design for Generating Limited White Noise Wave

2010 ◽  
Vol 34-35 ◽  
pp. 1228-1232
Author(s):  
Ming Ma ◽  
Run Jie Shen ◽  
Bing Fang ◽  
Ming Wei Sun ◽  
Wen He
Keyword(s):  
White Noise ◽  
Frequency Domain ◽  
Simulation Experiment ◽  
Amplitude Spectrum ◽  
Random Numbers ◽  
Zero Section ◽  
Signal Source ◽  
External Data ◽  
Noise Simulation ◽  
Data Memory

In this paper, based on the analysis of white noise generation, equably distributed pseudo-random numbers are generated by a method of mixed congruency. In the case that the pseudo-random numbers are taken as the phase spectrum and the amplitude spectrum is equally set, the waveform array of frequency-domain is made up. The array is transformed from frequency-domain to time-domain by the IFFT before stored into the external data memory. Based on the wave generating technology of DDS, the timer interruption of DSP2812 is installed to change the frequency for generating wave .Then the number is taken out from the external memory. The limited white noise is formed by the way of D/A and zero-section maintenance .This generator can be used as signal source in the noise simulation experiment.

CHARACTERIZATION OF NUCLEAR IMAGES BASED ON ANALYSIS OF FRACTIONAL SUMMATION SYSTEMS

Fractals ◽  
2004 ◽  
Vol 12 (02) ◽  
pp. 157-169 ◽  
Author(s):  
HAI-SHAN WU ◽  
ANDREW J. EINSTEIN ◽  
LIANE DELIGDISCH ◽  
TAMARA KALIR ◽  
JOAN GIL
Keyword(s):  
White Noise ◽  
Frequency Domain ◽  
Discrete System ◽  
Fractional Integral ◽  
Continuous System ◽  
Time Range ◽  
System Function ◽  
Autocovariance Function ◽  
Frequency Domain Methods

While frequency-based methods for the characterization of fractals are popular and effective in many applications, they have limitations when applied to irregularly shaped images, such as nuclear images. The irregularity renders texture characterization by frequency domain methods, based upon Fourier transform, problematic. To address this situation, this paper presents an algorithm based upon the signal analysis in the spatial domain. An autocovariance function can be estimated regardless of the shape and size of regions where the image is defined. As in the continuous fractional Brownian motion (FBM) that results from inputting white noise into a specific fractional integral system, a discrete FBM can be related to white noise by a specific fractional summation system (FSS) that is linear, causal and shift-invariant. Although the method of direct sampling is not valid for converting a continuous fractional integral to a discrete fractional summation, discrete fractional summations similar to the sampled system functions can be obtained through an iterative process. While the continuous system function of a fractional integral is linear in the frequency domain when plotted in log-log scales, unfortunately, it is not true for the comparable discrete system function. The discrete system function is actually approximately linear in the log-log scales over a very limited range. The slope of the straight line that approximates the function curve in the mean-square-error (MSE) sense in a specific time range provides a description of the autocovariance function that reveals the statistical relations among the local textures. Applications to characterization of ovary nuclear images in groups of normal, atypical and cancer cases are studied and presented.

Design of External Memory Based on the C8051F02x Microcomputer

2013 ◽  
Vol 722 ◽  
pp. 64-67
Author(s):  
Zhi Jing Liu
Keyword(s):  
External Memory ◽  
Address Space ◽  
Internal Memory ◽  
External Data ◽  
Memory Address ◽  
Data Memory ◽  
Address Data ◽  
On Chip

The C8051F02x microcomputer and its saving structure are introduced, I/O function expanding and connecting are analyzed for its data. The exterior data and the structure of the memory are elaborated with the technique expanding request. Access or expansion of external data memory, external memory interfaces (EMIF). Its data memory address space can be flexibly implemented by the on-chip internal memory can be extended to chip memory. EMIF can be configured as address / data multiplexed or non-multiplexed mode. When big capacity FLASH memorizer is needed, this paper provides a realistic design and methodology for microcomputer and string big capacity FLASH of total line, through the setup and analysis of the SPI of the C8051F02x MCU inner part.

Estimation of Eccentric Distance for Four-Tooth End Mills Based on Amplitude Spectrum

2013 ◽  
Vol 278-280 ◽  
pp. 207-211
Author(s):  
Can Liu ◽  
Jing Quan Wu ◽  
Guang Hui Li ◽  
Guang Yu Tan
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Mathematical Reasoning ◽  
Spectral Characteristics ◽  
Amplitude Spectrum ◽  
Frequency Component ◽  
Milling Force ◽  
End Mills ◽  
Domain Description ◽  
Eccentric Distance

Time-domain expressions of nominal component and eccentric component that composing horizontal peripheral milling force are derived from geometry of down milling, they are periodic functions with fundamental frequencies same as tooth-frequency and spindle-frequency respectively. By expanding these two time-domain expressions with Taylor series, the frequency-domain description of periheral milling force is obtained. Further mathematical reasoning is exerted on this frequency-domain description, and it proved that as for four-tooth end mills, even-order harmonics of eccentric milling force do not exist, and the amplitude of spindle-frequency component be linear with eccentric distance, but irrelevant with eccentric angle. Above research results imply that the tooth-frequency component of four-tooth end mills is irrelevant with eccentricity, and that eccentric distance can be estimated with amplitudes of tooth-frequency and spindle-frequency components. Results of milling experiment imply that this eccentric-distance estimating method be effective. Spectral characteristics of eccentric milling force for four-tooth end mills are revealed with theory deduction, and the estimation algorithm for eccentric distance with simple calculation is present. Study conclusions can be used in eccentric-geometry estimating and in milling-force modeling.

scholarly journals Simulation Experiment and Analysis of GNSS/INS/LEO/5G Integrated Navigation Based on Federated Filtering Algorithm

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 550
Author(s):  
Yuqiang Wang ◽  
Bohao Zhao ◽  
Wei Zhang ◽  
Keman Li
Keyword(s):  
Simulation Experiment ◽  
Signal Source ◽  
Integrated Navigation ◽  
Filtering Algorithm ◽  
Tightly Coupled ◽  
Order Of Magnitude ◽  
Federated Filtering ◽  
Navigation Mode ◽  
High Degree ◽  
New Infrastructure

This article examines the positioning effect of integrated navigation after adding an LEO constellation signal source and a 5G ranging signal source in the context of China’s new infrastructure construction. The tightly coupled Kalman federal filters are used as the algorithm framework. Each signal source required for integrated navigation is simulated in this article. At the same time, by limiting the range of the azimuth angle and visible height angle, different experimental scenes are simulated to verify the contribution of the new signal source to the traditional satellite navigation, and the positioning results are analyzed. Finally, the article compares the distribution of different federal filtering information factors and reveals the method of assigning information factors when combining navigation with sensors with different precision. The experimental results show that the addition of LEO constellation and 5G ranging signals improves the positioning accuracy of the original INS/GNSS by an order of magnitude and ensures a high degree of positioning continuity. Moreover, the experiment shows that the federated filtering algorithm can adapt to the combined navigation mode in different scenarios by combining different precision sensors for navigation positioning.

scholarly journals Mathematical model of parametrically controlled matched filters

2017 ◽  
Vol 1 (1) ◽  
pp. 27-31
Author(s):  
Borislav Georgiev Naydenov ◽  
Antim Hristov Yordanov ◽  
Lyubomir Petrov Kamburov
Keyword(s):  
Mathematical Model ◽  
White Noise ◽  
Frequency Domain ◽  
Mobile Communication ◽  
Communication Systems ◽  
Noise Resistance ◽  
Matched Filters ◽  
Variable Parameters ◽  
Radar Systems ◽  
Auto Correlation

A one model of parametrically controlled coherent filters is described and analyzed, applied also in radar systems and mobile communication systems to improve noise resistance. Application of the Nyquist-Shannon theorem in the frequency domain to obtain a set of frequency filters with variable parameters. The conversion of the signal at the output of the parameter filter using the auto correlation feature is shown when a normal white noise occurs.

scholarly journals Time-Frequency Domain Deconvolution based on Synchrosqueezing Generalized S Transform

2021 ◽  
pp. 148-155
Author(s):  
Shulin Zheng ◽  
Zijun Shen
Keyword(s):  
Frequency Domain ◽  
Seismic Data ◽  
Oil And Gas ◽  
Amplitude Spectrum ◽  
Frequency Resolution ◽  
Good Effect ◽  
Time Frequency ◽  
S Transform ◽  
Convolution Model ◽  
Generalized S Transform

Complex geological characteristics and deepening of the mining depth are the difficulties of oil and gas exploration at this stage, so high-resolution processing of seismic data is needed to obtain more effective information. Starting from the time-frequency analysis method, we propose a time-frequency domain dynamic deconvolution based on the Synchrosqueezing generalized S transform (SSGST). Combined with spectrum simulation to estimate the wavelet amplitude spectrum, the dynamic convolution model is used to eliminate the influence of dynamic wavelet on seismic records, and the seismic signal with higher time-frequency resolution can be obtained. Through the verification of synthetic signals and actual signals, it is concluded that the time-frequency domain dynamic deconvolution based on the SSGST algorithm has a good effect in improving the resolution and vertical resolution of the thin layer of seismic data.

Unified Transient and Frequency Domain Noise Simulation for Random Telegraph Noise and Flicker Noise Using a Physics-Based Model

2014 ◽  
Vol 61 (12) ◽  
pp. 4197-4203 ◽  
Author(s):  
Yusuke Higashi ◽  
Nobuyuki Momo ◽  
Hiroki Sasaki ◽  
Hisayo Sasaki Momose ◽  
Tatsuya Ohguro ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Flicker Noise ◽  
Random Telegraph Noise ◽  
Noise Simulation ◽  
Telegraph Noise
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