scholarly journals Design of sweep frequency signal source in residual stress detection platform based on Zynq

2021 ◽  
Vol 2085 (1) ◽  
pp. 012006
Author(s):  
Lei Yang ◽  
Zhipeng Li
Keyword(s):  
Residual Stress ◽  
High Frequency ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Signal Generator ◽  
Frequency Resolution ◽  
Frequency Error ◽  
Signal Source ◽  
Stress Detection ◽  
Direct Digital Frequency Synthesis

Abstract The signal generator based on DDS technology has high frequency and resolution, and is widely used in many fields such as instrument technology, radar, satellite timing, remote control and telemetry, and is one of the important directions of current signal generator research. In order to achieve a cost-effective, high frequency resolution signal source to stimulate the sensors in the residual stress detection system, this paper selects the Zynq-7020 on-chip system to control the 14-bit direct digital frequency synthesis chip AD9954 to obtain a 40Hz~1MHz sinusoidal signal output. Finally, the performance and technical parameters of the system are tested experimentally. The output signal of the signal source is stable, the signal-to-noise ratio is high, and the frequency error is within 0.1%.

A Method to Improve the Accuracy of Adjustable Phase Difference of Signal Generator

2011 ◽  
Vol 301-303 ◽  
pp. 823-827
Author(s):  
Jian Guo ◽  
Bing Wu Liu ◽  
Ping Ping Dong
Keyword(s):  
Phase Difference ◽  
Phase Control ◽  
Control Word ◽  
Signal Generator ◽  
Frequency Resolution ◽  
Frequency Synthesis ◽  
Direct Digital Frequency Synthesis ◽  
Working Principle ◽  
Phase Setting ◽  
Low Efficiency

Direct digital frequency synthesis (DDFS) technology is applied widely in traditional fields which need signal source since it has a lot of advantages such as high frequency resolution, fast frequency setting and conversion speed and so on. Based on the working principle of DDFS, it is very important to calculate the phase control word when synthesizing the continuous adjustable phase difference signals. To address the shortcoming of large computation, low efficiency of phase difference setting, more storage space occupied or significant cumulative errors of phase setting when calculating phase control word with traditional methods, a novel algorithm for computing phase control word is studied in this paper. This new method does not need large computation and more space and simultaneously it can decrease the error greatly, which plays an important role in improving the phase setting speed and precision in signal generator.

scholarly journals The Magnetic Fields in the Envelopes of Proto-Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 381-381 ◽  
Author(s):  
J.Y. Hu
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
Planetary Nebulae ◽  
Frequency Resolution ◽  
High Signal ◽  
Max Planck ◽  
Molecular Line ◽  
Protoplanetary Nebulae ◽  
The Magnetic Field

It is possible that the magnetic field plays important role in the formation of planetary nebulae(Poscoli, 1992). In order to measure the strength of magnetic field in the envelope of protoplanetary nebulae(PPNe) we have used the Max-Planck-Institut fur Radioastronomie 100-m telescope at Effelsberg to obtain the high frequency resolution and high signal-to-noise ratio 1612 MHz spectra of PPNe, IRAS08005-2356, 18276-1431, and 20406+2953 in both circular polarization. The nature of PPN of these objects are confirmed by Slikhuis et al.(1991), Le Bertre(1987), and Hu et al.(1992) based on the extensive optical, infrared and radio molecular line observations.

Investigation of Phase-Shifting and Frequency Conversion Sinusoidal Signal Generator Based on DDS and FPGA

2014 ◽  
Vol 556-562 ◽  
pp. 1580-1583
Author(s):  
Xu Han ◽  
Peng Wang ◽  
Shan Shan Li ◽  
Xue Zhao
Keyword(s):  
High Frequency ◽  
Frequency Conversion ◽  
Phase Shifting ◽  
Frequency Resolution ◽  
Frequency Synthesis ◽  
Output Frequency ◽  
Direct Digital Frequency Synthesis ◽  
Digital Frequency ◽  
Field Programmable ◽  
Low Phase Noise

The direct digital frequency synthesis (DDS) technology has high frequency resolution, fast frequency switching, low phase noise and higher frequency stability, so it is widely used in communications, aerospace, instrumentation and other fields. In this paper, the DDS system was designed based on Field Programmable Gate Array (FPGA) and hardware design language (VHDL). The experimental and simulation results show that the system has stable output frequency, high frequency accuracy, adjustable frequency and phase.

ARMA – Filtering of Evoked Potentials

1984 ◽  
Vol 23 (01) ◽  
pp. 29-36 ◽  
Author(s):  
H.-J. Heinze ◽  
H. Künkel
Keyword(s):  
Evoked Potentials ◽  
High Frequency ◽  
Theoretical Basis ◽  
Evoked Potential ◽  
Averaging Method ◽  
Signal To Noise Ratio ◽  
Arma Model ◽  
Frequency Resolution ◽  
Periodic Signal ◽  
Simulation Studies

SummaryA method of evoked potential data processing alternative to the averaging method will be discussed. It is to extract evoked potentials only from two segments. The theoretical basis of this procedure is the so-called ARMA model which gives a high frequency resolution of a periodic signal mixed with noise in a relatively low signal-to-noise ratio. The method is tested by simulation studies. The applicability will be demonstrated by clinical examples.

scholarly journals Impedance Cytometry for Detection of Particle and Counting using Low Phase Noise DDFS – LUT

2020 ◽  
Vol 9 (8) ◽  
pp. 847-850
Keyword(s):  
Power Consumption ◽  
High Frequency ◽  
Software Defined Radio ◽  
Frequency Resolution ◽  
Noise Power ◽  
Direct Digital Frequency Synthesis ◽  
Digital To Analog Converter ◽  
Digital Frequency ◽  
Impedance Cytometry ◽  
Direct Digital Frequency Synthesizers

The biotechnology is widely growing with many technologies, still we see a large gap in real-time implementation of complete blood counting. To increase the resolution and accuracy of the measurements advanced communication DDFS can be used. The elements in Direct Digital Frequency Synthesizers (DDFS) involved are: phase accumulator, a phase to amplitude converter which also called look up table (LUT), a digital to analog converter along with active filter. Direct digital frequency synthesis is a method for generating complex high - frequency waveforms for specific applications. This DDFS generates frequency resolution which makes it ideal components use in radar system, software defined radio, modern wireless communicating system, advanced satellite navigation purpose. Use cases for high frequency we get interrupt with spurious noise, larger ROM size, and high power consumption of DDFS signal. In this paper we are proposing the use of signal generated from DDFS to impedance cytometry in which the number of particles gets detected by getting the output frequency different from the input frequency. Due to use of small frequency range of signal spurious noise, power consumption and ROM size will be less with effective performance

A Signal Generator Based on AD9850

2013 ◽  
Vol 712-715 ◽  
pp. 1767-1770
Author(s):  
Xian Yi Zhang ◽  
Jian Xu ◽  
Xiang Quan Guo ◽  
Yan Ting Lan ◽  
Jia Yan Tao
Keyword(s):  
Cost Effective ◽  
Sine Wave ◽  
Signal Generator ◽  
Experimental Results ◽  
Signal Source ◽  
Frequency Synthesis ◽  
Direct Digital Frequency Synthesis ◽  
Basic Principles ◽  
Hardware System ◽  
Digital Frequency

This paper analyzes the advantages of the direct digital frequency synthesis (DDS) in signal generator applications, introduces the basic principles and characteristics of AD9850, a cost-effective chip, shows the overall scheme of a signal source design based on DDS and implements the hardware system. Experimental results show the signal generator can produce sine wave signals scoping from 100Hz to 5MHz, clock signals and triangular wave signals and can display frequency on the LCD.

scholarly journals Evaluation of working memory in relation to cochlear implant consonant speech discrimination

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Mai M. El Ghazaly ◽  
Mona I. Mourad ◽  
Nesrine H. Hamouda ◽  
Mohamed A. Talaat
Keyword(s):  
Working Memory ◽  
Speech Perception ◽  
High Frequency ◽  
Word List ◽  
Frequency Discrimination ◽  
Frequency Resolution ◽  
Speech Discrimination ◽  
Place Of Articulation ◽  
Strong Positive Relationship ◽  
Speech And Language Development

Abstract Background Speech perception in cochlear implants (CI) is affected by frequency resolution, exposure time, and working memory. Frequency discrimination is especially difficult in CI. Working memory is important for speech and language development and is expected to contribute to the vast variability in CI speech reception and expression outcome. The aim of this study is to evaluate CI patients’ consonants discrimination that varies in voicing, manner, and place of articulation imparting differences in pitch, time, and intensity, and also to evaluate working memory status and its possible effect on consonant discrimination. Results Fifty-five CI patients were included in this study. Their aided thresholds were less than 40 dBHL. Consonant speech discrimination was assessed using Arabic consonant discrimination words. Working memory was assessed using Test of Memory and Learning-2 (TOMAL-2). Subjects were divided according to the onset of hearing loss into prelingual children and postlingual adults and teenagers. Consonant classes studied were fricatives, stops, nasals, and laterals. Performance on the high frequency CVC words was 64.23% ± 17.41 for prelinguals and 61.70% ± 14.47 for postlinguals. These scores were significantly lower than scores on phonetically balanced word list (PBWL) of 79.94% ± 12.69 for prelinguals and 80.80% ± 11.36 for postlinguals. The lowest scores were for the fricatives. Working memory scores were strongly and positively correlated with speech discrimination scores. Conclusions Consonant discrimination using high frequency weighted words can provide a realistic tool for assessment of CI speech perception. Working memory skills showed a strong positive relationship with speech discrimination abilities in CI.

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