scholarly journals Extremely High Frequency Resolution and Low Harmonic Distortion Digital Look-Up-Table Sinusoidal Oscillators

2000 ◽  
Vol 23 (2) ◽  
pp. 101-113 ◽  
Author(s):  
M. M. Al-Ibrahim (Jarrah)
Keyword(s):  
High Frequency ◽  
Harmonic Distortion ◽  
Frequency Resolution ◽  
Trigonometric Interpolation ◽  
New Techniques ◽  
Interpolation Methods ◽  
Sinusoidal Oscillators ◽  
Look Up Table ◽  
Extremely High Frequency ◽  
Address Register

New techniques to efficiently increase the frequency resolution of digital sinusoidal oscillators based on look-up-table (LUT) methods are proposed. The increase in frequency resolution is achieved while maintaining very low level of spurious harmonic distortion. The proposed techniques increase the LUT length to a level at which the spurious harmonic distortion is negligible. The first proposed technique is based on partitioning the address register into three sets and dividing the available LUT length into three smaller tables addressed according to the content of the address register sets. The second proposed technique utilizes one LUT and interpolates the values of the samples that are not stored in the table. The third proposed technique is similar to the first technique with the advantage of simpler implementation and lower levels of spurious harmonic distortion. The proposed techniques are simulated and their performance is compared with that of the direct LUT and trigonometric interpolation methods. The simulation results show that the proposed techniques are superior to both direct LUT and trigonometric interpolation methods.

scholarly journals A Novel Coherent Digital Sweep Oscillator with Extremely Low Sweep Rates and Harmonic Distortion

2001 ◽  
Vol 23 (4) ◽  
pp. 197-217
Author(s):  
M. M. Al-Ibrahim (Jarrah)
Keyword(s):  
Harmonic Distortion ◽  
Novel Technique ◽  
Look Up Table ◽  
Address Register ◽  
Simulation Results ◽  
Low Levels

A novel technique to efficiently increase the resolution of coherent digital sweep oscillators based on look-up-table (LUT) methods is proposed. The increase in resolution measured in terms of sweep rates is achieved while maintaining very low levels of spurious harmonic distortion. The proposed technique increases the LUT length to a level at which the spurious harmonic distortion is negligible. The proposed technique is based on partitioning the address register into three sets and dividing the available LUT length into five smaller tables addressed according to the content of the three address register sets. The proposed technique is simulated and its performance is compared with that of the known sweep oscillators. The simulation results show that the proposed technique is superior to all sweep oscillators reported in the literature.

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.

Extremely High-Frequency Therapy in Oncology

2010 ◽  
Vol 16 (11) ◽  
pp. 1211-1216 ◽  
Author(s):  
Mikhail Teppone ◽  
Romen Avakyan
Keyword(s):  
High Frequency ◽  
Extremely High Frequency

scholarly journals High Frequency Resolution Technique of FFT.

2000 ◽  
Vol 66 (648) ◽  
pp. 2772-2777
Author(s):  
Yasuro HORI ◽  
Minoru SASAKI ◽  
Fumio FUJISAWA
Keyword(s):  
High Frequency ◽  
Frequency Resolution

Nanoelectromagnetic of the N-doped single wall carbon nanotube in the extremely high frequency band

Nanoscale ◽  
2017 ◽  
Vol 9 (37) ◽  
pp. 14192-14200 ◽  
Author(s):  
B. Aïssa ◽  
M. Nedil ◽  
J. Kroeger ◽  
M. I. Hossain ◽  
K. Mahmoud ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Frequency Band ◽  
Electromagnetic Interference ◽  
High Frequency ◽  
High Electrical Conductivity ◽  
High Frequency Band ◽  
High Demand ◽  
Extremely High Frequency ◽  
Minimal Thickness

Materials offering excellent mechanical flexibility, high electrical conductivity and electromagnetic interference (EMI) attenuation with minimal thickness are in high demand, particularly if they can be easily processed into films.

Sign in / Sign up

Export Citation Format

Share Document