Spectral averaging and low‐frequency sampling modifications for the IQS 401 fast Fourier transform spectrum analyzer

1985 ◽  
Vol 56 (1) ◽  
pp. 159-160 ◽  
Author(s):  
Steven W. Smith
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Low Frequency ◽  
Spectrum Analyzer ◽  
Frequency Sampling ◽  
Fast Fourier Transform Spectrum ◽  
Fourier Transform Spectrum ◽  
Spectral Averaging

A high performance fast-Fourier-transform spectrum analyzer for measuring spin noise spectrums

2020 ◽  
Vol 29 (9) ◽  
pp. 090704
Author(s):  
Yu Tong ◽  
Lin Wang ◽  
Wen-Zhe Zhang ◽  
Ming-Dong Zhu ◽  
Xi Qin ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
High Performance ◽  
Spectrum Analyzer ◽  
Spin Noise ◽  
Fast Fourier Transform Spectrum ◽  
Fourier Transform Spectrum

scholarly journals Is the algorithm used to process heart rate variability data clinically relevant? Analysis in male adolescents

2016 ◽  
Vol 14 (2) ◽  
pp. 196-201 ◽  
Author(s):  
Antonio Henrique Germano Soares ◽  
Breno Quintella Farah ◽  
Gabriel Grizzo Cucato ◽  
Carmelo José Albanez Bastos-Filho ◽  
Diego Giulliano Destro Christofaro ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
High Frequency ◽  
Low Frequency ◽  
Total Power ◽  
Cross Sectional ◽  
Negatively Associated ◽  
Male Adolescents

ABSTRACT Objective To analyze whether the algorithm used for the heart rate variability assessment (fast Fourier transform versus autoregressive methods) influenced its association with cardiovascular risk factors in male adolescents. Methods This cross-sectional study included 1,152 male adolescents (aged 14 to 19 years). The low frequency, high frequency components (absolute numbers and normalized units), low frequency/high frequency ratio, and total power of heart rate variability parameters were obtained using the fast Fourier transform and autoregressive methods, while the adolescents were resting in a supine position. Results All heart rate variability parameters calculated from both methods were different (p<0.05). However, a low effect size (<0.1) was found for all parameters. The intra-class correlation between methods ranged from 0.96 to 0.99, whereas the variation coefficient ranged from 7.4 to 14.8%. Furthermore, waist circumference was negatively associated with high frequency, and positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Systolic blood pressure was negatively associated with total power and high frequency, whereas it was positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Body mass index was negatively associated with high frequency, while it was positively associated with low frequency and sympatovagal balance (p values ranged from <0.001 to 0.007). Conclusion There are significant differences in heart rate variability parameters obtained with the fast Fourier transform and autoregressive methods in male adolescent; however, these differences are not clinically significant.

scholarly journals Digital processing of space images using global filtering in the frequency area

2021 ◽  
Vol 333 ◽  
pp. 01012
Author(s):  
Valeriy Tutatchikov ◽  
Mikhail Noskov
Keyword(s):  
Remote Sensing ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Satellite Images ◽  
Low Frequency ◽  
Digital Processing ◽  
Image Filtering ◽  
Two Dimensional ◽  
Space Images ◽  
Frequency Area

In modern systems, remote sensing widespread two-dimensional fast Fourier transform (FFT) for processing satellite images and the subsequent image filtering. In this paper we consider the possibility of using combinations of high and low frequency filters to improve global images terrestrial surface.

Analyzing the output performance of the knitted triboelectric nanogenerator based on the fish-scale shape using fast Fourier transform

2021 ◽  
pp. 004051752110445
Author(s):  
Li Niu ◽  
Shuqiang Zhao ◽  
Qing Liu ◽  
Guangjun Wu ◽  
Chaoyu Chen ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Power Spectrum ◽  
Fast Fourier Transform ◽  
Flexible Substrate ◽  
Three Dimensional ◽  
Low Frequency ◽  
Dimensional Structure ◽  
Triboelectric Nanogenerator ◽  
Fish Scale ◽  
Output Performance

Knitted textiles as one kind of outstanding flexible substrate that have been universally applied in smart wearables. Structural design and output performance analysis of knitted-based triboelectric nanogenerators (TENGs) is significant research points. It is essential to provide inspiration in the TENGs applications. In this study, we designed and fabricated a fish-scale-based triboelectric nanogenerator using a formed knitted textile composed of commercial threads as a pair of contact areas. The deformation of the scale-shaped fabric was from the three-dimensional structure, which provided an effective contact area. We investigated the elastic yarn specification and scale-shaped distribution and analyzed their output performance in the frequency domain using fast Fourier transform. The result illustrated that the amplitude, phase, and power spectrum had obvious differences and can reflect the working states during the motions. The power spectrum could reach the maximum value of 280, which showed the potential for applications in the low-frequency motion.

scholarly journals Rancang Bangun Spectrum Analyzer Menggunakan Fast Fouier Transform Pada Single Board Computer

2017 ◽  
Vol 7 (1) ◽  
pp. 71 ◽  
Author(s):  
Afandi Nur Aziz Thohari ◽  
Agfianto Eko Putra
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Frequency Spectrum ◽  
Measuring Equipment ◽  
Radio Signal ◽  
Spectrum Analyzer ◽  
Fast Fourier Transform Algorithm ◽  
Test Results ◽  
Single Board Computer ◽  
Disk Memory

Spectrum analyzer is an instrument device to measure the magnitude of the frequency and the power of signal. It has many benefits, such as used for testing telecommunication devices, determining the allocation of unused frequencies and also for practicum in schools or universities. However, because of these many benefits, the price of this signal measuring equipment soared in the market.As an alternative, a device that can serve as spectrum analyzer yet has an affordable price is invented in the form of the prototype of spectrum analyzer built using a single board computer by applying a fast Fourier transform algorithm. Feedback from the prototype is in the form of radio signal captured using RTL-SDR.The test results showed that the range of frequencies that can be displayed by the prototype is 24 MHz to 1.769 MHz. Then the test results of fast Fourier transform computing on N points showed that the prototype can work smoothly using the N from 512 to 32.768 points. The use of N more than 32.768 points will cause CPU and disk memory overloaded and lead to a slow performance. Finally, comparison of the levels of spectrum was performed using spectrum analyzer Anritsu MS2720T. As a result, it is known that prototype can be used to show the location of the frequency spectrum of the radio signal appropriately.

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