scholarly journals Spectral analysis of the f0F2 data obtained at five PRIME sites during a 15 minute campaign in June 1993

1996 ◽  
Vol 39 (4) ◽  
Author(s):  
Y. Tulunay ◽  
S. A. Baykal ◽  
Y. G. Yigit ◽  
I. Stanislawska ◽  
A. Rokicki ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Confidence Level ◽  
Original Data ◽  
Easy Method ◽  
The Cost

During the COST 238: PRIME project there was a campaign of 15-min intervals of the f0F2 soundings at Kandilli, Rome, Sofia, Poitiers and Lannion. The campaign took place for one month in June 1993. The spectral analysis of the data using a Fast Fourier Transform (FFT) algorithm proved a relatively easy method to reconstruct the original data at the confidence level = 0.05.

Comparison of fast Fourier transform and autoregressive spectral analysis for the study of heart rate variability in diabetic patients

2005 ◽  
Vol 104 (3) ◽  
pp. 307-313 ◽  
Author(s):  
Denis Chemla ◽  
Jacques Young ◽  
Fabio Badilini ◽  
Pierre Maison-Blanche ◽  
Hélène Affres ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Diabetic Patients

scholarly journals Reducing the Cost of Implementing Filters in LoRa Devices

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4037
Author(s):  
Shania Stewart ◽  
Ha H. Nguyen ◽  
Robert Barton ◽  
Jerome Henry
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
System Performance ◽  
Pulse Shaping ◽  
Error Rates ◽  
Lookup Table ◽  
Significant Performance ◽  
High Level ◽  
The Cost ◽  
The Impact

This paper presents two methods to optimize LoRa (Low-Power Long-Range) devices so that implementing multiplier-less pulse shaping filters is more economical. Basic chirp waveforms can be generated more efficiently using the method of chirp segmentation so that only a quarter of the samples needs to be stored in the ROM. Quantization can also be applied to the basic chirp samples in order to reduce the number of unique input values to the filter, which in turn reduces the size of the lookup table for multiplier-less filter implementation. Various tests were performed on a simulated LoRa system in order to evaluate the impact of the quantization error on the system performance. By examining the occupied bandwidth, fast Fourier transform used for symbol demodulation, and bit-error rates, it is shown that even performing a high level of quantization does not cause significant performance degradation. Therefore, the memory requirements of LoRa devices can be significantly reduced by using the methods of chirp segmentation and quantization so as to improve the feasibility of implementing multiplier-less filters in LoRa devices.

scholarly journals The Fast Fourier Transform and its application to tidal oscillations

1971 ◽  
Vol 20 (1) ◽  
pp. 145-199 ◽  
Author(s):  
A. dos Santos Franco ◽  
Norman J Rock
Keyword(s):  
Spectral Analysis ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Degrees Of Freedom ◽  
Noise Spectrum ◽  
Weighted Sum ◽  
Fast Fourier Transform Analysis ◽  
Dence Interval

This paper proposes a new way of tidal spectral analysis based on the Cooley-Tukey algorithm, known as the Fast Fourier Transform. The Fast Fourier Transform analysis is used to compute both the harmonic constants of the tide and the power spectrum.The latter is obtained by means of a weighted sum. A new way is also derived to obtain the formula giving the number of the degrees of freedom,on which is based the confi dence interval corresponding to the noise spectrum.

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