Chirp pseudo‐noise signal and its receiving scheme for LEO enhanced GNSS

Abstract Article clarified the optimum fiber amplifiers length for wide band fiber system applications. Optical suppressed carrier transceiver with various fiber amplifier lengths in long haul applications is simulated by using optisystem simulation program version 13. Max. Q coefficient and min. BER can be tested for various fiber amplifiers lengths from 5 to 30 m. The optimum performance efficiency is achieved with 5 m amplifier length which the max. Q coefficient is 62.5 and bits error rate is tended to zero. Peak power amplitude level, noise signal power level, noise signal amplitude level (NSAL) and peak signal amplitude level after channel with a 45 km length for optimum fiber optic amplifier length of 5 m are measured.

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Modified GSC Method to Reduce the Distortion of the Enhanced Speech Signal Using Cross-Correlation and Sidelobe Neutralization

Applied Sciences ◽

10.3390/app11146288 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6288

Author(s):

Hang Su ◽

Chang-Myung Lee

Keyword(s):

Speech Signal ◽

Output Signal ◽

Cross Correlation ◽

Acoustic Noise ◽

Audio Signal ◽

Noise Signal ◽

Lms Algorithm ◽

Least Mean Square ◽

Experiment Data ◽

Noise Component

The generalized sidelobe canceller (GSC) method is a common algorithm to enhance audio signals using a microphone array. Distortion of the enhanced audio signal consists of two parts: the residual acoustic noise and the distortion of the desired audio signal, which means that the desired audio signal is damaged. This paper proposes a modified GSC method to reduce both kinds of distortion when the desired audio signal is a non-stationary speech signal. First, the cross-correlation coefficient between the canceling signal and the error signal of the least mean square (LMS) algorithm was added to the adaptive process of the GSC method to reduce the distortion of the enhanced signal while the energy of the desired signal frame was increased suddenly. The sidelobe pattern of beamforming was then presented to estimate the noise signal in the beamforming output signal of the GSC method. The noise component of the beamforming output signal was decreased by subtracting the estimated noise signal to improve the denoising performance of the GSC method. Finally, the GSC-SN-MCC method was proposed by merging the above two methods. The experiment was performed in an anechoic chamber to validate the proposed method in various SNR conditions. Furthermore, the simulated calculation with inaccurate noise directions was conducted based on the experiment data to inspect the robustness of the proposed method to the error of the estimated noise direction. The experiment data and calculation results indicated that the proposed method could reduce the distortion effectively under various SNR conditions and would not cause more distortion if the estimated noise direction is far from the actual noise direction.

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Analysis of Real-time Noise Signal Characteristics of Power Transformer Based on All-phase Fast Fourier Transform

2020 International Conference on Sensing, Measurement & Data Analytics in the era of Artificial Intelligence (ICSMD) ◽

10.1109/icsmd50554.2020.9261707 ◽

2020 ◽

Author(s):

Xiaojuan Zhao ◽

Yaqi Zhou ◽

Xue Wang ◽

Ruilin Xu ◽

Shihai Han ◽

...

Keyword(s):

Fourier Transform ◽

Fast Fourier Transform ◽

Real Time ◽

Power Transformer ◽

Noise Signal ◽

Signal Characteristics

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High Ripple-Density Resolution for Discriminating Between Rippled and Nonrippled Signals: Effect of Temporal Processing or Combination Products?

Trends in Hearing ◽

10.1177/23312165211010163 ◽

2021 ◽

Vol 25 ◽

pp. 233121652110101

Author(s):

Dmitry I. Nechaev ◽

Olga N. Milekhina ◽

Marina S. Tomozova ◽

Alexander Y. Supin

Keyword(s):

Low Frequency ◽

Noise Signal ◽

Density Variation ◽

Choice Procedure ◽

Masker Level ◽

Reference Signals ◽

Forced Choice Procedure ◽

The Mean ◽

Density Resolution

The goal of the study was to investigate the role of combination products in the higher ripple-density resolution estimates obtained by discrimination between a spectrally rippled and a nonrippled noise signal than that obtained by discrimination between two rippled signals. To attain this goal, a noise band was used to mask the frequency band of expected low-frequency combination products. A three-alternative forced-choice procedure with adaptive ripple-density variation was used. The mean background (unmasked) ripple-density resolution was 9.8 ripples/oct for rippled reference signals and 21.8 ripples/oct for nonrippled reference signals. Low-frequency maskers reduced the ripple-density resolution. For masker levels from −10 to 10 dB re. signal, the ripple-density resolution for nonrippled reference signals was approximately twice as high as that for rippled reference signals. At a masker level as high as 20 dB re. signal, the ripple-density resolution decreased in both discrimination tasks. This result leads to the conclusion that low-frequency combination products are not responsible for the task-dependent difference in ripple-density resolution estimates.

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