scholarly journals Measurement Accuracy Enhancement via Radio Frequency Filtering in Distributed Brillouin Sensing

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2878 ◽  
Author(s):  
Cheng Feng ◽  
Stefan Preussler ◽  
Jaffar Emad Kadum ◽  
Thomas Schneider
Keyword(s):  
Radio Frequency ◽  
Noise Reduction ◽  
Measurement Accuracy ◽  
Signal To Noise Ratio ◽  
Rf Filters ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Optical Time ◽  
Rf Signal

In this article, we demonstrate the noise reduction and signal to noise ratio (SNR) enhancement in Brillouin optical time-domain analyzers (BOTDA). The results show that, although the main noise contribution comes from the Brillouin interaction itself, a simple low pass filtering on the detected radio frequency (RF) signal reduces remarkably the noise level of the BOTDA traces. The corresponding SNR enhancement depends on the employed cut-off frequency of the low pass filter. Due to the enhancement of the SNR, a mitigation of the standard deviation error of the Brillouin frequency shift (BFS) has been demonstrated. However, RF filters with low cut-off frequency could lead to distortions on the trace signals and therefore detection errors on a non-uniform BFS. The trade-off between the noise reduction and the signal distortion as well as an optimal cut-off frequency are discussed in detail.

scholarly journals Audio Watermarking Combined with Compressive Sampling Based on QIM and DST-QR Techniques

2019 ◽  
Vol 19 (1) ◽  
pp. 20
Author(s):  
Irma Safitri ◽  
Gelar Budiman ◽  
Arfidianti Kartika Meiza Putri
Keyword(s):  
Signal To Noise Ratio ◽  
Transformation Process ◽  
Compressive Sampling ◽  
Audio Watermarking ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Digital Copyright ◽  
Sine Transform ◽  
Low Pass ◽  
Speed Change

Abuse is not only done to copy or distribute data but also to the digital copyright labels. There is a way to protect data by inserting or hiding a piece of certain information, namely a watermarking technique. In this paper, we propose audio watermarking with Quantization Index Modulation (QIM) method as an embedding process combined with Compressive Sampling (CS), Discrete Sine Transform (DST) and QR decomposition. Binary image is used as a watermark inserted in host audio. DST is used for transformation process from time domain to frequency domain, while QR is used to decompose onedimension matrix into two-dimension matrix. Meanwhile, CS is used to obtain the compressed watermark file which is done before the embedding process. QIM method is used to embed the watermark file to the audio host file. Simulation results indicated that the proposed audio watermarking technique has good robustness against some attacks such as Low Pass Filter (LPF), resampling and linear speed change. In addition, it provides good performance in terms of imperceptibility with Signal to Noise Ratio (SNR) > 20 dB and capacity C = 689 bps.

The Human Controller as an Adaptive, Low Pass Filter

1967 ◽  
Vol 9 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Gordon H. Robinson
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Signal ◽  
Manual Control ◽  
Future Research ◽  
Research Needs ◽  
Descriptive Model ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Independent Variables ◽  
Low Pass

Data is presented on the ability of a human controller to track a signal contaminated with noise. Signal frequencies and signal-to-noise ratio are the independent variables. An optimal, adaptive filter is presented for comparison. A descriptive model is derived based on known human characteristics in manual control. Future research needs are discussed.

Weak Signal Detection System Based on Lock-in Amplifier Technology

2013 ◽  
Vol 389 ◽  
pp. 489-493
Author(s):  
Yong Lv ◽  
Chun Hui Niu ◽  
Yue Qiang Li ◽  
Qing Shan Chen ◽  
Xiao Ying Li ◽  
...  
Keyword(s):  
Signal Detection ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Weak Signal ◽  
Weak Signal Detection ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Phase Sensitive ◽  
Lock In

In order to detect the weak signal deeply buried in the noise, a weak signal detection system based on lock-in amplifier is proposed. The system includes the preamplifier circuit, active low pass filter circuit, AC amplifying circuit and phase sensitive demodulation circuit. Test results show that it can greatly increase the signal-to-noise ratio (SNR) up to 12.7db.

scholarly journals Noise Reduction Analysis of Radar Rainfall Using Chaotic Dynamics and Filtering Techniques

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Soojun Kim ◽  
Huiseong Noh ◽  
Narae Kang ◽  
Keonhaeng Lee ◽  
Yonsoo Kim ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Correlation Coefficient ◽  
Standard Error ◽  
Rainfall Series ◽  
Radar Rainfall ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Filtering Technique ◽  
Filtering Techniques

The aim of this study is to evaluate the filtering techniques which can remove the noise involved in the time series. For this, Logistic series which is chaotic series and radar rainfall series are used for the evaluation of low-pass filter (LF) and Kalman filter (KF). The noise is added to Logistic series by considering noise level and the noise added series is filtered by LF and KF for the noise reduction. The analysis for the evaluation of LF and KF techniques is performed by the correlation coefficient, standard error, the attractor, and the BDS statistic from chaos theory. The analysis result for Logistic series clearly showed that KF is better tool than LF for removing the noise. Also, we used the radar rainfall series for evaluating the noise reduction capabilities of LF and KF. In this case, it was difficult to distinguish which filtering technique is better way for noise reduction when the typical statistics such as correlation coefficient and standard error were used. However, when the attractor and the BDS statistic were used for evaluating LF and KF, we could clearly identify that KF is better than LF.

scholarly journals Design of CW THz PhotonicTtransmitter based on Low Pass-Filter and Bow-tie Wideband Antenna

2018 ◽  
Vol 8 (5) ◽  
pp. 3801
Author(s):  
Ibtissame Moumane ◽  
J. Zbitou ◽  
M. Latrach ◽  
A. Errkik ◽  
O. Chakkor ◽  
...  
Keyword(s):  
Circuit Design ◽  
Gaas Substrate ◽  
Continuous Wave ◽  
Design System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Wideband Antenna ◽  
Low Pass ◽  
Rf Signal ◽  
Bow Tie

This paper presents the design of Continuous Wave Terahertz photonic transmitters which is composed from photodetector (PD) associated to a wideband antenna, low–pass filter (LPF) and DC Probe. Firstly, we have developed the bow-tie wideband antenna using an EM solver Momentum integrated in ADS “Advanced Design System”. Then we had optimized a low-pass filter which is responsible of blocking the RF signal providing from the antenna to reach the DC probe. And finally, we have validated into simulation the CW THz photonic transmitter. The three structures are based on multi-layers GaAs substrate, which is the most widely used for THz circuit design. The dimensions of the Whole circuit are 776.788 × 303.39〖μm〗^2.<br /><br />

A 2nd-Order Continuous Time Delta-Sigma Modulator for Photoplethysmography Analog Front-End

2020 ◽  
Author(s):  
Eka Fitrah Pribadi ◽  
Rajeev Kumar Pandey ◽  
Paul C.-P. Chao
Keyword(s):  
Transfer Function ◽  
Continuous Time ◽  
Supply Voltage ◽  
Signal To Noise Ratio ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Low Pass ◽  
Order Continuous

Abstract A brief presents a 2nd order continuous-time delta-sigma modulator (CT-DSM) using a low pass filter to reduce the slew rate requirement of the output swing of the first integrator. By adding the low pass filter, the desired transfer function of the CT-DSM is altered. Thus a feed-forward based compensation circuit is introduced to transform the altered transfer function to the original condition. The CT-DSM is designed with a bandwidth of 100 Hz to satisfy the requirement of photoplethysmogram (PPG) detection. The CT-DSM is simulated using CMOS 180 nm technology with the layout area 460 μm × 460 μm. The circuit uses a 1.8 V supply voltage and consumes 35.61 μW. The signal-to-noise ratio of the CT-DSM is 101.2 dB, while the SFDR is 99.1 dB.

scholarly journals A Novel Sample Based Quadrature Phase Shift Keying Demodulator

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Asraf Mohamed Moubark ◽  
Sawal Hamid Md Ali
Keyword(s):  
Phase Noise ◽  
Signal To Noise Ratio ◽  
Local Oscillator ◽  
Coherent Detection ◽  
Signal Frequency ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Incoming Signal ◽  
Shift Keying ◽  
Low Pass

This paper presents a new practical QPSK receiver that uses digitized samples of incoming QPSK analog signal to determine the phase of the QPSK symbol. The proposed technique is more robust to phase noise and consumes up to 89.6% less power for signal detection in demodulation operation. On the contrary, the conventional QPSK demodulation process where it uses coherent detection technique requires the exact incoming signal frequency; thus, any variation in the frequency of the local oscillator or incoming signal will cause phase noise. A software simulation of the proposed design was successfully carried out using MATLAB Simulink software platform. In the conventional system, at least 10 dB signal to noise ratio (SNR) is required to achieve the bit error rate (BER) of 10−6, whereas, in the proposed technique, the same BER value can be achieved with only 5 dB SNR. Since some of the power consuming elements such as voltage control oscillator (VCO), mixer, and low pass filter (LPF) are no longer needed, the proposed QPSK demodulator will consume almost 68.8% to 99.6% less operational power compared to conventional QPSK demodulator.

scholarly journals A novel configuration of THz photonic transmitter

2019 ◽  
Vol 13 (1) ◽  
pp. 258
Author(s):  
Ibtissame Moumane ◽  
Jamal Zbitou ◽  
M. Latrach ◽  
A. Errkik ◽  
O. Chakkor
Keyword(s):  
Electrical Signal ◽  
Design System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Rf Signal ◽  
Thz Applications ◽  
Thz Waves ◽  
Thz Antenna

In this paper we present a new design of a photonic transmitter based on multi-layers substrate GaAs and using for generation of THz waves. The proposed circuit is composed from a photodetector (PD) “which converts the light to the electrical signal”, THz Antenna, low-pass filter and DC probe. Firstly we have optimized the THz antenna using an EM solver which is Momentum integrated in ADS “Advanced Design System”.Then we have optimized the low pass filter which plays the role of inductance that is an RF choke permiting to separate the RF signal from the DC one. Finally, we have associated the different components, add the DC probe and simulate the whole proposed system. The dimensions of the final circuit are 400.317x167.16 UM2 . The obtain results permit to validate the final circuit at THz and make it suitable for THz applications.

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