Noise Cancellation Technique Research Articles

Throughput improvement in ACO-OFDM-based VLC systems using noise cancellation and precoding techniques

One of the primary challenges faced by visible light communication (VLC) systems employing optical orthogonal frequency division multiplexing is the peak-to-average power ratio (PAPR). This study is dedicated to designing, simulating, and evaluating bit error rate (BER) and PAPR reduction methods tailored for the VLC broadcasting system. The asymmetric clipped optical orthogonal frequency division multiplexing (ACO-OFDM) scheme is highlighted in this work for its impressive performance. Therefore, the proposed PAPR mitigation methodologies applied to ACO-OFDM. The proposed PAPR reduction strategy involves 5 distinct precoding methodologies. The PAPR was mitigated by 3.485 dB after applying the DST precoding methodology. Still, the WHT precoding methodology can achieve PAPR reduction by 1.131 dB, without BER performance degradation, with respect to the conventional ACO-OFDM system. Furthermore, the work addresses another challenge in VLC systems: the bit error rate (BER). This is accomplished by introducing approaches to Time Domain Noise Cancelation and Frequency Domain Noise Cancelation (FDNC). The BER performance of these 2 receiver models is nearly the same. The simulation results indicate the system performance enhancement after applying noise cancellation approaches by 1.65 dB at the 4-QAM modulation scheme and 2.97 dB at the 1024-QAM modulation scheme. The 16-QAM modulation scheme, after applying DST and WHT methodologies alongside noise cancellation approaches, can enhance both PAPR by 20.83% and 6.76%, but the Eb/N0 performance enhancement by 10.10% and 14.64%, respectively. Additionally, the effectiveness and validity of the proposed schemes are verified by comparing them with relevant literature reviews on PAPR reduction techniques and selecting an optimal choice among them.

An improved kT/C noise cancellation technique with presampling for high‐speed SAR ADCs

AbstractThe kT/C noise cancellation technique can effectively reduce the digital‐to‐analog converter (DAC) size for successive approximation register ADCs and thus relax the burden for input drivers and reference buffers. However, the prior kT/C noise cancellation technique suffers from a hard trade‐off between the noise, amplifier bandwidth and linearity. Here, an improved kT/C noise cancellation technique is proposed to break the trade‐off. It uses presampling to hold the input signal unchanged during the noise cancelling phase, leading to significantly relaxed requirements on the bandwidth and linearity of the amplifier. The proposed technique is verified in a 14‐bit 200 MS/s SAR analog‐to‐digital converter (ADC) with a DAC size of 128 fF. Simulation results show that this work achieves 75.6 dB signal to noise and distortion ratio and consumes 1.56 mW power.

Displacement response waveform restoration of simply supported bridge during train passage using measured acceleration integration based on linear vibration theory

This study proposes a method for restoring the displacement waveform during train passage using the acceleration integration based on linear vibration theory and noise cancellation techniques. This method replaces the low-frequency region affected by noise with a linear theoretical solution; however, this method uses the actual measurement data around the natural frequency, where nonlinearities (such as concrete member cracks and the train–bridge interaction) can be observed. The method identifies only the ratio of single axle weight to modal stiffness. Numerical experiments clarify that the method can estimate the maximum displacement of a bridge from acceleration with an error of approximately 5% or less. Improved prediction accuracy can be achieved using the proposed noise cancellation technique not only in the high-speed range but also into the lower-speed ranges as well. Furthermore, the proposed method is applied to acceleration monitoring data, and results show that the displacement waveform can be restored from the acceleration waveform.

Joint optimization of seismometer arrays for the cancellation of Newtonian noise from seismic body waves in the Einstein Telescope

Seismic Newtonian noise (NN) is predicted to limit the sensitivity of the Einstein Telescope (ET). It can be reduced with coherent noise cancellation techniques using data from seismometers. To achieve the best results, it is important to place the seismic sensors in optimal positions. A preliminary study on this topic was conducted for the ET: it focused on the optimization of the seismic array for the cancellation of NN at an isolated test mass (TM). In this paper, we expand the study to include the nested shape of ET, i.e. four TMs of the low-frequency interferometers at each vertex of the detector. Results are investigated in function of the polarization content of the seismic field composed of body waves. The study also examines how performance can be affected by displacing the sensor array from its optimal position or by operating at frequencies other than those used for optimization.

A 28 nm CMOS low-noise amplifier with novel redundant noise cancellation technique beyond ultra-wideband for 6G-based wireless systems

In the current scenario, almost 5G-based wireless systems have been deployed everywhere but still performance trade-offs of RF amplifiers in the sub-nanometer regime are challenging. In this work, a high-performance low-noise amplifier (LNA) is realized in a 28 nm CMOS process with a novel redundant noise cancellation technique (RnC). The proposed technique improves the noise figure (NF) beyond the ultra-wideband of a low-noise amplifier (LNA) and minimizes the trade-off in the 28 nm process. An ultra-low NF is achieved in two approaches; Firstly, a current mirror network is employed in the primary path to cancel the thermal noise of the dominant transistor of a common gate-common source (CG-CS) without an extra power supply. Secondly, an auxiliary amplifier stage is introduced here to reduce the noise which contributes to the current mirror circuit and cancels the distortion in CG-CS topology without violating the traditional noise cancellation condition. In addition, an analytical approach is followed to optimize the input impedance, gain bandwidth and noise figure. Hence, the proposed RnC LNA benefits in achieving good tradeoffs among gain, bandwidth, NF, and power consumption in 28 nm technology node. The proposed RnC LNA is analyzed and fabricated using CMOS 28 nm technology, occupying an area of 0.011 mm2. The proposed design achieves an optimum performance: nearly flat gain of 15.3 dB, minimum NF of 1.7 dB over 1.7 to 12.52 GHz, and an IIP3 of − 2.6 dBm at 6.5 GHz. The proposed LNA consumes ultra-low power consumption of 1.8 mW under the power supply of 1 V.

A 79.2-μW 19.5-kHz-BW 94.8-dB-SNDR Fully Dynamic DT ΔΣ ADC Using CLS-Assisted FIA With Sampling Noise Cancellation

This brief proposes a fully dynamic discrete-time (DT) Σ ADC using a correlated level shifting (CLS)-assisted floating inverter amplifier (FIA) with a sampling noise cancellation (SNC) technique. The CLS-assisted FIA improves amplifier gain with a single-stage configuration, which has lower input-referred noise than the cascaded one. In combination with the proposed SNC, the noise contribution of the 1st-stage integrator can be minimized. We also propose a novel passive integrator cascaded with a passive adder that avoids unwanted inter-stage loading without a speed penalty. The prototype of the proposed ADC fabricated in a 65 nm bulk CMOS process realizes a fully dynamic operation and achieves 94.8 dB SNDR with an OSR of 256 for 19.5 kHz bandwidth while consuming 79.2 W from a 1.2V supply at a 10 MHz sampling frequency. The Schreier and Walden FoMs are respectively 178.7 dB and 45.2 fJ/conv.-step, which are the best among recent fully dynamic DT Σ ADCs with similar bandwidth.

Beamforming-based algorithms for recovering information from fetal electrocardiographic sensors

We deal with the extraction of the fetal electrocardiography (ECG) signal from the raw ECG signals of the mother by the beamforming- based algorithms. The foetal ECG sensors bring out signals containing information from the pregnant mother and the infant. Detailed and separate signals are already provided by the foetal ECG instruments; but for some specific studies related to the infant conditions, it is necessary to improve the quality of the signal with a dedicated processing. In this paper, four techniques, with some enhancements, are proposed to perform the processing; we have applied the following techniques: Least Mean Square (LMS) with adaptive noise cancellation technique, Discrete Wavelet Transform (DWT)-based technique, Empirical Wavelet Transform (EWT) technique, and Multiple Signal Classification (MUSIC). The LMS and the MUSIC pertain to beamforming approach. The techniques were used to decompose and identify the different elements constituting the source signal (mother's signal) and noise cancellation by Multivariate Empirical Mode Decomposition (MEMD) technique. The signal was adaptively decomposed by LMS, DWT and MUSIC according to optimised parameters to extract some hidden components of the source signal, such as the foetal features, QRS, heartbeat etc. The results have showed that LMS, with enhancements, is more effective in identifying and removing useless noise. The techniques were applied to the ECG signal of a 30-year-old healthy pregnant woman, which allowed to verify their applicability. The present research leads to the below main contributions among others: separation of the ECG signal of the foetus from the mother, highlighting the functional state of the foetal heart rhythm (heart rate and heartbeat,) and this can show us if the foetal ECG has malfunctions.

Spin-Dependent Dynamics of Photocarrier Generation in Electrically Detected Nitrogen-Vacancy-Based Quantum Sensing

Electrical detection of nitrogen-vacancy (N-V) centers in diamond is advantageous for developing and integrating quantum information processing devices and quantum sensors and has the potential to achieve a higher collection efficiency than that of optical techniques. However, the mechanism for the electrical detection of N-V spins is not fully understood. In this study, we observe positive contrast in photocurrent detected magnetic resonance (PDMR). Note that negative PDMR contrast is usually observed. To discuss the sign of the PDMR contrast, we numerically analyze the dynamics of photocarrier generation by N-V centers using a seven-level rate model. It is found that the sign of the PDMR contrast depends on the difference in the photocurrent generated from the excited states and the metastable state of N-V centers. Furthermore, we demonstrate ac magnetic field sensing using spin coherence with the PDMR technique. ac magnetic field measurement with the PDMR technique is still challenging because the noise from a fluctuating magnetic environment is greater than the measured signal. Here, we introduce noise suppression using a phase-cycling-based noise-canceling technique. We demonstrate electrically detected ac magnetic field sensing with a sensitivity of 29 nT ${\mathrm{Hz}}^{\ensuremath{-}1/2}$. Finally, we discuss sensitivity enhancement based on the proposed model.

Development of Adaptive Spectrum Noise Cancellation Technique for Enhancing Heartbeat Rate Monitoring

Most of the Heart Rate Monitor (HRM) seems to be a portable monitoring device that can measure and displays real-time heartbeat rate in addition to storing heartbeat rate data for future studies. It is generally used to capture heart rate data during various types of physical exercise. Heart rhythm problems arise whenever the electrical impulses that coordinate the heartbeats aren't working properly. The ineffective signaling causes the heart to beat too fast (tachycardia), overly slowly (bradycardia), or sporadically. In present study, a focused approach on Adaptive Spectrum Noise Cancellation (ASNC) were used for enhancing heartbeat rate monitoring for humans. It finds that simply a photodetector and a source of light are applied to the surface of the skin to monitor the proportional changes in the blood flow. It is concluded that for accurate measurement of heart rate while moving or running, the proposed device ASNC utilizes the application of embedded accelerometer and gyroscope sensors to identify and eradicate the artifacts adaptively. In future, the proposed model may adopted for modification and commercialization of wearable heart-rate sensors based upon photoplethysmography (PPG), it would be better in terms of utility as well as adoptability.

Wideband Cascaded and Stacked Receiver Front-Ends Employing an Improved Clock-Strategy Technique

A wideband cascaded receiver and a stacked receiver using an improved clock strategy are proposed to support the software-defined radio (SDR). The improved clock strategy reduces the number of mixer switches and the number of LO clock paths required to drive the mixer switches. This reduces the dynamic power consumption. The cascaded receiver includes an inverter-based low-noise transconductance amplifier (LNTA) using a feed-forward technique to enhance the noise performance; a passive mixer; and an inverter-based transimpedance amplifier (TIA). The stacked receiver architecture is used to reduce the power consumption by sharing the current between the LNTA and the TIA from a single supply. It utilizes a wideband LNTA with a capacitor cross-coupled (CCC) common-gate (CG) topology, a passive mixer to convert the RF current to an IF current, an active inductor (AI) and a 1/f noise-cancellation (NC) technique to improve the noise performance, and a TIA to convert the IF current to an IF voltage at the output. Both cascaded and stacked receivers are simulated in 22 nm CMOS technology. The cascaded receiver achieves a conversion-gain from 26 dB to 36 dB, a double-sideband noise-figure (NFDSB) from 1.4 dB to 3.9 dB, S11<−10 dB and an IIP3 from −7.5 dBm to −10.5 dBm, over the RF operating band from 0.4 GHz to 12 GHz. The stacked receiver achieves a conversion-gain from 34.5 dB to 36 dB, a NFDSB from 4.6 dB to 6.2 dB, S11<−10 dB, and an IIP3 from −21 dBm to −17.5 dBm, over the RF operating band from 2.2 GHz to 3.2 GHz. The cascaded receiver consumes 11 m from a 1 V supply voltage, while the stacked receiver consumes 2.4 m from a 1.2 V supply voltage.

Improved Phase Noise Cancellation Technology for Auxiliary Reference Interferometer Demodulation Scheme

In an unbalanced interferometer, the phase noise level is positively related to the optical path length difference (OPD) and the wavelength instability of the light source. The effective current solution for reducing phase noise is to use an auxiliary reference interferometer to measure the phase noise signal. However, this method requires that all interferometers have the same OPD, otherwise the phase modulation depth of different interferometers with the same light source will be different and the noise reduction effect will be severely reduced. It is difficult to provide interferometers with precisely the same OPD in practical. In this paper, an improved phase-generated carrier (PGC) demodulation technique for phase noise cancellation that does not require strictly equal OPDs of interferometers is proposed. Combining an auxiliary reference interferometer scheme with an ellipse fitting algorithm (EFA) can eliminate the effect of different phase modulation depths due to different OPDs, and phase modulation depth drift on demodulation results, significantly reducing harmonic distortion. The additional phase modulation signal ensures the correct calculation of small signals by the EFA, while the OPDs of the interferometers are evaluated in real time to achieve constant phase noise cancellation capability under different OPD. Experimental results show that the proposed technique achieves a highly stable phase demodulation result with a maximum phase noise reduction of about 9dB and a minimum THD of -74.59 dB in interferometers with non-strict equal OPD.

3-D Wireless Power Transfer With Noise Cancellation Technique for −62-dB Noise Suppression and 90.1% Efficiency

3-D Wireless Power Transfer With Noise Cancellation Technique for −62-dB Noise Suppression and 90.1% Efficiency

Technoeconomic assessment of an FTTH network investment in the Greek telecommunications market

Recent years have seen an increasing need for higher broadband connections, fueled by novel applications including fifth generation wireless networks (5G). The European Commission is working on achieving specific milestones regarding the development of next generation networks. Many EU countries have opted to adopt a gradual migration path towards the Fiber-to-the-Home (FTTH) technology in view of the high costs of implementation. The Fiber-to-the-Cabinet (FTTC) architecture, combined with very-high-bit-rate digital subscriber line 2 (VDSL2) and vectoring noise cancellation techniques may therefore provide a viable short-term basis solution. Techno-economic modeling and assessment is vital at the initial stages of the development of a telecommunication network investment project involving high capital expenditures for the infrastructure. The present work provides a techno-economic model in order to assess the prospects of such a network upgrade project from a financial perspective, following a three-way migration path. The three stages are: the implementation of the FTTC architecture with VDSL2 vectoring technology, the upgrade to FTTC with G.Fast and finally the migration to FTTH. The analysis is implemented over a suburb of the city of Athens, Greece. Different scenarios are evaluated, predicting profits even from the first years following the investment. The analysis includes the estimation of the degree of market penetration, analytical cost calculations for the implementation and operation of the network and the evaluation of crucial financial indicators, regarding the prospects of the investment in vectoring services. The study can serve as a complete road-map and can be applied in similar upgrade scenarios. The most important outcome of the analysis is that the profits resulted from each upgrade will finance the next step.

Active Noise Cancellation and Its Applications

The goal of this review is to introduce the concept of Active Noise Cancellation (ANC) technique and explain the core algorithms supporting this technology. Through showing the implementations and major features of those algorithms, we were able to gain a better understanding of what’re the dominating algorithms used by the ANC technology and both the traditional and non-traditional applications of ANC in today’s market. Finally, the review also reveals the potential problem with the ANC technique and the opportunities for improvements.

A Comparison of Off-Chip Differential and LC Input Matching Baluns in a Wideband and Low-Power RF-to-BB Current-Reuse Receiver Front-End

A wideband and low-power RF-to-baseband (BB) current-reuse receiver (CRR) front-end is proposed, and its performance is verified using two matching networks, one with an LC balun and on-chip biasing inductor, CRR1, and another with a differential balun and without on-chip biasing inductor, CRR2, requiring less area. The transimpedance amplifier (TIA) and low-noise transconductance amplifier (LNTA) share the bias current from a single supply to reduce power consumption. It employs both an active-inductor (AI) and a 1/f noise-cancellation technique to improve the NF and RF bandwidth performance. A passive mixer is utilized for RF to BB conversion, which does not require any DC power and voltage headroom. Both CRR1 and CRR2 are fabricated in TSMC 130 nm CMOS technology on a single die and packaged using a QFN48. CRR1 occupies an active area of 0.54 mm2. From 1 to 1.7 GHz, it achieves a conversion gain of 41.5 dB, a double-sideband (DSB) NF of 6.5 dB, S11<−10 dB, and an IIP3 of −28.2 dBm, while the local-oscillator (LO) frequency is at 1.3 GHz. CRR2 occupies an active area of 0.025 mm2. From 0.2 to 1 GHz, it achieves an average conversion gain of 37 dB, an average DSB NF of 8 dB, and an IIP3 of −21.5 dBm while the LO frequency is at 0.7 GHz. Both CRR1 and CRR2 consume 1.66 mA from a 1.2 V supply voltage.

Design of Common Gate Current-Reuse Noise Cancellation UWB Low Noise Amplifier in 90nm CMOS

In this paper, an ultra-wide band (UWB) low noise amplifier (LNA) is implemented by using 90nm RF CMOS technology. The designed LNA achieves high flat band gain (S21) and low noise figure (NF) in the frequency of interest. The proposed LNA operates in the frequency range of 3GHz to 8GHz. In this work, wide band matching is achieved by designing common gate configuration at the input stage. The current reuse and noise cancellation techniques are introduced to improve flat band gain and minimize both noise figure and power consumption. The noise figure is improved by cancelling dominant noise sources with additional hardware. The proposed LNA attains flat band gain of 26.5dB and input matching less than -12dB for entire UWB band. This work achieves noise figure of 2.1dB to 2.59dB in frequency band of interest. Additionally, power consumption of the circuit is 20mW at 1.8V supply voltage.

Precision frequency transfer with fiber frequency combs

We review methods for precision transfer of frequencies across broad optical wavelength ranges. Single-branch supercontinuum generation allows for a frequency transfer stability of < 1 × 10−17in 1 s across an octave. With supercontinuum stitching, highly coherent supercontinuum spectra spanning across more than two octaves are generated. With noise cancellation techniques a relative frequency transfer stability of ≈ 2 × 10−18in 1 s can be achieved. Highly stable frequency transfer along with a maximization of power per mode at multiple freely selectable frequency bands is further enabledviapulse shaping techniques. We also include a brief review of general fiber combs and research aimed at frequency extension of frequency combs covering the whole spectral range from the XUV to the mid IR, power scaling of frequency combs as well as low noise microwave and mmwave technology enabled with frequency combs.

Coherence Function and Adaptive Noise Cancellation Performance of an Acoustic Sensor System for Use in Detecting Coronary Artery Disease.

Adaptive noise cancellation is a useful linear technique to attenuate unwanted background noise that cannot be removed using traditional frequency-selective filters. Usually, this is due to the signal and noise co-existing in the same frequency band. This paper tests a weighted least mean squares (WLMS) algorithm on a stethoscope system for use in detecting coronary artery disease in the presence of background noise. Each stethoscope is equipped with two microphones: one used to detect heart signals and one used to detect background noise. The WLMS method was used for four different sources of background noise whilst measuring a heartbeat, including a single tone, multiple tones, hospital/clinic noise, and breathing noise. The magnitude-squared coherence between both microphones was unity for the tone scenarios, resulting in complete attenuation. For the other background noise sources, a less-than-unity magnitude-squared coherence resulted in minor and no attenuation. Thus, the coherence function is a tool that can be used to predict the amount of attenuation achievable by linear adaptive noise-cancellation techniques, such as WLMS, as presented in this article.

A low jitter sub‐sampling phase‐locked loop with sampling thermal noise cancellation technique

AbstractThe traditional sub‐sampling phase‐locked loop faces the tradeoffs between phase noise and spur, in that low in‐band phase noise requires large sampling capacitor size but at the sacrifice of spur performance. This paper presents a sub‐sampling PLL aimed at minimizing in‐band phase noise via sampling thermal noise cancellation technique. It enables the substantial reduction of in‐band phase noise while reducing the sampling capacitor size. In addition, due to the reduction of the sampling capacitance, the reference spur performance of the PLL is improved, and the power consumption of the isolation buffer is reduced. Implemented in a 65 nm CMOS process, the in‐band phase noise at 200 kHz offset is −133.4 dBc/Hz at 2.2 GHz and integrated jitter is 80 fsrms. The reference spur is −67 dBc. It consumes 5.5 mA from 1.2 V supply and occupies 0.72 mm2.

Miniature Wide-Band Noise-Canceling CMOS LNA.

In this paper, a wide-band noise-canceling (NC) current conveyor (CC)-based CMOS low-noise amplifier (LNA) is presented. The circuit employs a CC-based approach to obtain wide-band input matching without the need for bulky inductances, allowing broadband performance with a very small area used. The NC technique is applied by subtracting the input transistor’s noise contribution to the output and achieves a noise figure (NF) reduction from 4.8 dB to 3.2 dB. The NC LNA is implemented in a UMC 65-nm CMOS process and occupies an area of only 160 × 80 μm2. It achieves a stable frequency response from 0 to 6.2 GHz, a maximum gain of 15.3 dB, an input return loss (S11) < −10 dB, and a remarkable IIP3 of 7.6 dBm, while consuming 18.6 mW from a ±1.2 V DC supply. Comparisons with similar works prove the effectiveness of this new implementation, showing that the circuit obtains a noteworthy performance trade-off.