Bipolar Signals Research Articles

Memristive properties of transparent oxide semiconducting (Ti,Cu)Ox-gradient thin film

The paper presents the results of the analysis of memristive properties observed in (Ti,Cu)-oxide thin film with gradient distribution of elements, prepared using the multi-source reactive magnetron co-sputtering process. The performed electrical measurements showed the presence of pinched hysteresis loops in the voltage–current plane for direct and alternating current bipolar periodic signal stimulation. Investigations performed using a transmission electron microscope equipped with an energy dispersive spectrometer showed that the elemental composition at the cross section of the thin film was very well correlated with the gradient V-shaped profile of the powering of the magnetron source equipped with a Cu target. The prepared samples were transparent in the visible part of optical radiation. The obtained results showed that the prepared gradient (Ti,Cu)Ox thin film could be an interesting alternative to the conventional multilayer stack construction of memristive devices, which makes them a promising material for manufacturing transparent memory devices for transparent electronics.

Enhanced and stable strain memory in Mn‐doped Pb(Mn1/3Sb2/3)O3–Pb(Zr,Ti)O3 ceramics realized by sesquipolar loading

AbstractThe negative electric field, field cycling and frequency dependence of strain memory effect in poled and aged Mn‐doped Pb(Mn1/3Sb2/3)O3–Pb(Zr,Ti)O3 (PMS–PZT) piezoceramics under sesquipolar loading were investigated. The strain memory effect of Mn‐doped PMS–PZT is especially sensitive to the applied negative electric field. Maximum strain memory of 0.32% is achieved when the negative electric field is around negative coercive field of ~2.1 kV/mm, which can be ascribed to the partially depoled state with randomized domains. And this strain memory shows very good cycling stability, varying less than 5% up to 104 cycles, while almost 40% degradation is found under bipolar signal. In addition, due to the stabilized defect dipoles, the strain memory exhibits stable characteristic over a broad frequency range from 0.01 Hz to 20 Hz. The results may shed new insights into designing the novel strain memory actuators where stable strain state could be realized after the removal of electric field.

A novel wiring scheme for standard chips enabling high-accuracy impedance cytometry

While there is a great interest in microfluidic impedance cytometry as a label-free approach for single-particle analysis, the accuracy of the technique is challenged by the positional dependence issue, i.e. identical particles flowing in the microchannel along different trajectories provide different signals. We solve this issue without resorting to particle focusing, by means of a straightforward modification of the conventional wiring scheme for the standard impedance chip comprising two pairs of facing electrodes. Instead of applying the AC voltage to electrodes on the same side of the channel and collecting the differential current flowing through the electrodes on the other side, we apply the AC voltage to diagonally opposite electrodes and collect the differential current flowing through the remaining ones. Therefore, the bipolar signal recorded upon the passage of a particle shows opposite pulses with different amplitude. The relative difference of the latter is a new metric enabling a simple compensation procedure of the signal impedance for off-center particles. Impedance data for 5.2, 6, and 7μm particles are collected, and coefficients of variation in (electrical) diameter of particles respectively of 2.8%, 1%, and 1.2%, similar to the manufacturers’ quoted values, are obtained. The novel operation mode is successfully implemented also in a coplanar electrode configuration, exploiting two pairs of liquid electrodes.

Linear synchronization and circuit implementation of chaotic system with complete amplitude control * *Project supported by the Startup Foundation for Introducing Talent of Nanjing University of Information Science & Technology, China (Grant No. 2016205), the Natural Science Foundation of the Jiangsu Higher Education Institutions of Jiangsu Province, China (Grant No. 16KJB120004), the Priority Academic Program Development of Jiangsu Higher Education

Although chaotic signals are considered to have great potential applications in radar and communication engineering, their broadband spectrum makes it difficult to design an applicable amplifier or an attenuator for amplitude conditioning. Moreover, the transformation between a unipolar signal and a bipolar signal is often required. In this paper, a more intelligent hardware implementation based on field programmable analog array (FPAA) is constructed for chaotic systems with complete amplitude control. Firstly, two chaotic systems with complete amplitude control are introduced, one of which has the property of offset boosting with total amplitude control, while the other has offset boosting and a parameter for partial control. Both cases can achieve complete amplitude control including amplitude rescaling and offset boosting. Secondly, linear synchronization is established based on the special structure of chaotic system. Finally, experimental circuits are constructed on an FPAA where the predicted amplitude control is realized through only two independent configurable analog module (CAM) gain values.

A hierarchical structure for human behavior classification using STN local field potentials

BackgroundClassification of human behavior from brain signals has potential application in developing closed-loop deep brain stimulation (DBS) systems. This paper presents a human behavior classification using local field potential (LFP) signals recorded from subthalamic nuclei (STN). MethodA hierarchical classification structure is developed to perform the behavior classification from LFP signals through a multi-level framework (coarse to fine). At each level, the time-frequency representations of all six signals from the DBS leads are combined through an MKL-based SVM classifier to classify five tasks (speech, finger movement, mouth movement, arm movement, and random segments). To lower the computational cost, we alternatively use the inter-hemispheric synchronization of the LFPs to make three pairs out of six bipolar signals. Three classifiers are separately trained at each level of the hierarchical approach, which lead to three labels. A fusion function is then developed to combine these three labels and determine the label of the corresponding trial. ResultsUsing all six LFPs with the proposed hierarchical approach improves the classification performance. Moreover, the synchronization-based method reduces the computational burden considerably while the classification performance remains relatively unchanged. Comparison with existing methodsOur experiments on two different datasets recorded from nine subjects undergoing DBS surgery show that the proposed approaches remarkably outperform other methods for behavior classification based on LFP signals. ConclusionThe LFP signals acquired from STNs contain useful information for recognizing human behavior. This can be a precursor for designing the next generation of closed-loop DBS systems.

Orthogonality-Based Generalized Multicarrier Constant Envelope Multiplexing for DSSS Signals

The new generation global navigation satellite systems will broadcast multiple direct sequence spread spectrum signals on multiple different central frequencies, with complex spreading chip waveforms. There is a strong demand for efficient and flexible multiplexing techniques to combine these signals into a constant envelope composite signal. In this paper, a high efficiency generalized multicarrier joint constant envelope multiplexing (CEM) technique for multilevel DSSS signals is proposed. The basic idea of this technique is adding an auxiliary component into the direct superposition of signals to keep the envelope of the integrated signal constant. Design principle, constraints, and optimization method of the auxiliary component are investigated. An analysis with typical case studies demonstrates the high efficiency and high flexibility of the proposed technique. Compared with existing CEM techniques, the proposed technique has much higher design flexibility in the number of subbands, the number of signal components, power ratio and phase relationship among components, and the spreading chip waveforms. It can be applied to any number of bipolar or multilevel DSSS signals with arbitrary power distribution at one or more subcarrier frequencies. Such high-level design flexibility provides system designers great room in signal scheme optimization for varied navigation applications in the future.

P3979Using large-tip ablation catheter markedly decreases bipolar signal amplitude near spiral wave center but this is not the case with using multi-electrode mapping catheter: A simulation study

P3979Using large-tip ablation catheter markedly decreases bipolar signal amplitude near spiral wave center but this is not the case with using multi-electrode mapping catheter: A simulation study

Compressed sensing for finite-valued signals

The need of reconstructing discrete-valued sparse signals from few measurements, that is solving an underdetermined system of linear equations, appears frequently in science and engineering. Whereas classical compressed sensing algorithms do not incorporate the additional knowledge of the discrete nature of the signal, classical lattice decoding approaches such as the sphere decoder do not utilize sparsity constraints.In this work, we present an approach that incorporates discrete values prior into basis pursuit. We consider bipolar finite-valued and unipolar finite-valued sparse signals, i.e., sparse signals with entries in {−L1,…,L2}, respectively in {0,…,L}, with L1,L2,L∈N. For those signals, we will show that the phase transition for our approach takes place earlier than in the case of basis pursuit. We will in particular derive highly improved performance guarantees for the special type of unipolar binary and bipolar ternary sparse signals, i.e., sparse signals having entries in {0,1}, respectively in {−1,0,1}. More precisely, we will show that independently of the sparsity of the signal, at most N/2, respectively 3N/4, measurements are necessary to recover a unipolar binary, and a bipolar ternary signal uniquely, where N is the dimension of the ambient space. We will further discuss robustness of the algorithm and phase transition under noisy measurements.

Asymmetrically Clipped Absolute Value Optical OFDM for Intensity-Modulated Direct-Detection Systems

Orthogonal frequency division multiplexing (OFDM) is attracting increasing attention in optical communication systems, thanks to its inherent benefits such as high spectral efficiency and resistance to frequency-selective channels. In this paper, a novel energy and spectrally efficient scheme called asymmetrically clipped absolute value optical OFDM (AAO-OFDM) is proposed for intensity-modulated direct-detection systems. In AAO-OFDM, absolute value optical OFDM (AVO-OFDM) signals on the even subcarriers and asymmetrically clipped optical OFDM (ACO-OFDM) signals on the odd subcarriers are combined for simultaneous transmission, which employs all the subcarriers requiring no dc biases. For AVO-OFDM scheme, the frequency symbols are first modulated on the even subcarriers, which are then fed into an inverse fast Fourier transform block. Afterward, the absolute values of the bipolar time-domain signals are taken to guarantee non-negativity, while their signs are mapped to the complex-valued symbols and modulated on the odd subcarriers. Since there remain unused odd subcarriers, other useful symbols can be modulated on them, which leads to the conventional ACO-OFDM scheme. At the receiver, the ACO-OFDM symbols on the odd subcarriers are demodulated first, which are reconstructed and removed from the received signals. Afterward, the remaining signals are utilized to detect the AVO-OFDM symbols with the aid of the demodulated sign symbols on the odd subcarriers. Theoretical analysis and simulation results show that AAO-OFDM has lower peak-to-average power ratio than other optical OFDM schemes, which makes it less sensitive to the nonlinearity of the optical devices. Furthermore, it achieves better bit error rate performance compared to its counterparts for the same spectral efficiency.

A Bipolar Voltage Modulation Spectrum Analysis

Features of power grid based on renewable energy sources are described. The necessity of isolated power converters in the power grid is shown. Low harmonics negative impact in modulated AC voltage based on unipolar pulse width modulation for transformer weight of isolated invertors is underlined. An approach of bipolar voltage generation with inverting every second modulation pulse that significantly decreases the low harmonics amplitude and allows to decrease the transformer weight in several times is described. A double Fourier series implementation for bipolar voltage analysis that allows expressing a signal spectrum characteristic in compact form for any multiplicity parameter value is proposed. Representation of modulated signal based on two variables of carrier and modulation functions is considered. Two different cases of modulated voltage generation depending on multiplicity parameter value are described. Bipolar voltage signal representation based on the sum of two unipolar signals with two times lower carrier function frequency is proposed. Bipolar and unipolar modulated signals spectrum components of double Fourier series are calculated. Spectrum characteristic of bipolar voltage modulation is analyzed. Transmission of the significant energy amount of bipolar voltage by harmonics with frequencies near two times lower value than carrier function frequency is proved. A case with multiplicity parameter which is multiplied to number four is noted as more desirable due to decreasing the first harmonic value. A proposition about subsequent improvements of bipolar voltage modulation is given

Right ventricular outflow tract high-density endocardial unipolar voltage mapping in patients with Brugada syndrome: evidence for electroanatomical abnormalities.

Epicardial structural abnormalities at the right ventricular outflow tract (RVOT) may provide the arrhythmia substrate in Brugada syndrome (BrS). Electroanatomical endocardial unipolar voltage mapping is an emerging tool that accurately identifies epicardial abnormalities in different clinical settings. This study investigated whether endocardial unipolar voltage mapping of the RVOT detects electroanatomical abnormalities in patients with BrS. Ten asymptomatic patients (8 males, 34.5 ± 11.2 years) with spontaneous type 1 ECG pattern of BrS and negative late gadolinium enhancement-cardiac magnetic resonance imaging (LGE-c-MRI) underwent high-density endocardial electroanatomical mapping (>800 points). Using a cut-off of 1 mV and 4 mV for normal bipolar and unipolar voltage, respectively, derived from 20 control patients without structural heart disease established by LGE-c-MRI, the extend of low-voltage areas within the RVOT was estimated using a specific calculation software. The mean RVOT area presenting low-voltage bipolar signals in BrS patients was 3.4 ± 1.7 cm2 (range 1.5-7 cm2). A significantly greater area of abnormal unipolar signals was identified (12.6 ± 4.6 cm2 [range 7-22 cm2], P: 0.001). Both bipolar and unipolar electroanatomical abnormalities were mainly located at the free wall of the RVOT. The mean RVOT activation time was significantly prolonged in BrS patients compared to control population (86.4 ± 16.5 vs. 63.4 ± 9.7 ms, P < 0.001). Isochronal mapping demonstrated lines of conduction slowing within the RVOT in 8/10 BrS patients. Wide areas of endocardial unipolar voltage abnormalities that possibly reflect epicardial structural abnormalities are identified at the RVOT of BrS patients.

A Bipolar-Pulse Voltage Method for Junction Temperature Measurement of Alternating Current Light-Emitting Diodes

We introduce a new method for measuring the junction temperature of alternating current light-emitting diodes. This method employs a periodic bipolar voltage pulse signal as the input, and utilizes the amplitude of corresponding output current as the temperature sensitive parameter (TSP), of which a linear temperature dependence is proven in a prior experiment in this paper. On the basis of the TSP, we devise a detailed procedure—first, measure the thermal resistance of the package of ac-LEDs, which further contributes to the calculation of junction temperatures under various power inputs. Comparisons between values calculated by using this method and those obtained directly from a thermocouple indicate a decent accuracy of the former. The advantage of this method benefits from the stability of thermal resistance under different driving conditions that one could immediately obtain the junction temperature by measuring the electric and optical powers.

Assessment of the DC Bias to Mitigate the Clipping Noise in DCO-OFDM, ACO-OFDM; and Non-linear Distortion of DFB Laser Transmitted through Dispersive Single Mode Fibers in IM/DD Systems

An analytical investigation on the impact of the DC bias on the clipping noise and the laser non-linearity in Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACO-OFDM) and Direct Current--Biased Optical OFDM (DCO-OFDM) is performed. Clipping noise in the OFDM system is introduced either by transmitter non-linearity or due to the low power sensitivity of the receiver. However the clipping noise in the DCO-OFDM is also dependent upon the DC bias applied to make the bipolar OFDM signal unipolar. The addition of this extra DC bias increases the average signal power of the DCO-OFDM signal. The non-linearity of the DFB laser increases with the optical modulation index, which gives rise to intermodulation and harmonic distortions at the receiver. The OFDM signal when transmitted through the Single Mode Fiber (SMF) suffers from group--velocity dispersion (GVD) which limits its performance in the Passive Optical Networks (PON). In this paper, an assessment of the DC bias to reduce the clipping noise in the two systems under consideration is performed. A practical laser model is considered and analysis is performed to estimate the average laser drive power to maintain its non-linearities within a tolerable region for both the OFDM systems. A simulation is performed to transmit 5 and 8 Gb/s (ACO and DCO) OFDM signal over 120 km SMF where the effect of GVD is taken into consideration. An optimum OFDM drive signal power is calculated to maintain the laser transmitter in its linear region such that the effect of second order harmonic distortions (HD2) and third order intermodulation distortion (IMD3) is low. The SNR requirement of DCO-OFDM being higher than the ACO-OFDM leads to more clipping noise, HD2 and IMD3.

Frequency spectrum of induced transmembrane potential and permeabilization efficacy of bipolar electric pulses

In this paper a simple prediction method for the bipolar pulse cancellation effect is proposed, based on the frequency analysis of the TMP spectra of a single cell and the computed relative global spectral content up to a defined frequency threshold. We present a spectral analysis of pulses applied in experiments, and we extract the induced TMP from a microdosimetric model of the cell. The induced TMP computation is carried out on a hemispherical multi-layered cell model in the time domain.The analysis is presented for a variety of unipolar and bipolar input signals in the nanosecond and the microsecond time scales. Our evaluations are in good agreement with experimental results for bipolar pulse cancellation of electropermeabilization-induced Ca2+ influx using 300ns, 750kV/m pulses and with other results reported in recent literature.

LEFT ATRIAL ELECTROANATOMIC SUBSTRATE AS A PREDICTOR OF ATRIAL FIBRILLATION RECURRENCE AFTER CIRCULAR RADIOFREQUENCY PULMONARY VEINS ISOLATION. OBSERVATIONAL PROSPECTIVE STUDY RESULTS

Aim . To evaluate an extent of left arrial (LA) electroanatomical substrate (EAS) by the method of high density contact mapping in patients with atrial fibrillation (AF) and estimate its impact on recurrence rate following circular radiofrequency pulmonary veins (PV) isolation in prospective observational study. Material and methods. Totally 181 high symptomatic subjects with paroxysmal (142 pts) and persistent (39 pts) AF, who underwent circular RF PVI were enrolled. We created and prospectively analyzed LA electroanatomical high density bipolar maps. Bipolar signals ≤0.75mV, associated with local conduction velocity delay &lt;1 m/s were tagged on LA maps and considered as EAS. Relative EAS areas outside PV ostia were consistently measured. All of the patients were followed up at least for 3 years and AF recurrence rate and redo procedures were recorded. Results . A mean relative EAS area was 13.8±10.3% and 32.6±18.5% in patients with paroxysmal and persistent AF, respectively (P=0,02). During a mean follow-up of 32±7 months, AF recurrence was diagnosed in 69 (38%) of patients. Following a redo ablation in 51 (28%) of patients, subsequent AF recurrence developed in 31 pts (19%). Multivariate analysis showed that only relative EAS areas was independently associated with AF recurrence (HR 1.05, CI 95% 1.02-1.09, P=0.002) and ach 10% increase in the extent of relative EAS area was associated with a 1.6-fold elevation of AF recurrence rate after the index ablation. But the impact of the EAS on clinical outcome after redo ablation was even higher (HR =1,09, p=0,0018) and each 10% increase in the extent of relative EAS area was associated with a 2.4-fold elevation of AF recurrence rate after a redo ablation. Conclusion. The present study suggests that an extent of LA EAS in patients undergoing PVI — is a significant and independent predictor of AF recurrence. This data can have important role for further development and personalization of strategy of interventional treatment in patients with AF.

Generalized unambiguous tracking method based on pseudo correlation function for multi-level coded symbol modulated signals

The global navigation satellite system (GNSS) signal modulation type plays a crucial role in determining the performances of positioning, navigation and timing (PNT) services. Currently, the binary offset carrier (BOC) modulation signal and binary coded symbol (BCS) modulation signal are both bipolar signals, which greatly restrict the room of improving the GNSS signal performance. Therefore, multi-level coded symbol (MCS) modulation has received great attention in the field of GNSS signal design. The MCS modulation is the most extensive step-coded symbol modulation mode, where BOC modulation and BCS modulation are its special cases. Since the waveform symbol of the MCS modulation signal can be arbitrarily valued, the optimal GNSS signal can be designed. However, like the BOC modulation signal, the MCS modulation signal also has the problem of ambiguous tracking, and then results in a large pseudo range measurement error, which is unacceptable for the new generation GNSS with high accuracy. In recent years, the unambiguous tracking of GNSS signals has become a hot research subject in the navigation signal processing domain and many methods are presented, and those methods can be divided into three categories:BPSK-like method, bump jump (BJ) method, and side-peak cancellation (SC) method. However, these methods are designed for BOC signal, and they are not suitable for MCS signal. Therefore, in this paper we propose a general unambiguous tracking algorithm based on the pseudo correlation function (PCF), which is suitable for MCS modulated signals. Firstly, the unitary expression of MCS modulated signal based on waveform value vector is given, then the unitary formula of cross-correlation function for MCS signal is derived and the definition of PCF is given. Then the constraint condition which should be satisfied to realize unambiguous tracking is analyzed in depth, and the universal constructing method of two reference signals and the relationship between each other are derived according to this constraint condition, which brings great convenience for solving the specific MCS signal. The code tracking loop model of GNSS receiver based on the proposed method is illustrated. It is observed that the proposed method can receive different MCS signals under the same receiver loop framework, and can simplify the design of the receiver while eliminating the tracking ambiguous problem. Finally, as a special case of MCS signal, the applications of the proposed method in four kinds of BOC signals are discussed respectively, and then the waveform value vector of the reference signal and the unitary expression of code discriminator are derived. Simulation results show that the proposed method can effectively solve the ambiguous tracking problem of MCS signal, which has good performance and broad application prospect.

Optical MIMO-OFDM with Generalized LED Index Modulation

Visible light communications (VLC) is a promising and uncharted new technology for the next generation of wireless communication systems. This paper proposes a novel generalized light emitting diode (LED) index modulation method for multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM)-based VLC systems. The proposed scheme avoids the typical spectrum efficiency losses incurred by time- and frequency-domain shaping in OFDM signals. This is achieved by exploiting spatial multiplexing along with LED index modulation. Accordingly, real and imaginary components of the complex time-domain OFDM signals are separated first, then resulting bipolar signals are transmitted over a VLC channel by encoding sign information in LED indexes. As a benchmark, we demonstrate the performance analysis of our proposed system for both analytical and physical channel models. Furthermore, two novel receiver designs are proposed. Each one is suitable for frequency-flat or selective channel scenarios. It has been shown via extensive computer simulations that the proposed scheme achieves considerably better bit error ratio versus signal-to-noise-ratio performance than the existing VLC-MIMO-OFDM systems that use the same number of transmit and receive units [LEDs and photo diodes (PDs)]. Compared with the single-input single-output (SISO) DC biased optical (DCO)-OFDM system, both spectral efficiency and DC bias can be doubled and removed respectively simply by exploiting a MIMO configuration.

Sensitivity analysis of HD-sEMG amplitude descriptors relative to grid parameter variations of a cylindrical multilayered muscle model

The aim of this work is to perform a sensitivity analysis of a high density surface electromyogram (HD-sEMG) amplitude descriptors according to several grid parameters. This study is motivated by the fact that the electrode grid position and layout are crucial to record relevant electromyographic data. For this purpose, an analytical limb model is used, where the upper limb is modeled as a multilayered cylinder with three layers: muscle, fat tissue and skin tissue. Using this model, HD-sEMG signals are computed over the skin as a 2D surface along angular and longitudinal directions. Electrode recording is performed through a surface integration on the 2D surface according to the electrode shape. 16 simulations on 10 anatomies (350 Motor Units) with the same parameters were computed for 3 constant contraction levels: 30%, 50% and 70% of the maximal voluntary contraction. Then, a global sensitivity analysis using the elementary effect method is performed to explore the sensitivity of amplitude descriptors (average rectified value, root mean square value and high order statistics) relative to varying parameters from the electrode grid (inter-electrode distances, electrodes radius, position and rotation). From those grid definitions, monopolar, bipolar and laplacian signals are also computed to see the electrode arrangement sensitivity. The obtained results exposed a huge impact of the grid rotation on the studied criteria. They also showed that parameters specific to the electrode grid layout (inter-electrode distances) have the less impact. Moreover, they exhibited the laplacian arrangement as the most sensitive electrode arrangement to grid modifications.

Stochastic resonator to detect bipolar binary pulse amplitude modulated signals; analysis, parameter‐induced SR designs and sine‐induced SR

A stochastic resonator has been considered as an alternative signal processing tool because of its noise-induced performance enhancement ability. Here, the resonator parameters, steady states and transition time of the system are redefined for bipolar binary pulse amplitude modulated (BPAM) signals such that the region in which the resonator benefits from noise can be identified. Simple parameter-induced SR (PSR) designs are then built, based on this analysis in order to configure the resonator in the optimum region. Furthermore, sine-induced SR based on using a periodic signal instead of noise is introduced to enhance the system performance and compared with noise-enhanced SR (NSR). It is shown that sine-induced SR provides a performance enhancement as it needs less power and does not require an adjustment relevant to the background noise. The results indicate that a resonator improves the receiver performance by eliminating noise if its parameters and BPAM characteristics are set accurately as given in the PSR designs, otherwise the resonator can benefit from either a noise as in NSR, or a sine wave as proposed.

Neuromuscular, metabolic and ventilatory fatigue threshold from an incremental cycling test using 1-min exercise periods

Aim: Extensive research has been directed towards the identification of the threshold that demarcates fatiguing from non-fatiguing exercise during an incremental workout on a cycle ergometer. As the exercise intensity increases, fatigue compromises not only the cardiovascular and respiratory systems, but also the neuromuscular system. The objective of this work was to calculate the neuromuscular fatigue threshold from surface electromyographic amplitude (EMG-FT) and determine possible associations between this threshold and the metabolic (onset of blood lactate accumulation, OBLA) and ventilatory (ventilatory threshold, VT, and respiratory compensation point, RCP) thresholds.  Methods: Sixteen cyclists performed incremental cycle ergometer rides to exhaustion with bipolar surface sEMG signals recorded from the vastus lateralis. The participants were road cyclists engaged in regular training and amateur road races. On average, cyclists trained at least four times a week covering a weekly distance ranging between 400 and 600 km, plus competition or Sunday training. Cyclists had a national competitive experience of 4.3 (1.7) years and had performed an average of 20,000 km riding. Before the incremental exercise test started, cyclists performed 5 min of unloaded cycling. The test was initiated at a workload of 125 W and the load was increased by 25 W every 1 min until the subjects could no longer continue to exercise (Fig. 1a). At this time, the power achieved was referred to as the maximal power. To calculate the EMG-FT, the deVries’ model was employed using 1-min exercise periods. Blood samples were taken every two minutes during the test. OBLA was calculated as the power output corresponding to a blood lactate concentration of 4.0 mmol/L. During the incremental exercise, breath by breath analysis was performed using a turbine flow-meter connected to a face mask and data of oxygen uptake and carbon dioxide production and ventilatory parameters. One-way repeated-measures ANOVA was used to determine whether there were significant differences in average power output among the EMG-FT, OBLA, VT, and RCP. Pearson correlation coefficients were calculated to determine the relationships among EMG-FT, OBLA, VT, and RCP.  Results: The maximal power tolerated was 403.8 ± 36.5 W. The power output at EMG-FT (372 ± 25 W) was comparable (P>0.05) to that of RCP (381 ± 36 W), but significantly higher (P 0.05), but it was positively correlated with those of VT (0.78, P<0.001) and RCP (0.85, P<0.001).  Conclusions: Our results do not support the existence of a relationship between EMG-FT and lactate concentration. A significant correlation was found between the sEMG-based threshold and gas exchange thresholds, although this correlation may not be causative. Second, application of deVries’ model using of 1-min exercise periods could result in overestimation of the fatigue threshold since such short exercise periods could be insufficient to detect EMG signs of neuromuscular fatigue