Muscle fatigue is the decline in ability of a muscle to create force. Electromyography (EMG) is a medical technique for measuring muscle response to nervous stimulation. During a sustained muscle contraction, the power spectrum of the EMG shifts towards lower frequencies. These effects are due to muscle fatigue. Muscle fatigue is often a result of unhealthy work practice. In this research, the effectiveness of the wavelet transform applied to the surface EMG (SEMG) signal as a means of understanding muscle fatigue during walk is presented. Power spectrum and bispectrum analysis on the EMG signal getting from right rectus femoris muscle is executed utilizing various wavelet functions (WFs). It is possible to recognize muscle fatigue appreciably with the proper choice of the WF. The outcome proves that the most momentous changes in the EMG power spectrum are symbolized by WF Daubechies45. Moreover, this research has compared bispectrum properties to the other WFs. To determine muscle fatigue during gait, Daubechies45 is used in this research to analyze the SEMG signal.

Schmitt triggers are electronic comparators that are widely used to enhance the immunity of circuits to noise and disturbances and are inherent components of various emerging applications. Conventional Schmitt triggers, composed of operational amplifiers, suffer from some inevitable drawbacks which are not prominent in CMOS Schmitt triggers. In this paper, a review on the advancement of Schmitt trigger circuits are illustrated in different literatures is discussed with their merits and demerits.

Schmitt triggers are commonly used in communication and signal processing techniques to solve noise problem. A low voltage Schmitt trigger circuit with tunable hysteresis is proposed in this paper. For obtaining hysteresis under low voltage, a cross-coupled static inverter pair is used. By adjusting the symmetrical load operation, the hysteresis of the Schmitt trigger is varied. The cross-coupled inverter pair regenerative operation is controlled by it. Designed in 0.18 um CMOS process technology, the simulation results show that the proposed Schmitt trigger circuit’s triggering voltage can be adjusted approximately 0.5 V to 1.2 V. The proposed design is suitable to be implemented in buffers, sub-threshold SRAMs, retinal focal plane sensors, wireless transponders and pulse width modulation circuits.

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