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Electronic Devices and Communication Applications
Published in Mike Tooley, BTEC First Engineering, 2010
The duty cycle of a pulse wave is the ratio of the on time to the on plus off time (and usually expressed as a percentage). Hence: Duty cycle=ton/(ton+toff)×100%=ton/t×100%
Research on a low-cost ultra-wideband frequency measurement circuit design
Published in Fei Lei, Qiang Xu, Guangde Zhang, Machinery, Materials Science and Engineering Applications, 2017
Qi Li, Zhong Wang, Jieling Wang, Jiayuan Li
This design is supported by the framework of the FPGA and analog circuit. It is the simple and reliable external analog circuit design that makes the whole system’s testing frequency range wider and the test signal amplitude’s range wider. It is a low-cost system and is easy for popularization and use [10,11]. The system is superior to those test equipment that may cost more than 10,000 Yuan, for its cost is controlled within 200 Yuan. This system can carry out accurate measurements of the triangle wave, sine wave, and square wave waveform and it can also count duty ratio and the phase difference of the pulse wave. The system can realize flexible control, low cost, strong practicability and is valuable to popularize.
Trauma Outcome Prediction in the Era of Big Data: From Data Collection to Analytics
Published in Ervin Sejdić, Tiago H. Falk, Signal Processing and Machine Learning for Biomedical Big Data, 2018
Shiming Yang, Peter F. Hu, Colin F. Mackenzie
Similarly, blood pressure variability (BPV) has been derived from noninvasive blood pressure (NIBP) as a cardiovascular risk factor [46]. The ABP waveform also carries a pulse wave. With identified NN intervals, NIBP or even ABP could be used to calculate BPV in the time domain and frequency domain, as well as the nonlinear dynamics features.
A Systematic Review on Muscle Stimulation Techniques
Published in IETE Technical Review, 2023
Nishtha Kashyap, Vinay Kumar Baranwal, Bijit Basumatary, Rajinder Bansal, Ashish Sahani
There are many types of signal characteristics for the present used in ES systems for giving perfect stimulation, which is defined as direct current (DC), alternating current (AC), and pulsed current (PC). DC is mainly used for activating denervated muscles and for directly stimulating muscles. Thus, it does not improve motor learning; rather, it simply stops the loss of muscle tissue. There are many types of waveform used in electrical stimulation like monophasic, biphasic, and pulse wave. It can be asymmetric and symmetric also. On the other side, AC and PC are mostly used with distinct signal waveforms for attaining motor learning results. According to the shape and phase of these current waveforms. It can be classified as sinusoidal, rectangular, triangular, square, and also as monophasic, biphasic, or polyphasic [23]. Symmetric waveforms are more comfortable and target larger muscles to contract, and asymmetric are for smaller muscles. Pulse current is generally used in pain therapy that is TENS.
Study of Heart Rate and Blood Pressure Subject to Pulsed LED Lighting
Published in LEUKOS, 2022
Luyao Tang, Xiaolin Zhang, Xiaoli Zhou, Xin Gu, Shenglong Fan, Muqing Liu
In recent years, many researchers found a relationship between blood pressure, heart rate, and lighting conditions. The previous study by Tsutsumi et al. revealed that different color temperatures of fluorescent lights could affect heart rate and blood pressure (Tsutsumi et al. 2002). In 2005, Cajochen et al. found that changes in the wavelength of light could affect human heart rate and body temperature (Cajochen et al. 2005). A recent study conducted by Tang et al. showed that full-spectrum lighting could cause a significant effect on heart rate (Tang et al. 2020). To the best of our knowledge, few studies have reported blood pressure and heart rate changes in response to pulsed light. If certain parameters should have a negative impact, then the use of these pulsed lights must be cautiously considered. In the meantime, the widespread use of Pulse Width Modulation (PWM) LED Dimmers (whose principle is based on adjusting the duty cycle of the pulse wave to adjust the light brightness) makes the research of its physiological effects even more important. Therefore, we chose to investigate the effect of pulsed lights by measuring heart rate and blood pressure.
Calibration of Electrocardiograph (ECG) Simulators
Published in NCSLI Measure, 2018
Steven Yang, Brenda Lam, Chris M. N. Ng
An ECG simulator is a device which generates reference voltage signals to the electrodes of an ECG. A list of reference signals that are generally available from ECG simulators is illustrated in Figure 2. The reference signals are designated for verification and training purpose, which includes normal sinus rhythm waveform, performance waveforms, and abnormal waveforms. a For normal sinus waveform, the signal amplitude is defined as peak to null (R to zero). For performance waveforms, the ECG simulator generally outputs sine wave, square wave, triangle wave, and pulse wave, with signal amplitude defined in peak to peak (Vpp) value. Some ECG simulators have the capability to generate abnormal waveforms, such as supraventricular arrhythmia, ventricular arrhythmia, symptomatic bradycardia, irregular tachycardia, etc. These waveforms are mainly designated for medical training purpose, therefore the calibration of these waveforms is not required.