Pulse-width modulation

industrial drives) three-level inverters are used extensively [1]-[2], and recently, their application in low-voltage, high-power traction applications have been introduced [3]-[5]. In these applications, the three-level inverters often need to operate with modulation indices (m) lower than 0.5 [6]- [10]. Additionally, at lower modulation indices, traction drives operating with induction motors (IMs), interior permanent magnet motors (IPMs) or synchronous reluctance motors (SynRMs) may need to provide higher reactive power, thus operating with a lower power factor (pf) [9], [11]- [17]. For example, in [9], the power factor of IPMSMs at 0.2 modulation index is shown to be 0.52. The power factor of SynRMs also varies between 0.3-0.7 based on designed saliency [17]. Hence, the three-level inverters for these applications need to be controlled appropriately at lower modulation indices and lower power factors for optimum…

same theme but it appears in 5th above which starts in ‘G’ (1 Figure). This theme appears again and again as the modulated form through the whole movement. It sounds pretty simple but it plays very important role in this movement because it sets center tonality of this movement. Also, this movement starts with this theme and also ends with this theme so it contributes to establishing coherence of the movement (2 Figure). This can explain the ‘organic’ sense which Solie, the author of article…

In order to get a good design, the bandwidth of modulation need to be minimized for transmission. A transmission bandwidth that has a greater magnitude than the bandwidth required for the minimum signal is used by the spread spectrum. The advantage of spread spectrum is that it can be many users use the same bandwidth at the same time without interfering with each other. However, this is not good for a few number of users because it is not economic. Spread spectrum is a form of wireless…

This artifact is primary based on sample rates and to see the effects of sample rates by using Sinusoidal waves. Sinusoidal waves can be represented using frequency and period. The Frequency of a Sinusoidal wave is the number of complete cycles that happen in a particular period of time or in a given sample. The Period in terms of Sinusoidal waves, is the time it takes to perform one complete cycle. The Sinusoidal wave is a series of identical cycles happening repeatedly. The sample rate is the…

Chapter eight of the text Sound and Recording by Francis Rumsey and Tim McCormick, discusses the principles of digital audio, and contrasts digital with analog. The text also illustrates how digital and analog work together to produce desired sound. In the world of audio there are two types; digital and analog. Analog can be described as physical or tangible in a sense, being etched onto some type of media. Digital however, is a representation of the audio waveform, which is converted into a…

2. QPSK: When a data is transmitted using BPSK technique the channel bandwidth required is 2fb. The QPSK technique reduces that bandwidth to fb. It is a multilevel phase modulation. In this two successive bits in a bit stream are combined together to form a message and each message is represented by distinct value of phase shift of a carrier. The QPSK signal is represented as. Since there are 4 phases it is called as 4-PSK or Quadrature PSK systems [6][7]. 3. QAM: QAM improves the noise…

RADIOWAVE OUTDOOR PROPAGATION MODELS General definition: • They are empirical mathematical formulation for the characterization of radio wave propagation as a function of frequency, distance and other conditions. • These models predict the path loss (i.e. the reduction in power density of an electromagnetic wave as it propagates through space or underground) of a transmitter and also the effective coverage area of transmitter. We know that when a signal travels from a wireless channel, it…

2 OFDM SYSTEM:- OFDM system is divided into three parts 1. multi carrier modulation 2. frequency division multiplexing 3. Orthogonal frequency division multiplexing. 1.Frequency division multiplexing:- Frequency Division Multiplexing is a form of signal multiplexing which involves assigning non – overlapping frequency ranges or channels to different signals or to each user of a medium. A gap is left between each of these channels to ensure that the signal of one channel does not overlap with…

Peripheral Pulse Checks and Amplitude Absence or diminished leg pulses may suggest peripheral arterial disease of intermittent claudication. Absence suggests occlusion by thrombus, embolus, or dissection. If the pulse is hypokinetic or of low volume and amplitude, this could suggest shock or myocardial infarction indicative of low cardiac output such in the case of cardiomyopathy, stenosis, tamponade, or pericarditis. Hyperkinetic or bounding pulses are large-amplitude and strong pulses may be…

Exercise effects the human body in many fascinating ways; as it causes the body to adapt and alter to aid the body’s stimulation. Take when carrying out the Harvard step test practical. This test is where a person carries out a period of exercise for a certain length of time and then records their heart rate before and for so long after the period. This shows how fit and healthy the heart is by showing how long it takes for the heart to go back to a regular resting pulse rate. “The…