Rise time

About: Rise time is a research topic. Over the lifetime, 4748 publications have been published within this topic receiving 47512 citations.

Superior electro-optic response in multiferroic bismuth ferrite nanoparticle doped nematic liquid crystal device

Abstract: A superior electro-optic (E-O) response has been achieved when multiferroic bismuth ferrite (BiFeO3/BFO) nanoparticles (NPs) were doped in nematic liquid crystal (NLC) host E7 and the LC device was addressed in the large signal regime by an amplitude modulated square wave signal at the frequency of 100 Hz. The optimized concentration of BFO is 0.15 wt%, and the corresponding total optical response time (rise time + decay time) for a 5 μm-thick cell is 2.5 ms for ~7 V(rms). This might be exploited for the construction of adaptive lenses, modulators, displays, and other E-O devices. The possible reason behind the fast response time could be the visco-elastic constant and restoring force imparted by the locally ordered LCs induced by the multiferroic nanoparticles (MNPs). Polarized optical microscopic textural observation shows that the macroscopic dislocation-free excellent contrast have significant impact on improving the image quality and performance of the devices.

Temperature rise and thermal rise‐time measurements of a semiconductor laser diode

Abstract: A novel method is presented for measurement of the rise in temperature and thermal rise time of a semiconductor laser diode (LD) under pulsed operation. The technique employs the shift in LD threshold current which occurs with a rise in junction temperature. Practical results are given, showing a rise time of about 10 ns.

A power control method for a voltage controlled power amplifier and circuitry used in the method

Abstract: In a digital radio telephone transmitter an output pulse with eg cos 2 -shaped edges is produced by a voltage controlled power amplifier (4) When known control loop circuitry is used, the power (Pout) of the output pulse will rise almost step-wise at the beginning of the pulse, which leads to the spreading of the spectrum and to rise time delays of the output pulse with respect to the control pulse (TXC) at different power levels According to the invention a good cos 2 -shape of the output pulse (Pout) and its tracking of the control pulse (TXC) almost without delay is achieved so that a squarewave pulse (V p ) is added to the control voltage (V2) of the power amplifier (4), the pulse (V p ) starting and ending substantially at the same time as the control pulse (TXC) In a preferred embodiment the squarewave pulse (V p ) is added to the control voltage (V2) only during that time when the control voltage (V2) is below that value, at which the control loop begins to operate

Improved inductorless phase control dimmer power stage with semiconductor controlled voltage rise time

Abstract: An electronic dimming apparatus includes a semiconductor power controller which couples a lamp to an alternating current source and variably controls the average power supplied to the lamp by adjusting the relative proportion of each half-cycle in which the power controller is in a conductive condition. The semiconductor power controller is controlled by the output of a transition controller which in turn is connected to a triggering circuit. The triggering circuit is responsive to a first input condition corresponding to desired average power and also responsive to the zero-crossing of the alternating current waveform. The transition controller gradually changes the condition state of the semiconductor power controller between non-conduction and conduction and controls the voltage across the lamp load to maintain a stable rate of voltage change despite lamp impedance variations, thus reducing electromagnetic interference.

Method for analysis of single pulse pressure waves

Abstract: This invention relates to a method for analysing pressure-signals derivable from pressure measurements on or in a body of a human being or animal, comprising the steps of identifying during given time sequences in a series of time sequences the single pressure waves, including related parameters [pressure amplitude ΔP, latency (ΔT), rise time coefficient (ΔP/ΔT)], determining numbers of single pressure waves with pre-selected combinations of two or more of said single pressure wave parameters during said time sequence. For the time sequences is further determined the balanced positions of single wave parameters. Two dimensional values of balanced position may be presented as a one dimensional value after weighting of the matrix cells. The signal processing method may be used for more optimal detection of single pressure waves by means of non-invasive sensor devices.