Hard and rapid switching causes a voltage waveform with a very high dv/dt (rate of change in voltage) causing high.
#Modulation of hollow cathode lamp series
The result is application of a series of pulses to the load, and if the load is inductive, sine wave current flows into the load. In these modulation techniques, the switches are hard switched. In variable speed motor drive and uninterruptible power supply (UPS) applications, taditional method is to employ some kind of a modulation technique at a high frequency typically 6 kHz to 20 kHz range. Şedele, Serkan Paki Ertan, Hulusi Bülent Department of Electrical and Electronics Engineering (2004) This is shown by designing an asynchronous arithmetic logic unit (ALU), implemented in the style of micropipelines, on th.Ī novel approach for synthesising sinus waveforms at power level Therefore potential advantages of the asynchronous circuits could not be observed when they are implemented on commercial FPGAs. Both the architecture of the FPGAs and the synthesis tools are mostly tailored to synchronous design. However commercial FPGAs are not very suitable for asynchronous design. This saved storage space and analysis time.Īn asynchronous system design and implementation of an FPGAĪyyıldız, Nizam Güran, Hasan Department of Electrical and Electronics Engineering (2006)įield Programmable Gate Arrays (FPGAs) are widely used in prototyping digital circuits. A large number of data collected during atomization period is compressed in machine code. A sampling rate of 16 during a signal period at 50-Hz chopping frequency is found to be the optimum value. The data acquisition program is written in machine language and synchronization between light sources and computer is provided by chopper position signal through the interrupts. The D2 lamp is chopped by a mechanical chopper driven by a stepper motor and a hollow cathode lamp is modulated electronically. This system is applied to D2-lamp background correction graphite furnace atomic absorption spectrometer. A dual high-voltage switch can modulate dc light sources under computer control. A light chopper connected to the stepper motor is controlled easily by computer.
A stepper motor runs under the control of timer/counter chip independent of computer. The timer/counter chip with 16 built-in registers can be programmed in many modes which provides a time base for real-time measurements. The interface card consists of a multiplexed analog-to-digital converter, a digital-to-analog converter, and a timer/counter chip. A versatile interface card for Apple IIe computer and various peripheral devices are designed to control instruments which generates transient signals like in graphite furnace atomic spectrometer.
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