Browsing by Author "Bilal Amjad"

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    Preamplifier And Loudspeaker & Muting design for a studio series stereo amplifying system
    (University of Management and Technology, 2012) Bilal Amjad; Hassan Tariq
    In our final year project we successfully amplified any random signal with less power dissipation and higher efficiency using Class D amplifying System. Firstly we implement using Class A and calculated power dissipation that is too large.So, we did research on different Classes of amplifying system and selected Class D because this is highly efficient amplifying Class. For Analog Class D amplifying System, we implemented three blocks.Firstly,modulation blocks which takes the random audio signal and compares it with triangular carrier signal and superimpose into the carrier and generate PWM signal. Secondly, Switching Output block (Inverter, Gate Driver, Switching MOSFET’S) takes the output of PWM and amplifies it up to the required level. Gate driver is necessary to operate switching MOSFET’S according to the requirement, the proposed gate driver features consumes much less energy as well as minimized conduction and switching (delay time, rise time, reverse recovery time, fall time and decay time)losses.Thirldy,Low Pass Filter block is to recover back our original random signal. For Digital Class D amplifying system, we implemented three blocks. Firstly, UPWM (Uniform Pulse Width Modulation) block which takes the digital signal and turn into in stair-case signal which further is given to the Switching output block. We implemented UPWM using microcontroller PIC 16F877A.
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    Preamplifier and loudspeaker & muting design for a studio series stereo amplifying system
    (UMT Lahore, 2012) Bilal Amjad; Hassan Tariq
    In our final year project, we successfully amplified a random signal with less power dissipation and higher efficiency using a Class D amplifying system. Firstly, we implemented a Class A amplifier and calculated its power dissipation, which was too large. Therefore, we researched different classes of amplifying systems and selected Class D because it is a highly efficient amplifying class. For the analog Class D amplifying system, we implemented three blocks. Firstly, the modulation block takes the random audio signal, compares it with a triangular carrier signal, superimposes it onto the carrier, and generates a PWM signal. Secondly, the switching output block (inverter, gate driver, switching MOSFETs) takes the PWM output and amplifies it to the required level. The gate driver is necessary to operate the switching MOSFETs according to requirements, and the proposed gate driver consumes much less energy while minimizing conduction and switching losses (delay time, rise time, reverse recovery time, fall time, and decay time). Thirdly, the low-pass filter block is used to recover the original random signal. For the digital Class D amplifying system, we implemented three blocks. Firstly, the UPWM (uniform pulse width modulation) block takes the digital signal and converts it into a staircase signal, which is then fed into the switching output block. We implemented UPWM using the PIC 16F877A microcontroller