Pulse width modulation
- 1. PulseWidth Modulation Course No: EEE 3218 CourseTitle: Communication Engineering II Sessional
- 2. Contents What is Pulse Width Modulation? Why is PulseWidth Modulation needed? Theory of Pulse Width Modulation. Waveshapes of PWM. PWM Kit of Laboratory Input & Output of PWM Method Advantages & Disadvantages Applications
- 3. What is PulseWidth Modulation? In Pulse Width Modulation, the width of the pulse of the carrier signal is varied according to the message signal. Pulse Width Modulation is a process or technique in most communication systems for encoding the amplitude of a signal right into a pulse width.
- 4. Why is pulse width Modulation needed? To understand the need of Pulse width modulation, we must know what the difference between a pulse signal and a continuous signal is.
- 5. The average value of the pulse signal depends upon the duty cycle and the duty cycle depends upon the width of the pulse. So, by the technique of pulse width modulation, we can control the average value of the signal. Why is pulse width Modulation needed?
- 6. Theory of PulseWidth Modulation A Message signal is used as input for a sample and hold circuit. At the same time, a sampling or carrier signal is used at another input of the sample and hold circuit. The output of the sample and hold circuit goes to a chopper. The output of the chopper circuit is used as one input of a summer circuit and another input of that summer circuit comes from the output of a triangular wave generator.
- 7. After that, the output of the summer circuit goes to the non- inverting terminal of a comparator circuit. On the other hand, a reference DC voltage is applied to the inverting terminal of the comparator circuit. The output of the comparator circuit will be the PulseWidth Modulated signal . Fig: PulseWidth Modulation Circuit
- 9. PWM Kit of Laboratory
- 10. Input & Output of PWM Method Fig.: Input Modulating Signal Fig.: Output PWM Signal
- 11. Advantages Noise inference is less System is moderate in complexity High Power Capacity Disadvantages High Switching Loss Expensive
- 12. Applications To control the speed of motors in industries To control electrical Power Use for dimming light
- 13. ThankYou