PULSE WIDTH MODULATION &DEMODULATION

Pulse width modulation is a technique that generates variable width signal generally based on modulator signal information

1. PULSE WIDTH MODULATION &DEMODULATION Guide Presented by Mr.M Cheenya V.Abhinav Kumar 11E31A0422 Asst.Professor K.Shiva Kumar 11E31A0423 K.Rajashekhar 11E31A0424 K.Chaithanya Sree 11E31A0428 K.Pramitha 11E31A0429

2. INTRODUCTION Modulation : Modulation can be defined as the process of varying a parameter of carrier signal in accordance with the instantaneous value of the message signal. Modulation is used to reduce the size of the antenna and increases efficiency.

3. Types of modulation techniques PAM--Pulse Amplitude Modulation PWM—Pulse Width Modulation PPM—Pulse Position Modulation

4. What is PWM…? Pulse width modulation is a technique that generates variable width signal generally based on modulator signal information. The general purpose of PWM is to control power delivery.

5. Block Diagram of PWM

6. Power supply

7. Transformer It is a device used to increment or decrement the input voltage as per the requirement. In this we used step down transformer to convert 230V AC to 12V AC.

8. Rectifier A circuit which is used to convert A.C to D.C is known as rectifier.

9. Voltage Regulator Here we used LM-7812 Voltage regulator. It is used to supply a stable voltage.

10. LED LED is a two lead semiconductor light source. It resembles a basic pn-junction diode, which emits light when active. Representation of LED

11. Pulse width modulation PWM is a modulation technique, which converts an analog signal into a digital signal for transmission. PWM converts an audio signal into a sequence of pulses having constant amplitude, but the width is proportional to amplitude of an audio signal.

12. Circuit diagram

13. 555 Timer

14. Features of IC 555 Maximum operating voltage 16V. Operates in the temperature range of -55 to 125 degrees. Maximum output current 200mA. 8-pin metal can.

15. Applications of 555 timer Ramp and Square wave generator. Frequency dividers. Voltage controlled oscillators. Pulse generators .

16. Output waveform of Modulation

17. Demodulation Demodulation is the act of extracting the original information bearing signal from a modulated carrier wave. It is used to recover the information content from the modulated carrier wave.

18. Pulse width demodulation

19. Working of demodulation The regenerated PWM is then applied to the ramp generator & synchronization generator. The ramp generator produces ramps for the duration of pulses such that height of ramps are proportional to the width of ramp pulses. Synchronous pulse generator produces references pulses with constant amplitude and pulse width.

20. Output waveforms of demodulation

21. Results Input waveform

22. Output waveform

23. Advantages Low Noise Low power consumption High efficient Does not require synchronization between transmitter and receiver.

24. Applications Telecommunications Voltage regulation Power delivery Amplification Use as ADC

25. Conclusion The design of a compact circuit board with good track routing requires experience in PCB design. With the help of protel software the kit is developed and can be used as an experimental kit, it provides user friendly environment for the users.

26. THANK YOU