Different types of Pulse Modulation.pptx

This presentation discusses the different types of pulse modulation

1. Pulse Modulation Cervantes, Mary Joy Neverio , Fulgencio Estallo , Michae l BSECE-2C

2. DEFINITION The process of changing a binary pulse signal to represent the information to be transmitted The variation of a regularly spaced constant amplitude pulse stream to superimpose information contained in a message signal

3. TYPES OF MODULATION Pulse Amplitude Modulation (PAM) Pulse Width Modulation (PWM) Pulse Position Modulation (PPM) Pulse Code Modulation (PCM)

4. PULSE AMPLITUDE MODULATION Simplest and least expensive to implement Since the pulses vary in amplitude, they are far more susceptible to noise, and clipping techniques to eliminate nose cannot be used because they would also remove modulation

5. PULSE WIDTH MODULATION The width of the pulse reflects the sampled signal amplitude. The position of the leading edge, trailing edge or both may be modified to reflect the changing duration of the pulse also known as: pulse width modulation or pulse length modulation PWM is wasteful of energy when the pulses are long, but the information is only in the pulse transitions

6. PULSE POSITION MODULATION The position of the pulse reflects the sampled signal amplitude. PPM can be represented as: where kp is the sensitivity factor the adjacent pulses must be strictly non-overlapping

7. PULSE CODE MODULATION M ost widely used technique for digitizing information signals for electronic data transmission Most basic form of digital pulse modulation Elements of pulse-code modulation 1 . Transmitter 2 . Transmission Path 3 . Receiver

8. COMPANDING A process of signal compression and expansion that is used to overcome problems of distortion and noise in the transmission of audio signals The most common means of overcoming the problems of quantizing error and noise

9. COMPANDING Two basic types of companding the μ-law (pronounced “mu law”) compander -used in telephone systems in the United States and Japan the A-law compander -used in European telephone networks The two are incompatible, but conversion circuits have been developed to convert μ-law to A-law and vice versa. The voltage formulas for both are as follows:

10. SAMPLE PROBLEM Click here for the solution

11. SAMPLE PROBLEM Click here for the solution