Pulse Modulation PPT Physics Class 12

 Page 1


The Chapter includes:
• Pulse Amplitude 
Modulation
• Pulse Width Modulation
• Pulse Position 
Modulation
• Pulse Code Modulation
PULSE MODULATION
The process of transmitting signals in the form of 
pulses (discontinuous signals) by using special 
techniques.
Page 2


The Chapter includes:
• Pulse Amplitude 
Modulation
• Pulse Width Modulation
• Pulse Position 
Modulation
• Pulse Code Modulation
PULSE MODULATION
The process of transmitting signals in the form of 
pulses (discontinuous signals) by using special 
techniques.
Analog Pulse Modulation Digital Pulse Modulation
Pulse Amplitude (PAM)
Pulse Width (PWM)
Pulse Position (PPM)
Pulse Code (PCM)
Delta (DM)
Pulse Modulation
Pulse Amplitude Modulation (PAM):            
* The signal is sampled at regular intervals such that each sample 
is proportional to the amplitude of the signal at that sampling 
instant. This technique is called “sampling”.
* For minimum distortion, the sampling rate should be more than 
twice the signal frequency.
Page 3


The Chapter includes:
• Pulse Amplitude 
Modulation
• Pulse Width Modulation
• Pulse Position 
Modulation
• Pulse Code Modulation
PULSE MODULATION
The process of transmitting signals in the form of 
pulses (discontinuous signals) by using special 
techniques.
Analog Pulse Modulation Digital Pulse Modulation
Pulse Amplitude (PAM)
Pulse Width (PWM)
Pulse Position (PPM)
Pulse Code (PCM)
Delta (DM)
Pulse Modulation
Pulse Amplitude Modulation (PAM):            
* The signal is sampled at regular intervals such that each sample 
is proportional to the amplitude of the signal at that sampling 
instant. This technique is called “sampling”.
* For minimum distortion, the sampling rate should be more than 
twice the signal frequency.
AND 
Gate
Pulse Shaping 
Network
FM 
Modulator
Analog 
Signal
PAM - FM
Pulses at sampling frequency
HF Carrier Oscillator
PAM
Pulse Amplitude Modulator
Analog Signal
Amplitude Modulated 
Pulses
Page 4


The Chapter includes:
• Pulse Amplitude 
Modulation
• Pulse Width Modulation
• Pulse Position 
Modulation
• Pulse Code Modulation
PULSE MODULATION
The process of transmitting signals in the form of 
pulses (discontinuous signals) by using special 
techniques.
Analog Pulse Modulation Digital Pulse Modulation
Pulse Amplitude (PAM)
Pulse Width (PWM)
Pulse Position (PPM)
Pulse Code (PCM)
Delta (DM)
Pulse Modulation
Pulse Amplitude Modulation (PAM):            
* The signal is sampled at regular intervals such that each sample 
is proportional to the amplitude of the signal at that sampling 
instant. This technique is called “sampling”.
* For minimum distortion, the sampling rate should be more than 
twice the signal frequency.
AND 
Gate
Pulse Shaping 
Network
FM 
Modulator
Analog 
Signal
PAM - FM
Pulses at sampling frequency
HF Carrier Oscillator
PAM
Pulse Amplitude Modulator
Analog Signal
Amplitude Modulated 
Pulses
*  In this type, the amplitude is maintained constant but the duration 
or length or width of each pulse is varied in accordance with 
instantaneous value of the analog signal.  
* The negative side of the signal is brought to the positive side by 
adding a fixed d.c. voltage.
Analog Signal
Width Modulated Pulses
Pulse Width Modulation  (PWM or PLM or PDM):
Page 5


The Chapter includes:
• Pulse Amplitude 
Modulation
• Pulse Width Modulation
• Pulse Position 
Modulation
• Pulse Code Modulation
PULSE MODULATION
The process of transmitting signals in the form of 
pulses (discontinuous signals) by using special 
techniques.
Analog Pulse Modulation Digital Pulse Modulation
Pulse Amplitude (PAM)
Pulse Width (PWM)
Pulse Position (PPM)
Pulse Code (PCM)
Delta (DM)
Pulse Modulation
Pulse Amplitude Modulation (PAM):            
* The signal is sampled at regular intervals such that each sample 
is proportional to the amplitude of the signal at that sampling 
instant. This technique is called “sampling”.
* For minimum distortion, the sampling rate should be more than 
twice the signal frequency.
AND 
Gate
Pulse Shaping 
Network
FM 
Modulator
Analog 
Signal
PAM - FM
Pulses at sampling frequency
HF Carrier Oscillator
PAM
Pulse Amplitude Modulator
Analog Signal
Amplitude Modulated 
Pulses
*  In this type, the amplitude is maintained constant but the duration 
or length or width of each pulse is varied in accordance with 
instantaneous value of the analog signal.  
* The negative side of the signal is brought to the positive side by 
adding a fixed d.c. voltage.
Analog Signal
Width Modulated Pulses
Pulse Width Modulation  (PWM or PLM or PDM):
*  In this type, the sampled waveform has fixed amplitude and 
width whereas the position of each pulse is varied as per 
instantaneous value of the analog signal.
*  PPM signal is further modification of a PWM signal.  It has 
positive thin pulses (zero time or width) corresponding to the 
starting edge of a PWM pulse and negative thin pulses
corresponding to the ending edge of a pulse.
*  This wave can be 
further amended 
by eliminating the 
whole positive 
narrow pulses.  
The remaining 
pulse is called 
clipped PPM.
PWM
PPM
Pulse Position Modulation  (PPM):