PAM, PPM, PWM, DM, ADM, PCM, DPCM digital communication

1. Pulse Modulation
By-
herin gala
keval mamaniya
keval gada
dattaprasad shenoy

2. Pulse-amplitude modulation (PAM)
Pulse-duration modulation (PDM)
Pulse-position modulation (PPM)
Pulse code modulation (PCM)
DPCM, DM,ADM
Analog pulse
modulation
Digital pulse
modulation

3. Lets start the
seminar from
analog pulse
modulation

4.  A modulation system in which amplitude of discrete
carrier signal changes in accordance with the
instantaneous amplitude of modulating
signal(message signal) keeping width and position of
carrier constant is called as PAM.

6.  There are 2 types of PAM :
1. Natural sampling
2. Flat top sampling

9.  Generation and detection is easy.
Disadvantages of PAM
 Added noise cannot be removed easily as it has impact
on amplitude which carries information.
 Transmission bandwidth is too large.

10.  The modulation system in which width of the discrete
carrier signal changes in accordance with the
instantaneous amplitude of modulating
signal(message signal) keeping amplitude and position
of carrier constant is called as PWM.

13. 1. Very good noise immunity.
2. Its possible to separate out signal from noise.
Disadvantages of PWM
1. Bandwidth requirement is large as compared to
PAM.

14.  The modulation system in which position of
the discrete carrier signal changes in
accordance with the instantaneous
amplitude of modulating signal(message
signal) keeping amplitude and Width of
carrier constant is called as PPM.

17.  High noise immunity.
Disadvantage of PPM
 Generation and detection is complex.

18. Now lets move on
to digital pulse
modulation.

19.  It is the type of pulse modulation in
which the group of pulses or codes are
transmitted which represent binary
numbers corresponding to modulating
signal voltage.

22. 1. Secured.
2. Encoding is possible.
3. Very high noise immunity.
4. Convenient for long distance communication.
5. Good signal to noise ratio.

23. 1. Complex circuitry.
2. Requires large bandwidth.
3. Synchronization is required between transmitter &
receiver.

24.  In DPCM instead of transmitting digital equivalent of
each quantized sampled signal the difference between
the present sample value and previously sampled value
is transmitted.

26. 1. Less signaling rate.
2. Less bandwidth.
Disadvantages of DPCM
1. High bit rate.
2. Needs the predictor circuit to be used which is
complex.

27.  In PCM system ‘N’ no of binary digit are transmitted
per quantized sample which demand high signaling
rate and transmission bandwidth.

30. 1. One bit code word for output.
2. Low signaling rate.
3. Low channel bandwidth.
Disadvantages of DM
1. Slope overload present.
2. Granular noise present.

31.  This is the advanced version of DM.
 In this step size is kept variable to avoid
slope over load error and granular noise
problem.

34. 1. Improved SNR.
2. Low signaling rate.
3. Reduction in slope overload and granular noise.

35.  In this presentation we came across various
different PULSE Modulation techniques
and saw how they are transmitted and we
also saw their waveforms.
 We also came across advantages and
disadvantages of these modulation
techniques.