Your SlideShare is downloading. ×
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Pulse amplitude modulation (PAM)
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Pulse amplitude modulation (PAM)

2,525

Published on

Gives brief idea about pulse amplitude modulation.

Gives brief idea about pulse amplitude modulation.

Published in: Education, Technology, Business
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,525
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
182
Comments
0
Likes
2
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Pulse-amplitude modulation, acronym PAM, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. Example: A two bit modulator (PAM-4) will take two bits at a time and will map the signal amplitude to one of four possible levels, for example −3 volts, −1 volt, 1 volt, and 3 volts. Demodulation is performed by detecting the amplitude level of the carrier at every symbol period. Pulse-amplitude modulation is widely used in baseband transmission of digital data, with non-baseband applications having been largely superseded by pulsecode modulation, and, more recently, by pulse-position modulation.
  • 2. Analog pulse modulation PAM PWM PPM Digital pulse modulation PCM DM ADM
  • 3.  In the pulse amplitude modulation of pulsed carrier is changed in proportion with the instantaneous amplitude of the modulating signal x(t). So the information is continued in the amplitude variation of PAM signal.  the carrier is in the form of train of narrow pulses .  If you compare the PAM system with the sampling process ,you will find these two processes are identical.  The PAM signal is then sent by either wire or cable or it is used to modulate a carrier.
  • 4.  Natural PAM (Chopper PAM)  Flat top PAM
  • 5.  Generation of natural PAM Continuous modulating signal x(t) Low pass filter Multiplier Pulse train generator PAM signal
  • 6. MOSFET acting as switch x(t) c(t) Natural RL PAM Signal
  • 7. PAM signal Low pass filter Demodulated PAM signal
  • 8.  The PAM signal can be detected (demodulated) by passing it through a low pass filter.  The low pass filter cutoff frequency is adjusted to fm so that all the high frequency ripple is removed and the original modulating signal is recovered back.
  • 9. Waveform of Flat-top PAM
  • 10. Due to the aperture effect an amplitude distortion introduces. This distortion can be corrected by equalizer
  • 11. Advantages:  Better SNR due to increased signal power.  Generation is easy. Disadvantage:  Aperture effect introduces distortion.
  • 12. Parameters Natural PAM Flat top PAM Nature of sampling Train of finite duration pulses Train of finite duration pulses Circuit arrangement Uses a chopper Uses a sample n hold circuit Signal power Increases with increase in the pulse width Increases with increase in the pulse width Bandwidth requirement Increases with the reduction in pulse width Increases with reduction in the pulse width Effect of noise Moderate Moderate Waveforms
  • 13.  Since the information is contained in the amplitude variations, the noise will contaminate the information
  • 14.  Q. Explain generation and demodulation of PAM signal with the help of suitable diagrams. (10 marks-May 2008)

×