This is full slide in modulation techniques which include ASK, FSK and PSK.

1.  NAME > > > > > > > > > NOMAN KHAN
 CLASS NO > > > > > > > CS-14
 SEMESTER > > > > > > > > > > > 4TH
 DEPT > > > > > > > > >COMPUTER SCIENCE
 COLLEGE > > > > > > > > > GSSCP
 PRESENTATION TOPIC: ASK, FSK, PSK.

2.  ASK is implemented by changing the
amplitude of a carrier signal to reflect
amplitude levels in the digital signal.
 In this mechanism, both frequency and
phase remain constant while the
amplitude changes.

4.  ASK is highly susceptible to noise interference
 NOISE: Unintentional voltages introduced onto a line by
various sources such as Heat or Electromagnetic
Radiation from other sources
 These unintentional voltages combine with signal to
change the amplitude
 1 can be changed to 0 and 0 to 1
 Noise usually affects the amplitude, therefore ASK is
the modulating method, that is most affected by Noise

5.  It is the popular ASK technique.
 In OOK, one of the bit values is represented by
no voltage.

6.  The bandwidth ‘‘B’’ of ASK is proportional
to the signal rate ‘‘S’’.
B = (1+d)S
 “d” is due to modulation and filtering,
lies between 0 and 1.

7.  Frequency of signal is varied to represent
binary 1 or 0
 The frequency of the signal during each
bit duration is constant and depends on
the bit (0 or 1)
 Both peak amplitude and phase remains
constant

9. If the difference between the
two frequencies (f1 and f2) is 2f,
then the required BW B will be:
B = (1+d)x S +2f

10.  In phase shift keying, the phase of the carrier is
varied to represent two or more different signal
elements
 Both peak amplitude and frequency remain
constant as the phase changes
 Today, PSK is more common than ASK or FSK
 However, we will se the QAM, which combines
ASK and PSK
 The bandwidth requirement, B is:
B = (1+d)xS
