# 16 PSK 16-PHASE SHIFT KEYING (16-PSK):

• Angle modulated with constant amplitude digital modulation.
• 4 bits encoded forming and producing 16 different outputa are possible.
• N = 4, M = 2N = 24 = 16

Therefore 16 output phases will be produced

• Each channel bit rate is fb/4.
• The input bit is serially inputted and outputted simultanously as I,I’,Q,Q’ which are parallel to each other.
• I,Q determines the parity whereas I’,Q’ determines the magnitude (logic= 0.821V, logic 0= 0.22V).
• Two polarities and magnitudes are possible at 2 to 4 level convertor(±0.821 , ±0.22V).
• The output of I-product modulator, ±0.821 sin wct, ±0.22 sin wc
• The output of Q-product modulator, ±0.821 sin wct, ±0.22 sin wc
• The linear summer produces 16 output conditions.

Algorithm:

• I and Q represent the polarity.
• Logic 1 = +ve
• Logic 0 = -ve
• I’ and Q’ represent the magnitude.
• Logic 1 = 0.821V
• Logic 0 = 0.22V
•  I I’ output 0 0 -0.22V 0 1 -0.821V 1 0 +0.22V 1 1 +0.821V

 Q Q’ output 0 0 -0.22V 0 1 -0.821V 1 0 +0.22V 1 1 +0.821V

Truth table:

 I I’ Q Q’ 0 0 0 0 -0.22 sin wct – 0.22 cos wct 0 0 0 1 -0.22 sin wct – 0.821 cos wct 0 0 1 0 -0.22 sin wct + 0.22 cos wct 0 0 1 1 -0.22 sin wct + 0.821 cos wct 0 1 0 0 -0.821 sin wct – 0.22 cos wct 0 1 0 1 -0.821 sin wct – 0.821 cos wct 0 1 1 0 -0.821 sin wct + 0.22 cos wct 0 1 1 1 -0.821 sin wct + 0.821 cos wct 1 0 0 0 +0.22 sin wct – 0.22 cos wct 1 0 0 1 +0.22 sin wct – 0.821 cos wct 1 0 1 0 +0.22 sin wct + 0.22 cos wct 1 0 1 1 +0.22 sin wct + 0.821 cos wct 1 1 0 0 +0.821 sin wct – 0.22 cos wct 1 1 0 1 +0.821 sin wct – 0.821 cos wct 1 1 1 0 +0.821 sin wct + 0.22 cos wct 1 1 1 1 +0.821 sin wct + 0.821 cos wct 