University:
College
Course:
College Engineering
Academic year:

2023
Views:

152

Pages:

2
Author:

Dipin K.

DPSK Differential Phase shift keying * It is the nen-Cohuent version of PSK.. It eliminates the need for a coherent referenu signal at the teceiver by combining two basic operations at the Diffuntial encodip of the input binary aseve.) Phase shift beying transmittee. so the name * To sendo phase advance the current signal by 180° To send 1 No change. →The receiver is equipped with storage capacity. DPSK. Block diagrams DPSK Transmitter Yp binary Logic w dk Amplitude level shifter Product modulates DPSK signal- sequenu [bx] delay Th 2cos(2xfet) Receiver 2tt) BPF Correlater dr 12 Choose 1 if 120 cheese o 450. Dalay Decision devilu Transmitting Signal transmitting se signal for o&to for the case, when we Si(t) denotes the transmitting signal have binary symbol's' at the transmiter Yip for the second part of this Interval le Tosts2Tb le transmision of I leaves the caricu phase unchanged (+) = EL 276 ostelb Es Cos 2xfet 276 Tbsts 276. Let Selts denotes the transmitted signal for astezīb for Yp binayo in the firme Tbstsять Then the Carice phase will be advanced by 180°. 12 S₂(+) = 02476 Ces 2xfet+) Tosl≤ать. 274 Here S₁ (t) and Salt) are non coherent Orthogonal orthogonal alro. So DPSK is a special case modulation. with T=216 & E=2Eb. Averag Probability of error = exp(-)" working The opp of logic new Eda] dkdky bx + bx modulo 2 operariors. L dk-l in part of a logie niew The transmittere consists of in part of and a one bit delay element interconnected, so as to convut an input binary sequence {bk] in to a diffeunnally encoded sequence Edk. This is amplitude shifted and modulated. then transmitted. pass fitta ar Rer is Band pass to remove noce. At the receiver the inpur to the correlator receive is the filter. olp and the delayed version of Some phase thin the produir shift then the product con decode the data. with delay To So if both coll be tre. f it is with 180° phase will be ve. By with o' level we By compling with