About DPSK and its transmission and receiver with a waveform of DPSK with a digital signal. Numerical to find PSK, FSK, ASK, and DPSK. Advantages and Disadvantages of DPSK

1. DPSK
Presented By – Ashish Ranjan
M.Tech (ECE) 1st Year
Roll No-22904004
National Institute of Technology
Jalandhar

2. What is DPSK?
• Differential phase shift keying (DPSK) is a common type of
phase modulation that conveys data by changing the phase of
the carrier wave.
• In DPSK the phase of the modulated signal is shifted relative
to the previous signal element. The signal phase follows the
high or low state of the previous element.

3. DPSK Transmitter
A balanced modulator is a device that modifies a signal, usually in the form
of an amplitude modulated (AM) radio signal. It takes the original signal that
has both sidebands and a carrier signal, and then modulates it so that only
the sideband signals come through the output modulator. This creates a
balanced signal, as there is less noise because the carrier signal has been
removed.

4. Generation Of DPSK Signal
• If symbol bit is 0 then there is a transition in a binary
sequence.
• If symbol bit is 1 then there is no transition in a binary
sequence.
 Let’s take an example and draw the waveform for
it-
Digital bit -10110010
https://youtu.be/KNRYO-mbf0Y

5. STEPS
1. Draw polar NRZ encoding of the given binary sequence.
2. Two cases are there for active high(1), and for active low(0).
3. After that find the phases of the sequence
for 1 it is 0, and for 0 it is π
1. Then shift bit by one position phase
2. Repeat step 3
3. Then we receive the output i.e. received signal.

6. DPSK Receiver
For DPSK receiver there are two cases :
 CASE 1: Same polarity of input and delayed signal.
 CASE 2: Opposite polarity of input and delayed signal.

7. Numerical
https://youtu.be/PAqWflbx8Z8

8. Benefit and Drawback
• Advantage :
DPSK modulation does not require carrier at its receiver
circuit. Hence complex circuits are not needed.
• Disadvantage :
a) Probability of error or BER (Bit Error Rate) is higher in DPSK
compare to BPSK.
b) Noise interference in DPSK is more.
c) DPSK modulation uses two successive bits for its reception.
Hence error in first bit creates error in second bit and
consecutively error propagates.
https://www.rfwireless-world.com/Terminology/Advantages-and-Disadvantages-of-DPSK-modulation.html

9. Thank You