Question

Nyquist pulses are often used in communication systems as a solution to intersymbol interference
i. Sketch a Nyquist pulse making clear its important features.

The figure below shows a signal formed of a sequence of Nyquist pulses transmitted at the rate of one pulse every millisecond.

i. How many bits per symbol (pulse) were transmitted?
ii. What binary data was transmitted in the first three milliseconds? State the assumptions you have made and explain clearly how you calculated your answer.

6 Time (ms) Amplitude LO

Answer 1

i) Bits per symbol is decided by the amplitude range that the signal will take.In this case the amplitude range that the signal takes is from -3 to 4, which is 7.

Therefore this amplitude range can be represented using 3 bits / Symbol as the maximum value that can be represented using the 3 bits is 7.

ii)Since it is assumed that each pulse is transmitted every millisecond.In the figure there are 3 Pulses.,Which takes 3 Milliseconds.

The first Pulse amplitude is around 4.Therefore taking -3 as 0 4 can be assumed to be 7.Therefore the binary data for the first pulse will be 111.

Second Pulse amplitude is 3 which is equivalent to 6 considering -3 as 0. Therefore the binary data transmitted will be 110.

Third Pulse Amplitude is around 2 which is equal to 5 counting from -3 as 0.Therefore the binary data transmitted will be 101.