Question

Explain at least one modulation technique used for high speed modems.

Answer 1

hey
your answer is FSK - Frequency Shift Keying: In such technique the frequency of the carrier signal is changed as per to the data. The transmitter sends various frequencies for a "I" than for a "0" as demonstrated in figure. The disadvantages of this technique are which again (like this was with amplitude modulation) the rate of frequency changes is restricted by the bandwidth of the line, and which distortion caused by the lines makes the detection still harder than amplitude modulation.