for what Hilbert transform is used in digital commmunication. Give only important task it do

The Hilbert Transform is used in digital communication for two main tasks:

1. Signal Envelope Detection: The Hilbert Transform is used to determine the envelope of a signal. This is particularly useful in modulations like Amplitude Modulation (AM) where the information is contained in the envelope of the signal.

2. Single Sideband Modulation: The Hilbert Transform is also used in Single Sideband Modulation (SSB). SSB is a type of modulation that eliminates one of the sidebands and the carrier frequency, which makes it more bandwidth-efficient. The Hilbert Transform helps in creating the necessary phase shift of 90 degrees to generate the single sideband.

These are the two main tasks that the Hilbert Transform performs in digital communication.