‫Now we come to the question, their tall equaliser can be used at the receiver in order to compensate
‫for the inter symbol interference.
‫Now, if the channel has imperceptible interference, then the signal that is passing through the channel,
‫it would be discarded are in other words, we can see.
‫We can say that all channel is acting like up frequency, selective filter.
‫And that means some frequencies are attenuated more while other frequencies are being attenuated less.
‫So if we block such channel, then the response of this channel in the frequency domain.
‫May look like this.
‫So here we can see that these frequencies are being attenuated more and these frequencies are being
‫transmitted less.
‫No equalizer is used at the receiver and equalizer is a filter.
‫And the response of the equalizer is invites to the general.
‫For example, if this is the frequency response of the channel, then the frequency response of the
‫equalizer should look like this.
‫That means that the frequencies that are being attenuated more, they are being amplified more by the
‫equalizer and the frequencies that are being attenuated less.
‫They are being amplified less by the equalizer.
‫And as a result, the overall response of the overall response is a straight line.
‫And so and this signal can now easily be amplified without distortions.
‫Now, there are two types of equalizers.
‫First one is the training based equalizers.
‫And second one is the blind equalizers.
‫In the case of training Beiste equalizers, the transmitter periodically sends these are non training
‫sequence Buddah receiver.
‫And since this training sequence passes through the channel, it is distorted by the channel and then
‫it is received by the channel.
‫The channel knows what is the actual training sequence that was being sent and what is their distorted
‫version of this training sequence that is being received by it.
‫So using this information, the receiver estimates the channel and it trains the equalizer so that the
‫equalizer has inverse response to the channel and vile.
‫So this is the training Beiste equalizer in which a normal training sequence is sent by the transmitter.
‫And it is used by the receiver in order to train the equalizer, while in the case of blind equalizer.
‫No such training sequence is sent by the transmitter.
‫Rather, the receiver uses the received symbols in order to estimate the channel.
‫And in order to train the equalizer so that it has inverse response to the channel.