What is ISI (inter-symbol interference)?

In inter-symbol interference, one symbol interferes with subsequent symbols. This is an undesirable wonder as the previous symbols have comparable impacts as noise, along these lines making the correspondence less dependable. The presence of ISI in the framework presents errors in the decision device at the receiver output. Reasons for intersymbol interference is multipath propagation in which a signal from a transmitter reaches the receiver by means of numerous ways. It incorporates reflection, refraction and atmospheric impacts.