The equalizer attempts to unravel the ISI in the received signal to recover the transmitted symbols.

This extrinsic information is then mapped back into information about the transmitted symbols for use in the equalizer.

Naturally, we need to have at least a fraction of the transmitted symbols to be correct in order to recover the message.

This causes transmitted symbols that are adjacent in time to interfere with each other.

Therefore, the optimal receiver cannot make decisions on any isolated symbol without taking the entire sequence of transmitted symbols into account.

To derive the criterion, we first express the received signal in terms of the transmitted symbol and the channel response.

Apply a sequence detector at the receiver, that attempts to estimate the sequence of transmitted symbols using the Viterbi algorithm.

The question of meaning enters in with respect to the semantic problem (that is, how precisely do transmitted symbols of communication convey the desired meaning?)

Usually the transmitted symbols are represented as a time sequence of dirac delta pulses.

Weaver employed many conduit-metaphor expressions; for example, "How precisely do the transmitted symbols convey the desired meaning?"