One positive side-effect of bipolar encoding is that a bipolar violation (two consecutive + pulses or two consecutive — pulses separated by any number of zeros) indicates to the receiver that an error has occurred in transmission. Unfortunately, upon the receipt of such a violation, the receiver does not know which bit is in error (only that an error has occurred). The received bipolar sequence has one bipolar violation. Construct two scenarios (each of which involves a different transmitted bit stream with one transmitted bit being converted via an error) that will produce this same received bit pattern.
+ - 0 + - 0 - +