Consider the following sequences of 1s and Os: An alternating sequence of 1s and Os. A long sequence of 1s followed by a long sequence of Os. A long sequence of 1s followed by a single 0 and then a long sequence of 1s. Sketch the waveform for each of these sequences using the following methods of representing symbols 1 and 0: a. On-off signaling. b. Bipolar return-to-zero signaling.