Experiment: Transmitting a Short Text

• To transmit a text it must first be encoded in binary form.
• The ASCII code could be used for that purpose.
• Example: The word ``ECE'' would be encoded as ``45 43 45'' in hexadecimal, or ``0100 0101 0100 0011 0100 0101'' in binary form.
• Further, we must agree upon a mapping from binary symbols to transmitted pulses.
• For example:
  • ``0'' $\rightarrow$ . (a ``0'' bit is transmitted as a short pulse)
  • ``1'' $\rightarrow$ - (a ``1'' bit is transmitted as a long pulse)
• This process of mapping information symbols into physical signals is often called modulation.
• On the receiving end, physical signals must be mapped back to information symbols, i.e., the received signal is demodulated.
• Then, the binary sequence of symbols must be decoded to recover the original text.