i am reading a book by Tanenbaum on computer networks. i have some basic doubt about the max. data rate(MDR).
the eq'n is : MDR = 2H * log 2 (V) samples per second
if V uses m bits then MDR = 2H * log 2 (2^m) bits per second
= 2H * m
However, a line in this book on page 127 says, " if the symbol consists of 0 volts for a logical 0 and 1 volt for logical 1, the bit rate 2400bps. ( at a baud of 2400 bauds). if, however, if the voltages 0,1,2,3 are used, every symbol consists of 2 bits, ...... data rate of 4800 bps.
this last example of four voltages does not gel with the concept. it has to be other way i.e. if we choose 2 bits to form a symbol, then there will be four symbols and hence four levels .
rest all fits in but why Tanenbaum wrote like this ?
the eq'n is : MDR = 2H * log 2 (V) samples per second
if V uses m bits then MDR = 2H * log 2 (2^m) bits per second
= 2H * m
However, a line in this book on page 127 says, " if the symbol consists of 0 volts for a logical 0 and 1 volt for logical 1, the bit rate 2400bps. ( at a baud of 2400 bauds). if, however, if the voltages 0,1,2,3 are used, every symbol consists of 2 bits, ...... data rate of 4800 bps.
this last example of four voltages does not gel with the concept. it has to be other way i.e. if we choose 2 bits to form a symbol, then there will be four symbols and hence four levels .
rest all fits in but why Tanenbaum wrote like this ?