Feb 15, 2006 #1 A anup dhital Junior Member level 1 Joined Jun 16, 2005 Messages 19 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,398 the bandwidth of our telephone line is 4KHz . so for a 8- bit modem the signalling rate should be R=2*n*B=2*8*4=64 kbps but it is seen that the signalling rate never exceed 56kbps . Why? and why is the signalling rate not always constant?
the bandwidth of our telephone line is 4KHz . so for a 8- bit modem the signalling rate should be R=2*n*B=2*8*4=64 kbps but it is seen that the signalling rate never exceed 56kbps . Why? and why is the signalling rate not always constant?
Feb 15, 2006 #2 Davood Amerion Advanced Member level 2 Joined Mar 1, 2005 Messages 579 Helped 116 Reputation 232 Reaction score 24 Trophy points 1,298 Location Persia Activity points 6,345 signalling rate anup dhital, it is because of telephone signal is not digital. modem must change digital signal to analoge then send it through telephone line, and vice versa. In the centural office telephone exchange system channel signal rate is 64kbps with 8KHz sampleing rate.
signalling rate anup dhital, it is because of telephone signal is not digital. modem must change digital signal to analoge then send it through telephone line, and vice versa. In the centural office telephone exchange system channel signal rate is 64kbps with 8KHz sampleing rate.