unipolar signaling (unipolar transmission)

Unipolar signaling, also called unipolar transmission ,is a Baseband method of sending binary data over wire or cable. There are two logic states, low and high, represented by the digits 0 and 1 respectively.

The illustration shows a unipolar signal as it might appear on the screen of an oscilloscope . Each horizontal division represents one bit (binary digit). The logic 0 state is approximately 0 volts and logic 1 is approximately +5 volts. (There is some room for error.) This is positive logic . Alternatively, logic 0 might be approximately +5 volts, and logic 1 might be approximately 0 volts; this would be negative logic .

The bandwidth of a unipolar signal is inversely proportional to the duration of each data bit. Typical data speeds in baseband are several megabits per second ( Mbps ); hence the duration of each bit is a fraction of a microsecond.