bipolar method
The bipolar method is a transmission method used in the baseband which assigns the transmission amplitude "0" to the binary value "0" to be transmitted and the transmission amplitude "+A" and "-A" alternately to the logical "1".
To recover the information in the receiver, the decision thresholds must be set to the value ± A/2 for a received signal with the amplitudes 0 and ± A, respectively. The bipolar method eliminates the disadvantages of the single- current and double-current methods in the transmission of long "0" and "1" sequences, respectively, because it does not contain a DC component; however, it is not self- clocking. It was originally developed for Ethernetcoding and corresponds to Alternate Mark Inversion( AMI).