Duobinary data encoding is a form of correlative coding in partial response signaling. The modulator drive signal can be produced by adding one-bit-delayed data to the present data bit to give levels 0, 1, and 2. An identical effect can be achieved by applying a low-pass filter to the ideal binary data signal. The correlated three-level signal can be demodulated into a binary signal again using an optical direct detection receiver. The advantage of this correlative electrical data encoding is that the duobinary modulated optical signal has a narrower bandwidth compared to the binary NRZ modulated signal.

Author:Vihn Nikinos
Country:Puerto Rico
Language:English (Spanish)
Published (Last):26 February 2018
PDF File Size:10.52 Mb
ePub File Size:5.6 Mb
Price:Free* [*Free Regsitration Required]

Binary coding in which a a zero digit in the input sequence of binary digits is represented by a zero digit in the output sequence, whereas a one digit in the input sequence might cause a change in the output-sequence pulse power level, this change depending on the number of zero digits since the last one digit occurred, b if the number of zero digits since the last one digit in the input sequence is even, no change occurs in the output level, and c if the number of zero digits since the last one digit is odd, a change occurs in the output signal level to the appropriate level at which it was last positioned, positive or negative level.

Note 1: The duobinary coding bandwidth is about half of that required for nonreturn-to-zero NRZ coding. Duobinary coding requires a bandwidth of about 6. Note 2: Duobinary is a ternary signal and thus has a lower signal-to-noise ratio than pure binary. However, this loss is Skip to main content Skip to table of contents.

This service is more advanced with JavaScript available. Computer Science and Communications Dictionary Edition. Contents Search. Reference work entry First Online: 30 November How to cite.

This is a preview of subscription content, log in to check access. Weik There are no affiliations available.


DuoBinary Signaling

Such a signal is called a duobinary signal. Thus, the line always returns to the "zero" level to denote optionally a separation of bits or to denote idleness of the line. One kind of bipolar encoding is a paired disparity code , of which the simplest example is alternate mark inversion. In this code, a binary 0 is encoded as zero volts, as in unipolar encoding , whereas a binary 1 is encoded alternately as a positive voltage or a negative voltage.


duobinary signal


Related Articles