Return-to-zero
Return-to-zero (RZ or RTZ) describes a
The "zero" between each bit is a neutral or rest condition, such as a zero amplitude in pulse-amplitude modulation (PAM), zero phase shift in phase-shift keying (PSK), or mid-frequency in frequency-shift keying (FSK). That "zero" condition is typically halfway between the
Although return-to-zero (RZ) contains a provision for synchronization, it still has a DC component resulting in “baseline wander” during long strings of 0 or 1 bits, just like the line code non-return-to-zero.
Return-to-zero in optical communication
Return to zero, inverted
Return-to-zero, inverted (RZI) is a method of mapping for transmission. The two-level RZI signal has a
Bipolar return-to-Zero (bipolar RZ)
For bipolar return-to-zero (bipolar RZ), a binary one is encoded as +V volts, a binary zero is encoded as −V volts, and 0 volt is used to provide padding and separation between bits.
Bipolar return-to-zero encoding is used by the ARINC 429 bus.
See also
Other line codes that have 3 states:
References
Further reading
- Savard, John J. G. (2018) [2006]. "Digital Magnetic Tape Recording". quadibloc. Archived from the original on 2018-07-02. Retrieved 2018-07-16.