Hybrid ternary code: Difference between revisions

Content deleted Content added

Inline

Latest revision as of 06:20, 5 November 2024

In telecommunications, the hybrid (H-) ternary line code is a line code that operates on a hybrid principle combining the binary non-return-to-zero-level (NRZL) and the polar return-to-zero (RZ) codes.

The H-ternary code has three levels for signal representation; these are positive (+), zero (0), and negative (−). These three levels are represented by three states. The state of the line code could be in any one of these three states. A transition takes place to the next state as a result of a binary input 1 or 0 and the encoder's present output state. The encoding procedure is as follows.^[1]

Input bit	Prior output	Output level
0	+	−
	0	−
	−	0
1	+	0
	0	+
	−	+

In general, the encoder outputs + level for a binary 1 input and a − level for a binary 0 input.
However, if this would result in the same output level as the previous bit time, a 0 level is output instead.
Initially, the encoder output present state is assumed at 0 level when the first bit arrives at the encoder input.

The new line-coding scheme violates the encoding rule of NRZ-L when a sequence of 1s or 0s arrives and hence, it overcomes some of their deficiencies. During the violation period for a run of 1s or 0s, it operates on the same encoding rule of the polar RZ but with pulse occupancy of full period.

NRZ-L and polar RZ codes have deficiencies compared to the proposed H-ternary encoding scheme. NRZ-L code lacks sufficient timing information when the binary signal remains at one level in of either 1 or 0. This has direct influence on synchronising the receiver clock with that of the transmitter and, as a result, has impact on the detection of the received digital signal.

The H-ternary code has also timing superiority compared to similar ternary codes. Other ternary line code such as alternate mark inversion (AMI) also lacks the timing information when a run of zeros needs to be transmitted. This drawback is partly overcome by its modified version the high density bipolar with three zeros substitution (HDB3).

On the other hand, the new code has a smaller bandwidth in comparison with the polar RZ code. The latter has its frequency spectral components concentrated at twice the original binary data rate because the polar RZ code has a pulse duty cycle of 50 percent.

References

^ Glass, A.; Ali, B.; Bastaki, E. (2001). "Design and modeling of H-ternary line encoder for digital data transmission". 2001 International Conferences on Info-Tech and Info-Net. Proceedings (Cat. No.01EX479). Vol. 2. IEEE Xplore. pp. 503–507. doi:10.1109/ICII.2001.983628. ISBN 0-7803-7010-4. S2CID 62247348.

[1] Glass, A.; Ali, B.; Bastaki, E. (2001). "Design and modeling of H-ternary line encoder for digital data transmission". 2001 International Conferences on Info-Tech and Info-Net. Proceedings (Cat. No.01EX479). Vol. 2. IEEE Xplore. pp. 503–507. doi:10.1109/ICII.2001.983628. ISBN 0-7803-7010-4. S2CID 62247348.

[1]

@@ Line 1: / Line 1: @@
+{{Short description|Type of ternary line code in telecommunications}}
-The '''hybrid (H-) ternary line code''' operates on a hybrid principle that combines the binary non-return-to-zero-level (NRZ-L) and the polar [[return-to-zero]] (RZ) codes and thus it is called H-ternary.
+{{refimprove|date=August 2014}}
+In telecommunications, the '''hybrid (H-) ternary line code''' is a [[line code]] that operates on a hybrid principle combining the binary [[NRZL|non-return-to-zero-level]] (NRZL) and the polar [[return-to-zero]] (RZ) codes.
-The H-ternary code has three levels for signal representation; these are positive (+), zero (0), and negative (-). These three levels are represented by three states. The state of the [[line code]] could be in any one of these three states. A transition takes place to the next state as a result of a binary input 1 or 0 and the encoder's present output state. The encoding procedure is as follows (Glass and Bastaki 2001, Glass et al. 2001).
+The H-ternary code has three levels for signal representation; these are positive (+), zero (0), and negative (−). These three levels are represented by three states. The state of the [[line code]] could be in any one of these three states. A transition takes place to the next state as a result of a binary input 1 or 0 and the encoder's present output state. The encoding procedure is as follows.<ref>{{cite book|doi=10.1109/ICII.2001.983628|volume=2|pages=503–507|publisher=[[IEEE Xplore]]|author1=Glass, A. |author2=Ali, B. |author3=Bastaki, E. |date=2001 |title=2001 International Conferences on Info-Tech and Info-Net. Proceedings (Cat. No.01EX479) |chapter=Design and modeling of H-ternary line encoder for digital data transmission |isbn=0-7803-7010-4|s2cid=62247348 }}</ref>
+{|class=wikitable style="text-align:center;"
+! Input bit !! Prior output !! Output level
+|-
+!rowspan=3| 0
+| + ||rowspan=2| −
+|-
+| 0
+|-
+| − ||rowspan=2| 0
+|-
+!rowspan=3| 1
+| +
+|-
+| 0 ||rowspan=2| +
+|-
+| −
+|-
+|}
-# The encoder produces + level when the input is a binary 1 whether the encoder output present state is at 0 or – level.
+# In general, the encoder outputs + level for a binary 1 input and a − level for a binary 0 input.
+# However, if this would result in the same output level as the previous bit time, a 0 level is output instead.
-# The encoder produces – level when the input is a binary 0 whether the encoder output present state is at 0 or + level.
-# The encoder produces 0 level when the input is binary 1 and the encoder present state is + level or when the input is binary 0 and the encoder present state is – level.
 # Initially, the encoder output present state is assumed at 0 level when the first bit arrives at the encoder input.
-The new line-coding scheme violates the encoding rule of [[NRZ-L]] when a sequence of 1s or 0s arrives and hence, it overcomes some of their deficiencies. During the violation period for a run of 1s or 0s, it operates on the same encoding rule of the polar RZ but with pulse occupancy of full period.
+The new line-coding scheme violates the encoding rule of NRZ-L when a sequence of 1s or 0s arrives and hence, it overcomes some of their deficiencies. During the violation period for a run of 1s or 0s, it operates on the same encoding rule of the polar RZ but with pulse occupancy of full period.
-It is evident that NRZ-L and polar RZ codes have deficiencies compared to the proposed H-ternary encoding scheme. NRZ-L code lacks sufficient timing information when the binary signal remains at one level in of either 1 or 0. This has direct influence on synchronising the receiver clock with that of the transmitter and, as a result, has impact on the detection of the received digital signal.
+NRZ-L and polar RZ codes have deficiencies compared to the proposed H-ternary encoding scheme. NRZ-L code lacks sufficient timing information when the binary signal remains at one level in of either 1 or 0. This has direct influence on synchronising the receiver clock with that of the transmitter and, as a result, has impact on the detection of the received digital signal.
-The H-ternary code has also timing superiority compared to similar ternary codes.  Other ternary line code such as [[alternate mark inversion]] (AMI) also lacks the timing information when a run of zeros needs to be transmitted. This drawback is partly overcome by its modified version the high density bipolar with three zeros substitution ([[HDB3]]).
+The H-ternary code has also timing superiority compared to similar ternary codes.  Other ternary line code such as [[alternate mark inversion]] (AMI) also lacks the timing information when a run of zeros needs to be transmitted. This drawback is partly overcome by its modified version the high density bipolar with three zeros substitution ([[HDB3]]).
-On the other hand, the new code has a smaller [[bandwidth]] in comparison with the polar RZ code. The latter has its frequency spectral components concentrated at twice the original binary data rate because the polar RZ code has a pulse duty cycle of 50 percent.
+On the other hand, the new code has a smaller [[Bandwidth (signal processing)|bandwidth]] in comparison with the polar RZ code. The latter has its frequency spectral components concentrated at twice the original binary data rate because the polar RZ code has a pulse duty cycle of 50 percent.
-Concept by: Dr. Abdullatif Glass, Dr. Nedhal Abdulaziz & [http://www.bastaki.net/ Dr. Eesa Bastaki]
 ==See also==
-Other [[line code]]s that have 3 states:
+Other [[line code]]s that have three states:
-* [[bipolar encoding]]
+* [[Bipolar encoding]]
 * [[MLT-3 encoding]]
+* [[Manchester encoding]]
 * [[B3ZS]]
 * [[4B3T]]
+==References==
+{{reflist}}
+{{Bit-encoding}}
+{{DEFAULTSORT:Hybrid Ternary Code}}
 [[Category:Line codes]]

v t e Line coding (digital baseband transmission)
Main articles	Unipolar encoding Bipolar encoding On–off keying Mark and space
Basic line codes	Return to zero (RZ) Non-return-to-zero, level (NRZ/NRZ-L) Non-return-to-zero, inverted (NRZ-I) Non-return-to-zero, space (NRZ-S) Manchester Differential Manchester/biphase (Bi-φ)
Extended line codes	Conditioned diphase 4B3T 4B5B 2B1Q Alternate mark inversion Modified AMI code Coded mark inversion MLT-3 encoding Hybrid ternary code 6b/8b encoding 8b/10b encoding 64b/66b encoding Eight-to-fourteen modulation Delay/Miller encoding TC-PAM
Optical line codes	Carrier-suppressed return-to-zero Alternate-phase return-to-zero
See also: Baseband Baud Bit rate Digital signal Digital transmission Ethernet physical layer Pulse modulation methods Pulse-amplitude modulation (PAM) Pulse-code modulation (PCM) Serial communication Category:Line codes