CX28332 Conexant Systems, CX28332 Datasheet - Page 35

• Manufacturer Part Number: CX28332
• Description: (CX28331 - CX28333) Single/Dual/Triple E3/DS3/STS-1 Line Interface Unit
• Manufacturer: Conexant Systems

CX28331/CX28332/CX28333
Single/Dual/Triple E3/DS3/STS-1 Line Interface Unit
2.2.1 AMI B3ZS/HDB3 Encoder
2.2.2 Pulse Shaper
Figure 2-2. Pulse Shaper
100985A
Mode
E3
Shaper
Pulse
2.2 Transmitter
This section describes the detailed operation of the various blocks in the CX2833i
transmitter.
ENDECDIS and the E3MODE pins configure the encoder mode.
Zero (NRZ) data on the TNRZ (TPOS) pin alone, and the NC (no connect)
(TNEG) pin is ignored.
HDB3 (E3MODE = 1) signal (conforming to the coding rules as specified in
Appendix
representing the positive and negative three-level pulses.
already-encoded data over TPOS (TNRZ) and TNEG (NC) to the pulse shaper.
which must be equal to the symbol rate (line rate). A small delay added to the data
provides a certain amount of negative data hold time.
The pulse shaper converts the two digital (clocked) positive and negative pulses
into a single analog three-level Alternate Mark Inversion (AMI) pulse. The pulses
are in Return to Zero (RZ) format, meaning that all positive and negative pulses
have a duration of the first half of the symbol period.
square-shaped pulse with very little slope.
LBO
When ENDECDIS = 0, the encoder is receiving non-encoded Nonreturn to
Data is encoded into a representation of a three-level B3ZS (E3MODE = 0) or
When ENDECDIS = 1, the encoder is disabled. The encoder passes
The transmit digital data is clocked into the chip via a rising TCLK edge,
For the E3 rate (E3MODE = 1), the AMI pulse is a full-amplitude,
A) before going on to the pulse shaper in the form of two binary signals
Conexant
Line Driver
+ Pulse
LBO = 0
LBO = 1
– Pulse
2.0 Functional Description
2.2 Transmitter
100604_008
2-3