dp83251 National Semiconductor Corporation, dp83251 Datasheet - Page 8

• Manufacturer Part Number: dp83251
• Description: Player Device Fddi Physical Layer Controller
• Manufacturer: National Semiconductor Corporation

3 0 Functional Description
3 2 TRANSMITTER BLOCK
The Transmitter Block accepts 10-bit bytes from the Config-
uration Switch
The Transmitter Block performs the following operations
During normal operation the Transmitter Block presents se-
rial data to the fiber optic transmitter





Encodes the data from 4B to 5B coding
Filters out code violations from the data stream
Is capable of generating Idle Master Halt Quiet or oth-
er user defined symbol pairs
Converts the data stream from NRZ to NRZI ready for
transmission
Serializes data
FIGURE 3-2 Transmitter Block Diagram
(Continued)
8
While in the External Loopback mode the Transmitter Block
presents serial data to the Clock Recovery Device
The Transmitter Block consists of the following functional
blocks
See Figure 3-2
Data Registers
Parity Checker
4B 5B Encoder
Repeat Filter
Smoother
Line State Generator
Injection Control Logic
Shift Register
NRZ to NRZI Encoder
TL F 10386 – 4