Samsung KS8910 User Manual page 25

Preliminary Spec. ver
1.4
FUNCTIONAL BLOCKS KS8910 100/10 Mbps ETHERNET TRANSCEIVER
Serial Scrambler
The Serial Scrambler is used to minimize electromagnetic emissions from the TP-PMD physical link. Serial
Scrambling randomizes the data spectrum by the addition of a pseudo-random key sequence to the plain-text
sequence transmitted by the PHY. The length of the pseudo-random sequence is chosen to reduce radiated
emissions by approximately 20 dB when the station is transmitting the Idle Line State. This radiation reduction is
necessary in order to meet regulatory requirements in many countries.The Serial Scrambler also has the desirable
property that single bit errors in the received scramble serial stream decode as single bit errors in the recovered
plain-text stream.
Serial Descrambler
In the Serial Descrambler the pseudo-random sequence is subtracted by the receiver to recover the transmitted
data.
NRZ to NRZI Block
This block receives scrambled transmit data stream and NRZI encodes the data in order to comply with the TP-
PMD standard for 100Base-TX transmission over Category-5 unshielded twisted pair cable.
Serial to Parallel Block
The function of the Serial to Parallel block is to provide Serial to Parallel conversion of code-groups for reception
from the underlying Physical Medium attachment sublayer.
5B/4B
The 5B/4B functional block Maps 5-bit nibbles from the PCS into 4-bit code groups.
Link Monitor Block
The link monitor is responsible for determining whether the underlying receive channel is providing reliable data.
Failure of the underlying channel typically causes the PMA' s client to suspend normal operation. The Link Monitor
function takes advantage of the PMD sublayer' s continuously-signaled transmission scheme, which provides the
PMA with a continuous indication of signal detection on the channel through signal_status as communicated by a
signal from the PMD. It responds to control by Auto-Negotiation, when implemented, which is effected through the
link control parameter of PMA_SIGNAL request.
Loop-Back Function
Digital side
3-4