Data Sheet

Interconnects—Ethernet Controller I210

125

3.7.8.7.2 Transmit Functions

This section describes functions used when the MAC transmits data through the PHY and out onto the

twisted-pair connection (see Figure 3-18).

3.7.8.7.2.1 Scrambler

The scrambler randomizes the transmitted data. The purpose of scrambling is twofold:

1. Scrambling eliminates repeating data patterns (also known as spectral lines) from the 4DPAM5

waveform in order to reduce EMI.

2. Each channel (A, B, C, D) has a unique signature that the receiver uses for identification.

Figure 3-18. 1000BASE-T Functions Overview

Side

stream

Scrambler /

Descrambler

Trellis Viterbi

Encoder/ Decoder

MAC Interface

AGC, A/D,

Timing Recovery

4DPAM5

Encoder

ECHO, NEXT,

FEXT

Cancellers

Line

Interface

Pulse Shaper,

DAC, Filter

Hybrid

Line Driver

DSP