TNETEL1200

EtherLoop

™ MODEM

SPHS003D – FEBRUARY 1999 – REVISED JUNE 1999

4

POST OFFICE BOX 655303

transmitter and receiver

The TNETEL1200 performs modulation of the digital data stream transmitted from the EtherLoop modem and

demodulation of the digital data stream received by the EtherLoop modem. The TNETEL1200 supports a variety

of modulation schemes and symbol rates. This flexibility allows the modem to adapt to changing conditions on

the POTS line. The modem is designed to compensate for the presence of bridge taps on the POTS line,

allowing for easy service deployment.

Figure 4 shows the EtherLoop modem block diagram.

Modulator

TX

Clock

Generator

Register

File

Constellation

Display

Control

Logic

Microprocessor

Interface

JTAG

RX

Clock

Generator

Demodulator

Capture

Engine

Energy

Detect

To Clock Tree

D2A_9–D2A_0

D2ACLK

I_7–I_0

Q_7–Q_0

IQSTB

A2D_11–A2D_0

INRANGE

A2DCLK

TXD

TXON

TXRDY

TXCLK

TDI

TDO

TCLK

TMS

UPDAT_15–UPDAT_0

UPADDR_7–UPADDR_0

UPCSN

UPRWN

UPOEN

RESET

XTAL

RXD

RXCLK

RXON

RXRDY

TXFSEL_3–TXFSEL_0

RXFSEL_3–RXFSEL_0

TXGAIN_3–TXGAIN_0

RXGAIN_4–RXGAIN_0

RXLOGAIN

RXHIGAIN

OPEN

PREAMPEN

TERMEN

TXEN

Figure 4. EtherLoop Modem Block Diagram