DP83907 datasheet(18/70 Pages) NSC

No. de pieza	DP83907

Descripción Electrónicos	AT/LANTIC??II

PDF	70 Pages

Scroll/Zoom	100%

Fabricante Electrónico	NSC [National Semiconductor (TI)]

Página de inicio	http://www.national.com

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18 / 70 page

40 Functional Description (Continued)

Transmitter

The transmitter consists of four signals the true and compli-

ment Manchester encoded data (TXOg) and these signals

delayed by 50 ns (TXOdg)

These four signals are resistively combined TXOa with

TXOdb and TXOb with TXOda This is known as digital

pre-emphasis and is required to compensate for the twisted

pair cable which acts like a low pass filter causing greater

attenuation to the 10 MHz (50 ns) pulses of the Manchester

encoded waveform than the 5 MHz (100 ns) pulses

An example of how these signals are combined is shown in

the following diagram

TLF12082 – 10

FIGURE 15 Typical Summed Transmit Waveform

The signal with pre-emphasis shown above is generated by

resistively combining TXOa and TXOdb This signal along

with its compliment is passed to the transmit filter

TLF12082 – 11

FIGURE 16a Circuitry to Connect DP83907 to Twisted Pair Cable with External Filter

DP83907 Datasheet(PDF) 18 Page - National Semiconductor (TI)