DP83849IFVSSLASHNOPB datasheet(68/108 Pages) TI2

Part #	DP83849IFVS/NOPB

Description	DP83849IF PHYTER™ DUAL Industrial Temperature with Fiber Support (FX) and Flexible Port Switching Dual Port 10/100 Mb/s Ethernet Physical Layer Tranceiver

PDF	108 Pages

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Manufacturer	TI2 [Texas Instruments]

Direct Link	https://www.ti.com

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68 / 108 page

DP83849IF

SNOSAX8D – JUNE 2009 – REVISED APRIL 2013

www.ti.com

8.8.7

TDR Results

The TDR function monitors data from the Analog to Digital Converter (ADC) to detect both peak values

and values above a programmable threshold. It can be programmed to detect maximum or minimum

values. In addition, it records the time, in 8ns intervals, at which the peak or threshold value first occurs.

The results of a TDR peak and threshold measurement are available in the TDR Peak Measurement

19h. The threshold measurement may be a more accurate method of measuring the length for longer

cables to provide a better indication of the start of the received pulse, rather than the peak value.

Software utilizing the TDR function should implement an algorithm to send TDR pulses and evaluate

results. Multiple runs should be used to best qualify any received pulses as multiple reflections could exist.

In addition, when monitoring the transmitting pair, the window feature should be used to disqualify the

transmitted pulse. Multiple runs may also be used to average the values providing more accurate results.

Actual distance measurements are dependent on the velocity of propagation of the cable. The delay value

is typically on the order of 4.6 to 4.9 ns/m.

Design Guidelines

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DP83849IFVS/NOPB Datasheet(PDF) 68 Page - Texas Instruments