ICS1892Y datasheet(47/148 Pages) ICST

47 / 148 page

Chapter 7

Functional Blocks

ICS1892, Rev. D, 2/26/01

February 26, 2001

ICS1892

7.4.4

100Base-TX Operation: Adaptive Equalizer

The ICS1892 TP-PMD sublayer employs adaptive equalization circuitry to compensate for signal amplitude

and phase distortion incurred from the transmission medium. At a data rate of 100 Mbps, the transmission

medium (that is, the cable) introduces significant signal distortion because of high-frequency attenuation

and phase shift. The high-frequency loss occurs primarily because of the cable skin effect that causes the

conductor resistance to rise as the square of the frequency rises.

In shielded twisted-pair (STP) and unshielded twisted-pair (UTP) category 5 cables with maximum lengths

of 130 meters, the ICS1892 adaptive equalizer accurately compensates for these losses.

For a UTP Category 5 cable that is 100 meters long (the maximum length as per the EIA/TIA-568-A

standard), there are three distinct levels to resolve to recover the MLT-3 encoded data. As a result, the

pulse shape of the received signal is critical.

The ICS1892 employs a DSP-based adaptive equalization technique to compensate for a wide range of

cable lengths. The optimizing parameter for the equalizer adaptation process is the overall ICS1892 bit

error rate, which provides the ICS1892 with a very high overall reliability.

7.4.5

100Base-TX Operation: Twisted-Pair Transmitter

For both 10Base-T and 100Base-TX operations, the ICS1892 uses the same Twisted-Pair Transmit pins

(TP_TXP and TP_TXN) as well as the same internal functional module. The twisted-pair transmitter

module is a current-driven, differential driver that can supply either of the following:

• A two-level 10Base-T (that is, Manchester-encoded) signal

• A three-level 100Base-TX (that is, MLT-3 encoded) signal

The ICS1892 interfaces with the medium through an isolation transformer (also called a magnetic module).

The ICS1892 transmitter uses wave-shaping techniques to control the output signal rise and fall times

(thereby eliminating the need for expensive external filters) and interfaces directly to the isolation

transformer.

Note:

In reference to the ICS1892, the term ‘Twisted-Pair Transmitter’ refers to the set of Twisted-Pair

Transmit output pins (TP_TXP and TP_TXN).

For information on the 10Base-T Twisted-Pair Transmitter, see Section 7.5.11, “10Base-T Operation:

Twisted-Pair Transmitter”.

7.4.6

100Base-TX Operation: Twisted-Pair Receiver

Twisted-Pair Receiver operations are similar to Twister-Pair Transmitter operations, in that for both

10Base-T and 100Base-TX operations, the ICS1892 uses the same Twister-Pair Receive pins (TP_RXP

and TP_RXN).

However, unlike the transmitter operations (which use the same internal functional module), the ICS1892

employs separate internal twisted-pair receiver modules to process the incoming data: one for 10Base-T

operations and one for 100Base-TX operations. The internal twisted-pair receiver modules interface with

the medium through an isolation transformer. The 100Base-TX receiver module accepts and processes a

differential three-level 100Base-TX (that is, MLT-3 encoded) signal from the isolation transformer.

Note:

In reference to the ICS1892, the term ‘Twisted-Pair Receiver’ refers to the set of Twisted-Pair Receive

output pins (TP_RXP and TP_RXN).

For information on the 10Base-T Twisted-Pair Receiver, see Section 7.5.12, “10Base-T Operation:

Twisted-Pair Receiver”.

ICS1892Y датащи(PDF) 47 Page - Integrated Circuit Systems

ICS1892Y датащи(HTML) 47 Page - Integrated Circuit Systems

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL